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Diffstat (limited to 'doc/cephadm/host-management.rst')
| -rw-r--r-- | doc/cephadm/host-management.rst | 72 |
1 files changed, 50 insertions, 22 deletions
diff --git a/doc/cephadm/host-management.rst b/doc/cephadm/host-management.rst index 4b964c5f4..1fba8e582 100644 --- a/doc/cephadm/host-management.rst +++ b/doc/cephadm/host-management.rst @@ -74,9 +74,9 @@ To add each new host to the cluster, perform two steps: ceph orch host add host2 10.10.0.102 ceph orch host add host3 10.10.0.103 - It is best to explicitly provide the host IP address. If an IP is + It is best to explicitly provide the host IP address. If an address is not provided, then the host name will be immediately resolved via - DNS and that IP will be used. + DNS and the result will be used. One or more labels can also be included to immediately label the new host. For example, by default the ``_admin`` label will make @@ -104,7 +104,7 @@ To drain all daemons from a host, run a command of the following form: The ``_no_schedule`` and ``_no_conf_keyring`` labels will be applied to the host. See :ref:`cephadm-special-host-labels`. -If you only want to drain daemons but leave managed ceph conf and keyring +If you want to drain daemons but leave managed `ceph.conf` and keyring files on the host, you may pass the ``--keep-conf-keyring`` flag to the drain command. @@ -115,7 +115,8 @@ drain command. This will apply the ``_no_schedule`` label to the host but not the ``_no_conf_keyring`` label. -All OSDs on the host will be scheduled to be removed. You can check the progress of the OSD removal operation with the following command: +All OSDs on the host will be scheduled to be removed. You can check +progress of the OSD removal operation with the following command: .. prompt:: bash # @@ -148,7 +149,7 @@ cluster by running the following command: Offline host removal -------------------- -Even if a host is offline and can not be recovered, it can be removed from the +If a host is offline and can not be recovered, it can be removed from the cluster by running a command of the following form: .. prompt:: bash # @@ -250,8 +251,8 @@ Rescanning Host Devices ======================= Some servers and external enclosures may not register device removal or insertion with the -kernel. In these scenarios, you'll need to perform a host rescan. A rescan is typically -non-disruptive, and can be performed with the following CLI command: +kernel. In these scenarios, you'll need to perform a device rescan on the appropriate host. +A rescan is typically non-disruptive, and can be performed with the following CLI command: .. prompt:: bash # @@ -314,19 +315,43 @@ create a new CRUSH host located in the specified hierarchy. .. note:: - The ``location`` attribute will be only affect the initial CRUSH location. Subsequent - changes of the ``location`` property will be ignored. Also, removing a host will not remove - any CRUSH buckets. + The ``location`` attribute will be only affect the initial CRUSH location. + Subsequent changes of the ``location`` property will be ignored. Also, + removing a host will not remove an associated CRUSH bucket unless the + ``--rm-crush-entry`` flag is provided to the ``orch host rm`` command See also :ref:`crush_map_default_types`. +Removing a host from the CRUSH map +================================== + +The ``ceph orch host rm`` command has support for removing the associated host bucket +from the CRUSH map. This is done by providing the ``--rm-crush-entry`` flag. + +.. prompt:: bash [ceph:root@host1/]# + + ceph orch host rm host1 --rm-crush-entry + +When this flag is specified, cephadm will attempt to remove the host bucket +from the CRUSH map as part of the host removal process. Note that if +it fails to do so, cephadm will report the failure and the host will remain under +cephadm control. + +.. note:: + + Removal from the CRUSH map will fail if there are OSDs deployed on the + host. If you would like to remove all the host's OSDs as well, please start + by using the ``ceph orch host drain`` command to do so. Once the OSDs + have been removed, then you may direct cephadm remove the CRUSH bucket + along with the host using the ``--rm-crush-entry`` flag. + OS Tuning Profiles ================== -Cephadm can be used to manage operating-system-tuning profiles that apply sets -of sysctl settings to sets of hosts. +Cephadm can be used to manage operating system tuning profiles that apply +``sysctl`` settings to sets of hosts. -Create a YAML spec file in the following format: +To do so, create a YAML spec file in the following format: .. code-block:: yaml @@ -345,18 +370,21 @@ Apply the tuning profile with the following command: ceph orch tuned-profile apply -i <tuned-profile-file-name> -This profile is written to ``/etc/sysctl.d/`` on each host that matches the -hosts specified in the placement block of the yaml, and ``sysctl --system`` is +This profile is written to a file under ``/etc/sysctl.d/`` on each host +specified in the ``placement`` block, then ``sysctl --system`` is run on the host. .. note:: The exact filename that the profile is written to within ``/etc/sysctl.d/`` is ``<profile-name>-cephadm-tuned-profile.conf``, where ``<profile-name>`` is - the ``profile_name`` setting that you specify in the YAML spec. Because + the ``profile_name`` setting that you specify in the YAML spec. We suggest + naming these profiles following the usual ``sysctl.d`` `NN-xxxxx` convention. Because sysctl settings are applied in lexicographical order (sorted by the filename - in which the setting is specified), you may want to set the ``profile_name`` - in your spec so that it is applied before or after other conf files. + in which the setting is specified), you may want to carefully choose + the ``profile_name`` in your spec so that it is applied before or after other + conf files. Careful selection ensures that values supplied here override or + do not override those in other ``sysctl.d`` files as desired. .. note:: @@ -365,7 +393,7 @@ run on the host. .. note:: - Applying tuned profiles is idempotent when the ``--no-overwrite`` option is + Applying tuning profiles is idempotent when the ``--no-overwrite`` option is passed. Moreover, if the ``--no-overwrite`` option is passed, existing profiles with the same name are not overwritten. @@ -525,7 +553,7 @@ There are two ways to customize this configuration for your environment: We do *not recommend* this approach. The path name must be visible to *any* mgr daemon, and cephadm runs all daemons as - containers. That means that the file either need to be placed + containers. That means that the file must either be placed inside a customized container image for your deployment, or manually distributed to the mgr data directory (``/var/lib/ceph/<cluster-fsid>/mgr.<id>`` on the host, visible at @@ -578,8 +606,8 @@ Note that ``man hostname`` recommends ``hostname`` to return the bare host name: The FQDN (Fully Qualified Domain Name) of the system is the - name that the resolver(3) returns for the host name, such as, - ursula.example.com. It is usually the hostname followed by the DNS + name that the resolver(3) returns for the host name, for example + ``ursula.example.com``. It is usually the short hostname followed by the DNS domain name (the part after the first dot). You can check the FQDN using ``hostname --fqdn`` or the domain name using ``dnsdomainname``. |