--- title: Cloudflare Load Balancing description: Distribute traffic across origin servers for availability and performance. image: https://developers.cloudflare.com/core-services-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/load-balancing/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) # Cloudflare Load Balancing Maximize application performance and availability Paid add-on Cloudflare Load Balancing distributes traffic across your [endpoints](https://developers.cloudflare.com/glossary/?term=endpoint), which reduces endpoint strain and latency and improves the experience for end users. Note Enterprise customers can preview this product as a [non-contract service](https://developers.cloudflare.com/billing/understand/preview-services/), which provides full access, free of metered usage fees, limits, and certain other restrictions. --- ## Features ### Load balancing and failover Distribute traffic evenly across your healthy endpoints, automatically failing over when an endpoint is unhealthy or unresponsive. [ Use Load balancing and failover ](https://developers.cloudflare.com/load-balancing/load-balancers/) ### Active monitoring Monitor your endpoints at configurable intervals and across multiple data centers to look for specific status codes, response text, and timeouts. [ Use Active monitoring ](https://developers.cloudflare.com/load-balancing/monitors/) ### Intelligent routing Choose whether to distribute requests based on endpoint latency, a visitor's geographic region, or even a visitor's GPS coordinates. [ Use Intelligent routing ](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/) ### Custom rules Customize the behavior of your load balancer based on the characteristics of individual requests. [ Use Custom rules ](https://developers.cloudflare.com/load-balancing/additional-options/load-balancing-rules/) ### Analytics Review comprehensive analytics to evaluate traffic flow, assess endpoint health status, and review changes in pools and pool health over time. [ Use Analytics ](https://developers.cloudflare.com/load-balancing/reference/load-balancing-analytics/) --- ## Related products **[Standalone Health Checks](https://developers.cloudflare.com/health-checks/)** Actively monitor whether your origin server is online by sending specific requests at regular intervals. **[DNS](https://developers.cloudflare.com/dns/)** Get enterprise-grade authoritative DNS service with the fastest response time, unparalleled redundancy, and advanced security with built-in DDoS mitigation and DNSSEC. **[Waiting Room](https://developers.cloudflare.com/waiting-room/)** Route excess users to a custom-branded waiting room, helping preserve customer experience and protect origin servers from being overwhelmed with requests. --- ## More resources [Plans](https://www.cloudflare.com/plans/#overview) Compare available Cloudflare plans. [Pricing](https://dash.cloudflare.com/?to=/:account/:zone/traffic/load-balancing/) Explore pricing options for Load Balancing in the dashboard. [Reference Architecture](https://developers.cloudflare.com/reference-architecture/architectures/load-balancing/) Learn more about the structure of Cloudflare Load Balancers and their various configurations. [Learning Paths](https://developers.cloudflare.com/learning-paths/) Module-based guidance on Cloudflare product workflows. ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/load-balancing/","name":"Load Balancing"}}]} ``` --- --- title: Get started description: Set up Cloudflare Load Balancing for your applications. image: https://developers.cloudflare.com/core-services-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/load-balancing/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) # Get started Get started with load balancing in one of two ways: * [Quickstart](https://developers.cloudflare.com/load-balancing/get-started/quickstart/): Get up and running quickly with Load Balancing. * [Learning path](https://developers.cloudflare.com/learning-paths/load-balancing/concepts/): Check an in-depth walkthrough for how to plan and set up a load balancer. ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/load-balancing/","name":"Load Balancing"}},{"@type":"ListItem","position":3,"item":{"@id":"/load-balancing/get-started/","name":"Get started"}}]} ``` --- --- title: Enable description: Learn how to enable load balancing. image: https://developers.cloudflare.com/core-services-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/load-balancing/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) # Enable Load balancing is an add-on for your account, meaning your account needs a [billing profile](https://developers.cloudflare.com/billing/get-started/create-billing-profile/). To enable [Load Balancing ↗](https://dash.cloudflare.com/?to=/:account/:zone/traffic/load-balancing): 1. In the Cloudflare dashboard, go to the **Load Balancing** page. [ Go to **Load Balancing** ](https://dash.cloudflare.com/?to=/:account/load-balancing) 2. Select **Enable Load Balancing** in the **Status** column. 3. Choose your plan options and confirm payment. Note Enterprise customers can preview this product as a [non-contract service](https://developers.cloudflare.com/billing/understand/preview-services/), which provides full access, free of metered usage fees, limits, and certain other restrictions. ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/load-balancing/","name":"Load Balancing"}},{"@type":"ListItem","position":3,"item":{"@id":"/load-balancing/get-started/","name":"Get started"}},{"@type":"ListItem","position":4,"item":{"@id":"/load-balancing/get-started/enable-load-balancing/","name":"Enable"}}]} ``` --- --- title: Concepts description: Distribute traffic across servers with load balancing. image: https://developers.cloudflare.com/cf-twitter-card.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/learning-paths/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) # Concepts Learn the concepts behind load balancing, whether you are using Cloudflare or another provider. ## Objectives By the end of this module, you will be able to: * Explain what load balancing is. * Describe the differences between load balancers, pools, and servers. * Explain what pool health is and how it affects load balancer traffic. * List the different ways your traffic can be routed. ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/learning-paths/","name":"Learning Paths"}},{"@type":"ListItem","position":3,"item":{"@id":"/learning-paths/load-balancing/concepts/","name":"Concepts"}}]} ``` --- --- title: Quickstart description: Create a load balancer with pools and monitors in a few steps. image: https://developers.cloudflare.com/core-services-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/load-balancing/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) # Quickstart Get up and running quickly with Load Balancing. For more in-depth explanations, refer to the [Learning path](https://developers.cloudflare.com/learning-paths/load-balancing/concepts/). This guide assumes you are familiar with the Cloudflare [Load Balancing components](https://developers.cloudflare.com/load-balancing/understand-basics/load-balancing-components/). --- ## Before you begin Make sure you: * Have access to multiple endpoints (origin servers, private or public IP addresses, virtual IP addresses (VIPs), etc), either physical or cloud-based. * Have access to Load Balancing, available as an [add-on](https://developers.cloudflare.com/load-balancing/get-started/enable-load-balancing/) for any type of account. * Have test and production hostnames that are covered by [SSL/TLS certificates](https://developers.cloudflare.com/load-balancing/load-balancers/dns-records/#ssltls-coverage). ## Create a monitor A monitor issues health monitor requests at regular intervals to evaluate the health of each endpoint within a [pool](https://developers.cloudflare.com/load-balancing/pools/). When a pool [becomes unhealthy](https://developers.cloudflare.com/load-balancing/understand-basics/health-details/), your load balancer takes that pool out of the endpoint rotation. * [ Dashboard ](#tab-panel-6988) * [ API ](#tab-panel-6989) **Set up the monitor** You can create a monitor within the [load balancer workflow](https://developers.cloudflare.com/load-balancing/load-balancers/create-load-balancer/) or in the **Monitors** tab: 1. Go to **Load Balancing**. 2. Select the **Monitors** tab. 3. Select **Create monitor**. 