wordpress_with_ha.yaml

# http://docs.openstack.org/developer/heat/template_guide/hot_spec.html#heat-template-version
heat_template_version: 2014-10-16

description: >
  This template creates a sigle instance running wordpress, and a monitor that will kill and start a new instance if
  it finds that the running instance is not being responsive enough. Note that all resources that are dependent
  on the instance are also killed and rebuilt!
  Note that it uses a deprecated resource type (HARestarter).


parameters:

 # First off, the parameters that affect the environment
  key_name:
    description: Name of an existing KeyPair to enable SSH access to the instances
    type: string

  instance_type:
    description: The NeCTAR flavour the webserver is to run on
    type: string
    default: m2.xsmall
    constraints:
      - allowed_values: [m2.xsmall, m2.small, m1.small]
        description:
          Must be a valid NeCTAR flavour with 10G drive, limited to the smaller ones available

  image_id:
     description: A NeCTAR fedora image
     type: string
     default: d3bae233-a0cd-4533-a710-d7aa9de0a4b7

  # Then the installation specific parameters
  db_name:
    default: wordpress
    description: The WordPress database name
    type: string
    constraints:
      - length: { min: 6, max: 16}
        description: The database name must be between 6 to 16 characters in length.
      - allowed_pattern: '[a-zA-Z][a-zA-Z0-9]*'
        description: Must begin with a letter and contain only alphanumeric characters.
        
  db_username:
    description: The WordPress database admin account username
    default: bestAdminEver
    type: string
    constraints:
      - length: { min: 6, max: 16}
        description: The user name must be between 6 to 16 characters in length.
      - allowed_pattern: '[a-zA-Z][a-zA-Z0-9]*'
        description: Must begin with a letter and contain only alphanumeric characters.

  hup_poll_interval:
    default: '1'
    type: string
    description: Interval for cfn-hup


resources:

  # http://docs.openstack.org/developer/heat/template_guide/openstack.html#OS::Heat::RandomString
  db_password:
    type: OS::Heat::RandomString

  # http://docs.openstack.org/developer/heat/template_guide/openstack.html#OS::Heat::RandomString
  db_root_password:
    type: OS::Heat::RandomString

  # http://docs.openstack.org/developer/heat/template_guide/cfn.html#AWS::IAM::User
  cfn_user:
    type: AWS::IAM::User
    properties:
      Policies: [ { get_resource: access_policy }]

  # http://docs.openstack.org/developer/heat/template_guide/cfn.html#AWS::IAM::AccessKey
  web_server_access_key:
    type: AWS::IAM::AccessKey
    properties:
      UserName: { get_resource: cfn_user }

  # Deprecated!
  # http://docs.openstack.org/hot-reference/content/OS__Heat__HARestarter.html
  web_server_restart_policy:
    type: OS::Heat::HARestarter
    properties:
      InstanceId: { get_resource: wordpress_site }

  cpu_alarm_high:
    type: OS::Ceilometer::Alarm
    properties:
      description: Restart the vm if the cpu_utilization is over 90 for 6 minutes.
      meter_name: cpu_util
      statistic: avg
      period: 330
      evaluation_periods: 1
      threshold: 90
      alarm_actions:
        - { get_attr: [web_server_restart_policy, AlarmUrl] }
      comparison_operator: gt

  http_failure_alarm:
    # http://docs.openstack.org/developer/heat/template_guide/cfn.html#AWS::CloudWatch::Alarm
    type: AWS::CloudWatch::Alarm
    properties:
      AlarmDescription: Restart the wordpress_site if httpd fails > 3 times in 5 minutes
      MetricName: ServiceFailure
      # ServiceFailure
      # MemoryUtilization
      # MemoryUsed
      # MemoryAvailable
      # Heartbeat
      # SwapUtilization
      # SwapUsed
      # DiskSpaceUtilization
      # DiskSpaceUsed
      # DiskSpaceAvailable
      # CPUUtilization
      Statistic: SampleCount
      Period: 300
      EvaluationPeriods: 1
      Threshold: 2
      AlarmActions:
      - { get_attr: [web_server_restart_policy, AlarmUrl] }
      ComparisonOperator: GreaterThanThreshold

