Create the Template

The next step is to create a template yaml file with the definitions to deploy a stack with an Apache Web Server.

Refer to the Template Syntax section in this document for reference.

Create a new template file

Using your preferred text editor create a new template yaml file. Add the following statements, feel free to substitute values as appropriate.

template_author: Gary Forghetti
template_version: "1.00"
template_name: "Apache Web Server on Windows using Chef"
description: "Deploys an Apache Server on Windows using Chef"
long_description: This blueprint deploys a stack with an Apache Web Server on a windows machine. This blueprint has auto scaling and auto healing.

imports:
  - base_types.yaml                                                   # Import the DCM base type definitions that are referenced in this template

Define topology_template and inputs

topology_template:

  inputs:

Define AccountRegionSelector

The next step is to define a AccountRegionSelector to allow the Dell Cloud Manager console end user the ability to select the cloud, region and data center for launching the server in the stack.

  ################################################################################################################################################
  # This defines the AccountRegionSelector which allows the user to select the Cloud, Region and Datacenter
  ################################################################################################################################################
  account_region_zone_selector:                                     # Define the section for the Cloud, Region and Datacenter selection boxes
    type: dcm.inputs.AccountRegionSelector                          # Input type is dcm.inputs.accountRegionSelector 
    properties:
      regions:                                                      # Define the Cloud and Regions
        "Amazon":                                                   # Amazon
          "us-east-1": [ ]                                          # All data centers for the us-east-1 region
          "us-west-1": ["us-west-1a", "us-west-1c"]
          "us-west-2": ["us-west-2a", "us-west-2b", "us-west-2c"]
          "eu-west-1": ["eu-west-1a", "eu-west-1c"]

Define Product Selector

The next step is to define a Product selector to allow the Dell Cloud Manager console end user the ability to select the server product for launching the server(s) in the stack. This example will use the Amazon cloud and a subset of the regions and server products. An Windows 2012 R2 machine image will be defined in the template to be used for creating the server.

Note

If you do not have access to the Amazon cloud or wish to use a different cloud provider’s cloud that Dell Cloud Manager supports, you will need to make the necessary changes below for the cloud, region(s), image(s) and products.

Add the statements to the yaml file to define the inputs product_selector. The inputs: statement must be indented inside the topology_template: statement. Refer to the Product Selector section in this document for reference.

    ################################################################################################################################################
    # This defines the Product selector which allows the user to select the server product size
    ################################################################################################################################################
    product_selector:                                             # Define the product selector so the user can select the cloud and region
      type: dcm.inputs.Product
      properties:
        accountRegionSelector: account_region_zone_selector       # This connects the AccountRegionSelector to the Product selector
        platform: WINDOWS                                         # Virtual machine images are Windows
        architecture: I64                                         # 64 bit images
        productMappings:
          "Amazon":                                               # Amazon cloud
            "us-east-1":                                          # us-east-1 Region
              image: "ami-3f0c4628"                               # The AWS machine image identitier for the Windows 2012 R2 image in this region
              products: ['t1.micro', 'm1.small', 'm1.medium']     # The virtual machine product sizes for this region
            "us-west-1":                                          # us-west-1 Region
              image: "ami-123c7472"                               # The AWS machine image identitier for the Windows 2012 R2 image in this region
              products: ['t1.micro', 'm1.small', 'm1.medium']     # The virtual machine product sizes for this region
            "us-west-2":                                          # us-west-2 Region
              image: "ami-b871aad8"                               # The AWS machine image identitier for the Windows 2012 R2 image in this region
              products: ['t1.micro', 'm1.small', 'm1.medium']     # The virtual machine product sizes for this region
            "eu-west-1":                                          # eu-west-1 Region
              image: "ami-55084526"                               # The AWS machine image identitier for the Windows 2012 R2 image in this region
              products: ['t1.micro', 'm1.small', 'm1.medium']     # The virtual machine product sizes for this region

Define outputs

In this tutorial 2 outputs will be defined and displayed on the Stack details page.