4. Add the following information: * **Type**: The protocol to use for health monitors * _Non-enterprise customers_: Choose **HTTP**, **HTTPS**, or **TCP**. * _Enterprise customers_: Choose **HTTP**, **HTTPS**, **TCP**, **UDP ICMP**, **ICMP Ping**, or **SMTP**. * **Path**: The endpoint path to run health monitor requests against * **Port**: The destination port for health monitors 5. For additional settings, select **Advanced health monitor settings**: * **Interval**: * By increasing the default, you can improve failover time, but you may also increase load on your endpoints. * Minimum time in seconds is 60 (Pro), 15 (Business), and 10 (Enterprise). * **Timeout** and **Retries**: * The health monitor request will return unhealthy if it exceeds the duration specified in **Timeout** (and exceeds this duration more times than the specified number of **Retries**). * **Expected Code(s)**: The expected HTTP response codes listed individually (`200`, `302`) or as a range (for example, entering `2xx` would cover all response codes in the `200` range). * **Response Body**: * Looks for a case-insensitive substring in the response body. * Make sure that the value is relatively static and within the first 10 KB of the HTML page. * **Simulate Zone**: * It is recommended to use the same zone in which the Load Balancer exists. * Changes the egress zone settings of a health monitor request to ensure compatibility with features like [authenticated origin pulls](https://developers.cloudflare.com/ssl/origin-configuration/authenticated-origin-pull/), [Argo Smart Routing](https://developers.cloudflare.com/argo-smart-routing/), and [Dedicated CDN Egress IPs](https://developers.cloudflare.com/smart-shield/configuration/dedicated-egress-ips/). * **Follow Redirects**: * Instead of reporting a `301` or `302` code as unhealthy, the health monitor request follows redirects to the final endpoint. * **Configure Request Header(s)**: * Useful if your endpoints are expecting specific incoming headers. * **Header**: * The HTTP request headers to send in the health monitor. It is recommended that you set a Host header by default. The User-Agent header cannot be overridden. This parameter is only valid for HTTP and HTTPS monitors. 6. Select **Save**. Note To increase confidence in pool status, you can also increase the `consecutive_up` and `consecutive_down` fields when [creating a monitor with the API](https://developers.cloudflare.com/api/resources/load%5Fbalancers/subresources/monitors/methods/create/). To become healthy or unhealthy, monitored endpoints must pass this health monitor request the consecutive number of times specified in these parameters. **Prepare your servers** Make sure that your firewall or web server does not block or rate limit your configured health monitors or requests associated with [Cloudflare IP addresses ↗](https://www.cloudflare.com/ips). Each health monitor has the HTTP user-agent of `"Mozilla/5.0 (compatible; Cloudflare-Traffic-Manager/1.0; +https://www.cloudflare.com/traffic-manager/; pool-id: $poolid)"`, where the `$poolid` is the first 16 characters of the [associated pool](https://developers.cloudflare.com/load-balancing/pools/). Warning If you know that your endpoint is healthy but Load Balancing is reporting it as unhealthy, refer to our [Monitor troubleshooting guide](https://developers.cloudflare.com/load-balancing/troubleshooting/load-balancing-faq/#why-is-my-endpoint-or-pool-considered-unhealthy). **Set up the monitor** For a full list of monitor properties, refer to [Create Monitor](https://developers.cloudflare.com/api/resources/load%5Fbalancers/subresources/monitors/methods/create/). If you need help with API authentication, refer to [Cloudflare API documentation](https://developers.cloudflare.com/fundamentals/api/). Required API token permissions At least one of the following [token permissions](https://developers.cloudflare.com/fundamentals/api/reference/permissions/)is required: * `Load Balancing: Monitors and Pools Write` Create Monitor ``` curl "https://api.cloudflare.com/client/v4/accounts/$ACCOUNT_ID/load_balancers/monitors" \ --request POST \ --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \ --json '{ "type": "https", "description": "Login page monitor", "method": "GET", "path": "/health", "header": { "Host": [ "example.com" ], "X-App-ID": [ "abc123" ] }, "port": 8080, "timeout": 3, "retries": 0, "interval": 90, "expected_body": "alive", "expected_codes": "2xx", "follow_redirects": true, "allow_insecure": true, "consecutive_up": 3, "consecutive_down": 2, "probe_zone": "example.com" }' ``` The response contains the complete definition of the new monitor. Response ``` { "success": true, "errors": [], "messages": [], "result": { "id": ":monitor-id", "created_on": "2021-01-01T05:20:00.12345Z", "modified_on": "2021-01-01T05:20:00.12345Z", "type": "https", "description": "Login page monitor", "method": "GET", "path": "/health", "header": { "Host": [ "example.com" ], "X-App-ID": [ "abc123" ] }, "port": 8080, "timeout": 3, "retries": 0, "interval": 90, "expected_body": "alive", "expected_codes": "2xx", "follow_redirects": true, "allow_insecure": true, "consecutive_up": 3, "consecutive_down": 2, "probe_zone": "example.com" } } ``` **Prepare your servers** Make sure that your firewall or web server does not block or rate limit your configured health monitors or requests associated with [Cloudflare IP addresses ↗](https://www.cloudflare.com/ips). Each health monitor has the HTTP user-agent of `"Mozilla/5.0 (compatible; Cloudflare-Traffic-Manager/1.0; +https://www.cloudflare.com/traffic-manager/; pool-id: $poolid)"`, where the `$poolid` is the first 16 characters of the [associated pool](https://developers.cloudflare.com/load-balancing/pools/). Warning If you know that your endpoint is healthy but Load Balancing is reporting it as unhealthy, refer to our [Monitor troubleshooting guide](https://developers.cloudflare.com/load-balancing/troubleshooting/load-balancing-faq/#why-is-my-endpoint-or-pool-considered-unhealthy). Example monitor configuration | Field | Value | | ---------------- | --------- | | Type | HTTP | | Path | / | | Port | 80 | | Interval | 60 | | Method | GET | | Timeout | 5 seconds | | Retries | 2 | | Expected Code(s) | 200 | ## Create pools Within Cloudflare, pools represent your endpoints and how they are organized. As such, a pool can be a group of several endpoints, or you could also have only one endpoint (an origin server, for example) per pool. If you are familiar with DNS terminology, think of a pool as a “record set,” except Cloudflare only returns addresses that are considered healthy. You can attach health monitors to individual pools for customized monitoring. A pool can have either a single monitor or a monitor group attached — but not both. * [ Dashboard ](#tab-panel-6992) * [ API ](#tab-panel-6993) You can create a pool within the [load balancer workflow](https://developers.cloudflare.com/load-balancing/load-balancers/create-load-balancer/) or in the **Pools** tab: 1. Go to **Load Balancing**. 2. Select the **Pools** tab and then **Create pool**. 3. For your pool, enter the following information: * A name (must be unique) * A description to provide more detail on the name * A choice for [**Endpoint Steering**](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/origin-level-steering/), which affects how your pool routes traffic to each endpoint 4. For each endpoint, enter the following information: * A name (must be unique) * The endpoint address or associated hostname * (Optional) A [**Virtual Network**](https://developers.cloudflare.com/cloudflare-one/networks/connectors/cloudflare-tunnel/private-net/cloudflared/tunnel-virtual-networks/). Required when the endpoint has a private IP address. * A [**Weight**](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/origin-level-steering/#weights) * (Optional) A [hostname](https://developers.cloudflare.com/load-balancing/additional-options/override-http-host-headers/) by clicking **Add host header** * (Optional) The destination port to which the traffic will be served. Note If your endpoint is a website or application hosted on [Cloudflare Pages](https://developers.cloudflare.com/pages/), you will need to fill in the host header field with the project domain for it to resolve correctly. 1. Repeat this process for additional endpoints in the pool. 2. (Optional) Set up coordinates for [Proximity Steering](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/proximity-steering/) on the pool. 3. On the pool, update the following information: * **Health Threshold**: The Health Threshold is the number of healthy endpoints for the pool as a whole to be considered _Healthy_ and receive traffic based on pool order in a load balancer. Increasing this number makes the pool more reliable, but also more likely to become unhealthy. * **Monitor**: Attach a [monitor](https://developers.cloudflare.com/load-balancing/monitors/create-monitor/) * **Health Monitor Regions**: Choose whether to check pool health from [multiple locations](https://developers.cloudflare.com/load-balancing/monitors/#health-monitor-regions), which increases accuracy but can lead to probe traffic to your endpoint * **Pool Notifications**: You can set up new alerts - and view existing alerts - to be notified when pools are enabled or disabled, or pools or endpoints have changes in their [health status](https://developers.cloudflare.com/load-balancing/understand-basics/health-details/). 