[Debian-ha-maintainers] Split of HA agents into multiple binary packages

[Valentin Vidic]

On Wed, Mar 29, 2023 at 09:38:05PM -0300, Lucas Kanashiro wrote:
> I am changing my proposal now to only split the fence-agents package and
> keep resource-agents as is. After analyzing better I believe we should
> definitely follow RedHat here.

I'm not too interested in making Debian a RedHat clone, but if we
are doing the split maybe it makes sense to use the same model as
it helps with RedHat documentation mostly working for Debian too.

> Some concrete cases of dependencies that are missing:

I agree the missing dependencies are a usability problem and it
is worth considering the split for that reason.

> It does not mean that all those dependencies should be in Depends but they
> should be have some kind of relationship with the package.

The new fence-agents meta-package should have the new packages in Recommends
(and maybe some in Suggests like fence-virt) so the existing users that want to
install everything still get the majority of agents. This also allows them to
remove agents they don't want. Later when we have more usage info we can
move less used agents to Suggests.

> I do not have a very precise number regarding disk space to give you but the
> non-python packages above would result in more or less 2MB.

It seems the usage is not that small on a new system, so maybe the split
helps there too.

# apt install fence-agents --no-install-recommends
...
The following NEW packages will be installed:
  fence-agents libbrotli1 libcurl3-gnutls libldap-2.5-0 libnghttp2-14 libpsl5 librtmp1 libsasl2-2 libsasl2-modules-db
  libssh2-1 python3-boto3 python3-botocore python3-cachetools python3-certifi python3-cffi-backend python3-chardet
  python3-charset-normalizer python3-cryptography python3-dateutil python3-fasteners python3-google-auth
  python3-google-auth-httplib2 python3-googleapi python3-greenlet python3-httplib2 python3-idna python3-jmespath
  python3-monotonic python3-oauth2client python3-openssl python3-pexpect python3-pkg-resources python3-ptyprocess
  python3-pyasn1 python3-pyasn1-modules python3-pycurl python3-pyparsing python3-requests python3-rsa
  python3-s3transfer python3-six python3-sqlalchemy python3-suds python3-uritemplate python3-urllib3
0 upgraded, 45 newly installed, 0 to remove and 0 not upgraded.
Need to get 11.1 MB of archives.
After this operation, 106 MB of additional disk space will be used.

>> - impossible to co-install two web-server resource agents if they
>> pulled their servers with default configs, since they couldn't both
>> start, so the resource-agent meta-package wouldn't work
> You are right.  I gave up on this part of the proposal.

Yes, also when nginx is installed from the package it is managed by
systemd and this needs to be disabled first before it can be managed by
pacemaker. So not something that can easily be done just with package
management.

> Agreed. But we should not give up on improving because it will make our life
> harder, I prefer to think on the benefits our users will have with the
> proposed changes. I volunteer myself to help with any unpleasant work that
> might come up out of this.

Ok, let's give the fence-agents split a try after the Debian release as
it gives us enough time to go back if something does not work out as
planned.

-- 
Valentin