machine_batch

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Use the machine_batch resource to explicitly declare a parallel process when building machines.

Warning

This functionality is available with Chef provisioning and is packaged in the Chef development kit. Chef provisioning is a framework that allows clusters to be managed by the chef-client and the Chef server in the same way nodes are managed: with recipes. Use Chef provisioning to describe, version, deploy, and manage clusters of any size and complexity using a common set of tools.

Syntax

The syntax for using the machine_batch resource in a recipe is as follows:

machine_batch 'name' do
  attribute 'value' # see properties section below
  ...
  action :action # see actions section below
end

where

• machine_batch tells the chef-client to use the Chef::Provider::MachineBatch provider during the chef-client run
• name is the name of the resource block
• attribute is zero (or more) of the properties that are available for this resource
• action identifies which steps the chef-client will take to bring the node into the desired state

Actions

This resource has the following actions:

:allocate

:converge

Default.

:converge_only

:destroy

:nothing

Define this resource block to do nothing until notified by another resource to take action. When this resource is notified, this resource block is either run immediately or it is queued up to be run at the end of the Chef Client run.

:ready

:setup

:stop

In-Parallel Processing

In certain situations Chef provisioning will run multiple machine processes in-parallel, as long as each of the individual machine resources have the same declared action. The machine_batch resource is used to run in-parallel processes.

Chef provisioning will processes resources in-parallel automatically, unless:

• The recipe contains complex scripts, such as when a file resource sits in-between two machine resources in a single recipe. In this situation, the resources will be run sequentially
• The actions specified for each individual machine resource are not identical; for example, if resource A is set to :converge and resource B is set to :destroy, then they may not be processed in-parallel

To disable in-parallel processing, add the auto_machine_batch setting to the client.rb file, and then set it to false.

For example, a recipe that looks like:

machine 'a'
machine 'b'
machine 'c'

will show output similar to:

$ CHEF_DRIVER=fog:AWS chef-apply cluster.rb
...
Converging 1 resources
Recipe: @recipe_files::/Users/jkeiser/oc/environments/metal-test-local/cluster.rb
  * machine_batch[default] action converge
    - [a] creating machine a on fog:AWS:862552916454
    - [a]   key_name: "metal_default"
    - [a]   tags: {"Name"=>"a", ...}
    - [a]   name: "a"
    - [b] creating machine b on fog:AWS:862552916454
    - [b]   key_name: "metal_default"
    - [b]   tags: {"Name"=>"b", ...}
    - [b]   name: "b"
    - [c] creating machine c on fog:AWS:862552916454
    - [c]   key_name: "metal_default"
    - [c]   tags: {"Name"=>"c", ...}
    - [c]   name: "c"
    - [b] machine b created as i-eb778fb9 on fog:AWS:862552916454
    - create node b at http://localhost:8889
    -   add normal.tags = nil
    -   add normal.metal = {"location"=>{"driver_url"=>"fog:AWS:862552916454", ...}}
    - [a] machine a created as i-e9778fbb on fog:AWS:862552916454
    - create node a at http://localhost:8889
    -   add normal.tags = nil
    -   add normal.metal = {"location"=>{"driver_url"=>"fog:AWS:862552916454", ...}}
    - [c] machine c created as i-816d95d3 on fog:AWS:862552916454
    - create node c at http://localhost:8889
    -   add normal.tags = nil
    -   add normal.metal = {"location"=>{"driver_url"=>"fog:AWS:862552916454", ...}}
    - [b] waiting for b (i-eb778fb9 on fog:AWS:862552916454) to be ready ...
    - [c] waiting for c (i-816d95d3 on fog:AWS:862552916454) to be ready ...
    - [a] waiting for a (i-e9778fbb on fog:AWS:862552916454) to be ready ...
...
        Running handlers:
        Running handlers complete

        Chef Client finished, 0/0 resources updated in 4.053363945 seconds
    - [c] run 'chef-client -l auto' on c

Running handlers:
Running handlers complete
Chef Client finished, 1/1 resources updated in 59.64014 seconds

At the end, it shows 1/1 resources updated. The three machine resources are replaced with a single machine_batch resource, which then runs each of the individual machine processes in-parallel.

Properties

This resource has the following attributes:

chef_server

Ruby Type: Hash

The URL for the Chef server.

driver

Ruby Type: Chef::Provisioning::Driver

Use to specify the driver to be used for provisioning.

files

…

from_recipe

…

ignore_failure

Ruby Type: true, false | Default Value: false

Continue running a recipe if a resource fails for any reason.

machine_options

…

machines

…

max_simultaneous

…

notifies

Ruby Type: Symbol, ‘Chef::Resource[String]’

A resource may notify another resource to take action when its state changes. Specify a 'resource[name]', the :action that resource should take, and then the :timer for that action. A resource may notify more than one resource; use a notifies statement for each resource to be notified.

A timer specifies the point during the Chef Client run at which a notification is run. The following timers are available:

:before

Specifies that the action on a notified resource should be run before processing the resource block in which the notification is located.

:delayed

Default. Specifies that a notification should be queued up, and then executed at the end of the Chef Client run.

:immediate, :immediately

Specifies that a notification should be run immediately, per resource notified.