4. When finished, select **Save**. For a full list of properties, refer to [Create Pool](https://developers.cloudflare.com/api/resources/load%5Fbalancers/subresources/pools/methods/create/). If you need help with API authentication, refer to [Cloudflare API documentation](https://developers.cloudflare.com/fundamentals/api/). Required API token permissions At least one of the following [token permissions](https://developers.cloudflare.com/fundamentals/api/reference/permissions/)is required: * `Load Balancing: Monitors and Pools Write` Create Pool ``` curl "https://api.cloudflare.com/client/v4/accounts/$ACCOUNT_ID/load_balancers/pools" \ --request POST \ --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \ --json '{ "description": "Primary data center - Provider XYZ", "name": "primary-dc-1", "enabled": false, "load_shedding": { "default_percent": 0, "default_policy": "random", "session_percent": 0, "session_policy": "hash" }, "minimum_origins": 2, "monitor": "f1aba936b94213e5b8dca0c0dbf1f9cc", "check_regions": [ "WEU", "ENAM" ], "origins": [ { "name": "app-server-1", "address": "0.0.0.0", "enabled": true, "weight": 0.56, "header": { "Host": [ "example.com" ] } } ], "origin_steering": { "policy": "random" }, "notification_filter": { "origin": { "disable": false, "healthy": null }, "pool": { "disable": false, "healthy": null } } }' ``` The response contains the complete definition of the new pool. Response ``` { "success": true, "errors": [], "messages": [], "result": { "id": "17b5962d775c646f3f9725cbc7a53df4", "created_on": "2021-01-01T05:20:00.12345Z", "modified_on": "2021-01-01T05:20:00.12345Z", "description": "Primary data center - Provider XYZ", "name": "primary-dc-1", "enabled": false, "load_shedding": { "default_percent": 0, "default_policy": "random", "session_percent": 0, "session_policy": "hash" }, "minimum_origins": 2, "monitor": "f1aba936b94213e5b8dca0c0dbf1f9cc", "check_regions": [ "WEU", "ENAM" ], "origins": [ { "name": "app-server-1", "address": "0.0.0.0", "enabled": true, "weight": 0.56, "header": { "Host": [ "example.com" ] } } ], "origin_steering": { "policy": "random" }, "notification_filter": { "origin": { "disable": false, "healthy": null }, "pool": { "disable": false, "healthy": null } } } } ``` After creating the pool, you would also want to [create a new notification](https://developers.cloudflare.com/api/resources/alerting/subresources/policies/methods/create/) with the following parameters specified: ``` "alert_type": "load_balancing_health_alert", "filters": { "pool_id": <>, "new_health": <> ["Unhealthy", "Healthy"], "event_source": <> ["pool", "origin"] } ``` ## Confirm pool health Before directing any traffic to your pools, make sure that your pools and monitors are set up correctly. The status of your health check will be _unknown_ until the results of the first check are available. * [ Dashboard ](#tab-panel-6986) * [ API ](#tab-panel-6987) To confirm pool health using the dashboard: 1. Go to **Load Balancing**. 2. Select the **Pools** tab. 3. For pools and individual endpoints, review the values in the **Health** and **Endpoint Health** columns. For more information on pool and endpoint health statuses, refer to [How a pool becomes unhealthy](https://developers.cloudflare.com/load-balancing/understand-basics/health-details/#how-a-pool-becomes-unhealthy). To fetch the latest health status of all pools, use the [List Pools](https://developers.cloudflare.com/api/resources/load%5Fbalancers/subresources/pools/methods/list/) command, paying attention to the `healthy` value for pools and origins (endpoints). For troubleshooting a specific pool's health, use the [Pool Health Details](https://developers.cloudflare.com/api/resources/load%5Fbalancers/subresources/pools/subresources/health/methods/get/) command. ### Unexpected health status If you notice that healthy pools are being marked unhealthy: * Review [how endpoints and pools become unhealthy](https://developers.cloudflare.com/load-balancing/understand-basics/health-details/). * Refer to the [Troubleshooting section](https://developers.cloudflare.com/load-balancing/troubleshooting/). ## Create a load balancer on a test subdomain Instead of starting on your production domain, you likely should create a load balancer on a test or staging domain. This may involve temporary changes to your monitors and pools, depending on your infrastructure setup. Starting with a test domain allows you to verify everything is working correctly before routing production traffic. * [ Dashboard ](#tab-panel-6990) * [ API ](#tab-panel-6991) To create a Public or a Private load balancer in the dashboard: ### Create a Public load balancer 1. Go to **Load Balancing** and select **Create load balancer**. 2. On the **Load Balancer Setup**, select **Public load balancer** 3. Choose the website to which you want to add this load balancer. 4. On the **Hostname** page: * Enter a **Hostname**, which is the DNS name at which the load balancer is available. For more details on record priority, refer to [DNS records for load balancing](https://developers.cloudflare.com/load-balancing/load-balancers/dns-records/). * From the **Data Localization** dropdown, select the [region](https://developers.cloudflare.com/data-localization/how-to/load-balancing/#regional-services) you would like to use on your domain. * Toggle the orange cloud icon to update the [proxy mode](https://developers.cloudflare.com/load-balancing/understand-basics/proxy-modes/), which affects how traffic is routed and which IP addresses are advertised. * Add a description for your load balancer. * If you want [session-based load balancing](https://developers.cloudflare.com/load-balancing/understand-basics/session-affinity/), toggle the **Session Affinity** switch. * If you want [Adaptive Routing](https://developers.cloudflare.com/load-balancing/understand-basics/adaptive-routing/), toggle the **Adaptive Routing** switch. 5. Select **Next**. 6. On the **Add a Pool** page: * Select one or more existing pools or [create a new pool](https://developers.cloudflare.com/load-balancing/pools/create-pool/#create-a-pool). * If you are going to set [traffic steering](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/standard-options/) to **Off**, re-order the pools in your load balancer to adjust the fallback order. * If needed, update the [**Fallback Pool**](https://developers.cloudflare.com/load-balancing/understand-basics/health-details/#fallback-pools). * If you choose to set traffic steering to **Random**, you can set [Weights](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/standard-options/#random-steering) (via the API) to your pools to determine the percentage of traffic sent to each pool. 7. Select **Next**. 8. On the **Monitors** page: * Review the monitors attached to your pools. * If needed, you can attach an existing monitor or [create a new monitor](https://developers.cloudflare.com/load-balancing/monitors/create-monitor/#create-a-monitor). 9. Select **Next**. 10. On the **Traffic Steering** page, choose an option for [Traffic steering](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/) and select **Next**. 11. On the **Custom Rules** page, select an existing rule or [create a new rule](https://developers.cloudflare.com/load-balancing/additional-options/load-balancing-rules/). 12. Select **Next**. 13. On the **Review** page: * Review your configuration and make any changes. * Choose whether to **Save as Draft** or **Save and Deploy**. ### Create a Private load balancer 1. Go to **Load Balancing** and select **Create load balancer**. 2. On the **Load Balancer Setup**, select **Private load balancer** 3. Associate your load balancer with either a Cloudflare private IP or a specified IP address and create a description for your load balancer. 4. On the **Add a Pool** page: * Select one or more existing pools or [create a new pool](https://developers.cloudflare.com/load-balancing/pools/create-pool/#create-a-pool). * If you are going to set [traffic steering](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/standard-options/) to **Off**, re-order the pools in your load balancer to adjust the fallback order. * If needed, update the [**Fallback Pool**](https://developers.cloudflare.com/load-balancing/understand-basics/health-details/#fallback-pools). * If you choose to set traffic steering to **Random**, you can set [Weights](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/standard-options/#random-steering) (via the API) to your pools to determine the percentage of traffic sent to each pool. 5. Select **Next**. 6. On the **Monitors** page: * Review the monitors attached to your pools. * If needed, you can attach an existing monitor or [create a new monitor](https://developers.cloudflare.com/load-balancing/monitors/create-monitor/#create-a-monitor). 7. Select **Next**. 8. On the **Traffic Steering** page, choose an option for [Traffic steering](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/) and select **Next**. 