Different commands identify instances in a different ways

$ tt start replicaset_example
   • Starting an instance [replicaset_example:master]...
   • Starting an instance [replicaset_example:replica]...
$ tt start replicaset_example
   • The instance replicaset_example:replica (PID = 772688) is already running.
   • The instance replicaset_example:master (PID = 772687) is already running.
$ tt restart -y replicaset_example
   • The Instance replicaset_example:master (PID = 772687) has been terminated.
   • The Instance replicaset_example:replica (PID = 772688) has been terminated.
   • Starting an instance [replicaset_example:master]...
   • Starting an instance [replicaset_example:replica]...
$ tt logrotate replicaset_example
   • replicaset_example:master: logs has been rotated. PID: 777002.
   • replicaset_example:replica: logs has been rotated. PID: 777003.
$ tt clean replicaset_example
   • instance `master` must be stopped
   • instance `replica` must be stopped
$ tt stop replicaset_example
   • The Instance replicaset_example:master (PID = 777002) has been terminated.
   • The Instance replicaset_example:replica (PID = 777003) has been terminated.
$ tt clean -f replicaset_example
   • List of files to delete:

   • /var/log/tarantool/sys_env/replicaset_example/replica/tt.log
   • /var/lib/tarantool/sys_env/replicaset_example/replica/00000000000000000009.snap
   • /var/lib/tarantool/sys_env/replicaset_example/replica/00000000000000000009.xlog
   • replica: cleaning...	[OK]
   • List of files to delete:

   • /var/log/tarantool/sys_env/replicaset_example/master/tt.log
   • /var/lib/tarantool/sys_env/replicaset_example/master/00000000000000000000.snap
   • /var/lib/tarantool/sys_env/replicaset_example/master/00000000000000000000.xlog
   • /var/lib/tarantool/sys_env/replicaset_example/master/00000000000000000009.xlog
   • master: cleaning...	[OK] 
$ tt start replicaset_example
   • Starting an instance [replicaset_example:master]...
   • Starting an instance [replicaset_example:replica]...
$ tt kill -f replicaset_example
   • The instance replicaset_example:master (PID = 805812) has been killed.
   • The instance replicaset_example:replica (PID = 805813) has been killed.
$ tt kill -f replicaset_example
   • failed to kill the processes: can't get pid of running process: can't "stat" the PID file. Error: stat /var/run/tarantool/sys_env/replicaset_example/master/tt.pid: no such file or directory
   • failed to kill the processes: can't get pid of running process: can't "stat" the PID file. Error: stat /var/run/tarantool/sys_env/replicaset_example/replica/tt.pid: no such file or directory
$ tt logrotate replicaset_example
   ⨯ NOT RUNNING

In the above output various formats of instances can be found:

• [app:inst] - start (when not running), restart (starting section)
• app:inst - start, logrotate and kill (when running), stop, restart (stop section)
• inst - clean (when running)
• `inst` - clean (when not running)
• no instances at all - logrotate and kill (when not running)

Instances should be identified uniformly, for example in [app:instance] format.

Start by locating the CLI output handling for start, restart, logrotate, clean, stop, and kill, then compare how each command formats instance names in the examples. Standardize the displayed identifier to [app:instance] for every state and command, including error and cleanup output. Done means the listed commands consistently use that format.