Comment 0 for bug 1879632

The information in this launchpad is for the following LP: https://bugs.launchpad.net/starlingx/+bug/1819688

Brief Description
-----------------

This feature provides an optional filesystem that can be used by cinder for qcow2 image conversion to raw.
By default, qcow2 image conversion is done by using the docker_lv filesystem.
To avoid the scenario of filling up the docker_lv filesystem, a new filesystem should be dedicated for image conversion.

Add a new filesystem for image conversion
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    New host_fs CLI command was provided for adding 'image-conversion' filesystem dedicated only for qcow2
    image conversion:
        o system host-fs-add <hostname or id> <fs name=size>
    When 'image-conversion' filesystem is added, a new partition '/opt/conversion' is created and mounted.

    Notes
    =====
        1. The size of the 'image-conversion' should be big enough to accommodate any image that is
           uploaded to glance.
        2. Conversion filesystem can be added before/after stx-openstack is applied.
        3. If filesystem is not added on both controllers, stx-openstack will not use the new filesystem.
        4. If conversion filesystem is added after stx-openstack
           is applied, changes to stx-openstack will only take effect
           once the application is re-applied

    'Image-conversion' filesystem can be added only on controller nodes.

    Alarms for image-conversion will be raised:
    ===========================================
        o if image-conversion is not added on both controllers
        o if the size of the filesystem is not the same on both controllers

Remove the filesystem
~~~~~~~~~~~~~~~~~~~~~
    New host_fs CLI command was provided for removing 'image-conversion' filesystem
        o system host-fs-delete <hostname or id> <fs name>
    When 'image-conversion' is removed, '/opt/conversion' partition is also removed.

    Notes
    =====
        1. It is not allowed to delete image-conversion filesystem
           when stx-openstack is in applying/applied/removing state

Resize the filesystem
~~~~~~~~~~~~~~~~~~~~~~
    The size of 'image-conversion' filesystem can be changed at runtime by using the existing CLI command
        o system host-fs-modify