upgrade_storages

Upgrade storage instances by performing the following steps for each replica set:

1. Pick a replica (a read-only instance) from the replica set. Stop this replica and start it again on the target Tarantool version. Wait until it reaches the running status (box.info.status == running).

2. Restart all other read-only instances of the replica set on the target version one by one.

3. Make one of the updated replicas the new master using the applicable instruction from Switching the master.

4. Restart the last instance of the replica set (the former master, now a replica) on the target version.

5. Run box.schema.upgrade() on the new master. This will update the Tarantool system spaces to match the currently installed version of Tarantool. The changes will be propagated to other nodes via the replication mechanism later.