Add candlepin tuning

[Imaanpreet]

Why are you introducing these changes? (Problem description, related links)

Candlepin JVM heap is hardcoded in tomcat.conf. It should scale with the tuning profile like other components (httpd, PostgreSQL).

What are the changes introduced in this pull request?

• Templatized -Xms/-Xmx in tomcat.conf using candlepin_xms/candlepin_xmx variables
• Role defaults: 1g/4g (matches puppet-candlepin (https://github.com/theforeman/puppet-candlepin/blob/072f08a/manifests/init.pp#L216))
• Extra-large and extra-extra-large override candlepin_xmx: 8g (matches foreman-installer
  (https://github.com/theforeman/foreman-installer/blob/0448d5d/config/foreman.hiera/tuning/sizes/extra-extra-large.yaml#L5))

How to test this pull request

1. foremanctl deploy --tuning default
2. podman exec candlepin cat /proc/1/cmdline | tr '\0' ' ' → verify -Xms1g -Xmx4g
3. foremanctl deploy --tuning extra-large (32+ cores, 128GB+) → verify -Xms1g -Xmx8g

Steps to reproduce:

Checklist

• Tests added/updated (if applicable)
• Documentation updated (if applicable)

[pablomh]

+1

[ehelms]

How about including java_opts?

Suggested change

	candlepin_xmx: 4g
	candlepin_java_opts_xmx: 4g

[Imaanpreet]

Done! Renamed to candlepin_java_opts_xms / candlepin_java_opts_xmx.
Thanks @ehelms

[evgeni]

In puppet-candlepin, we used to just have a single java_opts string, that you could fill with whatever you wanted: https://github.com/theforeman/puppet-candlepin/blob/072f08a2e3d9bb1f5dc15bcb768151ec0015476c/manifests/init.pp#L216
It's basically a tradeoff between "being able to selectively override defaults" (this PR) and "be free to pass any opt you want" (puppet-candlepin).

My Tomcat knowledge is super rusty, so maybe @Imaanpreet and @pablomh know better: what are the odds that you want to alter only ms or only mx values (looking at this PR and the tuning in foreman-installer: high?)? and do we ever recommend adding any other options?

I only could find https://access.redhat.com/solutions/6999123 which adds -XX:+UseParallelGC -XX:ParallelGCThreads=16 but looks rather old (Satellite 6.9 on EL7)

[Imaanpreet]

In puppet-candlepin, we used to just have a single java_opts string, that you could fill with whatever you wanted: https://github.com/theforeman/puppet-candlepin/blob/072f08a2e3d9bb1f5dc15bcb768151ec0015476c/manifests/init.pp#L216 It's basically a tradeoff between "being able to selectively override defaults" (this PR) and "be free to pass any opt you want" (puppet-candlepin).

My Tomcat knowledge is super rusty, so maybe @Imaanpreet and @pablomh know better: what are the odds that you want to alter only ms or only mx values (looking at this PR and the tuning in foreman-installer: high?)? and do we ever recommend adding any other options?

I only could find https://access.redhat.com/solutions/6999123 which adds -XX:+UseParallelGC -XX:ParallelGCThreads=16 but looks rather old (Satellite 6.9 on EL7)

Thanks for raising this, @evgeni !

The separate variables work well for our use case since tuning profiles only need to adjust heap sizes — for example, XL and XXL just override xmx to 8g while keeping the default xms. The other JAVA_OPTS flags (-Dcom.redhat.fips=false, --enable-native-access=ALL-UNNAMED) are fixed in the template and don't change across profiles.

I don't think there's a current need for passing additional JVM options through tuning profiles. The GC tuning example you found looks like it was specific to Satellite 6.9/EL7. But if that need comes up in the future, we could always add something like candlepin_java_opts_extra without changing the existing setup.

Happy to hear what you and @pablomh think!