  wordpress_site:
    # http://docs.openstack.org/developer/heat/template_guide/cfn.html# AWS::EC2::Instance
    type: AWS::EC2::Instance
    metadata:
      # See http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-init.html
      # This will be placed as JSON at /var/lib/cloud/data/cfn-init-data on the instance
      # heat-cfntools will then unpack and act on it.
      # For more see: https://wiki.openstack.org/wiki/Heat/ApplicationDeployment
      AWS::CloudFormation::Init:
        config:
          files:
            # required to communicate with OpenStack
            /etc/cfn/cfn-credentials:
              content:
                str_replace:
                  template: |
                    AWSAccessKeyId=WebAccessKey
                    AWSSecretKey=WebSecretKey
                  params:
                    WebAccessKey: { get_resource: web_server_access_key }
                    WebSecretKey: { get_attr: [ web_server_access_key, SecretAccessKey ] }
              mode: '000400'
              owner: root
              group: root
            # configuration for the process that will install and monitor services, and call the hooks.
            /etc/cfn/cfn-hup.conf:
              content:
                str_replace:
                  template: |
                    [main]
                    stack=StackName
                    credential-file=/etc/cfn/cfn-credentials
                    region=ap-southeast-1
                    interval=Interval
                  params:
                    StackName: { get_param: 'OS::stack_name' }
                    Interval: { get_param: hup_poll_interval }
              mode: '000400'
              owner: root
              group: root
            # The hook that will report a service failure
            /etc/cfn/notify-on-httpd-restarted:
              content: |
                #!/bin/sh
                /opt/aws/bin/cfn-push-stats --service-failure
              mode: '000700'
              owner: root
              group: root
            # call the process at a regular interval (for monitoring and possible hook calling)
            /tmp/cfn-hup-crontab.txt:
              content: |
                MAIL=""
                * * * * * /opt/aws/bin/cfn-hup -f
              mode: '000600'
              owner: root
              group: root
            # a file required to configure mysql
            /tmp/setup.mysql:
              content:
                str_replace:
                  template: |
                    CREATE DATABASE db_name;
                    GRANT ALL PRIVILEGES ON db_name .* TO 'db_username'@'localhost' IDENTIFIED BY 'db_password';
                    FLUSH PRIVILEGES;
                    EXIT
                  params:
                    db_name: { get_param: db_name }
                    db_password: { get_resource: db_password }
                    db_username: { get_param: db_username }
              mode: '000644'
              owner: root
              group: root
            # The hook to call if the any of the services are restarted.
            /etc/cfn/hooks.conf:
              content: |
                [cfn-http-restarted]
                triggers=service.restarted
                path=Resources.wordpress_site.Metadata
                action=/etc/cfn/notify-on-httpd-restarted
                runas=root
              mode: '000400'
              owner: root
              group: root
          # the following packages will be installed
          packages:
            yum:
              cronie: []
              mariadb: []
              mariadb-server: []
              httpd: []
              wordpress: []
          # and the following services will be run
          services:
            systemd:
              mysqld: { enabled: true, ensureRunning: true }
              httpd: { enabled: true, ensureRunning: true }
              crond: { enabled: true, ensureRunning: true }
    properties:
      ImageId: { get_param: image_id }
      InstanceType: { get_param:  instance_type }
      KeyName: { get_param:  key_name }
      UserData:
        str_replace:
          template: |
            #!/bin/bash -v
            # Helper function
            function error_exit
            {
              /opt/aws/bin/cfn-signal -e 1 -r "$1" 'wait_handle'
              exit 1
            }
            echo "stack_name wordpress_site stack_region" > /root/args.txt
            /opt/aws/bin/cfn-init -s stack_name -r wordpress_site --access-key access_key --secret-key secret_key --region stack_region || error_exit 'Failed to run cfn-init'
            # Setup database root password and create a user
            mysqladmin -u root password db_root_password  || error_exit 'Failed to initialize root password'
            mysql -u root --password=db_root_password < /tmp/setup.mysql  || error_exit 'Failed to create database.'
            sed -i "/Deny from All/d" /etc/httpd/conf.d/wordpress.conf
            sed -i "s/Require local/Require all granted/" /etc/httpd/conf.d/wordpress.conf
            sed -i s/database_name_here/db_name/ /etc/wordpress/wp-config.php
            sed -i s/username_here/db_user/ /etc/wordpress/wp-config.php
            sed -i s/password_here/db_password/ /etc/wordpress/wp-config.php
            systemctl restart httpd.service
            # install cfn-hup crontab
            crontab /tmp/cfn-hup-crontab.txt
            /opt/aws/bin/cfn-signal -e 0 -r "Wiki server setup complete" 'wait_handle'
          params:
            stack_name:  { get_param: 'OS::stack_name' }
            stack_region: ap-southeast-1
            access_key: { get_resource: web_server_access_key }
            secret_key: { get_attr: [web_server_access_key, SecretAccessKey] }
            wait_handle: { get_resource: wait_handle }
            db_root_password: { get_resource: db_root_password }
            db_password: { get_resource: db_password }
            db_user: { get_param: db_username }
            db_name: { get_param: db_name }

  access_policy:
    # http://docs.openstack.org/developer/heat/template_guide/openstack.html#OS::Heat::AccessPolicy
    type: OS::Heat::AccessPolicy
    properties:
      AllowedResources: [ "wordpress_site" ]

  # http://docs.openstack.org/developer/heat/template_guide/cfn.html#AWS::CloudFormation::WaitConditionHandle
  wait_handle:
    type: 'AWS::CloudFormation::WaitConditionHandle'

  # http://docs.openstack.org/developer/heat/template_guide/cfn.html#AWS::CloudFormation::WaitCondition
  wait_condition:
    type: AWS::CloudFormation::WaitCondition
    depends_on: wordpress_site
    properties:
      Handle: { get_resource: wait_handle }
      Count: 1
      # Give it 11 minutes: there's a lot going on...
      Timeout: 700


outputs:

  restart_url:
    description: The Restart URL
    value: { get_attr: [web_server_restart_policy, AlarmUrl] }

  url:
    description: The URL of the website
    value:
      str_replace:
        template: http://ip_address/wordpress
        params:
          ip_address: { get_attr: [wordpress_site, PublicIp] }