haproxy combined with confd for HTTP load balancing
I apologise but I don't have the time to properly document this right now.
What's important to know:
- HAProxy 1.5.x backed by Confd 1.7.0 beta 1
- Uses zero-downtime reconfiguration (e.g - instead of harpy reload, which will drop all connections, will gradually transfer new connections to the new config)
- Added support for url rexeg (not reggae, damn you spell checker) for routing, in addition to the usual hostname pattern
- Added validation for existence of keys in backing kv store, to prevent failures
Create the paths allowing confd to find the services:
etcdctl mkdir "/haproxy-discover/services" etcdctl mkdir "/haproxy-discover/tcp-services"
Depending on your needs, create one or more services or tcp-services.
For instance, to create an http service named myapp linked to the domain example.org and load balancing on servers 220.127.116.11:80 (we'll call it nodeA) and 18.104.22.168:80 (called nodeB), run these commands:
etcdctl set "/haproxy-discover/services/myapp/domain" "example.org" etcdctl set "/haproxy-discover/services/myapp/upstreams/nodeA" "22.214.171.124:80" etcdctl set "/haproxy-discover/services/myapp/upstreams/nodeB" "126.96.36.199:80"
Start the container making sure to expose port 80 on the host machine
docker run -e ETCD_NODE=172.17.42.1:4001 -p 1000:1000 -p 80:8080 yaronr/haproxy-confd
To add an upstream node, let's say nodeB2, 188.8.131.52:90, you just have to run this, and the configuration should safely be updated !
etcdctl set "/haproxy-discover/services/myapp/upstreams/nodeB2" "184.108.40.206:90"
To remove an upstream server, let's say ... nodeB2 (added by mistake ?), just run
etcdctl rm "/haproxy-discover/services/myapp/upstreams/nodeB2"
To remove a service, and so a directory, you must type
etcdctl rmdir "/haproxy-discover/services/myapp"
The commands for a tcp-service are the same but with tcp-services instead of services
Have fun !