service

Use the service resource to manage a service.

Syntax

A service resource block manages the state of a service. For example:

service "tomcat" do
  action :start
end

will start the Apache Tomcat service.

The full syntax for all of the properties that are available to the service resource is:

service 'name' do
  init_command               String
  notifies                   # see description
  pattern                    String
  priority                   Integer, String, Hash
  provider                   Chef::Provider::Service
  reload_command             String
  restart_command            String
  service_name               String # defaults to 'name' if not specified
  start_command              String
  status_command             String
  stop_command               String
  subscribes                 # see description
  supports                   Hash
  timeout                    Integer # Microsoft Windows only
  action                     Symbol # defaults to :nothing if not specified
end

where

• service is the resource; depending on the platform, more specific providers are run: Chef::Provider::Service::Init, Chef::Provider::Service::Init::Debian, Chef::Provider::Service::Upstart, Chef::Provider::Service::Init::Freebsd, Chef::Provider::Service::Init::Gentoo, Chef::Provider::Service::Init::Redhat, Chef::Provider::Service::Solaris, Chef::Provider::Service::Windows, or Chef::Provider::Service::Macosx
• name is the name of the resource block; when the path property is not specified, name is also the path to the directory, from the root
• :action identifies the steps the chef-client will take to bring the node into the desired state
• init_command, pattern, priority, provider, reload_command, restart_command, service_name, start_command, status_command, stop_command, supports, and timeout are properties of this resource, with the Ruby type shown. See “Properties” section below for more information about all of the properties that may be used with this resource.

Actions

This resource has the following actions:

:disable

Disable a service.

:enable

Enable a service at boot.

:nothing

Default. Do nothing with a service.

:reload

Reload the configuration for this service.

:restart

Restart a service.

:start

Start a service, and keep it running until stopped or disabled.

:stop

Stop a service.

Properties

This resource has the following properties:

ignore_failure

Ruby Types: TrueClass, FalseClass

Continue running a recipe if a resource fails for any reason. Default value: false.

init_command

Ruby Type: String

The path to the init script that is associated with the service. Use init_command to prevent the need to specify overrides for the start_command, stop_command, and restart_command properties. When this property is not specified, the chef-client will use the default init command for the service provider being used.

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 notifiy 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:

:delayed

Default. Specifies that a notification should be queued up, and then executed at the very 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

pattern

Ruby Type: String

The pattern to look for in the process table. Default value: service_name.

priority

Ruby Types: Integer, String, Hash

Debian platform only. The relative priority of the program for start and shutdown ordering. May be an integer or a Hash. An integer is used to define the start run levels; stop run levels are then 100-integer. A Hash is used to define values for specific run levels. For example, { 2 => [:start, 20], 3 => [:stop, 55] } will set a priority of twenty for run level two and a priority of fifty-five for run level three.

provider

Ruby Type: Chef Class

Optional. Explicitly specifies a provider. See “Providers” section below for more information.

reload_command

Ruby Type: String

The command used to tell a service to reload its configuration.

restart_command

Ruby Type: String

The command used to restart a service.

retries

Ruby Type: Integer

The number of times to catch exceptions and retry the resource. Default value: 0.

retry_delay

Ruby Type: Integer

The retry delay (in seconds). Default value: 2.

service_name

Ruby Type: String

The name of the service. Default value: the name of the resource block See “Syntax” section above for more information.

start_command

Ruby Type: String

The command used to start a service.

status_command

Ruby Type: String

The command used to check the run status for a service.

stop_command

Ruby Type: String

The command used to stop a service.

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.

A timer specifies the point during the chef-client run at which a notification is run. The following timers are available:

:delayed

Default. Specifies that a notification should be queued up, and then executed at the very 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

supports

Ruby Type: Hash

A list of properties that controls how the chef-client is to attempt to manage a service: :restart, :reload, :status. For :restart, the init script or other service provider can use a restart command; if :restart is not specified, the chef-client attempts to stop and then start a service. For :reload, the init script or other service provider can use a reload command. For :status, the init script or other service provider can use a status command to determine if the service is running; if :status is not specified, the chef-client attempts to match the service_name against the process table as a regular expression, unless a pattern is specified as a parameter property. Default value: { :restart => false, :reload => false, :status => false } for all platforms (except for the Red Hat platform family, which defaults to { :restart => false, :reload => false, :status => true }.)

timeout

Ruby Type: Integer

Microsoft Windows platform only. The amount of time (in seconds) to wait before timing out. Default value: 60.

