# Deploying 2 ceph mgr daemons(1 active, 1 standby)

## Check if 2 mgr pods are there

oc get pods | grep mgr
rook-ceph-mgr-a-5d4b6ffb76-dpjtp                                  3/3     Running     0          37m
rook-ceph-mgr-b-56d6cffc8f-zvgtt                                  3/3     Running     0          36m

## Enable ceph tool box & rsh into it

## Check if 2 mgr daemons are there & their metadata

sh-4.4$ ceph mgr metadata
[
    {
        "name": "a",
        "addr": "10.131.0.101",
        "addrs": "10.131.0.101:0/4262363656",
        "arch": "x86_64",
        "ceph_release": "pacific",
        "ceph_version": "ceph version 16.2.10-94.el8cp (48ce8ed67474ea50f10c019b9445be7f49749d23) pacific (stable)",
        "ceph_version_short": "16.2.10-94.el8cp",
        "container_hostname": "rook-ceph-mgr-a-5d4b6ffb76-dpjtp",
        "container_image": "quay.io/rhceph-dev/rhceph@sha256:957294824e1cbf89ca24a1a2aa2a8e8acd567cfb5a25535e2624989ad1046a60",
        "cpu": "Intel(R) Xeon(R) Platinum 8259CL CPU @ 2.50GHz",
        "distro": "rhel",
        "distro_description": "Red Hat Enterprise Linux 8.7 (Ootpa)",
        "distro_version": "8.7",
        "hostname": "ip-10-0-210-69.ec2.internal",
        "kernel_description": "#1 SMP Tue Jan 3 09:45:26 EST 2023",
        "kernel_version": "4.18.0-372.40.1.el8_6.x86_64",
        "mem_cgroup_limit": "3221225472",
        "mem_swap_kb": "0",
        "mem_total_kb": "65127184",
        "os": "Linux",
        "pod_name": "rook-ceph-mgr-a-5d4b6ffb76-dpjtp",
        "pod_namespace": "openshift-storage"
    },
    {
        "name": "b",
        "addr": "10.129.2.99",
        "addrs": "10.129.2.99:0/4002442210",
        "arch": "x86_64",
        "ceph_release": "pacific",
        "ceph_version": "ceph version 16.2.10-94.el8cp (48ce8ed67474ea50f10c019b9445be7f49749d23) pacific (stable)",
        "ceph_version_short": "16.2.10-94.el8cp",
        "container_hostname": "rook-ceph-mgr-b-56d6cffc8f-zvgtt",
        "container_image": "quay.io/rhceph-dev/rhceph@sha256:957294824e1cbf89ca24a1a2aa2a8e8acd567cfb5a25535e2624989ad1046a60",
        "cpu": "Intel(R) Xeon(R) Platinum 8175M CPU @ 2.50GHz",
        "distro": "rhel",
        "distro_description": "Red Hat Enterprise Linux 8.7 (Ootpa)",
        "distro_version": "8.7",
        "hostname": "ip-10-0-140-183.ec2.internal",
        "kernel_description": "#1 SMP Tue Jan 3 09:45:26 EST 2023",
        "kernel_version": "4.18.0-372.40.1.el8_6.x86_64",
        "mem_cgroup_limit": "3221225472",
        "mem_swap_kb": "0",
        "mem_total_kb": "64439064",
        "os": "Linux",
        "pod_name": "rook-ceph-mgr-b-56d6cffc8f-zvgtt",
        "pod_namespace": "openshift-storage"
    }
]

Check active & standby mgr

sh-4.4$ ceph mgr stat
{
    "epoch": 15,
    "available": true,
    "active_name": "a",
    "num_standby": 1
}

## Fail the active mgr and check if the standby mgr takes over

## treat the named manager daemon as failed
sh-4.4$ ceph mgr fail a

sh-4.4$ ceph mgr stat
{
    "epoch": 17,
    "available": true,
    "active_name": "b",
    "num_standby": 1
}

We can see the mgr b is now active