9. Select **Next**. 10. On the **Review** page: * Review your configuration and make any changes. * Choose whether to **Save as Draft** or **Save and Deploy**. For a full list of properties, refer to [Create Load Balancer](https://developers.cloudflare.com/api/resources/load%5Fbalancers/methods/create/). If you need help with API authentication, refer to [Cloudflare API documentation](https://developers.cloudflare.com/fundamentals/api/). Note Since load balancers only exist on a zone — and not an account — you may need to get the zone `id` with the [List Zones](https://developers.cloudflare.com/api/resources/zones/methods/list/) command. Required API token permissions At least one of the following [token permissions](https://developers.cloudflare.com/fundamentals/api/reference/permissions/)is required: * `Load Balancers Write` Create Load Balancer ``` curl "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/load_balancers" \ --request POST \ --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \ --json '{ "description": "Load Balancer for lb.example.com", "name": "lb.example.com", "enabled": true, "ttl": 30, "fallback_pool": "17b5962d775c646f3f9725cbc7a53df4", "default_pools": [ "17b5962d775c646f3f9725cbc7a53df4", "9290f38c5d07c2e2f4df57b1f61d4196", "00920f38ce07c2e2f4df50b1f61d4194" ], "proxied": true, "steering_policy": "random_steering", "session_affinity": "cookie", "session_affinity_attributes": { "samesite": "Auto", "secure": "Auto", "drain_duration": 100, "zero_downtime_failover": "sticky" }, "session_affinity_ttl": 5000, "adaptive_routing": { "failover_across_pools": true }, "location_strategy": { "prefer_ecs": "always", "mode": "resolver_ip" }, "random_steering": { "pool_weights": { "de90f38ced07c2e2f4df50b1f61d4194": 0.3, "9290f38c5d07c2e2f4df57b1f61d4196": 0.5 }, "default_weight": 0.2 } }' ``` The response contains the complete definition of the new load balancer. Response ``` { "success": true, "errors": [], "messages": [], "result": { "id": "699d98642c564d2e855e9661899b7252", "created_on": "2021-01-01T05:20:00.12345Z", "modified_on": "2021-01-01T05:20:00.12345Z", "description": "Load Balancer for lb.example.com", "name": "lb.example.com", "enabled": true, "ttl": 30, "fallback_pool": "17b5962d775c646f3f9725cbc7a53df4", "default_pools": [ "17b5962d775c646f3f9725cbc7a53df4", "9290f38c5d07c2e2f4df57b1f61d4196", "00920f38ce07c2e2f4df50b1f61d4194" ], "proxied": true, "steering_policy": "random_steering", "session_affinity": "cookie", "session_affinity_attributes": { "samesite": "Auto", "secure": "Auto", "drain_duration": 100, "zero_downtime_failover": "sticky" }, "session_affinity_ttl": 5000, "random_steering": { "pool_weights": { "de90f38ced07c2e2f4df50b1f61d4194": 0.3, "9290f38c5d07c2e2f4df57b1f61d4196": 0.5 }, "default_weight": 0.2 } } } ``` ## Optional - Review load balancing analytics As you send sample requests to your test domain, review the [load balancing analytics](https://developers.cloudflare.com/load-balancing/reference/load-balancing-analytics/) page to make sure your load balancer is distributing requests like you were expecting. ## Route production traffic Now that you have set up your load balancer and verified everything is working correctly, you can put the load balancer on a live domain or subdomain: 1. If you update your pools and monitors, review the pool health again to make sure everything is working as expected. 2. Confirm that your production hostname has the correct [priority order](https://developers.cloudflare.com/load-balancing/load-balancers/dns-records/#priority-order) of DNS records and is covered by an [SSL/TLS certificate](https://developers.cloudflare.com/load-balancing/load-balancers/dns-records/#ssltls-coverage). 3. Configure your load balancer to receive production traffic, which could involve either: * Editing the **Hostname** of your existing load balancer. * Updating the `CNAME` record sending traffic to your load balancer. Note If you have an Enterprise account, also evaluate your application for any excluded paths. For example, you might not want the load balancer to distribute requests directed at your `/admin` path. For any exceptions, set up an [origin rule](https://developers.cloudflare.com/rules/origin-rules/features/#dns-record). ## Optional - Next steps Your load balancer should be receiving production traffic (and you can confirm this by reviewing the [analytics](https://developers.cloudflare.com/load-balancing/reference/load-balancing-analytics/)). Though your product is officially set up, you may want to consider the following suggestions. ### Usage-based notifications Since this is a service with [usage-based billing](https://developers.cloudflare.com/billing/understand/usage-based-billing/), Cloudflare recommends that you set up usage-based billing notifications to avoid unexpected bills. To set up those notifications: 1. In the Cloudflare dashboard, go to the **Notifications** page. [ Go to **Notifications** ](https://dash.cloudflare.com/?to=/:account/notifications) 2. On **Alert Type** of **Usage Based Billing**, click **Select**. 3. Fill out the following information: * **Name** * **Product** * **Notification limit** (exact metric will vary based on product) * **Notification email** Note Some plans also have access to alerts through [PagerDuty](https://developers.cloudflare.com/notifications/get-started/configure-pagerduty/) and [Webhooks](https://developers.cloudflare.com/notifications/get-started/configure-webhooks/). 4. Select **Save**. ### Additional configuration options You may want to further customize how your load balancer routes traffic or integrate your load balancer with other Cloudflare products: * [ Additional DNS records ](https://developers.cloudflare.com/load-balancing/additional-options/additional-dns-records/) * [ Cloudflare Tunnel (published applications) ](https://developers.cloudflare.com/load-balancing/additional-options/cloudflare-tunnel/) * [ Spectrum ](https://developers.cloudflare.com/load-balancing/additional-options/spectrum/) * [ Perform planned maintenance ](https://developers.cloudflare.com/load-balancing/additional-options/planned-maintenance/) * [ Load shedding ](https://developers.cloudflare.com/load-balancing/additional-options/load-shedding/) * [ DNS persistence ](https://developers.cloudflare.com/load-balancing/additional-options/dns-persistence/) * [ Load Balancing with the China Network ](https://developers.cloudflare.com/load-balancing/additional-options/load-balancing-china/) * [ Override HTTP Host headers ](https://developers.cloudflare.com/load-balancing/additional-options/override-http-host-headers/) * [ Custom load balancing rules ](https://developers.cloudflare.com/load-balancing/additional-options/load-balancing-rules/) * [ Integrate with PagerDuty ](https://developers.cloudflare.com/load-balancing/additional-options/pagerduty-integration/) ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/load-balancing/","name":"Load Balancing"}},{"@type":"ListItem","position":3,"item":{"@id":"/load-balancing/get-started/","name":"Get started"}},{"@type":"ListItem","position":4,"item":{"@id":"/load-balancing/get-started/quickstart/","name":"Quickstart"}}]} ``` --- --- title: Load balancers description: Configure load balancers to distribute traffic across pools. image: https://developers.cloudflare.com/core-services-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/load-balancing/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) # Load balancers A load balancer distributes traffic among pools according to [pool health](https://developers.cloudflare.com/load-balancing/understand-basics/health-details/) and [traffic steering policies](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/). Each load balancer is identified by its DNS hostname (`lb.example.com`, `dev.example.com`, etc.) or IP address. Note For an overview of how the Cloudflare Load Balancing solution works, refer to [Load Balancing components](https://developers.cloudflare.com/load-balancing/understand-basics/load-balancing-components/). For more background information on what load balancers are, refer to the Cloudflare [Learning Center ↗](https://www.cloudflare.com/learning/performance/what-is-load-balancing/). --- ## Common configurations For suggestions, refer to [Common load balancer configurations](https://developers.cloudflare.com/load-balancing/load-balancers/common-configurations/). ## Public vs. Private Load Balancers Public Load Balancers are designed to handle traffic from the public Internet. When deployed, they automatically receive a hostname, making them immediately accessible. These load balancers can direct traffic to a range of destinations, including public hostnames, public IP addresses, and private IP addresses. Private Load Balancers, in contrast, are meant for internal use within private networks. They do not automatically receive a hostname, but one can be assigned via Gateway Firewall