How to get etcd working with a remote cluster. (bonus points: uses vagrant, and systemd)

etcd.service

[Unit]
Description=etcd service
After=network.target

[Service]
Type=simple
User=vagrant
WorkingDirectory=/home/vagrant/etcd-v2.0.2-linux-amd64
ExecStart=/home/vagrant/etcd-v2.0.2-linux-amd64/etcd -name master3 -initial-advertise-peer-urls http://10.0.3.23:2380 -listen-peer-urls http://10.0.3.23:2380 -initial-cluster-token etcd-vagrant-1 -initial-cluster master1=http://10.0.3.21:2380,master2=http://10.0.3.22:2380,master3=http://10.0.3.23:2380 -initial-cluster-state new -listen-client-urls http://10.0.3.23:4001 -advertise-client-urls http://10.0.3.21:4001,http://10.0.3.22:4001,http://10.0.3.23:4001

[Install]
WantedBy=multi-user.target

Notes:

That execstart line is a little involved.  Changes between each cluster node:

change '-name master3' to be the name of this host in the cluster, as specified by the following '-initial-cluster' statement.

change -listen-peer-urls to the IP of this host in the cluster.

change '-listen-client-urls' to reference the IP of this host in the cluster.

You also may need to change the WorkingDirectory, and the path to the etcd binary.

Other steps are as documented elsewhere.  Per https://github.com/coreos/etcd/releases/ run this on all nodes to download:

curl -L  https://github.com/coreos/etcd/releases/download/v2.0.2/etcd-v2.0.2-linux-amd64.tar.gz -o etcd-v2.0.2-linux-amd64.tar.gz
tar xzvf etcd-v2.0.2-linux-amd64.tar.gz
cd etcd-v2.0.2-linux-amd64

drop the etcd.service file in /etc/systemd/system on the three masters (modified for each master)

Then you can run:

./etcdctl --peers 10.0.3.21:4001,10.0.3.22:4001,10.0.3.23:4001 ls / -recursive

Now you can play with etcd.

Vagrantfile

VAGRANTFILE_API_VERSION = "2"

Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
  config.vm.define "master1" do |master1|
    master1.vm.box = "matyunin/centos7"
    master1.vm.network "private_network", ip: "10.0.3.21", virtualbox__intnet: true
  end

  config.vm.define "master2" do |master2|
    master2.vm.box = "matyunin/centos7"
    master2.vm.network "private_network", ip: "10.0.3.22", virtualbox__intnet: true
  end

  config.vm.define "master3" do |master3|
    master3.vm.box = "matyunin/centos7"
    master3.vm.network "private_network", ip: "10.0.3.23", virtualbox__intnet: true
  end

  config.vm.define "client1" do |client1|
    client1.vm.box = "matyunin/centos7"
    client1.vm.network "private_network", ip: "10.0.3.31", virtualbox__intnet: true
  end

  config.vm.provider "virtualbox" do |vb|
    vb.gui = false
  end
end