dsc_resource Resource
This page is generated from the Chef Infra Client source code.To suggest a change, edit the dsc_resource.rb file and submit a pull request to the Chef Infra Client repository.
Windows PowerShell is a task-based command-line shell and scripting language developed by Microsoft. Windows PowerShell uses a document-oriented approach for managing Windows-based machines, similar to the approach that is used for managing Unix and Linux-based machines. Windows PowerShell is a tool-agnostic platform that supports using Chef for configuration management.
Desired State Configuration (DSC) is a feature of Windows PowerShell that provides a set of language extensions, cmdlets, and resources that can be used to declaratively configure software. DSC is similar to Chef, in that both tools are idempotent, take similar approaches to the concept of resources, describe the configuration of a system, and then take the steps required to do that configuration. The most important difference between Chef and DSC is that Chef uses Ruby and DSC is exposed as configuration data from within Windows PowerShell.
The dsc_resource resource allows any DSC resource to be used in a recipe, as well as any custom resources that have been added to your Windows PowerShell environment. Microsoft frequently adds new resources to the DSC resource collection.
Using the dsc_resource has the following requirements:
Windows Management Framework (WMF) 5.0 (or higher)
The dsc_resource resource can only use binary- or script-based resources. Composite DSC resources may not be used.
This is because composite resources aren’t “real” resources from the perspective of the Local Configuration Manager (LCM). Composite resources are used by the “configuration” keyword from the
PSDesiredStateConfiguration
module, and then evaluated in that context. When using DSC to create the configuration document (the Managed Object Framework (MOF) file) from the configuration command, the composite resource is evaluated. Any individual resources from that composite resource are written into the Managed Object Framework (MOF) document. As far as the Local Configuration Manager (LCM) is concerned, there is no such thing as a composite resource. Unless that changes, the dsc_resource resource and/orInvoke-DscResource
command cannot directly use them.
Warning
New in Chef Infra Client 12.2.
Syntax
A dsc_resource resource block allows DSC resources to be used in a
Chef recipe. For example, the DSC Archive
resource:
Archive ExampleArchive {
Ensure = "Present"
Path = "C:\Users\Public\Documents\example.zip"
Destination = "C:\Users\Public\Documents\ExtractionPath"
}
and then the same dsc_resource with Chef:
dsc_resource 'example' do
resource :archive
property :ensure, 'Present'
property :path, "C:\Users\Public\Documents\example.zip"
property :destination, "C:\Users\Public\Documents\ExtractionPath"
end```
The full syntax for all of the properties that are available to the dsc_resource resource is:
dsc_resource 'name' do
module_version String
reboot_action Symbol # default value: :nothing
timeout Integer
action Symbol # defaults to :run if not specified
end
where:
dsc_resource
is the resource.name
is the name given to the resource block.action
identifies which steps Chef Infra Client will take to bring the node into the desired state.module_version
,reboot_action
, andtimeout
are the properties available to this resource.
Actions
The dsc_resource resource has the following actions:
:nothing
- This resource block does not act unless notified by another resource to take action. Once notified, this resource block either runs immediately or is queued up to run at the end of a Chef Infra Client run.
:run
- (default)
Properties
The dsc_resource resource has the following properties:
module_name
- Ruby Type: String
The name of the module from which a DSC resource originates. If this property is not specified, it will be inferred.
module_version
- Ruby Type: String
The version number of the module to use. PowerShell 5.0.10018.0 (or higher) supports having multiple versions of a module installed. This should be specified along with the
module_name
property.New in Chef Client 12.21
property
- Ruby Type: String
A property from a Desired State Configuration (DSC) resource. Use this property multiple times, one for each property in the Desired State Configuration (DSC) resource. The format for this property must follow
property :dsc_property_name, "property_value"
for each DSC property added to the resource block. The:dsc_property_name
must be a symbol.Use the following Ruby types to define property_value:
Ruby PowerShell :array
Object[]
Chef::Util::Powershell:PSCredential
PSCredential
False
bool($false)
Fixnum
Integer
Float
Double
Hash
Hashtable
True
bool($true)
These are converted into the corresponding Windows PowerShell type during a Chef Infra Client run.
reboot_action
- Ruby Type: Symbol | Default Value:
:nothing
Allowed Values::nothing, :reboot_now, :request_reboot
Use to request an immediate reboot or to queue a reboot using the :reboot_now (immediate reboot) or :request_reboot (queued reboot) actions built into the reboot resource.
New in Chef Client 12.6
resource
- Ruby Type: Symbol
The name of the DSC resource. This value is case-insensitive and must be a symbol that matches the name of the DSC resource.
For built-in DSC resources, use the following values:
Value Description :archive
Use to unpack archive (.zip) files. :environment
Use to manage system environment variables. :file
Use to manage files and directories. :group
Use to manage local groups. :log
Use to log configuration messages. :package
Use to install and manage packages. :registry
Use to manage registry keys and registry key values. :script
Use to run PowerShell script blocks. :service
Use to manage services. :user
Use to manage local user accounts. :windowsfeature
Use to add or remove Windows features and roles. :windowsoptionalfeature
Use to configure Microsoft Windows optional features. :windowsprocess
Use to configure Windows processes. Any DSC resource may be used in a Chef recipe. For example, the DSC Resource Kit contains resources for configuring Active Directory components, such as
xADDomain
,xADDomainController
, andxADUser
. Assuming that these resources are available to Chef Infra Client, the corresponding values for theresource
attribute would be::xADDomain
,:xADDomainController
, andxADUser
.
timeout
- Ruby Type: Integer
The amount of time (in seconds) a command is to wait before timing out.
