Comment 5 for bug 1915511

The logs from the source model say that one unit, nrpe/42 failed to validate after the migration was done and so it was rolled back. And the rollback also failed.

2021-02-12 01:16:58 ERROR juju.worker.migrationmaster.87bbf5 worker.go:734 agents failed phase "validating" (units: nrpe/42)
2021-02-12 01:16:58 ERROR juju.worker.migrationmaster.87bbf5 worker.go:286 validating, some agents reported failure
2021-02-12 01:17:06 WARNING juju.worker.migrationmaster.87bbf5 worker.go:626 failed to remove model from target controller, cannot log in: context deadline exceeded

There's nothing in the destination controller logs that show why nrpe/42 was unhappy. But some logs may be missing. The pastebin for the destination controller ends at "2021-02-12 01:12:26" whereas the source controller logs show migration occurred around "2021-02-12 01:16:58". So it's hard to know what happened. Is nrpe/42 functioning normally?

It would also be good to try this on 2.8.8 since some migration issues have been fixed since 2.7.8 was released.