Load Balancing

Create a route with two upstream services, httpbin.org and mock.api7.ai, to distribute requests across. Both services respond with the request headers when receiving a request at /headers:

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"
  }
}'

❶ type: use roundrobin as the load balancing algorithm.

❷ nodes: upstream services.

❸ pass_host: use node to pass the host header to the upstream.

❹ scheme: use https to enable TLS with upstream.

You should receive an HTTP/1.1 201 Created response if the route was created successfully.

Create an ADC configuration file containing a route pointing to two upstream services, httpbin.org and mock.api7.ai. Both services will respond with the request headers when receiving a request at /headers.

services:
  - name: httpbin Service
    routes:
      - uris:
          - /headers
        name: getting-started-headers
    upstream:
      type: roundrobin
      nodes:
        - host: mock.api7.ai
          port: 443
          weight: 1
        - host: httpbin.org
          port: 443
          weight: 1
      pass_host: node
      scheme: https

❶ type: use roundrobin as the load balancing algorithm.

❷ nodes: upstream services.

❸ pass_host: use node to pass the host header to the upstream.

❹ scheme: use https to enable TLS with upstream.

Synchronize the configuration to APISIX:

adc sync -f adc.yaml

You will receive a similar response if the configuration was synchronized successfully:

[11:25:49 AM] [ADC] › ✔  success   Sync configuration
[11:25:49 AM] [ADC] › ★  star      All is well, see you next time!

Enter the following prompt in your AI client:

Create a route with the ID `getting-started-headers` that matches requests to `/headers`, and forward them to two upstream nodes, `httpbin.org` and `mock.api7.ai`, both on port `443`. Use the `roundrobin` algorithm and the HTTPS scheme, and pass the original host of each upstream node in the request.

You should see a response similar to the following:

Successfully created route "getting-started-headers" with:

URI: /headers
Two upstream nodes:
https://httpbin.org:443
https://mock.api7.ai:443
Round-robin load balancing
Original host headers preserved (pass_host: node)
Route ID: getting-started-headers
Status: Active (1)
Created at: 1744189246 (2025-04-09 09:00:46 UTC)
The route is now ready to distribute requests between the two upstream endpoints while maintaining the original host headers.

Generate 50 consecutive requests to APISIX /headers route to see the load-balancing effect:

resp=$(seq 50 | xargs -I{} curl "http://127.0.0.1:9080/headers" -sL) && \
  count_httpbin=$(echo "$resp" | grep "httpbin.org" | wc -l) && \
  count_mockapi7=$(echo "$resp" | grep "mock.api7.ai" | wc -l) && \
  echo httpbin.org: $count_httpbin, mock.api7.ai: $count_mockapi7

The command keeps count of the number of requests that were handled by the two services respectively. The output shows that requests were distributed over to the two services:

httpbin.org: 23, mock.api7.ai: 27

Generate 50 consecutive requests to APISIX /headers route to see the load-balancing effect:

resp=$(seq 50 | xargs -I{} curl "http://127.0.0.1:9080/headers" -sL) && \
  count_httpbin=$(echo "$resp" | grep "httpbin.org" | wc -l) && \
  count_mockapi7=$(echo "$resp" | grep "mock.api7.ai" | wc -l) && \
  echo httpbin.org: $count_httpbin, mock.api7.ai: $count_mockapi7

The command keeps count of the number of requests that were handled by the two services respectively. The output shows that requests were distributed over to the two services:

httpbin.org: 23, mock.api7.ai: 27

Enter the following prompt in your AI client:

Generate 50 consecutive requests to the APISIX /headers route to observe the load-balancing behavior, then count how many responses came from httpbin.org and how many came from mock.api7.ai.

You should see a response similar to the following:

Load balancing test results for 50 requests to /headers route:

httpbin.org responses: 23 (46%)
mock.api7.ai responses: 27 (54%)
The round-robin load balancing is working as expected, distributing requests between the two upstream nodes. The slight imbalance (46/54 split) could be due to connection timing or other network factors, but overall demonstrates effective load distribution.