Interlock

Dynamic, event-driven HAProxy using Citadel. Interlock configures backends for HAProxy by listening to Docker events (start/stop, etc).

Note: Interlock requires HAProxy 1.5+

Usage

To get started, generate a config (save this as /tmp/controller.conf):

Replace 1.2.3.4 in addr listed in the engines section with your IP for your Docker host. You must enable TCP in the Docker daemon (see the Docker Docs for details).

{
    "port": 8080,
    "connect_timeout": 5000,
    "server_timeout": 10000,
    "client_timeout": 10000,
    "max_conn": 2048,
    "sysload_addr": "",
    "proxy_config_path": "/tmp/proxy.conf",
    "stats_user": "stats",
    "stats_password": "stats",
    "pid_path": "/tmp/proxy.pid",
    "engines": [
        {
            "engine": {
                "id": "local",
                "addr": "http://1.2.3.4:4243",
                "cpus": 1.0,
                "memory": 1024,
                "labels": []
            },
            "ssl_cert": "",
            "ssl_key": "",
            "ca_cert": ""
        }
    ]
}

• Pull the Interlock image from the Docker Hub: docker pull ehazlett/interlock
• Then start the interlock container:

docker run -p 80:8080 -d -v /tmp/controller.conf:/etc/interlock/controller.conf ehazlett/interlock -config /etc/interlock/controller.conf

• You should then be able to access http://<your-host-ip>/haproxy?stats to see the proxy stats.
• Add some CNAMEs or /etc/host entries for your IP. Interlock uses the hostname in the container config to add backends to the proxy.

Shipyard Integration

There is also support for using the Shipyard API to get a list of engines. This means you do not need a configuration file.

To start Interlock using the Shipyard API:

docker run -it -p 80:8080 -d ehazlett/interlock -shipyard-url <your-shipyard-url> -shipyard-service-key <your-shipyard-service-key>

To start Interlock using the Shipyard API in a local host only setup:

docker run -it -p 80:8080 -d -v /var/run/docker.sock:/docker.sock ehazlett/interlock -shipyard-url <your-shipyard-url> -shipyard-service-key <your-shipyard-service-key>

Interlock will query the Shipyard API for a list of engines and then automatically connect and start listening for events.

Optional Data

There is also the ability to send configuration data when running containers. This allows for customization of the backend configuration in HAProxy. To use this, specify the options as a JSON payload in the environment variable INTERLOCK_DATA when launching a container. For example:

Data Fields

• alias_domains: specify a list of alias domains to add ({"alias_domains": ["foo.com", "bar.com"]})
• port: specify which container port to use for backend ({"port": 8080})
• warm: connect to the container before adding to the backend ({"warm": true})
• check: specify a custom check for the backend ({"check": "httpchk GET /"})
• backend_options: specify a list of additional options for the backend ({"backend_options": ["forceclose", "http-no-delay"]}) -- see http://cbonte.github.io/haproxy-dconv/configuration-1.5.html#4.1
• check_interval: specify the interval (in ms) when to run the health check ({"check_interval": 10000}) default: 5000

For example:

docker run -it -P -d --hostname www.example.com -e INTERLOCK_DATA='{"alias_domains": ["foo.com"], "port": 8080, "warm": true}' ehazlett/go-demo

This will create a backend to access the container at "www.example.com" and an alias domain foo.com, use the port that was allocated for the container port "8080" and make a GET request to the backend container before adding.

Monitoring

You can use /haproxy?monitor to check the status of HAProxy.