[8pt] Add instructions on how to operate with RPM / Deb packages

Add instructions on how to operate with RPM / Deb packages

Product: Tarantool
Since: all
Audience/target: admins
Root document:

• https://www.tarantool.io/en/download/
• https://www.tarantool.io/en/doc/latest/book/admin/

SME: @Totktonada, @Mons, other Tarantool admins
Peer reviewer: @

Details

After #1218 we'll provide RPM / Deb repositories for release packages in addition to per-push 'live' repositories we have now.

The documentation should answer the following questions:

• how to stick with certain tarantool version or version range;
• how to update from a release version to one with necessary bugfix ('live' one);
• how to move from a live version to the next release when it will be published.
• @Mons also points out that the instructions should clarify how to roll back an update if something is going wrong.

Are there other actions that should be described for a user? -- TBD: ask Tarantool admins what they really need in this regard.

Source: https://lists.tarantool.org/pipermail/tarantool-patches/2020-January/013736.html

Definition of done

• Installation and update instructions for the cases mentioned in Details are written.
• https://www.tarantool.io/en/download/ page contains clear indications of where to find the instructions for all the cases needed.

Start with the /en/download/ and /en/doc/latest/book/admin/ pages and review the linked January 2020 mailing-list discussion. Ask the listed Tarantool admins what package actions need coverage, then document version pinning, release/live updates, rollbacks, and transitions between them. Done means the installation and update cases are documented and the download page clearly links to them.