Providers

Where a resource represents a piece of the system (and its desired state), a provider defines the steps that are needed to bring that piece of the system from its current state into the desired state.

The chef-client will determine the correct provider based on configuration data collected by Ohai at the start of the chef-client run. This configuration data is then mapped to a platform and an associated list of providers.

Generally, it’s best to let the chef-client choose the provider, and this is (by far) the most common approach. However, in some cases, specifying a provider may be desirable. There are two approaches:

• Use a more specific short name—yum_package "foo" do instead of package "foo" do, script "foo" do instead of bash "foo" do, and so on—when available
• Use the provider property within the resource block to specify the long name of the provider as a property of a resource. For example: provider Chef::Provider::Long::Name

The service resource does not have service-specific short names. This is because the chef-client identifies the platform at the start of every chef-client run based on data collected by Ohai. The chef-client looks up the platform in the provider_mapping.rb file, and then determines the correct provider for that platform. In certain situations, such as when more than one init system is available on a node, a specific provider may need to be identified by using the provider attribute and the long name for that provider.

This resource has the following providers:

Chef::Provider::Service::Init, service

When this short name is used, the chef-client will determine the correct provider during the chef-client run.

Chef::Provider::Service::Init::Debian, service

The provider for the Debian and Ubuntu platforms.

Chef::Provider::Service::Upstart, service

The provider that is used when Upstart is available on the platform.

Chef::Provider::Service::Init::Freebsd, service

The provider for the FreeBSD platform.

Chef::Provider::Service::Init::Gentoo, service

The provider for the Gentoo platform.

Chef::Provider::Service::Init::Redhat, service

The provider for the Red Hat and CentOS platforms.

Chef::Provider::Service::Solaris, service

The provider for the Solaris platform.

Chef::Provider::Service::Windows, service

The provider for the Microsoft Windows platform.

Chef::Provider::Service::Macosx, service

The provider for the Mac OS X platform.

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.

Start a service

service 'example_service' do
  action :start
end

Start a service, enable it

service 'example_service' do
  supports :status => true, :restart => true, :reload => true
  action [ :enable, :start ]
end

Use a pattern

service 'samba' do
  pattern 'smbd'
  action [:enable, :start]
end

Use the :nothing common action

service 'memcached' do
  action :nothing
  supports :status => true, :start => true, :stop => true, :restart => true
end

Use the supports common attribute

service 'apache' do
  supports :restart => true, :reload => true
  action :enable
end

Use the supports and providers common attributes

service 'some_service' do
  provider Chef::Provider::Service::Upstart
  supports :status => true, :restart => true, :reload => true
  action [ :enable, :start ]
end

Manage a service, depending on the node platform

service 'example_service' do
  case node['platform']
  when 'centos','redhat','fedora'
    service_name 'redhat_name'
  else
    service_name 'other_name'
  end
  supports :restart => true
  action [ :enable, :start ]
end

Change a service provider, depending on the node platform

service 'example_service' do
  case node['platform']
  when 'ubuntu'
    if node['platform_version'].to_f >= 9.10
      provider Chef::Provider::Service::Upstart
    end
  end
  action [:enable, :start]
end

Reload a service using a template

To reload a service based on a template, use the template and service resources together in the same recipe, similar to the following:

template '/tmp/somefile' do
  mode '0755'
  source 'somefile.erb'
end

service 'apache' do
  supports :restart => true, :reload => true
  action :enable
  subscribes :reload, 'template[/tmp/somefile]', :immediately
end

where the subscribes notification is used to reload the service using the template specified by the template resource.