Common Resource Functionality
Chef resources include common properties, notifications, and resource guards.
Common Properties
The following properties are common to every resource:
compile_time
Ruby Type: true, false | Default Value:
false
Control the phase during which the resource is run on the node. Set to true to run while the resource collection is being built (the
compile phase
). Set to false to run while Chef Infra Client is configuring the node (theconverge phase
).ignore_failure
Ruby Type: true, false, :quiet | Default Value:
false
Continue running a recipe if a resource fails for any reason.
:quiet
will not display the full stack trace and the recipe will continue to run if a resource fails.retries
Ruby Type: Integer | Default Value:
0
The number of attempts to catch exceptions and retry the resource.
retry_delay
Ruby Type: Integer | Default Value:
2
The delay in seconds between retry attempts.
sensitive
Ruby Type: true, false | Default Value:
false
Ensure that sensitive resource data is not logged by Chef Infra Client.
Notifications
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 anotifies
statement for each resource to be notified.If the referenced resource does not exist, an error is raised. In contrast,
subscribes
will not fail if the source resource is not found.
A timer specifies the point during a Chef Infra 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 a Chef Infra Client run.
:immediate
,:immediately
Specifies that a notification should be run immediately, for each resource notified.
The syntax for notifies
is:
notifies :action, 'resource[name]', :timer
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.
If the other resource does not exist, the subscription will not raise an
error. Contrast this with the stricter semantics of notifies
, which
will raise an error if the other resource does not exist.
A timer specifies the point during a Chef Infra 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 a Chef Infra Client run.
:immediate
,:immediately
Specifies that a notification should be run immediately, for each resource notified.
The syntax for subscribes
is:
subscribes :action, 'resource[name]', :timer
Guards
A guard property can be used to evaluate the state of a node during the execution phase of a Chef Infra Client run. Based on the results of this evaluation, a guard property is then used to tell Chef Infra Client if it should continue executing a resource. A guard property accepts either a string value or a Ruby block value:
- A string is executed as a shell command. If the command returns
0
, the guard is applied. If the command returns any other value, then the guard property is not applied. String guards in a powershell_script run Windows PowerShell commands and may returntrue
in addition to0
. - A block is executed as Ruby code that must return either
true
orfalse
. If the block returnstrue
, the guard property is applied. If the block returnsfalse
, the guard property is not applied.
A guard property is useful for ensuring that a resource is idempotent by allowing that resource to test for the desired state as it is being executed, and then if the desired state is present, for Chef Infra Client to do nothing.
PropertiesThe following properties can be used to define a guard that is evaluated during the execution phase of a Chef Infra Client run:
not_if
Prevent a resource from executing when the condition returns
true
.only_if
Allow a resource to execute only if the condition returns
true
.
Examples
The following examples demonstrate various approaches for using the dsc_resource resource in recipes:
Open a Zip file
dsc_resource 'example' do
resource :archive
property :ensure, 'Present'
property :path, 'C:\Users\Public\Documents\example.zip'
property :destination, 'C:\Users\Public\Documents\ExtractionPath'
end
Manage users and groups
dsc_resource 'demogroupadd' do
resource :group
property :groupname, 'demo1'
property :ensure, 'present'
end
dsc_resource 'useradd' do
resource :user
property :username, 'Foobar1'
property :fullname, 'Foobar1'
property :password, ps_credential('P@assword!')
property :ensure, 'present'
end
dsc_resource 'AddFoobar1ToUsers' do
resource :Group
property :GroupName, 'demo1'
property :MembersToInclude, ['Foobar1']
end
Create and register a windows service
The following example creates a windows service, defines it’s execution path, and prevents windows from starting the service in case the executable is not at the defined location:
dsc_resource 'NAME' do
resource :service
property :name, 'NAME'
property :startuptype, 'Disabled'
property :path, 'D:\\Sites\\Site_name\file_to_run.exe'
property :ensure, 'Present'
property :state, 'Stopped'
end
Create a test message queue
The following example creates a file on a node (based on one that is
located in a cookbook), unpacks the MessageQueue.zip
Windows
PowerShell module, and then uses the dsc_resource to ensure that
Message Queuing (MSMQ) sub-features are installed, a test queue is
created, and that permissions are set on the test queue:
cookbook_file 'cMessageQueue.zip' do
path "#{Chef::Config[:file_cache_path]}\\MessageQueue.zip"
action :create_if_missing
end
windows_zipfile "#{ENV['PROGRAMW6432']}\\WindowsPowerShell\\Modules" do
source "#{Chef::Config[:file_cache_path]}\\MessageQueue.zip"
action :unzip
end
dsc_resource 'install-sub-features' do
resource :windowsfeature
property :ensure, 'Present'
property :name, 'msmq'
property :IncludeAllSubFeature, true
end
dsc_resource 'create-test-queue' do
resource :cPrivateMsmqQueue
property :ensure, 'Present'
property :name, 'Test_Queue'
end
dsc_resource 'set-permissions' do
resource :cPrivateMsmqQueuePermissions
property :ensure, 'Present'
property :name, 'Test_Queue_Permissions'
property :QueueNames, 'Test_Queue'
property :ReadUsers, node['msmq']['read_user']
end
Example to show usage of module properties
dsc_resource 'test-cluster' do
resource :xCluster
module_name 'xFailOverCluster'
module_version '1.6.0.0'
property :name, 'TestCluster'
property :staticipaddress, '10.0.0.3'
property :domainadministratorcredential, ps_credential('abcd')
end