Use the mdadm resource to manage RAID devices in a Linux environment using the mdadm utility. The mdadm provider will create and assemble an array, but it will not create the config file that is used to persist the array upon reboot. If the config file is required, it must be done by specifying a template with the correct array layout, and then by using the mount provider to create a file systems table (fstab) entry.
A mdadm resource block manages RAID devices in a Linux environment using the mdadm utility:
mdadm '/dev/md0' do devices [ '/dev/sda', '/dev/sdb' ] level 1 action [ :create, :assemble ] end
The full syntax for all of the properties that are available to the mdadm resource is:
mdadm 'name' do bitmap String chunk Integer devices Array exists TrueClass, FalseClass layout String level Integer mdadm_defaults TrueClass, FalseClass metadata String notifies # see description provider Chef::Provider::Mdadm raid_device String # defaults to 'name' if not specified subscribes # see description action Symbol # defaults to :create if not specified end
where
mdadm
is the resourcename
is the name of the resource block:action
identifies the steps the chef-client will take to bring the node into the desired statebitmap
, chunk
, devices
, exists
, layout
, level
, mdadm_defaults
, metadata
, provider
, and raid_device
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.This resource has the following actions:
:assemble
:create
:nothing
:stop
This resource has the following properties:
bitmap
Ruby Type: String
The path to a file in which a write-intent bitmap is stored.
chunk
Ruby Type: Integer
The chunk size. This property should not be used for a RAID 1 mirrored pair (i.e. when the level
property is set to 1
). Default value: 16
.
devices
Ruby Type: Array
A comma-separated list of devices to be part of a RAID array. Default value: []
.
exists
Ruby Types: TrueClass, FalseClass
Indicates whether the RAID array exists. Default value: false
.
ignore_failure
Ruby Types: TrueClass, FalseClass
Continue running a recipe if a resource fails for any reason. Default value: false
.
layout
Ruby Type: String
The RAID5 parity algorithm. Possible values: left-asymmetric
(or la
), left-symmetric
(or ls
), right-asymmetric
(or ra
), or right-symmetric
(or rs
).
level
Ruby Type: Integer
The RAID level. Default value: 1
.
mdadm_defaults
Ruby Types: TrueClass, FalseClass
When true
this property sets the default values for chunk
and metadata
to nil
allowing mdadm to use its own default values. Default value: false
.
metadata
Ruby Type: String
The superblock type for RAID metadata. Default value: 0.90
.
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:
:before
:delayed
:immediate
, :immediately
The syntax for notifies
is:
notifies :action, 'resource[name]', :timer
provider
Ruby Type: Chef Class
Optional. Explicitly specifies a provider.
raid_device
Ruby Type: String
The name of the RAID device. Default value: the name
of the resource block See “Syntax” section above 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]’
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:
:before
:delayed
:immediate
, :immediately
The syntax for subscribes
is:
subscribes :action, 'resource[name]', :timer
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.
Create and assemble a RAID 0 array
The mdadm command can be used to create RAID arrays. For example, a RAID 0 array named /dev/md0
with 10 devices would have a command similar to the following:
$ mdadm --create /dev/md0 --level=0 --raid-devices=10 /dev/s01.../dev/s10
where /dev/s01 .. /dev/s10
represents 10 devices (01, 02, 03, and so on). This same command, when expressed as a recipe using the mdadm resource, would be similar to:
mdadm '/dev/md0' do devices [ '/dev/s01', ... '/dev/s10' ] level 0 action :create end
(again, where /dev/s01 .. /dev/s10
represents devices /dev/s01, /dev/s02, /dev/s03, and so on).
Create and assemble a RAID 1 array
mdadm '/dev/md0' do devices [ '/dev/sda', '/dev/sdb' ] level 1 action [ :create, :assemble ] end
Create and assemble a RAID 5 array
The mdadm command can be used to create RAID arrays. For example, a RAID 5 array named /dev/sd0
with 4, and a superblock type of 0.90
would be similar to:
mdadm '/dev/sd0' do devices [ '/dev/s1', '/dev/s2', '/dev/s3', '/dev/s4' ] level 5 metadata '0.90' chunk 32 action :create end
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https://docs-archive.chef.io/release/12-13/resource_mdadm.html