Policies or through an internal DNS system. Private Load Balancers only accept traffic over a private network on-ramp, such as [the Cloudflare One Client](https://developers.cloudflare.com/warp-client/) or [Cloudflare WAN](https://developers.cloudflare.com/cloudflare-wan/). They are capable of forwarding traffic exclusively to private IP addresses. ## Load balancing and existing DNS records For details about DNS records, refer to [DNS records for load balancing](https://developers.cloudflare.com/load-balancing/load-balancers/dns-records/). ## HTTP keep-alive (persistent HTTP connection) Cloudflare maintains keep-alive connections to improve performance and reduce cost of recurring TCP connects in the request transaction as Cloudflare proxies customer traffic from its edge network to the site's origin. Ensure HTTP Keep-Alive connections are enabled on your origin. Cloudflare reuses open TCP connections for up to 15 minutes (900 seconds) after the last HTTP request. Origin web servers close TCP connections if too many are open. HTTP Keep-Alive helps avoid premature reset of connections for requests proxied by Cloudflare. ### Session cookies **When using HTTP cookies to track and bind user sessions to a specific server**, configure [Session Affinity](https://developers.cloudflare.com/load-balancing/understand-basics/session-affinity/) to parse HTTP requests by cookie header. Doing so directs each request to the correct application server even when HTTP requests share the same TCP connection due to keep-alive. **For example, F5 BIG-IP load balancers set a session cookie at the beginning of a TCP connection** (if none exists) and then ignore all cookies from subsequent HTTP requests on the same TCP connection. This tends to break session affinity because Cloudflare sends multiple HTTP sessions on the same TCP connection. Configuring the load balancer to parse HTTP requests by cookie headers avoids this issue. --- ## Create load balancers For step-by-step guidance, refer to [Create a load balancer](https://developers.cloudflare.com/load-balancing/load-balancers/create-load-balancer/). --- ## Properties For an up-to-date list of load balancer properties, refer to [Load balancer properties](https://developers.cloudflare.com/api/resources/load%5Fbalancers/methods/get/) in the Cloudflare API documentation. --- ## API commands The Cloudflare API supports the following commands for load balancers. | Command | Method | Endpoint | | ------------------------------------------------------------------------------------------------------------------ | ------ | ------------------------------------ | | [Create Load Balancer](https://developers.cloudflare.com/api/resources/load%5Fbalancers/methods/create/) | POST | /zones/:zone\_id/load\_balancers | | [Delete Load Balancer](https://developers.cloudflare.com/api/resources/load%5Fbalancers/methods/delete/) | DELETE | /zones/:zone\_id/load\_balancers/:id | | [List Load Balancers](https://developers.cloudflare.com/api/resources/load%5Fbalancers/methods/list/) | GET | /zones/:zone\_id/load\_balancers | | [Load Balancer Details](https://developers.cloudflare.com/api/resources/load%5Fbalancers/methods/get/) | GET | /zones/:zone\_id/load\_balancers/:id | | [Overwrite specific properties](https://developers.cloudflare.com/api/resources/load%5Fbalancers/methods/edit/) | PATCH | /zones/:zone\_id/load\_balancers/:id | | [Overwrite entire Load Balancer](https://developers.cloudflare.com/api/resources/load%5Fbalancers/methods/update/) | PUT | /zones/:zone\_id/load\_balancers/:id | ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/load-balancing/","name":"Load Balancing"}},{"@type":"ListItem","position":3,"item":{"@id":"/load-balancing/load-balancers/","name":"Load balancers"}}]} ``` --- --- title: Common configurations description: Common load balancer configurations for active-active and failover. image: https://developers.cloudflare.com/core-services-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/load-balancing/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) # Common configurations Consider the following sections to understand how to achieve some commonly used load balancer configurations. This page assumes you understand the Cloudflare [Load Balancing components](https://developers.cloudflare.com/load-balancing/understand-basics/load-balancing-components/) and how to create and edit each of them. ## Active - Passive Failover An **active-passive failover** sends traffic to the endpoints in your active pool until a failure threshold (configurable) is reached. At the point of failure, your load balancer then redirects traffic to the passive pool. This setup ensures uninterrupted service and helps with planned outages, but it might lead to slower traffic overall. To set up a load balancer with **active-passive failover**: 1. Create a load balancer with two pools (`primary` and `secondary`). 2. In the list of pools, set the following order: 1. `primary` 2. `secondary` 3. For **Traffic Steering**, select [**Off**](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/standard-options/#off---failover). With this setup, your load balancer will direct all traffic to `primary` until `primary` has fewer available endpoints than specified in its **Health Threshold**. Only then will your load balancer direct traffic to `secondary`. In the event that all pools are marked down, Cloudflare uses the **fallback pool**, which is the option of last resort for successfully sending traffic to an endpoint. Since the fallback pool is a last resort, its health is not taken into account, and Cloudflare reports its status as **No Health**. You can select the fallback pool via the API or in the Cloudflare dashboard. For more on working with fallback pools, refer to [Pool-level steering](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/). ## Active - Active Failover An **active-active failover** distributes traffic to endpoints in the same pool until the pool reaches its failure threshold (configurable). At the point of failure, your load balancer would then re-direct traffic to the **fallback pool**. This setup speeds up overall requests, but is more vulnerable to planned or unplanned outages. To set up a load balancer with **active-active failover**, either: * Create a load balancer with a single pool (`primary`) with multiple endpoints (`endpoint-1` and `endpoint-2`) and set the same [**Weight**](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/origin-level-steering/#weights) for each endpoint. * Create a load balancer with two pools (`primary` and `secondary`) and — for [**Traffic Steering**](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/) — select any option except for **Off**. Note For more background reading on server failover and common configurations, refer to [our Learning Center ↗](https://www.cloudflare.com/learning/performance/what-is-server-failover/). ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/load-balancing/","name":"Load Balancing"}},{"@type":"ListItem","position":3,"item":{"@id":"/load-balancing/load-balancers/","name":"Load balancers"}},{"@type":"ListItem","position":4,"item":{"@id":"/load-balancing/load-balancers/common-configurations/","name":"Common configurations"}}]} ``` --- --- title: Manage load balancers description: Learn how to set up and maintain load balancers. image: https://developers.cloudflare.com/core-services-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/load-balancing/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) # Manage load balancers A load balancer distributes traffic among pools according to [pool health](https://developers.cloudflare.com/load-balancing/understand-basics/health-details/) and [traffic steering policies](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/). Each load balancer is identified by its DNS hostname (`lb.example.com`, `dev.example.com`, etc.) or IP address. For more details about load balancers, refer to [Load balancers](https://developers.cloudflare.com/load-balancing/load-balancers/). ## Create a load balancer * [ Dashboard ](#tab-panel-6998) * [ API ](#tab-panel-6999) To create a Public or a Private load balancer in the dashboard: ### Create a Public load balancer 1. Go to **Load Balancing** and select **Create load balancer**. 2. On the **Load Balancer Setup**, select **Public load balancer** 3. Choose the website to which you want to add this load balancer. 4. On the **Hostname** page: * Enter a **Hostname**, which is the DNS name at which the load balancer is available. For more details on record priority, refer to [DNS records for load balancing](https://developers.cloudflare.com/load-balancing/load-balancers/dns-records/). * From the **Data Localization** dropdown, select the [region](https://developers.cloudflare.com/data-localization/how-to/load-balancing/#regional-services) you would like to use on your domain. * Toggle the orange cloud icon to update the [proxy mode](https://developers.cloudflare.com/load-balancing/understand-basics/proxy-modes/), which affects how traffic is routed and which IP addresses are advertised. * Add a description for your load balancer. * If you want [session-based load balancing](https://developers.cloudflare.com/load-balancing/understand-basics/session-affinity/), toggle the **Session Affinity** switch. * If you want [Adaptive Routing](https://developers.cloudflare.com/load-balancing/understand-basics/adaptive-routing/), toggle the **Adaptive Routing** switch. 