tt CLI (2.6): `tt replicaset upgrade` on remote replica sets

Product: tt cli
Since: tt 2.6.0
Audience/target: all
Root document: https://www.tarantool.io/en/doc/latest/reference/tooling/tt_cli/replicaset/
SME: @ mandesero @ oleg-jukovec

https://github.com/tarantool/tt/pull/1030

Details

To be done together with #4641

tt replicaset upgrade now allows upgrade database schema on remote
replica sets within a Tarantool cluster. The feature enables to perform
upgrades by targeting specific instances of each replica set.

Usage Example:

Cluster configuration:

• router-001
    • router-001-a localhost:3305 rw
• storage-001
    • storage-001-a localhost:3301 rw
    • storage-001-b localhost:3302 read
• storage-002
    • storage-002-a localhost:3303 rw
    • storage-002-b localhost:3304 read

To update the schema across this cluster:

1. Update each replica set individually.
2. Select one instance from each replica set to run the command.

Commands:

$ tt replicaset upgrade tcp://client:secret@127.0.0.1:3301
  • storage-001: ok
$ tt replicaset upgrade tcp://client:secret@127.0.0.1:3304
  • storage-002: ok
$ tt replicaset upgrade tcp://client:secret@127.0.0.1:3305
  • router-001: ok

Requested by @mandesero in https://github.com/tarantool/tt/commit/6a9c221cbac8f909a17e1595498b79ff6e33b1fd.

Start with the root document at reference/tooling/tt_cli/replicaset/ and review the linked pull request #1030 for the existing feature details. Document remote replica-set upgrades, including the cluster example and commands shown in the issue; done means the page accurately explains the workflow and usage.