% etcd docker : service discovery
% Fabrice Le Coz
% August, 2015

etcd

etcd is an open-source distributed key value store that provides shared configuration and service discovery. ( cf https://coreos.com/etcd )

This container will run etcd in a docker. The etcd service is only accessible to the docker running on the same host.

To keep configuration on etcd remove, it's useful to store the database on the host file-system.

Nota : the version of the docker image will reflect the version of the embedded etcd server.

Running

Nota : you can obtain the last builded images from the NAS /exploitation/Docker, to deploy the image on a server ( {{serverName}} ) with docker-machine :

 docker-machine scp /Volumes/exploitation/Docker/etcd-v2.1.1.tar.bz2 {{serverName}}:
 docker-machine ssh {{serverName}} 'bzip2 -c -d etcd-v2.1.1.tar.bz2 | docker load'
 docker-machine ssh {{serverName}} rm etcd-v2.1.1.tar.bz2

docker run -it --rm \
    --name etcd \
    -v /opt/data/etcd:/data \
    etcd:2.1.1

properties

• Exposed port : 2379 & 4001
• Volumes :
  • /data : the database directory
• link : none

Nota : As ETCD may contain vital information about your configuration, it is not recommanded to bind the ports to the host public interface.

Using etcd

to facilitate the administration, you could create an alias :

alias etcdctl="docker exec -it etcd etcdctl"

get the entries tree :

etcdctl ls --recursive

Write a key :

etcdctl set mykey "This is awesome"

Read a key :

etcdctl get mykey

Remove a key :

etcdctl rm mykey

For further documentation about etcd, consult the official website