5. Select **Next**. 6. On the **Add a Pool** page: * Select one or more existing pools or [create a new pool](https://developers.cloudflare.com/load-balancing/pools/create-pool/#create-a-pool). * If you are going to set [traffic steering](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/standard-options/) to **Off**, re-order the pools in your load balancer to adjust the fallback order. * If needed, update the [**Fallback Pool**](https://developers.cloudflare.com/load-balancing/understand-basics/health-details/#fallback-pools). * If you choose to set traffic steering to **Random**, you can set [Weights](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/standard-options/#random-steering) (via the API) to your pools to determine the percentage of traffic sent to each pool. 7. Select **Next**. 8. On the **Monitors** page: * Review the monitors attached to your pools. * If needed, you can attach an existing monitor or [create a new monitor](https://developers.cloudflare.com/load-balancing/monitors/create-monitor/#create-a-monitor). 9. Select **Next**. 10. On the **Traffic Steering** page, choose an option for [Traffic steering](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/) and select **Next**. 11. On the **Custom Rules** page, select an existing rule or [create a new rule](https://developers.cloudflare.com/load-balancing/additional-options/load-balancing-rules/). 12. Select **Next**. 13. On the **Review** page: * Review your configuration and make any changes. * Choose whether to **Save as Draft** or **Save and Deploy**. ### Create a Private load balancer 1. Go to **Load Balancing** and select **Create load balancer**. 2. On the **Load Balancer Setup**, select **Private load balancer** 3. Associate your load balancer with either a Cloudflare private IP or a specified IP address and create a description for your load balancer. 4. On the **Add a Pool** page: * Select one or more existing pools or [create a new pool](https://developers.cloudflare.com/load-balancing/pools/create-pool/#create-a-pool). * If you are going to set [traffic steering](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/standard-options/) to **Off**, re-order the pools in your load balancer to adjust the fallback order. * If needed, update the [**Fallback Pool**](https://developers.cloudflare.com/load-balancing/understand-basics/health-details/#fallback-pools). * If you choose to set traffic steering to **Random**, you can set [Weights](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/standard-options/#random-steering) (via the API) to your pools to determine the percentage of traffic sent to each pool. 5. Select **Next**. 6. On the **Monitors** page: * Review the monitors attached to your pools. * If needed, you can attach an existing monitor or [create a new monitor](https://developers.cloudflare.com/load-balancing/monitors/create-monitor/#create-a-monitor). 7. Select **Next**. 8. On the **Traffic Steering** page, choose an option for [Traffic steering](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/steering-policies/) and select **Next**. 9. Select **Next**. 10. On the **Review** page: * Review your configuration and make any changes. * Choose whether to **Save as Draft** or **Save and Deploy**. For a full list of properties, refer to [Create Load Balancer](https://developers.cloudflare.com/api/resources/load%5Fbalancers/methods/create/). If you need help with API authentication, refer to [Cloudflare API documentation](https://developers.cloudflare.com/fundamentals/api/). Note Since load balancers only exist on a zone — and not an account — you may need to get the zone `id` with the [List Zones](https://developers.cloudflare.com/api/resources/zones/methods/list/) command. Required API token permissions At least one of the following [token permissions](https://developers.cloudflare.com/fundamentals/api/reference/permissions/)is required: * `Load Balancers Write` Create Load Balancer ``` curl "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/load_balancers" \ --request POST \ --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \ --json '{ "description": "Load Balancer for lb.example.com", "name": "lb.example.com", "enabled": true, "ttl": 30, "fallback_pool": "17b5962d775c646f3f9725cbc7a53df4", "default_pools": [ "17b5962d775c646f3f9725cbc7a53df4", "9290f38c5d07c2e2f4df57b1f61d4196", "00920f38ce07c2e2f4df50b1f61d4194" ], "proxied": true, "steering_policy": "random_steering", "session_affinity": "cookie", "session_affinity_attributes": { "samesite": "Auto", "secure": "Auto", "drain_duration": 100, "zero_downtime_failover": "sticky" }, "session_affinity_ttl": 5000, "adaptive_routing": { "failover_across_pools": true }, "location_strategy": { "prefer_ecs": "always", "mode": "resolver_ip" }, "random_steering": { "pool_weights": { "de90f38ced07c2e2f4df50b1f61d4194": 0.3, "9290f38c5d07c2e2f4df57b1f61d4196": 0.5 }, "default_weight": 0.2 } }' ``` The response contains the complete definition of the new load balancer. Response ``` { "success": true, "errors": [], "messages": [], "result": { "id": "699d98642c564d2e855e9661899b7252", "created_on": "2021-01-01T05:20:00.12345Z", "modified_on": "2021-01-01T05:20:00.12345Z", "description": "Load Balancer for lb.example.com", "name": "lb.example.com", "enabled": true, "ttl": 30, "fallback_pool": "17b5962d775c646f3f9725cbc7a53df4", "default_pools": [ "17b5962d775c646f3f9725cbc7a53df4", "9290f38c5d07c2e2f4df57b1f61d4196", "00920f38ce07c2e2f4df50b1f61d4194" ], "proxied": true, "steering_policy": "random_steering", "session_affinity": "cookie", "session_affinity_attributes": { "samesite": "Auto", "secure": "Auto", "drain_duration": 100, "zero_downtime_failover": "sticky" }, "session_affinity_ttl": 5000, "random_steering": { "pool_weights": { "de90f38ced07c2e2f4df50b1f61d4194": 0.3, "9290f38c5d07c2e2f4df57b1f61d4196": 0.5 }, "default_weight": 0.2 } } } ``` ### Sharing your load balancer with other sites You can share your load balancer with other sites in your account by [creating a canonical name (CNAME) record](https://developers.cloudflare.com/dns/manage-dns-records/how-to/create-dns-records/). This is useful for sharing configurations with multiple other domains so you do not have to create new load balancers for each site. You can also configure separate load balancers for each domain and reuse monitors and pools. This is especially useful for changing the failover order for different domains, such as when your `example.co.uk` server has a different failover priority from `example.com` or `example.com.au`. Note Sharing load balancers across sites is only supported if the target zone is on a [full DNS setup](https://developers.cloudflare.com/dns/zone-setups/full-setup/). It is not supported if the target zone is on a `CNAME` setup. --- ## Edit a load balancer * [ Dashboard ](#tab-panel-6994) * [ API ](#tab-panel-6995) To edit a load balancer in the dashboard: 1. Go to **Load Balancing**. 2. On a specific load balancer, select **Edit**. 3. While going through the [creation workflow](#create-a-load-balancer), update settings as needed. 4. On the **Review** step, select **Save**. When you edit a load balancer with the API, your request type depends on how much you want to edit. To update specific settings without having to resubmit the entire configuration, use a [PATCH](https://developers.cloudflare.com/api/resources/load%5Fbalancers/methods/edit/) request. For broader changes, use a [PUT](https://developers.cloudflare.com/api/resources/load%5Fbalancers/methods/update/) request. --- ## Delete a load balancer If you delete or disable a load balancer, your endpoint's response to requests will depend on your [existing DNS records](https://developers.cloudflare.com/load-balancing/load-balancers/dns-records/#disabling-a-load-balancer). * [ Dashboard ](#tab-panel-6996) * [ API ](#tab-panel-6997) To delete a load balancer in the dashboard: 1. Go to **Load Balancing**. 2. On a specific load balancer, click **Delete**. To delete a load balancer using the API, send a [DELETE](https://developers.cloudflare.com/api/resources/load%5Fbalancers/methods/delete/) request. --- ## Set up alerts You can configure alerts to receive notifications for changes in the health status of your pools or endpoints. Load Balancing Health Alert **Who is it for?