Automatically registers services running in Docker containers with Consul.
docker run \
--net=host \
-v /var/run/docker.sock:/var/run/docker.sock:ro \
silvenga/emissaryThe network should be host to allow Emissary to access the local Consul agent. This is not required if the Consul agent is running as a container or on another host.
For container services to be discovered, the container must be anotated with Docker labels, see Docker's configuration docs for more information. Currently, a single label type exists representing a Consul service:
com.silvenga.emissary.service[-1..n] = <service name>[;service port][;tags=tag1,tag2]
Multiple services can be described by incrementing the label key. Tags are optional, multiple tags are delimited with commas. The service port is optional if the container defines a single published port.
For example:
com.silvenga.emissary.service-1=redis;6379;tags=primary
Will create the following service in Consul:
{
"service": {
"name": "redis",
"tags": ["primary"],
"address": "",
"port": 6379
}
}Emissary is configured using environment variables. The following are possible configuration options - Note the double underscores in some variables.
| Name | Required? | Defaults | Description |
|---|---|---|---|
DOCKER__HOST |
Yes | unix:///var/run/docker.sock |
Address to connect to the Docker daemon - defaults to the UNIX socket if not specified. Supported protocols are http, tcp, unix, and npipe. Authentication and https are not supported, open an issue if this is important. |
CONSUL__HOST |
Yes | http://localhost:8500 |
The API of the local Consul agent - defaults to localhost and the default Consul port if not specified. |
CONSUL__TOKEN |
No | null |
An ACL token to use on API requests to Consul (not required by default). Defaults to disabled if not specified. See Consul's ACL guide for more info. |
CONSUL__DATACENTER |
No | null |
The Consul datacenter to use - defaults at Consul's default if not specified (the datacenter specified in the Consul agent's configurations). |
POLLINGINTERVAL |
Yes | 60 |
The interval in seconds to poll for container updates (creations/deletions). Polling is normally not required, and is only used as a backup if subscribing to the Docker event stream fails. This value must be greater then 0. |
version: "3"
services:
apache-1:
image: httpd:alpine
ports:
- 80:80
labels:
com.silvenga.emissary.service-1: test-service # Creates a service using the port 80.
apache-2:
image: httpd:alpine
ports:
- 80:80
- 443:443
labels:
com.silvenga.emissary.service-1: test-service;80 # Service ports must be specified here because more then one port is exposed.
com.silvenga.emissary.service-2: test-service;443;tags=tag1,test2version: "3"
services:
emissary:
image: silvenga/emissary
network_mode: host
volumes:
- /var/run/docker.sock:/var/run/docker.sock:ro
restart: unless-stopped