  • IP address of the Apache web server
  • Web URL of the Apache web server

Add the statements to the yaml file to define the outputs. The outputs: statement must be indented inside the topology_template: statement and aligned with the inputs: statement. Refer to the Template Outputs section in this document for reference.

##################################################################################################################################################
# This defines the outputs which appear on the DCM console Stack Overview page
##################################################################################################################################################
outputs:                                                        # Define outputs
  application_group:                                            # Create a Group
    type: dcm.outputs.DisplayGroup                              # It's a displayGroup
    properties:
      displayName: "Apache"                                     # Set the display name for the group containing the outputs which appears on the Stack Overview page

  vm_ip:                                                        # Define an output
    type: string                                                # It's a string output
    description: IP of the server                               # Set the description for the string output
    value: {get_attribute: [web_vm, publicIpAddress]}           # Set the value to the public IP address of the Apache server running in the stack
    properties:
      displayName: Windows Apache Server                        # Set the display name (label) for the string output
      displayGroup: application_group                           # Place this output in the displayGroup named application_group

  link:                                                         # Define another output for the URL of the Apache server
    type: dcm.outputs.Uri                                       # It's a URI output
    value: http://xxxxxxxxxxxxx                                 # Set the initial value
    properties:
      host: {get_attribute: [web_vm, publicIpAddress]}          # Set the hostname/ipaddress of the URI to the public IP address of the server running in the stack
      displayName: Windows Apache Server URL                    # Set the display name (label) for the URI output
      displayGroup: application_group                           # Place this output in the displayGroup named application_group

Define the node templates

The next step is to define 2 node_templates.

  1. A node_template to create a server for the Apache Web server.
  2. A node_template to install the Apache Web server using Chef.

Define the server

Add the statements to define the server. In this example the server name will be hardcoded to be apache-server. The remaining server properties will be retrieved from the corresponding properties derived from the product_selector and the Dell Cloud Manager console end user’s Launch Blueprint selections. Refer to the Server node section in this document for reference.

node_templates:

  ##################################################################################################################################################
  # This node_template defines a virtual machine named "web_vm" which will host the Apache Web Server
  ##################################################################################################################################################
  web_vm:
    type: dcm.nodes.Server
    properties:
      name: "web"
      cloud: { get_input: [account_region_zone_selector, cloud] }              # Retrieve cloud from the AccountRegionSelector
      cloudAccountId: { get_input: [account_region_zone_selector, accountId] } # Retrieve the cloud account ID from the AccountRegionSelector
      region: { get_input: [account_region_zone_selector, region] }            # Retrieve region from the AccountRegionSelector
      zone: { get_input: [account_region_zone_selector, zone] }                # Retrieve zone from the AccountRegionSelector
      platform: { get_input: [product_selector, platform] }                    # Retrieve platform from the Product selector
      architecture: { get_input: [product_selector, architecture] }            # Retrieve architecture from the Product selector
      product: { get_input: [product_selector, product] }                      # Retrieve product from the Product selector
      image: { get_input: [product_selector, image] }                          # Retrieve machine from the Product selector
      serverProductId: { get_input: [product_selector, serverProductId] }      # Retrieve server product id from the Product selector
      startupScript:  |
        ###########################################################################################################################################
        # Install the Dell Cloud Manager agent, point it to the Dell Cloud Manager server and start it.
        ###########################################################################################################################################
        <powershell>

        ###########################################################################################################################################
        # Extract the hostname/ip address and port from the DCM variable ${dcm.callback.url}.
        ###########################################################################################################################################
        $callback_url = "${dcm.callback.url}"
        $host_port = ${callback_url}.TrimStart("wss://").TrimEnd("/agentManager").Split(":", 2)
        $host_name = ${host_port}[0]
        $port = ${host_port}[1]
        if (${port} -eq ${null}) {
          $port = 443
        }

        ###########################################################################################################################################
        # Download the DCM Windows Agent
        ###########################################################################################################################################
        Invoke-WebRequest "http://windows.stable.agent.enstratius.com/DCM.Agent.Setup-latest.msi" -OutFile "c:\windows\temp\dcm_agent.msi"