** Customers who want to be warned about [changes in health status](https://developers.cloudflare.com/load-balancing/understand-basics/health-details/) in their pools or origins. **Other options / filters** Available filters include: * You can search for and add pools from your list of pools, as well as **Include future pools** (if all pools are selected). * You can choose the trigger that fires the notification when the health status becomes **unhealthy**, **healthy**, or **either unhealthy or healthy** * You can choose the trigger that fires the notification when the event source health status changes in **pool**, **origin**, or **either pool or origin**. **Included with** Purchase of [Load Balancing](https://developers.cloudflare.com/load-balancing/get-started/enable-load-balancing/). **What should you do if you receive one?** Evaluate [load balancing analytics](https://developers.cloudflare.com/load-balancing/reference/load-balancing-analytics/) to review changes in health status over time. Refer to [Cloudflare Notifications](https://developers.cloudflare.com/notifications/get-started/) for more information on how to set up an alert. ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/load-balancing/","name":"Load Balancing"}},{"@type":"ListItem","position":3,"item":{"@id":"/load-balancing/load-balancers/","name":"Load balancers"}},{"@type":"ListItem","position":4,"item":{"@id":"/load-balancing/load-balancers/create-load-balancer/","name":"Manage load balancers"}}]} ``` --- --- title: DNS records description: DNS records created for load balanced hostnames. image: https://developers.cloudflare.com/core-services-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/load-balancing/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) # DNS records When you [create a load balancer](https://developers.cloudflare.com/load-balancing/load-balancers/create-load-balancer/), Cloudflare automatically creates an LB DNS record for the specified **Hostname**. This functionality allows you to use a hostname with or without an existing DNS record. Private load balancers do not receive an automatic DNS record. Instead, you can configure a hostname using your internal DNS system or by applying a [Gateway Firewall override](https://developers.cloudflare.com/cloudflare-one/traffic-policies/dns-policies/#override) to a hostname. ## Supported records For customers on non-Enterprise plans, Cloudflare supports load balancing for `A`, `AAAA`, and `CNAME` records. For customers on Enterprise plans, Cloudflare supports load balancing for `A`, `AAAA`, `CNAME`, **MX**, and **SRV** records. ## Priority order For hostnames with existing DNS records, the LB record takes precedence when it is more or equally specific: * **Scenario 1**: * **A, AAAA, or CNAME**: `x.example.com` * **LB record**: `x.example.com` * **Outcome**: LB record takes precedence because it is as specific as the DNS record. * **Scenario 2**: * **A, AAAA, or CNAME**: `y.example.com` * **LB record**: `*.example.com` (wildcard record) * **Outcome**: DNS record takes precedence because it is more specific. * **Scenario 3**: * **A, AAAA, or CNAME**: `*.example.com` * **LB record**: `*.example.com` * **Outcome**: LB record takes precedence because it is as specific as the DNS record. Note This behavior only applies to [supported records](#supported-records) (determined by your plan type). If the DNS record points to a [SaaS provider](https://developers.cloudflare.com/cloudflare-for-platforms/cloudflare-for-saas/) and an active [custom hostname](https://developers.cloudflare.com/cloudflare-for-platforms/cloudflare-for-saas/domain-support/) exists, the custom hostname will take precedence over the Load Balancing record: * **Scenario 4**: * **CNAME**: `x.example.com` with target to a Cloudflare for SaaS provider * **LB record**: `x.example.com` * **Active custom hostname on the SaaS provider side**: `x.example.com` * **Outcome**: Custom hostname takes precedence. ## Disabling a load balancer When you disable a load balancer, requests to a specific hostname depend on your existing DNS records: * If you have existing DNS records, these records will be served. * If there are no existing records, requests to the hostname will fail. In both cases, disabling your load balancer prevents traffic from going to any associated endpoint or fallback pools. If you already have an existing `A`, `AAAA`, or `CNAME` record, be aware that the change may take some time to propagate due to [Time to Live (TTL)](https://developers.cloudflare.com/dns/manage-dns-records/reference/ttl/) and any record changes is affected, as your local DNS cache may take longer to update. ## SSL/TLS coverage Due to internal limitations, on [Partial (CNAME) setup](https://developers.cloudflare.com/dns/zone-setups/partial-setup/) the Cloudflare [Universal SSL certificates](https://developers.cloudflare.com/ssl/edge-certificates/universal-ssl/) do not cover load balancing hostnames by default. This behavior will be corrected in the future. As a current workaround for a domain or first-level subdomain (`lb.example.com`), create a [proxied CNAME/A/AAAA record](https://developers.cloudflare.com/dns/manage-dns-records/how-to/create-dns-records/) for that hostname. For example, if your load balancer hostname was `lb.example.com`, you could create the following record solely for the purpose of SSL/TLS coverage. | Type | Name | IPv4 address | Proxy status | | ---- | ---- | ------------ | ------------ | | A | lb | 192.0.2.1 | Proxied | Based on the [priority order](#priority-order), it would not receive any traffic because it is as equally specific as the LB hostname. To get coverage for any deeper subdomain (`lb.dev.example.com`), purchase an [advanced certificate](https://developers.cloudflare.com/ssl/edge-certificates/advanced-certificate-manager/). ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/load-balancing/","name":"Load Balancing"}},{"@type":"ListItem","position":3,"item":{"@id":"/load-balancing/load-balancers/","name":"Load balancers"}},{"@type":"ListItem","position":4,"item":{"@id":"/load-balancing/load-balancers/dns-records/","name":"DNS records"}}]} ``` --- --- title: Pools description: Pools of origin servers for load balancing traffic distribution. image: https://developers.cloudflare.com/core-services-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/load-balancing/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) # Pools Within Cloudflare, pools represent your endpoints and how they are organized. As such, a pool can be a group of several endpoints, or you could also have only one endpoint (an origin server, for example) per pool. If you are familiar with DNS terminology, think of a pool as a “record set,” except Cloudflare only returns addresses that are considered healthy. You can attach health monitors to individual pools for customized monitoring. A pool can have either a single monitor or a monitor group attached — but not both. For more details about how endpoints and pools become unhealthy, refer to [Endpoint and pool health](https://developers.cloudflare.com/load-balancing/understand-basics/health-details/). Warning Since load balancing targets are not limited to origin web servers, the term `endpoints` has been introduced. Refer to [Service-Specific Terms ↗](https://www.cloudflare.com/service-specific-terms-other-terms/) for its use in the context of Cloudflare offerings, and to [load balancing concepts](https://developers.cloudflare.com/load-balancing/understand-basics/load-balancing-components/) or [Reference Architecture](https://developers.cloudflare.com/reference-architecture/architectures/load-balancing/) for use case examples. On the [Load Balancing API](https://developers.cloudflare.com/api/resources/load%5Fbalancers/methods/get/), `origin` has been maintained. --- ## Properties For an up-to-date list of pool properties, refer to [Pool properties](https://developers.cloudflare.com/api/resources/load%5Fbalancers/subresources/pools/methods/list/) in our API documentation. --- ## Create pools For step-by-step guidance, refer to [Create pools](https://developers.cloudflare.com/load-balancing/pools/create-pool/). --- ## Per-endpoint Host header override When your application needs specialized routing (`CNAME` setup or custom hosts like Heroku), change the `Host` header used in health monitor requests. For more details, refer to [Override HTTP Host headers](https://developers.cloudflare.com/load-balancing/additional-options/override-http-host-headers/). --- ## API commands The Cloudflare API supports the following commands for pools. Examples are given for user-level endpoint but apply to the account-level endpoint as well. | Command | Method | Endpoint | | ------------------------------------------------------------------------------------------------------------------------------------------------ | ------ | ---------------------------------------------------------- | | [Create Pool](https://developers.cloudflare.com/api/resources/load%5Fbalancers/subresources/pools/methods/create/) | POST | accounts/:account\_id/load\_balancers/pools | | [Delete