The syntax for notifies is:

notifies :action, 'resource[name]', :timer

retries

Ruby Type: Integer | Default Value: 0

The number of times to catch exceptions and retry the resource.

retry_delay

Ruby Type: Integer | Default Value: 2

The retry delay (in seconds).

subscribes

Ruby Type: Symbol, ‘Chef::Resource[String]’

A resource may listen to another resource, and then take action if the state of the resource being listened to changes. Specify a 'resource[name]', the :action to be taken, and then the :timer for that action.

Note that subscribes does not apply the specified action to the resource that it listens to - for example:

file '/etc/nginx/ssl/example.crt' do
   mode '0600'
   owner 'root'
end

service 'nginx' do
   subscribes :reload, 'file[/etc/nginx/ssl/example.crt]', :immediately
end

In this case the subscribes property reloads the nginx service whenever its certificate file, located under /etc/nginx/ssl/example.crt, is updated. subscribes does not make any changes to the certificate file itself, it merely listens for a change to the file, and executes the :reload action for its resource (in this example nginx) when a change is detected.

A timer specifies the point during the Chef Client run at which a notification is run. The following timers are available:

:before

Specifies that the action on a notified resource should be run before processing the resource block in which the notification is located.

:delayed

Default. Specifies that a notification should be queued up, and then executed at the end of the Chef Client run.

:immediate, :immediately

Specifies that a notification should be run immediately, per resource notified.

The syntax for subscribes is:

subscribes :action, 'resource[name]', :timer

Examples

The following examples demonstrate various approaches for using resources in recipes. If you want to see examples of how Chef uses resources in recipes, take a closer look at the cookbooks that Chef authors and maintains: https://github.com/chef-cookbooks.

Set up multiple machines, in-parallel

machine_batch do
  action :setup
  machines 'a', 'b', 'c', 'd', 'e'
end

Converge multiple machines, in-parallel

machine_batch do
  action :converge
  machines 'a', 'b', 'c', 'd', 'e'
end

Stop multiple machines, in-parallel

machine_batch do
  action :stop
  machines 'a', 'b', 'c', 'd', 'e'
end

Destroy multiple machines, in-parallel

machine_batch do
  action :delete
  machines 'a', 'b', 'c', 'd', 'e'
end

Destroy all machines

machine_batch do
  machines search(:node, '*:*').map { |n| n.name }
  action :destroy
end

Converge multiple machine types, in-parallel

The machine_batch resource can be used to converge multiple machine types, in-parallel, even if each machine type has different drivers. For example:

machine_batch do
  machine 'db' do
    recipe 'mysql'
  end
  1.upto(50) do |i|
    machine "#{web}#{i}" do
      recipe 'apache'
    end
  end
end

Set up primary and secondary machines for high availability

machine_batch do
  machines %w(primary secondary web1 web2)
end

machine_batch do
  machine 'primary' do
    recipe 'initial_ha_setup'
  end
end

machine_batch do
  machine 'secondary' do
    recipe 'initial_ha_setup'
  end
end

machine_batch do
  %w(primary secondary).each do |name|
    machine name do
      recipe 'rest_of_setup'
    end
  end
end

Destroy EBS volumes for batch of machines, along with keys

The following example destroys an Amazon Elastic Block Store (EBS) volume for the specified batch of machines, along with any associated public and/or private keys:

['ref-volume-ebs', 'ref-volume-ebs-2'].each { |volume|
  aws_ebs_volume volume do
    action :destroy
  end
}

machine_batch do
  machines 'ref-machine-1', 'ref-machine-2'
  action :destroy
end

aws_key_pair 'ref-key-pair-ebs' do
  action :destroy
end

Define subnets for a batch of machines on Amazon AWS

require 'chef/provisioning/aws_driver'

with_driver 'aws::eu-west-1'
  aws_vpc 'provisioning-vpc' do
    cidr_block '10.0.0.0/24'
    internet_gateway true
    main_routes '0.0.0.0/0' => :internet_gateway
  end

  aws_subnet 'provisioning-vpc-subnet-a' do
    vpc 'provisioning-vpc'
    cidr_block '10.0.0.0/26'
    availability_zone 'eu-west-1a'
    map_public_ip_on_launch true
  end

  aws_subnet 'provisioning-vpc-subnet-b' do
    vpc 'provisioning-vpc'
    cidr_block '10.0.0.128/26'
    availability_zone 'eu-west-1a'
    map_public_ip_on_launch true
  end

machine_batch do
  machines %w(mario-a mario-b)
  action :destroy
end

machine_batch do
  machine 'mario-a' do
    machine_options bootstrap_options: { subnet: 'provisioning-vpc-subnet-a' }
  end

  machine 'mario-b' do
    machine_options bootstrap_options: { subnet: 'provisioning-vpc-subnet-b' }
  end
end

aws_security_group 'provisioning-vpc-security-group' do
  inbound_rules [
    {:port => 2223, :protocol => :tcp, :sources => ['10.0.0.0/24'] },
    {:port => 80..100, :protocol => :udp, :sources => ['1.1.1.0/24'] }
  ]
  outbound_rules [
    {:port => 2223, :protocol => :tcp, :destinations => ['1.1.1.0/16'] },
    {:port => 8080, :protocol => :tcp, :destinations => ['2.2.2.0/24'] }
  ]
  vpc 'provisioning-vpc'
end