openssl_dhparam

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Use the openssl_dhparam resource to generate dhparam.pem files. If a valid dhparam.pem file is found at the specified location, no new file will be created. If a file is found at the specified location, but it is not a valid dhparam file, it will be overwritten.

Syntax

This resource has the following syntax:

openssl_dhparam 'name' do
  generator                  Integer # default value: '2'
  group                      String, nil
  key_length                 Integer # default value: '2048'
  mode                       Integer, String # default value: '0640'
  notifies                   # see description
  owner                      String, nil
  path                       String # default value: 'name'
  subscribes                 # see description
  action                     Symbol # defaults to :create if not specified

where:

  • openssl_dhparam is the name of the resource
  • 'name' is the path where the dhparam file will be written, or the name of the resource block
  • generator, group, key_length, mode, notifies, owner, and path, and subscribes are the properties available to this resource

Actions

:create
Default. Create the dhparam.pem file.
: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.

Properties

generator

Ruby Type: Integer | Default Value: 2

The desired Diffie-Hellmann generator; available options are 2 and 5.

group

Ruby Types: String, nil

The system group of all files created by the resource.

key_length

Ruby Type: Integer | Default Value: 2048

The desired bit length of the generated key; available options are 1024, 2048, 4096, and 8192.

mode

Ruby Types: Integer, String | Default Value: 0640

The permission mode applied to all files created by the resource.

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
owner

Ruby Types: String, nil

The owner of all files created by the resource.

path

Ruby Type: String

The path to write the file to, if it differs from the resource name.

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

Create a dhparam file

openssl_dhparam '/etc/httpd/ssl/dhparam.pem'

Create a dhparam file with a specific key length

openssl_dhparam '/etc/httpd/ssl/dhparam.pem' do
  key_length 4096
end

Create a dhparam file with specific user/group ownership

openssl_dhparam '/etc/httpd/ssl/dhparam.pem' do
  owner 'www-data'
  group 'www-data'
end

Manually specify the dhparam file path

openssl_dhparam 'httpd_dhparam' do
  path '/etc/httpd/ssl/dhparam.pem'
end