** Description changed:
[Impact]
On tentacle/edge rev 1956 (20.2.4+snap2b1a2cf17b), the prometheus and
dashboard mgr modules fail to import:
ModuleNotFoundError: No module named 'cherrypy_mgr'
cherrypy_mgr.py is not shipped in the snap. The only top-level files in
share/ceph/mgr/ are:
$ unsquashfs -l microceph_1956.snap | grep -E 'share/ceph/mgr/[^/]+\.py$'
squashfs-root/share/ceph/mgr/mgr_module.py
squashfs-root/share/ceph/mgr/mgr_util.py
squashfs-root/share/ceph/mgr/object_format.py
latest/edge rev 1967 has the same content.
The Ceph exporter never starts: nothing listens on :9283, and ceph mgr
services returns {}. No Ceph metrics or alerts reach COS.
- The dashboard cannot start, now for this reason rather than the missing
- smb module in Tentacle 20.2.1: Dashboard fails to start due to missing
- mgr/smb module (ModuleNotFoundError: No module named 'smb') #811.
-
With the microceph charm (rev 327, the same revision on tentacle/stable,
candidate and edge), a fresh deployment never forms a cluster. The leader
bootstraps, then its config-changed hook fails on every retry, and the other
units stay Leader not ready. There are two failures in sequence:
ceph mgr module enable prometheus returns ENOENT: module 'prometheus'
reports that it cannot run on the active manager daemon: No module named
'cherrypy_mgr'.
After ceph mgr module enable prometheus --force: ceph config set mgr
mgr/prometheus/exclude_perf_counters False returns EINVAL: unrecognized config
option. The option is only registered once the module loads.
- The charm's cos-agent refresh runs both calls on config-changed whether
- or not a cos-agent relation exists
- (lib/charms/ceph_mon/v0/ceph_cos_agent.py _on_refresh, src/microceph.py
- cos_agent_mgr_config_set_cb). No charm config value avoids them, so
- there is no operator-side workaround.
-
- The first error in the log, Unable to initialize cluster: Database is
- online, is not the cause. The first bootstrap succeeded, and every hook
- retry repeats it harmlessly.
-
Suggested fix:
- Snap: ship usr/share/ceph/mgr/cherrypy_mgr.py (fix the ceph-mgr install list
in the PPA packaging, or stage the file explicitly).
- Charm (secondary, for charm-microceph): do not fail the hook when the
prometheus module cannot run. Catch the error in the cos-agent refresh and set
a status instead, so a broken optional mgr module cannot block cluster
formation.
+ Ship usr/share/ceph/mgr/cherrypy_mgr.py in ceph-mgr.install, just like the
+ upstream ceph packaging:
+
+ commit 1384ae37c700e08688952bf437c40cac860c0fc7
+ From: Nizamudeen A <[email protected]>
+ Date: Thu, 5 Feb 2026 16:12:47 +0530
+ Subject: mgr: isolated CherryPy to prevent global state sharing
+ Link:
https://github.com/ceph/ceph/commit/1384ae37c700e08688952bf437c40cac860c0fc7#diff-1eaa1ccbdfb8f283ed4e96972d902b6048073fe77adc21ba9708a93705b650fcR6
[Test Case]
+
+ $ sudo apt install ceph-mgr
+ $ cd /usr/share/ceph/mgr
+ $ python3
+ >>> from cherrypy_mgr import CherryPyMgr
+ Traceback (most recent call last):
+ File "<python-input-0>", line 1, in <module>
+ from cherrypy_mgr import CherryPyMgr
+ ModuleNotFoundError: No module named 'cherrypy_mgr'
+
+ If you enable -proposed and install the fixed package, the import completes
+ correctly.
+
+ >>> from cherrypy_mgr import CherryPyMgr
+ >>>
+
+ The prometheus and mgr modules can be tested to ensure they work
+ correctly by:
Deploy the microceph charm with snap-channel=tentacle/edge:
juju deploy microceph --channel tentacle/edge --config snap-
channel=tentacle/edge -n 3
+
+ Note for SRU verification, the snap will be built with packages from
+ resolute-proposed.
Watch the leader: bootstrap succeeds, then config-changed fails with failure
1 above.
On the leader, run sudo microceph.ceph mgr module enable prometheus --force,
then juju resolve microceph/<leader>. The hook now fails with failure 2.
Snap only, without the charm. We saw the same module failure in a
single-node VM on rev 1956 via tentacle/candidate. The enable command is
the same one the charm runs:
sudo snap install microceph --channel tentacle/edge
sudo microceph cluster bootstrap
sudo microceph.ceph mgr module enable prometheus
- # Error ENOENT: module 'prometheus' reports that it cannot run on the active
manager daemon: No module named 'cherrypy_mg
+ # Error ENOENT: module 'prometheus' reports that it cannot run on the active
manager daemon: No module named 'cherrypy_mgr'
The Ceph team has validated that the inclusion of this new dependency
fixes the associated problems by running the functional test suite for
Microceph and Ceph Rocks.
[ Where problems can occur ]
Shipping the proper python modules in their correct locations is unlikely to
create any issues. If an import was being skipped previously, it will now
function correctly, and may add new functionality.
In order to mitigate the regression potential, the results of the
aforementioned tests can be seen here:
https://github.com/canonical/ceph-containers/pull/104
[ Other info ]
For more details, see: https://github.com/canonical/microceph/issues/874
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https://bugs.launchpad.net/bugs/2169663
Title:
ceph dashboard fails to start due to missing cherrypy_mgr dependency
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