Ceph » Orchestrator

We are upgrading a test cluster from Octopus to Pacific via "ceph orch upgrade start quay.io/ceph/ceph:v16.2.7"

In the output of "ceph -W cephadm" we notice these lines:

2022-02-09T15:48:18.851098+0100 mgr.ceph03.wdkzcv [INF] inventory: adjusted host ceph01 addr 'ceph01' -> '10.24.4.128'
2022-02-09T15:48:18.852908+0100 mgr.ceph03.wdkzcv [INF] inventory: adjusted host ceph02 addr 'ceph02' -> '10.24.4.129'
2022-02-09T15:48:18.857070+0100 mgr.ceph03.wdkzcv [INF] inventory: adjusted host ceph04 addr 'ceph04' -> '10.24.4.131'
2022-02-09T15:48:29.687798+0100 mgr.ceph03.wdkzcv [INF] Filtered out host ceph01: does not belong to mon public_network (10.24.4.0/24)
2022-02-09T15:48:29.688702+0100 mgr.ceph03.wdkzcv [INF] Filtered out host ceph02: does not belong to mon public_network (10.24.4.0/24)
2022-02-09T15:48:29.689774+0100 mgr.ceph03.wdkzcv [INF] Filtered out host ceph03: does not belong to mon public_network (10.24.4.0/24)

10.24.4.128 is obviously in the public_network 10.24.4.0/24, why does it complain about it?

Shortly after that this happens:

2022-02-09T15:55:21.086293+0100 mgr.ceph01.faewwr [INF] Safe to remove mon.ceph03: new quorum should be ['ceph01', 'ceph02'] (from ['ceph01', 'ceph02'])
2022-02-09T15:55:21.086455+0100 mgr.ceph01.faewwr [INF] Removing monitor ceph03 from monmap...
2022-02-09T15:55:21.111598+0100 mgr.ceph01.faewwr [INF] Removing daemon mon.ceph03 from ceph03
2022-02-09T15:55:58.438551+0100 mgr.ceph01.faewwr [INF] Filtered out host ceph03: does not belong to mon public_network (10.24.4.0/24)

And now the cluster runs with only two MONs.