Quelltext der Seite Cloudcomputing Kochbuch Orchestrierung

== Praxisbeispiel Autoscaling Group mit Loadbalancer ==
Nachfolgend finden Sie noch ein Beispiel einer Umfangreicheren Konfiguration eines Stacks. 
Bei dem ersten Template (Stack.yaml) wird über einen Loadbalancer eine selbsskalierende Gruppe von Instanzen gesteuert, über die ein Webserver bereitgestellt wird. Zusätzlich wird ein Netzwerk und die für den Loadbalancer nötigen Ressourcen (Pool, Monitor, etc) angelegt.
Der Loadbalancer bekommt zum Schluss eine Floating IP zugeteilt und abschließend werden noch die URLs ausgegeben, über welche die Autoscaling Group hoch- bzw. herunter skaliert werden können.

Für die einzelnen Instanzen der Autoscaling Group wurde ein separates Template angelegt (lb_member.yaml), in dem auch gleichzeitig die Konfiguration über ''cloud-config'' erfolgt. Diese Instanzen werden dann als ''Member'' dem Loadbalancer zugeteilt.

'''Stack.yaml'''
<source lang=YAML>
heat_template_version: 2018-08-31
description: A load-balancer webserver

parameters:
  public_net_id:
    type: string
    description: Public network ID
    default: external
  timeout:
    type: number
    description: Timeout for stack creation to finish
    default: 900
  floatingip_ID:
    type: string
    description: Floating IP to associate
  user_key:
    type: string
    description: Key ID or name

resources:
  server_security_group:
    type: OS::Neutron::SecurityGroup
    properties:
      description: Neutron security group rules
      name: kochbuch_security_group
      rules:
      - remote_mode: 'remote_group_id'
        direction: ingress
      - remote_ip_prefix: 0.0.0.0/0
        protocol: icmp
      - remote_ip_prefix: 0.0.0.0/0
        protocol: tcp
        direction: ingress
        port_range_min: 22
        port_range_max: 22
      - remote_ip_prefix: 0.0.0.0/0
        protocol: tcp
        direction: ingress
        port_range_min: 80
        port_range_max: 80

  kochbuch_net:
    type: OS::Neutron::Net
    properties:
      name: kochbuch-net

  kochbuch_sub_net:
    type: OS::Neutron::Subnet
    properties:
      name: kochbuch-sub-net
      network_id: { get_resource: kochbuch_net }
      cidr: 192.168.0.0/24
      gateway_ip: 192.168.0.1
      enable_dhcp: true
      allocation_pools:
        - start: "192.168.0.2"
          end: "192.168.0.50"

  router:
    type: OS::Neutron::Router

  router_gateway:
    type: OS::Neutron::RouterGateway
    properties:
      router_id: { get_resource: router }
      network_id: { get_param: public_net_id }

  router_interface:
    type: OS::Neutron::RouterInterface
    properties:
      router_id: { get_resource: router }
      subnet_id: { get_resource: kochbuch_sub_net }

  monitor:
    type: OS::Octavia::HealthMonitor
    properties:
      delay: 3
      type: HTTP
      http_method: GET
      expected_codes: 200
      timeout: 3
      max_retries: 3
      pool: { get_resource: pool }

  pool:
    type: OS::Octavia::Pool
    properties:
      lb_algorithm: ROUND_ROBIN
      protocol: HTTP
      listener: { get_resource: listener }
      loadbalancer: { get_resource: loadbalancer }

  listener:
    type: OS::Octavia::Listener
    properties:
      loadbalancer: { get_resource: loadbalancer }
      protocol: HTTP
      protocol_port: 80

  loadbalancer:
    type: OS::Octavia::LoadBalancer
    properties:
      vip_subnet: { get_resource: kochbuch_sub_net }

