ceph/doc/cephadm/upgrade.rst
Sebastian Wagner f454a77d5e
Merge pull request #41186 from zdover23/wip-doc-cephadm-upgrade-starting-the-upgrade-2021-05-06
doc/cephadm: rewriting "starting the upgrade"

Reviewed-by: Juan Miguel Olmo Martínez <jolmomar@redhat.com>
2021-05-06 13:18:09 +02:00

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==============
Upgrading Ceph
==============
Cephadm is capable of safely upgrading Ceph from one bugfix release to
another. For example, you can upgrade from v15.2.0 (the first Octopus
release) to the next point release v15.2.1.
The automated upgrade process follows Ceph best practices. For example:
* The upgrade order starts with managers, monitors, then other daemons.
* Each daemon is restarted only after Ceph indicates that the cluster
will remain available.
Keep in mind that the Ceph cluster health status is likely to switch to
`HEALTH_WARNING` during the upgrade.
Starting the upgrade
====================
Before you begin using cephadm to upgrade Ceph, verify that all hosts are currently online and that your cluster is healthy:
.. prompt:: bash #
ceph -s
To upgrade (or downgrade) to a specific release:
.. prompt:: bash #
ceph orch upgrade start --ceph-version <version>
For example, to upgrade to v15.2.1:
.. prompt:: bash #
ceph orch upgrade start --ceph-version 15.2.1
Monitoring the upgrade
======================
Determine whether an upgrade is in process and what version the cluster is
upgrading to with:
.. prompt:: bash #
ceph orch upgrade status
While the upgrade is underway, you will see a progress bar in the ceph
status output. For example:
.. prompt:: bash #
ceph -s
Expected output::
[...]
progress:
Upgrade to docker.io/ceph/ceph:v15.2.1 (00h 20m 12s)
[=======.....................] (time remaining: 01h 43m 31s)
You can also watch the cephadm log by running the following command:
.. prompt:: bash #
ceph -W cephadm
Canceling an upgrade
====================
You can stop the upgrade process at any time with:
.. prompt:: bash #
# ceph orch upgrade stop
Potential problems
==================
There are a few health alerts that can arise during the upgrade process.
UPGRADE_NO_STANDBY_MGR
----------------------
This alert means that Ceph requires an active and standby manager daemon in
order to proceed, but there is currently no standby.
You can ensure that Cephadm is configured to run 2 (or more) managers by running the following command:
.. prompt:: bash #
ceph orch apply mgr 2 # or more
You can check the status of existing mgr daemons by running the following command:
.. prompt:: bash #
ceph orch ps --daemon-type mgr
If an existing mgr daemon has stopped, you can try to restart it by running the following command:
.. prompt:: bash #
ceph orch daemon restart <name>
UPGRADE_FAILED_PULL
-------------------
This alert means that Ceph was unable to pull the container image for the
target version. This can happen if you specify a version or container image
that does not exist (e.g. "1.2.3"), or if the container registry can not
be reached by one or more hosts in the cluster.
To cancel the existing upgrade and to specify a different target version, run the following commands:
.. prompt:: bash #
ceph orch upgrade stop
ceph orch upgrade start --ceph-version <version>
Using customized container images
=================================
For most users, upgrading requires nothing more complicated than specifying the
Ceph version number to upgrade to. In such cases, cephadm locates the specific
Ceph container image to use by combining the ``container_image_base``
configuration option (default: ``docker.io/ceph/ceph``) with a tag of
``vX.Y.Z``.
But it is possible to upgrade to an arbitrary container image, if that's what
you need. For example, the following command upgrades to a development build:
.. prompt:: bash #
ceph orch upgrade start --image quay.io/ceph-ci/ceph:recent-git-branch-name
For more information about available container images, see :ref:`containers`.