ceph-mgr-dashboard: missing dependency on python3-yaml

[James Page]

As reported on ceph-users:

Duncan Bellamy XXXXX via ceph.io

Hi,
I have installed ceph on Ubuntu Focal Fossa using the ubuntu repo, instead of ceph-deploy (as ceph-deploy install does not work for Focal Fossa yet) install I used:
sudo apt-get install -y ceph ceph-mds radosgw ceph-mgr-dashboard

The rest of the setup was the same as the quickstart on ceph.io <http://ceph.io/> with ceph-deploy.

It installed ceph version 15.2.1 (octopus).

If I do a 'ceph -s' I get the warning:
health: HEALTH_WARN
            2 mgr modules have failed dependencies

If I run 'ceph mgr module ls', for enabled and active modules I get:

 "always_on_modules": [
        "balancer",
        "crash",
        "devicehealth",
        "orchestrator",
        "osd_support",
        "pg_autoscaler",
        "progress",
        "rbd_support",
        "status",
        "telemetry",
        "volumes"
    ],
    "enabled_modules": [
        "iostat",
        "restful”

Then when I run 'ceph mgr module enable dashboard’ I get the error:

Error ENOENT: module 'dashboard' reports that it cannot run on the active manager daemon: No module named 'yaml' (pass --force to force enablement)

I have tried searching, and searching with apt but cannot find any ‘yaml’ package that might be used by ceph.

Duncan

[Chris MacNaughton (chris.macnaughton)]

After installing Ceph on a focal machine, I could not reproduce this issue as I already had python3-yaml installed on the machine. To rule out deployment tooling installing python3-yaml, I started to remove it and discovered that there are a lot of dependencies on python3-yaml:

# sudo apt remove python3-yaml
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following package was automatically installed and is no longer required:
  libnetplan0
Use 'sudo apt autoremove' to remove it.
The following packages will be REMOVED:
  cloud-init netplan.io python3-yaml ubuntu-advantage-tools ubuntu-minimal

The ceph-mgr-dashaboard package is missing a dependency on python3-yaml so there is a fix proposed to the Ubuntu package (https://code.launchpad.net/~chris.macnaughton/ubuntu/+source/ceph/+git/ceph/+merge/383332) and there is a package in https://launchpad.net/~chris.macnaughton/+archive/ubuntu/focal-ussuri off of the linked merge proposal.

[Launchpad Janitor (janitor)]

This bug was fixed in the package ceph - 15.2.3-0ubuntu1

---------------
ceph (15.2.3-0ubuntu1) groovy; urgency=medium

  [ Chris MacNaughton ]
  * d/control: Add python3-yaml to the Ceph dashboard depends (LP: #1876325)

  [ James Page ]
  * New upstream release (LP: #1880084).
  * d/p/revert-rgw-move-frontends-initial-init-to-after-glob.patch:
    Dropped, fix upstream.
  * d/p/32bit-fixes.patch: Misc updates for 32bit arch build failures.
  * d/p/*: Refresh.

 -- James Page <email address hidden> Mon, 08 Jun 2020 09:20:21 +0100