feat: Virt a local virtual machine provider

[pvoborni]

Sort of working PoC, Opening as a preview and for early comments.

This week, when looking at https://pagure.io/testcloud project, I was thinking that it can be used for the "libvirt" provider for Mrack. Basically the testcloud lib would do all the heavy lifting. Creating the provider was so-far super easy as I basically copy&pasted podman provider and just changed few things.

So far I tested:

• [x] creation of 2 Fedora vms
• [x] ssh action
• [x] destroy action
• [x] list action

Missing:

• [ ] trying windows or RHEL
• [x] advanced image management. Currenly provisioning config expects to have URL to image. Which then is downloaded by testcloud. I fear a race condition or misuse of resources when provisioning vms in parallel and not having the image downloaded. This can be a common scenario.
• [x] documentation
• [ ] thinking about splitting the spec file to have packages like mrack, mrack-all, mrack-openstack, mrack-virt, mrack-containers, mrack-aws, ... + associated changes to handle missing python deps
• [x] amendment of provisioning config to have example

Used provisioning config changes:

virt:
    images:
        fedora-33: https://kojipkgs.fedoraproject.org/compose/cloud/Fedora-Cloud-33-20210421.0/compose/Cloud/x86_64/images/Fedora-Cloud-Base-33-20210421.0.x86_64.qcow2
    options: # default for undefined
        #vcpus: 2
        ram: 1024 # in MiB
        disksize: 10 # in GiB
    groups: # per-group overrides, similar to flavors
        ipaserver:
            ram: 2560
        ad:
            ram: 3072

feat: Virt a local virtual machine provider

PoC implementation which uses testcloud library to do most of the
heavy lifting. The idea is to use cloud images for local provisioning.

First implementation doesn't do much about image sources and expects
urls of images to be in provisioning config. Later this should be
improved to allow dynamic loading of latest images from the sources
without a need to change them often manually.

Signed-off-by: Petr Vobornik <pvoborni@redhat.com>

feat: password authentication in ssh_to_host

ssh_to_host had some code for password authentication but it never
worked so this is basically a new feature.

Password authentication is preferred over sshkey as sshkey is often
defined globally and preffering it would e.g. not work for virt
provider. It is assuming that if a host has a password set then
it should work.

Signed-off-by: Petr Vobornik <pvoborni@redhat.com>

[pvoborni]

How to test:

Do installation steps from testcloud:

Install the testcloud.

$ sudo dnf install testcloud

Add yourself to the testcloud group.

$ sudo usermod -a -G testcloud $USER

After installing mrack from rpm, only the second step will be needed. Mrack should probably somehow check if the user is part of the group and provide a hint if not.

[pvoborni]

This is ready for review. The packaging part should be done separately. Successfully tested with RHEL. And I see windows as a next RFE.

[pvoborni]

Also a next step would be some better solution about composes/images. E.g. so that we can somehow either automatically or semi-automatically fetch the latest image e.g. from https://kojipkgs.fedoraproject.org/compose/cloud/latest-Fedora-Cloud-33/ But this exact behavior is not yet well defined so starting without it is sufficient.