Pool](https://developers.cloudflare.com/api/resources/load%5Fbalancers/subresources/pools/methods/delete/) | DELETE | accounts/:account\_id/load\_balancers/pools/:id | | [List Pools](https://developers.cloudflare.com/api/resources/load%5Fbalancers/subresources/pools/methods/list/) | GET | accounts/:account\_id/load\_balancers/pools | | [Pool Details](https://developers.cloudflare.com/api/resources/load%5Fbalancers/subresources/pools/methods/get/) | GET | accounts/:account\_id/load\_balancers/pools/:id | | [Pool Health Details](https://developers.cloudflare.com/api/resources/load%5Fbalancers/subresources/pools/subresources/health/methods/get/) | GET | account/:account\_id/load\_balancers/pools/:id/health | | [Overwrite specific properties](https://developers.cloudflare.com/api/resources/load%5Fbalancers/subresources/pools/methods/edit/) | PATCH | accounts/:account\_id/load\_balancers/pools/:id | | [Overwrite existing pool](https://developers.cloudflare.com/api/resources/load%5Fbalancers/subresources/pools/methods/update/) | PUT | accounts/:account\_id/load\_balancers/pools/:id | | [Preview Pool](https://developers.cloudflare.com/api/resources/load%5Fbalancers/subresources/pools/subresources/health/methods/create/) | POST | account/:account\_id/load\_balancers/pools/:id/preview | | [List Pool References](https://developers.cloudflare.com/api/resources/load%5Fbalancers/subresources/pools/subresources/references/methods/get/) | GET | accounts/:account\_id/load\_balancers/pools/:id/references | ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/load-balancing/","name":"Load Balancing"}},{"@type":"ListItem","position":3,"item":{"@id":"/load-balancing/pools/","name":"Pools"}}]} ``` --- --- title: Use Pages as an origin for Load Balancing description: This tutorial is intended as an introductory example of how you can leverage Cloudflare's global traffic management. image: https://developers.cloudflare.com/core-services-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/load-balancing/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) # Use Pages as an origin for Load Balancing **Last reviewed:** almost 2 years ago This tutorial is intended as an introductory example of how you can leverage Cloudflare's global traffic management. The following sections will guide you through setting up an [active-passive failover](https://developers.cloudflare.com/load-balancing/load-balancers/common-configurations/#active---passive-failover) load balancer with [Cloudflare Pages](https://developers.cloudflare.com/pages/) as one of the [endpoints](https://developers.cloudflare.com/load-balancing/understand-basics/load-balancing-components/#endpoints), while also going into details about the Load Balancing dashboard workflow, and some important field values and troubleshooting. ## Use cases This setup can be useful if you are migrating your production website or application to Pages or if you just want to have a backup or a personalized web page for when your primary origin goes down. ## Before you begin Make sure you: * Are familiar with the Cloudflare [Load Balancing components](https://developers.cloudflare.com/load-balancing/understand-basics/load-balancing-components/). * Own a domain and use Cloudflare as a [primary DNS provider](https://developers.cloudflare.com/dns/zone-setups/full-setup/). * Have [deployed a website or application](https://developers.cloudflare.com/pages/get-started/git-integration/) with Cloudflare Pages. * Have [enabled Load Balancing](https://developers.cloudflare.com/load-balancing/get-started/enable-load-balancing/) in your account. ## Create health monitor Although you can create all the components in the **Create Load Balancer** workflow, using the **Manage Monitors** and **Manage Pools** sections separately makes it easier to test and troubleshoot the configurations of each of these components before bringing them together in a load balancer. Monitors define the criteria based on which an endpoint will be considered healthy or not. Start by setting up a monitor as follows. 1. In the Cloudflare dashboard, go to the **Load Balancing** page. [ Go to **Load Balancing** ](https://dash.cloudflare.com/?to=/:account/load-balancing) 2. Select the **Monitors** tab and then **Create monitor**. 3. Give the monitor a descriptive name and confirm the other fields are filled in as the following: | Field | Value | | ----- | ----- | | Type | HTTP | | Path | / | | Port | 80 | 1. Under **Advanced health check settings**, keep the default values and enable the **Follow Redirects** option. When you are using a service like Cloudflare Pages, it is possible that requests from the health monitor - as well as the ones from your visitors - are redirected before reaching their destination. Enabling this option prevents the monitor from reporting an unhealthy endpoint when it actually has only been redirected (with a `301` code, for example). Tip You can name the monitor after the parameters you have defined. For example: `HTTP - 200 - Follow Redirects`. This way you can easily remember the criteria a certain monitor is using when you decide to attach it to other endpoints as well. 1. Select **Save** to confirm. ## Create pools Pools hold information about where the health monitor requests and your visitors requests will be directed to. To support the [use cases](#use-cases) mentioned above, and assuming you only have one origin server for your production website and one for the Cloudflare Pages instance, create two pools with one endpoint each: Important The endpoint pointing to [Cloudflare Pages](https://developers.cloudflare.com/pages/) must have **host header** filled in with the project domain (`.pages.dev`) for it to resolve correctly. You can find a reference table for correct setup in Step 8 below. Failing to add the host header will result in [response code mismatch error](https://developers.cloudflare.com/load-balancing/troubleshooting/common-error-codes/#response-code-mismatch-error) for the monitor, and [Error 1000: DNS points to prohibited IP](https://developers.cloudflare.com/support/troubleshooting/http-status-codes/cloudflare-1xxx-errors/error-1000/) for visitors (if the load balancer is enabled despite the unhealthy monitor status). 1. In the Cloudflare dashboard, go to the **Load Balancing** page. [ Go to **Load Balancing** ](https://dash.cloudflare.com/?to=/:account/load-balancing) 2. Select the **Pools** tab and then **Create monitor**. 3. For the first pool, start by filling out the fields: * A name for the pool (must be unique). Suggestion: `primary` * A description to provide more details on the name. Suggestion: `production website` 1. Leave the choice for [**Endpoint Steering**](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/origin-level-steering/) as is. Since each pool will only have one endpoint, this steering method will not interfere in this case. 2. Add your origin server as an endpoint with the following information: * A name for the endpoint (must be unique). Suggestion: `my-website`. * The endpoint IP address or hostname. Warning As exemplified in Step 8 below, when using Cloudflare as an endpoint, **do not** specify one of Cloudflare's anycast IP addresses. Because these IPs can change at any time, you should use a hostname instead. * The endpoint [weight](https://developers.cloudflare.com/load-balancing/understand-basics/traffic-steering/origin-level-steering/#weights), which can be set to `1`. Since each pool will only have one endpoint, the endpoint weight will not make a difference in this case. * A [hostname](https://developers.cloudflare.com/load-balancing/additional-options/override-http-host-headers/) by selecting **Add host header**. Warning If your production website is hosted on a platform like Cloudflare Pages, where you have a default subdomain (`example.pages.dev`) and then configure a [custom domain](https://developers.cloudflare.com/pages/configuration/custom-domains) (`my-app.com`), you will need to add a host header to avoid failing the health monitor request. 1. Finish configuring the first pool with the following information: * Leave the **Health Threshold** set to `1`. Since each pool will only have one endpoint, this is the only possible value for this field. * Select the **Monitor** configured in the previous step. * Select **Health Check Regions** to choose from which [locations](https://developers.cloudflare.com/load-balancing/monitors/#health-monitor-regions) Cloudflare should send monitor requests to periodically test the endpoint health. 1. Select **Save** 2. Repeat the process for the second pool using the following values: | Field | Value | | -------------------------- | --------------------------------------- | | Pool name | secondary | | Description | Pages version | | Endpoint steering | | | Endpoint name | my-pages-website | | Endpoint address | | | Weight | 1 | | Host (**Add host header**) | | | Health threshold | 1 | | Monitor | | | Health check regions |