  kochbuch_asg:
    type: OS::Heat::AutoScalingGroup
    properties:
      min_size: 1
      desired_capacity: 3
      max_size: 5
      resource:
        type: lb_member.yaml
        properties:
          user_key: { get_param: user_key }
          security_groups: { get_resource: server_security_group }
          network: { get_resource: kochbuch_net }
          subnet: { get_resource: kochbuch_sub_net }
          pool: {get_resource: pool}

  web_server_scaleup_policy:
    type: OS::Heat::ScalingPolicy
    properties:
      adjustment_type: change_in_capacity
      auto_scaling_group_id: { get_resource: kochbuch_asg }
      cooldown: 60
      scaling_adjustment: 1

  web_server_scaledown_policy:
    type: OS::Heat::ScalingPolicy
    properties:
      adjustment_type: change_in_capacity
      auto_scaling_group_id: { get_resource: kochbuch_asg }
      cooldown: 60
      scaling_adjustment: '-1'

  cpu_alarm_high:
    type: OS::Aodh::GnocchiAggregationByResourcesAlarm
    properties:
      description: Scale up if CPU > 75%
      metric: cpu_util
      aggregation_method: mean
      granularity: 600
      evaluation_periods: 1
      threshold: 75
      resource_type: instance
      comparison_operator: gt
      alarm_actions:
        - str_replace:
            template: trust+url
            params:
              url: { get_attr: [web_server_scaleup_policy, signal_url] }
      query:
        list_join:
          - ''
          - - { '=': { server_group: { get_param: "OS::stack_id" } } }

  cpu_alarm_low:
    type: OS::Aodh::GnocchiAggregationByResourcesAlarm
    properties:
      description: Scale down if CPU < 15%
      metric: cpu_util
      aggregation_method: mean
      granularity: 600
      evaluation_periods: 1
      threshold: 15
      resource_type: instance
      comparison_operator: lt
      alarm_actions:
        - str_replace:
            template: trust+url
            params:
              url: {get_attr: [web_server_scaledown_policy, signal_url]}
      query:
        list_join:
          - ''
          - - { '=': { server_group: { get_param: "OS::stack_id" } } }

  lb_floating_ip:
    type: OS::Neutron::FloatingIPAssociation
    properties:
      floatingip_id: { get_param: floatingip_ID }
      port_id: { get_attr: [loadbalancer, vip_port_id ]}

outputs:
  scale_up_url:
    description: This URL is the webhook to scale up the group.
    value: { get_attr: [web_server_scaleup_policy, alarm_url] }
  scale_dn_url:
    description: This URL is the webhook to scale down the group.
    value: { get_attr: [web_server_scaledown_policy, alarm_url] }
</source>

'''lb_member.yaml'''
<source>
heat_template_version: 2018-08-31

parameters:
  user_key:
    type: string
    description: Key ID or name
    default: uni_pb
  security_groups:
    type: string
    description: Security Group
  network:
    type: string
    description: Network
  subnet:
    type: string
    description: Subnet ID or name
  pool:
    type: string
    description: Pool ID or name

resources:
  dev_config:
    type: OS::Heat::CloudConfig
    properties:
      cloud_config:
        hostname: kochbuch-server
        manage_etc_hosts: localhost
        package_update: true
        package_upgrade: true
        packages:
          - apache2
          - php7.2
        runcmd:
          - "sh -c 'hostname -I > /var/www/html/index.html'"
        final_message: "The system is finally up, after $UPTIME seconds"
  
  web_server:
    type: OS::Nova::Server
    properties:
      flavor: upb-medium
      image: c315dc8d-8a9a-499d-a03e-9988d246bb77
      key_name: { get_param: user_key }
      security_groups:
        - { get_param: security_groups }
      networks: 
        - network: { get_param: network }
        - subnet: { get_param: subnet }
      user_data: { get_resource: dev_config }
      user_data_format: RAW

  member:
    type: OS::Octavia::PoolMember
    properties:
      pool: {get_param: pool}
      address: { get_attr: [web_server, first_address] }
      protocol_port: 80
      subnet: { get_param: subnet }
</source>