.Performing a DR test with two sites stretch cluster no longer causes Ceph to become unresponsive Previously, when performing a DR test with two sites stretch-cluster, removing and adding new monitors to the cluster would cause an incorrect rank in `ConnectionTracker` class. Due to this, the monitor would fail to identify itself in the `peer_tracker` copy and would never update its correct field, causing a deadlock in the election process which would lead to Ceph becoming unresponsive. With this fix, the following corrections are made: * Added an assert in the function `notify_rank_removed()`, to compare the expected rank provided by the `Monmap` against the rank that is manually adjusted as a sanity check. * Cleared the variable `removed_ranks` from every `Monmap` update. * Added an action to manually reset `peer_tracker.rank` when executing the command - `ceph connection scores reset` for each monitor. The `peer_tracker.rank` matches the current rank of the monitor. * Added functions in the `Elector` and `ConnectionTracker` classes to check for clean `peer_tracker` when upgrading the monitors, including booting up. If found unclean, `peer_tracker` is cleared. * In {storage-product}, the user can choose to manually remove a monitor rank before shutting down the monitor, causing inconsistency in `Monmap`. Therefore, in `Monitor::notify_new_monmap()` we prevent the function from removing our rank or ranks that don't exist in `Monmap`. The cluster now works as expected and there is no unwarranted downtime. The cluster no longer becomes unresponsive when performing a DR test with two sites stretch-cluster.