Linux Storage Role
==================
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This role allows users to configure local storage with minimal input.

As of now, the role supports managing file systems and mount entries on
- unpartitioned disks
- lvm (unpartitioned whole-disk physical volumes only)


Role Variables
--------------

__NOTE__: Beginning with version 1.3.0, unspecified parameters are interpreted
differently for existing and non-existing pools/volumes. For new/non-existent
pools and volumes, any omitted omitted parameters will use the default value as
described in `defaults/main.yml`. For existing pools and volumes, omitted
parameters will inherit whatever setting the pool or volume already has.
This means that to change/override role defaults in an existing pool or volume,
you must explicitly specify the new values/settings in the role variables.

#### `storage_pools`
The `storage_pools` variable is a list of pools to manage. Each pool contains a
nested list of `volume` dicts as described below, as well as the following
keys:

##### `name`
This specifies the name of the pool to manage/create as a string. (One
example of a pool is an LVM volume group.)

##### `type`
This specifies the type of pool to manage.
Valid values for `type`: `lvm`.

##### `disks`
A list which specifies the set of disks to use as backing storage for the pool.
Supported identifiers include: device node (like `/dev/sda` or `/dev/mapper/mpathb`),
device node basename (like `sda` or `mpathb`), /dev/disk/ symlink
(like `/dev/disk/by-id/wwn-0x5000c5005bc37f3f`).

##### `raid_level`
When used with `type: lvm` it manages a volume group with a mdraid array of given level
on it. Input `disks` are in this case used as RAID members.
Accepted values are: `linear`, `striped`, `raid0`, `raid1`, `raid4`, `raid5`, `raid6`, `raid10`

##### `volumes`
This is a list of volumes that belong to the current pool. It follows the
same pattern as the `storage_volumes` variable, explained below.

##### `encryption`
This specifies whether or not the pool will be encrypted using LUKS.
__WARNING__: Toggling encryption for a pool is a destructive operation, meaning
             the pool itself will be removed as part of the process of
             adding/removing the encryption layer.

##### `encryption_password`
This string specifies a password or passphrase used to unlock/open the LUKS volume(s).

##### `encryption_key`
This string specifies the full path to the key file on the managed nodes used to unlock
the LUKS volume(s).  It is the responsibility of the user of this role to securely copy
this file to the managed nodes, or otherwise ensure that the file is on the managed
nodes.

##### `encryption_cipher`
This string specifies a non-default cipher to be used by LUKS.

##### `encryption_key_size`
This integer specifies the LUKS key size (in bytes).

##### `encryption_luks_version`
This integer specifies the LUKS version to use.


#### `storage_volumes`
The `storage_volumes` variable is a list of volumes to manage. Each volume has the following
variables:

##### `name`
This specifies the name of the volume.

##### `type`
This specifies the type of volume on which the file system will reside.
Valid values for `type`: `lvm`, `disk` or `raid`.
The default is determined according to the OS and release (currently `lvm`).

##### `disks`
This specifies the set of disks to use as backing storage for the file system.
This is currently only relevant for volumes of type `disk`, where the list
must contain only a single item.

##### `size`
The `size` specifies the size of the file system. The format for this is intended to
be human-readable, e.g.: "10g", "50 GiB". The size of LVM volumes can be specified as a
percentage of the pool/VG size, eg: "50%" as of v1.4.2.

When using `compression` or `deduplication`, `size` can be set higher than actual available space,
e.g.: 3 times the size of the volume, based on duplicity and/or compressibility of stored data.

__NOTE__: The requested volume size may be reduced as necessary so the volume can
          fit in the available pool space, but only if the required reduction is
          not more than 2% of the requested volume size.

##### `fs_type`
This indicates the desired file system type to use, e.g.: "xfs", "ext4", "swap".
The default is determined according to the OS and release
(currently `xfs` for all the supported systems).

##### `fs_label`
The `fs_label` is a string to be used for a file system label.

##### `fs_create_options`
The `fs_create_options` specifies custom arguments to `mkfs` as a string.

##### `mount_point`
The `mount_point` specifies the directory on which the file system will be mounted.

##### `mount_options`
The `mount_options` specifies custom mount options as a string, e.g.: 'ro'.

##### `raid_level`
Specifies RAID level when type is `raid`.
Accepted values are: `linear`, `striped`, `raid0`, `raid1`, `raid4`, `raid5`, `raid6`, `raid10`

#### `raid_device_count`
When type is `raid` specifies number of active RAID devices.

#### `raid_spare_count`
When type is `raid` specifies number of spare RAID devices.

#### `raid_metadata_version`
When type is `raid` specifies RAID metadata version as a string, e.g.: '1.0'.

#### `raid_chunk_size`
When type is `raid` specifies RAID chunk size as a string, e.g.: '512 KiB'.
Chunk size has to be multiple of 4 KiB.

##### `encryption`
This specifies whether or not the volume will be encrypted using LUKS.
__WARNING__: Toggling encryption for a volume is a destructive operation, meaning
             all data on that volume will be removed as part of the process of
             adding/removing the encryption layer.

##### `encryption_password`
This string specifies a password or passphrase used to unlock/open the LUKS volume.

##### `encryption_key`
This string specifies the full path to the key file on the managed nodes used to unlock
the LUKS volume(s).  It is the responsibility of the user of this role to securely copy
this file to the managed nodes, or otherwise ensure that the file is on the managed
nodes.

##### `encryption_cipher`
This string specifies a non-default cipher to be used by LUKS.

##### `encryption_key_size`
This integer specifies the LUKS key size (in bits).

##### `encryption_luks_version`
This integer specifies the LUKS version to use.

##### `deduplication`
This specifies whether or not the Virtual Data Optimizer (VDO) will be used.
When set, duplicate data stored on storage volume will be
deduplicated resulting in more storage capacity.
Can be used together with `compression` and `vdo_pool_size`.
Volume has to be part of the LVM `storage_pool`.
Limit one VDO `storage_volume` per `storage_pool`.
Underlying volume has to be at least 9 GB (bare minimum is around 5 GiB).

##### `compression`
This specifies whether or not the Virtual Data Optimizer (VDO) will be used.
When set, data stored on storage volume will be
compressed resulting in more storage capacity.
Volume has to be part of the LVM `storage_pool`.
Can be used together with `deduplication` and `vdo_pool_size`.
Limit one VDO `storage_volume` per `storage_pool`.

##### `vdo_pool_size`
When Virtual Data Optimizer (VDO) is used, this specifies the actual size the volume
will take on the device. Virtual size of VDO volume is set by `size` parameter.
`vdo_pool_size` format is intended to be human-readable,
e.g.: "30g", "50GiB".
Default value is equal to the size of the volume.

#### `storage_safe_mode`
When true (the default), an error will occur instead of automatically removing existing devices and/or formatting.


Example Playbook
----------------

```yaml
- hosts: all

  roles:
    - name: rhel-system-roles.storage
      storage_pools:
        - name: app
          disks:
            - sdb
            - sdc
          volumes:
            - name: shared
              size: "100 GiB"
              mount_point: "/mnt/app/shared"
              #fs_type: xfs
              state: present
            - name: users
              size: "400g"
              fs_type: ext4
              mount_point: "/mnt/app/users"
      storage_volumes:
        - name: images
          type: disk
          disks: ["mpathc"]
          mount_point: /opt/images
          fs_label: images

```


License
-------

MIT