        ###########################################################################################################################################
        # Install the Windows DCM Agent.  Note: the backtick character (`) can be used to split a command in powershell into multiple lines
        ###########################################################################################################################################
        msiexec /i "c:\windows\temp\dcm_agent.msi" /log "c:\windows\temp\dcm_agent_install.log" `
        /q INSTALLFOLDER="c:\Enstratius\" INSTALL_ENVIRONMENT="Staging" SERVER_ADDRESS=${host_name} `
        SERVER_PORT=${port} CLOUD_PROVIDER="Amazon" | Out-Null

        ###########################################################################################################################################
        # Start the DCM Agent
        ###########################################################################################################################################
        start-service DCMAgent
        </powershell>

  requirements:                                                 # This virtual machine node has a requirement on the firewall
    - firewall: vm_firewall_rules
      relationship_type: tosca.relationships.DependsOn

Define Chef for Apache

Add the statements to define the Chef node to install the Apache Web server.

Attention

The chefServer: value must exactly match the name of the Chef Account you configured in Dell Cloud Manager.

Refer to the Chef section in this document for reference.

########################################################################################################################################a##########
# This node_template will result in Chef installing the Apache Web Server on the launched virtual machine named "web_vm"
########################################################################################################################################a##########
chef_apache:
  type: dcm.nodes.Chef                                            # This is a Chef node
  properties:
    chefServer: "ACME Chef"                                       # Name of the Chef Server Account defined to the Dell Cloud Manager Server
    environment: "_default"                                       # Chef environment
    roles: ['ACME-Webserver']                                     # Chef role which contains the cookbooks and recipes to install Apache
  requirements:
    - host: web_vm                                                # This requires (is "HostedOn") the Server defined in the template named "web_vm"
      relationship_type: tosca.relationships.HostedOn

Define the Firewall

Add the statements to define the firewall vm_firewall_rules. Define a rule to open HTTP port 80

Refer to the FirewallGroup node section in this document for reference.

###################################################################################################################################################
# This node_template defines a firewall which opens the HTTP port 80 and HTTPS port 443
###################################################################################################################################################
vm_firewall_rules:
  type: dcm.nodes.FirewallGroup                                              # This is a firewall
  properties:                                                                # Retrieve the cloud properties from the "inputs"
    name: "web-server-firewall"                                              # Set the firewall name
    cloud: { get_input: [account_region_zone_selector, cloud] }              # Retrieve the cloud from the AccountRegionSelector
    cloudAccountId: { get_input: [account_region_zone_selector, accountId] } # Retrieve the cloud account ID from the AccountRegionSelector
    region: { get_input: [account_region_zone_selector, region] }            # Retrieve the region from the AccountRegionSelector
    zone: { get_input: [account_region_zone_selector, zone] }                # Retrieve the zone from the AccountRegionSelector
    rules:
      - remote_ip_prefix: 0.0.0.0/0
        port: 80                                                             # Allow port 80 (HTTP) from Anywhere (0.0.0.0/0)
      - remote_ip_prefix: 0.0.0.0/0
        port: 443                                                            # Allow port 443 (HTTPS) from Anywhere (0.0.0.0/0)

Define Auto Scaling Policy

In this tutorial 2 auto scaling policies will be defined to auto scale the Apache Web Server. Refer to the Auto scaling section in this document for reference.

  • A scale up will be performed when the last 3 consecutive periods of cpu idle time are less than 20%.
  • A scale down will be performed when the last 2 consecutive periods of cpu idle time are greate than 80%.
  ###################################################################################################################################################
  # This group defines the auto scaling and auto healing policies for the Apache Web server (web_vm)
  ###################################################################################################################################################
  groups:
    scaling_and_healing_group:
      members: [web_vm]                            # The node_template with the statement named "web_vm" is in this group
      properties:
        instances: 1                               # Launch 1 server when the stack is started
        minInstances: 1                            # The minimum number of servers
        maxInstances: 5                            # The maximum number of servers
        coolDown: 300                              # The number of seconds to wait before performing a auto scale or auto repair operation.

