Chef

Table Of Contents

mount

A resource defines the desired state for a single configuration item present on a node that is under management by Chef. A resource collection—one (or more) individual resources—defines the desired state for the entire node. During a chef-client run, the current state of each resource is tested, after which the chef-client will take any steps that are necessary to repair the node and bring it back into the desired state.

Use the mount resource to manage a mounted file system.

Syntax

A mount resource block manages a mounted file system:

mount node['mysql']['ec2_path'] do
  device ebs_vol_dev
  fstype 'xfs'
  action :mount
end

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

mount 'name' do
  device                     String
  device_type                Symbol
  domain                     String
  dump                       Integer, FalseClass
  enabled                    TrueClass, FalseClass
  fsck_device                String
  fstype                     String
  mount_point                String # defaults to 'name' if not specified
  mounted                    TrueClass, FalseClass
  notifies                   # see description
  options                    Array, String
  pass                       Integer, FalseClass
  password                   String
  provider                   Chef::Provider::Mount
  subscribes                 # see description
  supports                   Array
  username                   String
  action                     Symbol # defaults to :mount if not specified
end

where

  • mount is the resource
  • name is the name of the resource block
  • :action identifies the steps the chef-client will take to bring the node into the desired state
  • device, device_type, domain, dump, enabled, fsck_device, fstype, mount_point, mounted, options, pass, password, provider, supports, and username 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:

Action Description
:disable Remove an entry from the file systems table (fstab).
:enable Add an entry to the file systems table (fstab).
:mount Default. Mount a device.
:nothing Define a resource block that does nothing until it is notified by another resource to take action. When notified, this resource block is either run immediately or it is queued up to be run at the end of the chef-client run.
:remount Remount a device.
:umount Unmount a device.

Note

Order matters when passing multiple actions. For example: action [:mount, :enable] ensures that the file system is mounted before it is enabled.

Properties

This resource has the following properties:

Property Description
device

Ruby Type: String

Required for :umount and :remount actions (for the purpose of checking the mount command output for presence). The special block device or remote node, a label, or a uuid to be mounted.

device_type

Ruby Type: Symbol

The type of device: :device, :label, or :uuid. Default value: :device.

domain

Ruby Type: String

Microsoft Windows only. Use to specify the domain in which the username and password are located.

dump

Ruby Types: Integer, FalseClass

The dump frequency (in days) used while creating a file systems table (fstab) entry. Default value: 0.

enabled

Ruby Types: TrueClass, FalseClass

Use to specify if a mounted file system is enabled. Default value: false.

fsck_device

Ruby Type: String

The fsck device on the Solaris platform. Default value: -.

fstype

Ruby Type: String

Required. The file system type (fstype) of the device.

ignore_failure

Ruby Types: TrueClass, FalseClass

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

mount_point

Ruby Type: String

The directory (or path) in which the device is to be mounted. Default value: the name of the resource block. See “Syntax” section above for more information.

mounted

Ruby Types: TrueClass, FalseClass

Use to specify if a file system is already mounted. Default value: false.

notifies

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

Which resource takes action when this resource’s state changes. A resource may notify more than one resource; use a notifies statement for each resource to be notified.

Specify the :action, 'resource[name]', and timer (:delayed or :immediately). Use multiple notifies statements to notify more than one resource.

resource 'name' do
  ...
  notifies :action, 'resource[name]', :timer
end

Use the following timers to specify when a notification is triggered:

Timer Description
:delayed Use to specify that a notification should be queued up, and then executed at the very end of a chef-client run.
:immediately Use to specify that a notification should be run immediately, per resource notified.
options

Ruby Types: Array, String

An array or string that contains mount options. If this value is a string, it is converted to an array. Default value: defaults.

pass

Ruby Types: Integer, FalseClass

The pass number used by the file system check (fsck) command while creating a file systems table (fstab) entry. Default value: 2.

password

Ruby Type: String

Microsoft Windows only. Use to specify the password for username.

provider

Ruby Type: Chef Class

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

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.

subscribes

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

Specify that this resource is to listen to another resource, and then take action when that resource’s state changes.

Specify the :action, 'resource[name]', and timer (:delayed or :immediately). Use multiple subscribes statements to listen to more than one resource.

resource 'name' do
  ...
  subscribes :action, 'resource[name]', :timer
end

The subscribes property uses the same timers as the notifies property.

supports

Ruby Type: Array

A Hash of options for supported mount features. Default value: { :remount => false }.

username

Ruby Type: String

Microsoft Windows only. Use to specify the user name.

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 an property of a resource. For example: provider Chef::Provider::Long::Name

This resource has the following providers:

Long name Short name Notes
Chef::Provider::Mount mount The default provider for all platforms, except for Microsoft Windows.
Chef::Provider::Mount::Windows mount The default provider for the Microsoft Windows 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/opscode-cookbooks.

Mount a labeled file system

mount '/mnt/volume1' do
  device 'volume1'
  device_type :label
  fstype 'xfs'
  options 'rw'
end

Mount a local block drive

mount '/mnt/local' do
  device '/dev/sdb1'
  fstype 'ext3'
end

Mount a non-block file system

mount '/mount/tmp' do
  pass     0
  fstype   'tmpfs'
  device   '/dev/null'
  options  'nr_inodes=999k,mode=755,size=500m'
  action   [:mount, :enable]
end

Mount and add to the file systems table

mount '/export/www' do
  device 'nas1prod:/export/web_sites'
  fstype 'nfs'
  options 'rw'
  action [:mount, :enable]
end

Mount a remote file system

mount '/export/www' do
  device 'nas1prod:/export/web_sites'
  fstype 'nfs'
  options 'rw'
end

Mount a remote folder in Microsoft Windows

mount 'T:' do
  action :mount
  device '\\\\hostname.example.com\\folder'
end

Unmount a remote folder in Microsoft Windows

mount 'T:' do
  action :umount
  device '\\\\hostname.example.com\\D$'
end

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/opscode-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