add Vagrantfile, for testing this script

.gitignore

@@ -0,0 +1 @@
+.vagrant

Vagrantfile

@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+
+# -*- mode: ruby -*-
+# vi: set ft=ruby :
+
+Vagrant.configure('2') do |config|
+
+  config.vm.box = "chaifeng/ubuntu-18.04-docker-18.06"
+
+  config.vm.provider 'virtualbox' do |vb|
+    vb.memory = '1024'
+  end
+
+  ip_prefix="192.168.56"
+
+  config.vm.provision 'docker', type: 'shell', inline: <<-SHELL
+    set -ex
+    if [[ ! -f /etc/docker/daemon.json ]]; then
+      echo '{' >> /etc/docker/daemon.json
+      echo '  "insecure-registries": ["localhost:5000", "#{ip_prefix}.130:5000"]' >> /etc/docker/daemon.json
+      [[ -n "#{ENV['DOCKER_REGISTRY_MIRROR']}" ]] &&
+        echo '  , "registry-mirrors": ["#{ENV['DOCKER_REGISTRY_MIRROR']}"]' >> /etc/docker/daemon.json
+      echo '}' >> /etc/docker/daemon.json
+      if type systemctl &>/dev/null; then
+        systemctl restart docker
+      else
+        service docker restart
+      fi
+    fi
+  SHELL
+
+  config.vm.provision 'ufw-docker', type: 'shell', inline: <<-SHELL
+    set -ex
+    /vagrant/ufw-docker is-installed || {
+      ufw allow OpenSSH
+      ufw allow from #{ip_prefix}.128/28 to any
+
+      yes | ufw enable
+      /vagrant/ufw-docker install
+
+      sed -i -e 's,192\.168\.0\.0/16,#{ip_prefix}.128/28,' /etc/ufw/after.rules
+
+      ufw reload
+
+      ln -s /vagrant/ufw-docker /usr/local/bin/
+    }
+  SHELL
+
+  config.vm.define "master" do |master|
+    master.vm.hostname = "master"
+    master.vm.network "private_network", ip: "#{ip_prefix}.130"
+
+    master.vm.provision "swarm-init", type: 'shell', inline: <<-SHELL
+      set -ex
+      docker run -d -p 5000:5000 --restart=always --name registry registry:2
+      docker swarm init --advertise-addr eth1
+      docker swarm join-token worker --quiet > /vagrant/.vagrant/docker-join-token
+    SHELL
+  end
+
+  1.upto 2 do |ip|
+    config.vm.define "node#{ip}" do | node |
+      node.vm.hostname = "node#{ip}"
+      node.vm.network "private_network", ip: "#{ip_prefix}.#{ 130 + ip }"
+
+      node.vm.provision "swarm-join", type: 'shell', inline: <<-SHELL
+        set -ex
+        [[ -f /vagrant/.vagrant/docker-join-token ]] &&
+        docker swarm join --token "$(</vagrant/.vagrant/docker-join-token)" #{ip_prefix}.130:2377
+      SHELL
+    end
+  end
+end