ceph/doc/cephadm/troubleshooting.rst

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Troubleshooting
===============
Sometimes there is a need to investigate why a cephadm command failed or why
a specific service no longer runs properly.
As cephadm deploys daemons as containers, troubleshooting daemons is slightly
different. Here are a few tools and commands to help investigating issues.
Pausing or disabling cephadm
----------------------------
If something goes wrong and cephadm is doing behaving in a way you do
not like, you can pause most background activity with::
ceph orch pause
This will stop any changes, but cephadm will still periodically check hosts to
refresh its inventory of daemons and devices. You can disable cephadm
completely with::
ceph orch set backend ''
ceph mgr module disable cephadm
This will disable all of the ``ceph orch ...`` CLI commands but the previously
deployed daemon containers will still continue to exist and start as they
did before.
Checking cephadm logs
---------------------
You can monitor the cephadm log in real time with::
ceph -W cephadm
You can see the last few messages with::
ceph log last cephadm
If you have enabled logging to files, you can see a cephadm log file called
``ceph.cephadm.log`` on monitor hosts (see :ref:`cephadm-logs`).
Gathering log files
-------------------
Use journalctl to gather the log files of all daemons:
.. note:: By default cephadm now stores logs in journald. This means
that you will no longer find daemon logs in ``/var/log/ceph/``.
To read the log file of one specific daemon, run::
cephadm logs --name <name-of-daemon>
Note: this only works when run on the same host where the daemon is running. To
get logs of a daemon running on a different host, give the ``--fsid`` option::
cephadm logs --fsid <fsid> --name <name-of-daemon>
where the ``<fsid>`` corresponds to the cluster ID printed by ``ceph status``.
To fetch all log files of all daemons on a given host, run::
for name in $(cephadm ls | jq -r '.[].name') ; do
cephadm logs --fsid <fsid> --name "$name" > $name;
done
Collecting systemd status
-------------------------
To print the state of a systemd unit, run::
systemctl status "ceph-$(cephadm shell ceph fsid)@<service name>.service";
To fetch all state of all daemons of a given host, run::
fsid="$(cephadm shell ceph fsid)"
for name in $(cephadm ls | jq -r '.[].name') ; do
systemctl status "ceph-$fsid@$name.service" > $name;
done
List all downloaded container images
------------------------------------
To list all container images that are downloaded on a host:
.. note:: ``Image`` might also be called `ImageID`
::
podman ps -a --format json | jq '.[].Image'
"docker.io/library/centos:8"
"registry.opensuse.org/opensuse/leap:15.2"
Manually running containers
---------------------------
Cephadm writes small wrappers that run a containers. Refer to
``/var/lib/ceph/<cluster-fsid>/<service-name>/unit.run`` for the
container execution command.
.. _cephadm-ssh-errors:
ssh errors
----------
Error message::
xxxxxx.gateway_bootstrap.HostNotFound: -F /tmp/cephadm-conf-kbqvkrkw root@10.10.1.2
raise OrchestratorError('Failed to connect to %s (%s). Check that the host is reachable and accepts connections using the cephadm SSH key' % (host, addr)) from
orchestrator._interface.OrchestratorError: Failed to connect to 10.10.1.2 (10.10.1.2). Check that the host is reachable and accepts connections using the cephadm SSH key
Things users can do:
1. Ensure cephadm has an SSH identity key::
[root@mon1~]# cephadm shell -- ceph config-key get mgr/cephadm/ssh_identity_key > key
INFO:cephadm:Inferring fsid f8edc08a-7f17-11ea-8707-000c2915dd98
INFO:cephadm:Using recent ceph image docker.io/ceph/ceph:v15 obtained 'mgr/cephadm/ssh_identity_key'
[root@mon1 ~] # chmod 0600 key
If this fails, cephadm doesn't have a key. Fix this by running the following command::
[root@mon1 ~]# cephadm shell -- ceph cephadm generate-ssh-key
or::
[root@mon1 ~]# cat key | cephadm shell -- ceph cephadm set-ssk-key -i -
2. Ensure that the ssh config is correct::
[root@mon1 ~]# cephadm shell -- ceph cephadm get-ssh-config > config
3. Verify that we can connect to the host::
[root@mon1 ~]# ssh -F config -i key root@mon1
4. There is a limitation right now: the ssh user is always `root`.
Verifying that the Public Key is Listed in the authorized_keys file
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
To verify that the public key is in the authorized_keys file, run the following commands::
[root@mon1 ~]# cephadm shell -- ceph config-key get mgr/cephadm/ssh_identity_pub > key.pub
[root@mon1 ~]# grep "`cat key.pub`" /root/.ssh/authorized_keys
Failed to infer CIDR network error
----------------------------------
If you see this error::
ERROR: Failed to infer CIDR network for mon ip ***; pass --skip-mon-network to configure it later
Or this error::
Must set public_network config option or specify a CIDR network, ceph addrvec, or plain IP
This means that you must run a command of this form::
ceph config set mon public_network <mon_network>
For more detail on operations of this kind, see :ref:`deploy_additional_monitors`
Accessing the admin socket
--------------------------
Each Ceph daemon provides an admin socket that bypasses the
MONs (See :ref:`rados-monitoring-using-admin-socket`).
To access the admin socket, first enter the daemon container on the host::
[root@mon1 ~]# cephadm enter --name <daemon-name>
[ceph: root@mon1 /]# ceph --admin-daemon /var/run/ceph/ceph-<daemon-name>.asok config show