The majority of the role's logic is in library/blivet.py, which is a module
that does the heavy lifting of managing the actual storage configuration. The
next biggest piece is in tasks/, followed by defaults/.
This is where we define the structure of the vars available to users to specify
how they want the storage to be layed out. There are two top-level lists:
storage_pools is a list of pools, which contain volumes, and
storage_volumes, which are volumes that are not associated with any pool.
Examples of pools include LVM volume groups and disks with partition tables.
Most volumes will exist within a pool, with the exception of whole-disk file-
systems.
This is the ansible logic to take the user's specification and translate it
into a storage configuration. For the most part, it applies defaults as needed
and then delegates the real work to the embedded blivet module and ansible's
mount module.
The blivet module does most of the actual work of modifying the storage
configuration. It provides an interface to blivet, which is a python module
for storage management used by the Fedora and Red Hat OS installer (anaconda).
It accepts a list of pools and a list of standalone volumes, manages the
storage configuration accordingly, then returns several pieces of data: a
slightly enhanced copy of the pool/volume lists, a list of actions it took,
and a list of mounts to manage using ansible's built-in mount module.
The bsize module translates human-readable size specifications into a
flexible format.
The blockdev_info module gathers information about the storage devices in the
system, and is only used for test result validation.
The find_unused_disk module lists unused disks that match a set of user-
provided constraints.
There are unit tests for the embedded modules in tests/unit/ and integration
tests for the role in tests/.
All of the integration tests are designed to use extra/unused disks in a vm. Keep in mind that containers do not provide any storage isolation, and so are not appropriate for testing of storage management.
Here is the command line I have been using to run individual integration tests from the command line in a virtual machine running Fedora 29:
ansible-playbook -K --flush-cache -i inventory tests/tests_change_fs.yml
Here's what the inventory file contains:
localhost ansible_connection=local ansible_python_interpreter=/usr/bin/python3
There is more than enough output on the console to overrun the buffers, so it
is often useful to redirect/duplicate to a log by setting ANSIBLE_LOG_PATH.
There is also /tmp/blivet.log in case there are problems doing the actual
storage management.