Add notice of deprecation of sendmail

[jafiala]

What changes are you introducing?

Add mentions that sendmail is deprecated.

Why are you introducing these changes? (Explanation, links to references, issues, etc.)

Sendmail is deprecated in Satellite 6.18 and will be removed. To prevent users from relying on deprecated features, I want to update the docs so that it's clear which method is future-proof.

Anything else to add? (Considerations, potential downsides, alternative solutions you have explored, etc.)

Also some minor style improvements in the procedure.

Contributor checklists

• I am okay with my commits getting squashed when you merge this PR.
• I am familiar with the contributing guidelines.

Please cherry-pick my commits into:

• Foreman 3.16/Katello 4.18 (Satellite 6.18)
• Foreman 3.15/Katello 4.17
• Foreman 3.14/Katello 4.16 (Satellite 6.17; orcharhino 7.4)
• Foreman 3.13/Katello 4.15 (EL9 only)
• Foreman 3.12/Katello 4.14 (Satellite 6.16; orcharhino 7.2 on EL9 only; orcharhino 7.3)
• Foreman 3.11/Katello 4.13 (orcharhino 6.11 on EL8 only; orcharhino 7.0 on EL8+EL9; orcharhino 7.1 with Leapp)
• Foreman 3.10/Katello 4.12
• Foreman 3.9/Katello 4.11 (Satellite 6.15; orcharhino 6.8/6.9/6.10)
• We do not accept PRs for Foreman older than 3.9.

[github-actions]

The PR preview for ded7dff is available at theforeman-foreman-documentation-preview-pr-4386.surge.sh

The following output files are affected by this PR:

• Installing_Server/index-foreman-deb.html
• Installing_Server/index-foreman-el.html
• Installing_Server/index-katello.html
• Installing_Server/index-orcharhino.html
• Installing_Server/index-satellite.html
• Installing_Server_Disconnected/index-satellite.html

show diff

show diff as HTML

[jafiala]

@maximiliankolb Hi Max, I'm not sure how to handle the deprecation information. Do you also want to have it on your side, or should I add conditionals?

EDIT: For context, sendmail was deprecated in RHEL 7 already, and is being removed in RHEL 10.

[ekohl]

I'm hesitant to merge this now. The out of the box experience is that you use sendmail and upstream we haven't provided any notice in the 3.16 release notes.

[maximiliankolb]

@maximiliankolb Hi Max, I'm not sure how to handle the deprecation information. Do you also want to have it on your side, or should I add conditionals?

EDIT: For context, sendmail was deprecated in RHEL 7 already, and is being removed in RHEL 10.

If the application is not packaged for EL10 anymore, I think it's fair to show the deprecation for all flavors in foreman-documentation. -> Please also include the change for orcharhino.

[ekohl]

EDIT: For context, sendmail was deprecated in RHEL 7 already, and is being removed in RHEL 10.

This is unrelated. /usr/bin/sendmail is provided by many packages. RHEL by default uses postfix but there are other implementations.

The reason we're dropping it is that often it doesn't work due to modern anti-spam protection.

[jafiala]

I'm hesitant to merge this now. The out of the box experience is that you use sendmail and upstream we haven't provided any notice in the 3.16 release notes.

Right, but what we want to avoid is pointing from the Satellite deprecation note to a procedure that recommends the deprecated method. I think adding the language about the deprecation without removing content should be fine?

If not, I could add conditionals so that the deprecation shows only for downstream docs and not upstream. Though of course I'd rather not, as it adds complexity and increases maintenance for the docs.

[Lennonka]

We have a deprecation snippet for standardized wording.
Please, use that instead.

[Lennonka]

@ekohl Can we just add it to 3.16 release notes?

[ekohl]

@Lennonka I should be more explicit, but that was my thinking yes. If we properly deprecate it in the Foreman 3.16 release noted then this change becomes logical.

[Lennonka]

LGTM, thank you!

Tech ack would be appreciated.

[stejskalleos]

TECH ACK

[Lennonka]

Cherry picked:

• 487ac81..7c5cedc 3.16 -> 3.16