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Changing Container Image for Running Cephadm Daemon

Problem​

Change the container image for a single running cephadm daemon or downgrade the container image for a cephadm daemon.

Cephadm does not support upgrading daemons out of order, for good reason. However, if you need to change the container image for a running cephadm daemon, you can do so by editing the unit.run file on the host of the daemon.

Solution​

This example is for an osd daemon, but the same applies to any cephadm daemon like the mgr or mon.

  1. Bring down the daemon systemctl stop ceph-fsid@osd.1.service
  2. Edit the unit.run on the host of the daemon located at /var/lib/ceph/fsid/osd.1 and change the CONTAINER_IMAGE variable to the new image.

Change it in both places CONTAINER_IMAGE= variable appears in the unit.run file.

Example of the command to change the image to my.new.image:tag when inside the daemon's directory:

sed -i 's|CONTAINER_IMAGE=[^ ]*|CONTAINER_IMAGE=my.new.image:tag|g' unit.run
  1. Start the daemon again systemctl start ceph-fsid@osd.1.service. This will also pull the image if it is not already present on the host.
$ ceph versions

{
    "mon": {
        "ceph version 18.2.6 (ff498e17d264a1a4d588c361cbce9cc65afa2327) reef (stable)": 3
    },
    "mgr": {
        "ceph version 18.2.6 (ff498e17d264a1a4d588c361cbce9cc65afa2327) reef (stable)": 3
    },
    "osd": {
        "ceph version 18.2.6 (ff498e17d264a1a4d588c361cbce9cc65afa2327) reef (stable)": 7,
        "ceph version 18.2.5 (a5b0e13f9c96f3b45f596a95ad098f51ca0ccce1) reef (stable)": 1
    },
    "overall": {
        "ceph version 18.2.6 (ff498e17d264a1a4d588c361cbce9cc65afa2327) reef (stable)": 14,
    }
}