ceph/doc/cephadm/troubleshooting.rst
Adam King 31959dd6d3 doc/cephadm: wrong command for single daemon events
Fixes: https://tracker.ceph.com/issues/50257

Signed-off-by: Adam King <adking@redhat.com>
2021-04-08 15:43:45 -04:00

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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.
.. _cephadm-pause:
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.
Please refer to :ref:`cephadm-spec-unmanaged` for disabling individual
services.
Per-service and per-daemon events
---------------------------------
In order to aid debugging failed daemon deployments, cephadm stores
events per service and per daemon. They often contain relevant information::
ceph orch ls --service_name=<service-name> --format yaml
for example:
.. code-block:: yaml
service_type: alertmanager
service_name: alertmanager
placement:
hosts:
- unknown_host
status:
...
running: 1
size: 1
events:
- 2021-02-01T08:58:02.741162 service:alertmanager [INFO] "service was created"
- '2021-02-01T12:09:25.264584 service:alertmanager [ERROR] "Failed to apply: Cannot
place <AlertManagerSpec for service_name=alertmanager> on unknown_host: Unknown hosts"'
Or per daemon::
ceph orch ps --service-name <service-name> --daemon-id <daemon-id> --format yaml
.. code-block:: yaml
daemon_type: mds
daemon_id: cephfs.hostname.ppdhsz
hostname: hostname
status_desc: running
...
events:
- 2021-02-01T08:59:43.845866 daemon:mds.cephfs.hostname.ppdhsz [INFO] "Reconfigured
mds.cephfs.hostname.ppdhsz on host 'hostname'"
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::
execnet.gateway_bootstrap.HostNotFound: -F /tmp/cephadm-conf-73z09u6g -i /tmp/cephadm-identity-ky7ahp_5 root@10.10.1.2
...
raise OrchestratorError(msg) from e
orchestrator._interface.OrchestratorError: Failed to connect to 10.10.1.2 (10.10.1.2).
Please make sure 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 > ~/cephadm_private_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 ~/cephadm_private_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 ~/cephadm_private_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 ~/cephadm_private_key root@mon1
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 cephadm get-pub-key > ~/ceph.pub
[root@mon1 ~]# grep "`cat ~/ceph.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
Restoring the MON quorum
------------------------
In case the Ceph MONs cannot form a quorum, cephadm is not able
to manage the cluster, until the quorum is restored.
In order to restore the MON quorum, remove unhealthy MONs
form the monmap by following these steps:
1. Stop all MONs. For each MON host::
ssh {mon-host}
cephadm unit --name mon.`hostname` stop
2. Identify a surviving monitor and log in to that host::
ssh {mon-host}
cephadm enter --name mon.`hostname`
3. Follow the steps in :ref:`rados-mon-remove-from-unhealthy`
Manually deploying a MGR daemon
-------------------------------
cephadm requires a MGR daemon in order to manage the cluster. In case the cluster
the last MGR of a cluster was removed, follow these steps in order to deploy
a MGR ``mgr.hostname.smfvfd`` on a random host of your cluster manually.
Disable the cephadm scheduler, in order to prevent cephadm from removing the new
MGR. See :ref:`cephadm-enable-cli`::
ceph config-key set mgr/cephadm/pause true
Then get or create the auth entry for the new MGR::
ceph auth get-or-create mgr.hostname.smfvfd mon "profile mgr" osd "allow *" mds "allow *"
Get the ceph.conf::
ceph config generate-minimal-conf
Get the container image::
ceph config get "mgr.hostname.smfvfd" container_image
Create a file ``config-json.json`` which contains the information neccessary to deploy
the daemon:
.. code-block:: json
{
"config": "# minimal ceph.conf for 8255263a-a97e-4934-822c-00bfe029b28f\n[global]\n\tfsid = 8255263a-a97e-4934-822c-00bfe029b28f\n\tmon_host = [v2:192.168.0.1:40483/0,v1:192.168.0.1:40484/0]\n",
"keyring": "[mgr.hostname.smfvfd]\n\tkey = V2VyIGRhcyBsaWVzdCBpc3QgZG9vZi4=\n"
}
Deploy the daemon::
cephadm --image <container-image> deploy --fsid <fsid> --name mgr.hostname.smfvfd --config-json config-json.json