Kumogata+Serf - template.rb

template.rb

hosts = [:cthulhu, :hastur, :nyar]

Parameters do
  SerfURL do
    Type "String"
    Default "https://dl.bintray.com/mitchellh/serf/0.4.5_linux_amd64.zip"
  end

  EventHandlerURL do
    Type "String"
    Default "https://gist.githubusercontent.com/winebarrel/9447917/raw/event_handler.rb"
  end
end

Resources do
  hosts.each {|name|
    _(name) do
      Type "AWS::EC2::Instance"

      Properties do
        # amzn-ami-pv-2013.09.2.x86_64-ebs
        ImageId "ami-0d13700c"
        InstanceType "t1.micro"
        KeyName "XXX"

        NetworkInterfaces [
          _{
            DeviceIndex 0
            SubnetId "subnet-XXXXXXXX"
            AssociatePublicIpAddress true
          }
        ]

        UserData do
          Fn__Base64 (<<-EOS).fn_join
            #!/bin/bash
            /opt/aws/bin/cfn-init -s <%= Ref "AWS::StackName" %> -r #{name} --region <%= Ref "AWS::Region" %>
            /opt/aws/bin/cfn-signal -e 0 '<%= Ref "#{name}WaitHandle" %>'
          EOS
        end

        Tags [
          _{
            Key "Name"
            Value name
          }
        ]
      end # Properties

      Metadata do
        AWS__CloudFormation__Init do
          config do
            commands do
              setup do
                command (<<-EOS).fn_join
                  hostname #{name}

                  # Install Serf
                  wget <%= Ref "SerfURL" %> -O /tmp/serf.zip
                  unzip /tmp/serf.zip -d /tmp
                  mv /tmp/serf /usr/bin

                  # Install serf-hosts
                  mkdir -p /usr/libexec/serf
                  wget <%= Ref "EventHandlerURL" %> -O /usr/libexec/serf/event_handler
                  chmod 755 /usr/libexec/serf/event_handler

                  IP_ADDR=`/sbin/ip addr show dev eth0 | awk -F '[ /]+' '/inet /{print $3}'`

                  exec serf agent -node=#{name} \\
                    -bind=$IP_ADDR \\
                    -event-handler=/usr/libexec/serf/event_handler > /var/log/serf.log 2>&1 &

                  <% if "#{name}" != "cthulhu" %>
                  for i in {1..12}; do
                    sleep 5
                    serf join -replay <%= Fn__GetAtt "cthulhu", "PrivateIp" %>
                    [ $? -eq 0 ] && break
                  done
                  <% end %>
                EOS
              end
            end
          end
        end
      end
    end

    _("#{name}WaitHandle") do
      Type "AWS::CloudFormation::WaitConditionHandle"
    end

    _("#{name}WaitCondition") do
      Type "AWS::CloudFormation::WaitCondition"
      DependsOn name

      Properties do
        Handle { Ref "#{name}WaitHandle" }
        Timeout 300
      end
    end
  } # end of each
end

Outputs do
  hosts.each do |name|
    _("#{name}PublicIp") do
      Value { Fn__GetAtt name, "PublicIp" }
    end
  end
end