haproxy-consul-template

HAProxy with configuration file generated by consul-template for automatically update nodes in Consul KV and reload HAProxy when the KV changes.

Quick start

• Run a Consul instance (server/agent) on current machine
• Run this Docker container:

$ docker run -d --net=host -p 80:80 --name=haproxy gnhuy91/haproxy-consul-template

• Start some test services, note the rest tag - it makes Registrator add the tag to Consul (and SERVICE_CHECK_* env vars for registering health checks to Consul):

# This will create 3 containers
$ for i in $(seq 1 3); do \
  docker run -d -P \
  -e SERVICE_TAGS=rest \
  -e SERVICE_CHECK_HTTP=/ \
  -e SERVICE_CHECK_INTERVAL=5s \
  -e SERVICE_CHECK_TIMEOUT=1s \
  --name=node$i -h=node$i \
  jlordiales/python-micro-service:latest \
  ; done

• In another terminal, try calling the services via HAProxy:

$ while true; do curl <HAProxy IP>:80/python-micro-service/; echo -----; sleep 1; done;

You can stop and start those test services (docker stop node1) on a new terminal and see the output of above curl changes accordingly.

Bonus

curl localhost:8500/v1/health/checks/python-micro-service | jq . for health checks status.

References

• http://sirile.github.io/2015/05/18/using-haproxy-and-consul-for-dynamic-service-discovery-on-docker.html
• https://github.com/CiscoCloud/haproxy-consul
• https://jlordiales.me/2015/04/01/consul-template/