Interestingly, no one has reported this failure before #662 (Github
Issue).
It doesn't make sense to keep saying that we support such old Ansible
versions, when we're not even testing on anything close to those.
Time is also passing and such versions are getting more and more
ancient. It's time we bumped our requirements to something that is more
likely to work.
Certain more-minimal Debian installations may not have
lsb-release installed, which makes the playbook fail.
We need lsb-release on Debian, so that ansible_lsb
could tell us if this is Debian or Raspbian.
`matrix_container_images_self_build` was not really doing anything
anymore. It previously was influencing `matrix_*_self_build` variables,
but it's no longer the case since some time ago.
Individual `matrix_*_self_build` variables are still available.
People that would like to toggle self-building for a specific component
ought to use those.
These variables are also controlled automatically (via
`group_vars/matrix_servers`) depending on `matrix_architecture`.
In other words, self-building is being done automatically for
all components when they don't have a prebuilt image for the specified
architecture. Some components only support `amd64`, while others also
have images for other architectures.
Depending on the distro, common commands like sleep and chown may either
be located in /bin or /usr/bin.
Systemd added path lookup to ExecStart in v239, allowing only the
command name to be put in unit files and not the full path as
historically required. At least Ubuntu 18.04 LTS is however still on
v237 so we should maintain portability for a while longer.
We don't really need to fail in such a spectactular way,
but it's probably good to do. It will only happen for people
who are defining their own user/group id, which is rare.
It seems like a good idea to tell them that this doesn't work
as they expect anymore and to ask them to remove these variables,
which otherwise give them a fake sense of hope.
Related to #486 (Github Pull Request).
If one runs the playbook with `--tags=setup-all`, it would have been
fine.
But running with a specific tag (e.g. `--tags=setup-riot-web`) would
have made that initialization be skipped, and the `matrix-riot-web` role
would fail, due to missing variables.
