| --- |
| title: Load Balancing |
| slug: /getting-started/load-balancing |
| --- |
| |
| <head> |
| <link rel="canonical" href="https://docs.api7.ai/apisix/getting-started/load-balancing" /> |
| </head> |
| |
| > The Getting Started tutorials are contributed by [API7.ai](https://api7.ai/). |
| |
| Load balancing manages traffic between clients and servers. It is a mechanism used to decide which server handles a specific request, allowing for improved performance, scalability, and reliability. Load balancing is a key consideration in designing systems that need to handle a large volume of traffic. |
| |
| Apache APISIX supports weighted round-robin load balancing, in which incoming traffic are distributed across a set of servers in a cyclical pattern, with each server taking a turn in a predefined order. |
| |
| In this tutorial, you will create a route with two upstream services and enable round-robin load balancing to distribute traffic between the two services. |
| |
| ## Prerequisite(s) |
| |
| 1. Complete [Get APISIX](./README.md) to install APISIX. |
| 2. Understand APISIX [Route and Upstream](./configure-routes.md#what-is-a-route). |
| |
| ## Enable Load Balancing |
| |
| Let's create a route with two upstream services. All requests sent to the `/headers` endpoint will be forwarded to [httpbin.org](https://httpbin.org/headers) and [mock.api7.ai](https://mock.api7.ai/headers), which should echo back the requester's headers. |
| |
| ```shell |
| curl -i "http://127.0.0.1:9180/apisix/admin/routes" -X PUT -d ' |
| { |
| "id": "getting-started-headers", |
| "uri": "/headers", |
| "upstream" : { |
| "type": "roundrobin", |
| "nodes": { |
| "httpbin.org:443": 1, |
| "mock.api7.ai:443": 1 |
| }, |
| "pass_host": "node", |
| "scheme": "https" |
| } |
| }' |
| ``` |
| |
| You will receive an `HTTP/1.1 201 OK` response if the route was created successfully. |
| |
| :::info |
| |
| 1. The `pass_host` field is set to `node` to pass the host header to the upstream. |
| 2. The `scheme` field is set to `https` to enable TLS when sending requests to the upstream. |
| |
| ::: |
| |
| ## Validate |
| |
| The two services respond with different data. |
| |
| From `httpbin.org`: |
| |
| ```json |
| { |
| "headers": { |
| "Accept": "*/*", |
| "Host": "httpbin.org", |
| "User-Agent": "curl/7.58.0", |
| "X-Amzn-Trace-Id": "Root=1-63e34b15-19f666602f22591b525e1e80", |
| "X-Forwarded-Host": "localhost" |
| } |
| } |
| ``` |
| |
| From `mock.api7.ai`: |
| |
| ```json |
| { |
| "headers": { |
| "accept": "*/*", |
| "host": "mock.api7.ai", |
| "user-agent": "curl/7.58.0", |
| "content-type": "application/json", |
| "x-application-owner": "API7.ai" |
| } |
| } |
| ``` |
| |
| Let's generate 100 requests to test the load-balancing effect: |
| |
| ```shell |
| hc=$(seq 100 | xargs -i curl "http://127.0.0.1:9080/headers" -sL | grep "httpbin" | wc -l); echo httpbin.org: $hc, mock.api7.ai: $((100 - $hc)) |
| ``` |
| |
| The result shows the requests were distributed over the two services almost equally: |
| |
| ```text |
| httpbin.org: 51, mock.api7.ai: 49 |
| ``` |
| |
| ## What's Next |
| |
| You have learned how to configure load balancing. In the next tutorial, you will learn how to configure key authentication. |