      policies:
        # This scale up policy will perform a scale up when the last 3 periods of idle time reported are < 20%
        scale_up_on_cpu:
          type: dcm.policy.types.BasicPolicy
          actions: [scale_up]                      # The scale_up action is defined in the actions: section of the template
          measurement: cpu_idle_time               # The cpu_idle_time label is defined in the measurements: section of the template
          criterion: less_than_20                  # The less_than_20 is a label defined in the criteria: section of the template

        # This scale down policy will perform a scale down when the last 2 periods of idle time reported are > 80%
        scale_down_on_cpu:
          type: dcm.policy.types.BasicPolicy
          actions: [scale_down]                    # The scale_down action is defined in the actions: section of the template
          measurement: cpu_idle_time               # The cpu_idle_time label is defined in the measurements: section of the template
          criterion: more_than_80                  # The more_than_80 is a label defined in the criteria: section of the template

      # Actions define the details of the various actions that could be taken.
      actions:
        scale_up:                                  # The scale_up action label is referenced in the policy in the actions[] statement
          type: dcm.policy.action.ScaleUpGroup
          properties:
            instances: 1                           # The number of resources to scale up on a scale_up action
            changeType: ADD                        # Add resource(s) on a scale_up action
            recordTask: RESOURCES_CHANGE           # Check to see if the scale up action would actually create a new resource, 
                                                   # or a scale-down operation would actually destroy a resource before creating a task to perform the action.

        scale_down:                                # The scale_down action label is referenced in the policy in the actions[] statement
          type: dcm.policy.action.ScaleDownGroup
          properties:
            instances: 1                           # The number of resources to scale down on a scale_down action 
            changeType: REMOVE                     # Remove resource(s) on a scale_down action
            recordTask: ALWAYS                     # Always attempt to perform a scale up or scale down action when the policy determines the actions should occur.
                                                   # Do not check the minInstances and maxInstances limits beforehand.

          type: dcm.policy.action.ReplaceResource                                           

      # Measurements define the "measurements" used to determine when to perform the actions
      measurements:
        cpu_idle_time:                             # The cpu_idle_time measurements label is referenced in the policy in a measurements: statement
        # The Dell Cloud Manager agent will collect and store the last 15 samples of cpu %idle time measured in 30-second intervals
          type: dcm.policy.measurement.CpuIdle
          properties:
            period: 30                             # Take a measurement every 30 seconds
            count: 15                              # Take 15 measurements

      # Criteria specify the "criteria" which is used along with the measurements to determine when to perform the actions
      criteria:
        less_than_20:                              # The less_than_20 criteria label is referenced in the policy in a criterion: statement
          type: dcm.policy.criteria.SeriesLessThan
          properties:
            count: 3                               # 3 consecutive periods 
            threshold: 20                          # Threshold is 20% 

        more_than_80:                              # The more_than_80 criteria label is referenced in the policy in a criterion: statement 
          type: dcm.policy.criteria.SeriesMoreThan
          properties: 
            count: 2                               # 2 consecutive periods
            threshold: 80                          # Threshold is 80%

Define Auto Healing Policy

Now lets add an auto healing policy to the template.

Add the following statements inside the policy: section and align them with the two scaling policies.

repair_on_status:
  type: dcm.policy.types.BasicPolicy
  measurement: cloud_reported_status
  criterion: check_fails
  actions: [repair]

Add the following statements inside the actions: section and align it with the two scaling actions.

repair:                                    # This auto healing action will terminate a degraded resource and then create a new resource
  type: dcm.policy.action.ReplaceResource

Add the following statements inside the measurements: section and align them with the two scaling measurements.

cloud_reported_status:
  type: dcm.policy.measurement.ResourceActive

resource_status:
  type: dcm.policy.measurement.ResourceStatus

Lastly add the following statements inside the criteria: section and align them with the two scaling criteria.

check_fails:                               # This is the criteria for auto healing
  type: dcm.policy.criteria.False          # "False" tells the policy to perform the action in the policy if the measurement result matches "False".