Enable a service after a restart or reload

service 'apache' do
  supports :restart => true, :reload => true
  action :enable
end

Set an IP address using variables and a template

The following example shows how the template resource can be used in a recipe to combine settings stored in an attributes file, variables within a recipe, and a template to set the IP addresses that are used by the Nginx service. The attributes file contains the following:

default['nginx']['dir'] = '/etc/nginx'

The recipe then does the following to:

• Declare two variables at the beginning of the recipe, one for the remote IP address and the other for the authorized IP address
• Use the service resource to restart and reload the Nginx service
• Load a template named authorized_ip.erb from the /templates directory that is used to set the IP address values based on the variables specified in the recipe

node.default['nginx']['remote_ip_var'] = 'remote_addr'
node.default['nginx']['authorized_ips'] = ['127.0.0.1/32']

service 'nginx' do
  supports :status => true, :restart => true, :reload => true
end

template 'authorized_ip' do
  path "#{node['nginx']['dir']}/authorized_ip"
  source 'modules/authorized_ip.erb'
  owner 'root'
  group 'root'
  mode '0755'
  variables(
    :remote_ip_var => node['nginx']['remote_ip_var'],
    :authorized_ips => node['nginx']['authorized_ips']
  )

  notifies :reload, 'service[nginx]', :immediately
end

where the variables property tells the template to use the variables set at the beginning of the recipe and the source property is used to call a template file located in the cookbook’s /templates directory. The template file looks similar to:

geo $<%= @remote_ip_var %> $authorized_ip {
  default no;
  <% @authorized_ips.each do |ip| %>
  <%= "#{ip} yes;" %>
  <% end %>
}

Use a cron timer to manage a service

The following example shows how to install the crond application using two resources and a variable:

# the following code sample comes from the ``cron`` cookbook:
# https://github.com/chef-cookbooks/cron

cron_package = case node['platform']
  when 'redhat', 'centos', 'scientific', 'fedora', 'amazon'
    node['platform_version'].to_f >= 6.0 ? 'cronie' : 'vixie-cron'
  else
    'cron'
  end

package cron_package do
  action :install
end

service 'crond' do
  case node['platform']
  when 'redhat', 'centos', 'scientific', 'fedora', 'amazon'
    service_name 'crond'
  when 'debian', 'ubuntu', 'suse'
    service_name 'cron'
  end
  action [:start, :enable]
end

where

• cron_package is a variable that is used to identify which platforms apply to which install packages
• the package resource uses the cron_package variable to determine how to install the crond application on various nodes (with various platforms)
• the service resource enables the crond application on nodes that have Red Hat, CentOS, Red Hat Enterprise Linux, Fedora, or Amazon Web Services (AWS), and the cron service on nodes that run Debian, Ubuntu, or openSUSE

Restart a service, and then notify a different service

The following example shows how start a service named example_service and immediately notify the Nginx service to restart.

service 'example_service' do
  action :start
  provider Chef::Provider::Service::Init
  notifies :restart, 'service[nginx]', :immediately
end

where by using the default provider for the service, the recipe is telling the chef-client to determine the specific provider to be used during the chef-client run based on the platform of the node on which the recipe will run.

Stop a service, do stuff, and then restart it

The following example shows how to use the execute, service, and mount resources together to ensure that a node running on Amazon EC2 is running MySQL. This example does the following:

• Checks to see if the Amazon EC2 node has MySQL
• If the node has MySQL, stops MySQL
• Installs MySQL
• Mounts the node
• Restarts MySQL

# the following code sample comes from the ``server_ec2``
# recipe in the following cookbook:
# https://github.com/chef-cookbooks/mysql

if (node.attribute?('ec2') && ! FileTest.directory?(node['mysql']['ec2_path']))

  service 'mysql' do
    action :stop
  end

  execute 'install-mysql' do
    command "mv #{node['mysql']['data_dir']} #{node['mysql']['ec2_path']}"
    not_if do FileTest.directory?(node['mysql']['ec2_path']) end
  end

  [node['mysql']['ec2_path'], node['mysql']['data_dir']].each do |dir|
    directory dir do
      owner 'mysql'
      group 'mysql'
    end
  end

  mount node['mysql']['data_dir'] do
    device node['mysql']['ec2_path']
    fstype 'none'
    options 'bind,rw'
    action [:mount, :enable]
  end

  service 'mysql' do
    action :start
  end

end

where

• the two service resources are used to stop, and then restart the MySQL service
• the execute resource is used to install MySQL
• the mount resource is used to mount the node and enable MySQL

Control a service using the execute resource

Do something like this:

service 'tomcat' do
  action :start
end

and NOT something like this:

execute 'start-tomcat' do
  command '/etc/init.d/tomcat6 start'
  action :run
end

There is no reason to use the execute resource to control a service because the service resource exposes the start_command property directly, which gives a recipe full control over the command issued in a much cleaner, more direct manner.