Ceph » mgr

After migrating from Luminous 12.1.4 (rc) to Luminous 12.2.0, I found that 'ceph versions' command showa one mgr daemon as "Unknown".

Looking with 'ceph mgr metadata' display something like:

[
    {
        "id": "mon01" 
    },
    {
        "id": "mon02",
        "arch": "x86_64",
        "ceph_version": "ceph version 12.2.0 (32ce2a3ae5239ee33d6150705cdb24d43bab910c) luminous (rc)",
        "cpu": "Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz",
        "distro": "centos",
        "distro_description": "CentOS Linux 7 (Core)",
        "distro_version": "7",
        "hostname": "mon02",
        "kernel_description": "#1 SMP Tue Jul 4 15:04:05 UTC 2017",
        "kernel_version": "3.10.0-514.26.2.el7.x86_64",
        "mem_swap_kb": "19435516",
        "mem_total_kb": "65693900",
        "os": "Linux" 
    },
    {
        "id": "mon03",
        "arch": "x86_64",
        "ceph_version": "ceph version 12.2.0 (32ce2a3ae5239ee33d6150705cdb24d43bab910c) luminous (rc)",
        "cpu": "Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz",
        "distro": "centos",
        "distro_description": "CentOS Linux 7 (Core)",
        "distro_version": "7",
        "hostname": "mon03",
        "kernel_description": "#1 SMP Tue Jul 4 15:04:05 UTC 2017",
        "kernel_version": "3.10.0-514.26.2.el7.x86_64",
        "mem_swap_kb": "19435516",
        "mem_total_kb": "65693900",
        "os": "Linux" 
    }
]

and ceph status shows:

  services:
    mon: 3 daemons, quorum mon01,mon02,mon03
    mgr: mon01(active), standbys: mon03, mon02
    osd: 30 osds: 30 up, 30 in

If we downs active mgr with 'ceph mgr fail mon01', matadata shows:

[
    {
        "id": "mon01",
        "arch": "x86_64",
        "ceph_version": "ceph version 12.2.0 (32ce2a3ae5239ee33d6150705cdb24d43bab910c) luminous (rc)",
        "cpu": "Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz",
        "distro": "centos",
        "distro_description": "CentOS Linux 7 (Core)",
        "distro_version": "7",
        "hostname": "mon01",
        "kernel_description": "#1 SMP Tue Jul 4 15:04:05 UTC 2017",
        "kernel_version": "3.10.0-514.26.2.el7.x86_64",
        "mem_swap_kb": "16449532",
        "mem_total_kb": "32665780",
        "os": "Linux" 
    },
    {
        "id": "mon02",
        "arch": "x86_64",
        "ceph_version": "ceph version 12.2.0 (32ce2a3ae5239ee33d6150705cdb24d43bab910c) luminous (rc)",
        "cpu": "Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz",
        "distro": "centos",
        "distro_description": "CentOS Linux 7 (Core)",
        "distro_version": "7",
        "hostname": "mon02",
        "kernel_description": "#1 SMP Tue Jul 4 15:04:05 UTC 2017",
        "kernel_version": "3.10.0-514.26.2.el7.x86_64",
        "mem_swap_kb": "19435516",
        "mem_total_kb": "65693900",
        "os": "Linux" 
    },
    {
        "id": "mon03" 
    }
]

And cehp status shows:

  services:
    mon: 3 daemons, quorum mon01,mon02,mon03
    mgr: mon03(active), standbys: mon02, mon01
    osd: 30 osds: 30 up, 30 in

This is a cyclic behaviour. Active mgr always is shown as Uknown.

On Luminous 12.1.4 it works as expected.