From 19fcec84d8d7d21e796c7624e521b60d28ee21ed Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sun, 7 Apr 2024 20:45:59 +0200
Subject: Adding upstream version 16.2.11+ds.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 doc/cephadm/host-management.rst | 436 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 436 insertions(+)
 create mode 100644 doc/cephadm/host-management.rst

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diff --git a/doc/cephadm/host-management.rst b/doc/cephadm/host-management.rst
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+.. _orchestrator-cli-host-management:
+
+===============
+Host Management
+===============
+
+Listing Hosts
+=============
+
+Run a command of this form to list hosts associated with the cluster:
+
+.. prompt:: bash #
+
+   ceph orch host ls [--format yaml] [--host-pattern <name>] [--label <label>] [--host-status <status>]
+
+In commands of this form, the arguments "host-pattern", "label" and
+"host-status" are optional and are used for filtering. 
+
+- "host-pattern" is a regex that matches against hostnames and returns only
+  matching hosts.
+- "label" returns only hosts with the specified label.
+- "host-status" returns only hosts with the specified status (currently
+  "offline" or "maintenance").
+- Any combination of these filtering flags is valid. It is possible to filter
+  against name, label and status simultaneously, or to filter against any
+  proper subset of name, label and status.
+
+.. _cephadm-adding-hosts:    
+    
+Adding Hosts
+============
+
+Hosts must have these :ref:`cephadm-host-requirements` installed.
+Hosts without all the necessary requirements will fail to be added to the cluster.
+
+To add each new host to the cluster, perform two steps:
+
+#. Install the cluster's public SSH key in the new host's root user's ``authorized_keys`` file:
+
+   .. prompt:: bash #
+
+      ssh-copy-id -f -i /etc/ceph/ceph.pub root@*<new-host>*
+
+   For example:
+
+   .. prompt:: bash #
+
+      ssh-copy-id -f -i /etc/ceph/ceph.pub root@host2
+      ssh-copy-id -f -i /etc/ceph/ceph.pub root@host3
+
+#. Tell Ceph that the new node is part of the cluster:
+
+   .. prompt:: bash #
+
+      ceph orch host add *<newhost>* [*<ip>*] [*<label1> ...*]
+
+   For example:
+
+   .. prompt:: bash #
+
+     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
+   not provided, then the host name will be immediately resolved via
+   DNS and that IP 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
+   cephadm maintain a copy of the ``ceph.conf`` file and a
+   ``client.admin`` keyring file in ``/etc/ceph``:
+
+   .. prompt:: bash #
+
+      ceph orch host add host4 10.10.0.104 --labels _admin
+
+.. _cephadm-removing-hosts:
+
+Removing Hosts
+==============
+
+A host can safely be removed from the cluster after all daemons are removed
+from it.
+
+To drain all daemons from a host, run a command of the following form:
+
+.. prompt:: bash #
+
+   ceph orch host drain *<host>*
+
+The ``_no_schedule`` label will be applied to the host. See
+:ref:`cephadm-special-host-labels`.
+
+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:
+
+.. prompt:: bash #
+
+   ceph orch osd rm status
+
+See :ref:`cephadm-osd-removal` for more details about OSD removal.
+
+Use the following command to determine whether any daemons are still on the
+host:
+
+.. prompt:: bash #
+
+   ceph orch ps <host> 
+
+After all daemons have been removed from the host, remove the host from the
+cluster by running the following command: 
+
+.. prompt:: bash #
+
+   ceph orch host rm <host>
+
+Offline host removal
+--------------------
+
+Even 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 #
+
+   ceph orch host rm <host> --offline --force
+
+.. warning:: This can potentially cause data loss. This command forcefully
+   purges OSDs from the cluster by calling ``osd purge-actual`` for each OSD.
+   Any service specs that still contain this host should be manually updated.
+
+.. _orchestrator-host-labels:
+
+Host labels
+===========
+
+The orchestrator supports assigning labels to hosts. Labels
+are free form and have no particular meaning by itself and each host
+can have multiple labels. They can be used to specify placement
+of daemons. See :ref:`orch-placement-by-labels`
+
+Labels can be added when adding a host with the ``--labels`` flag:
+
+.. prompt:: bash #
+
+   ceph orch host add my_hostname --labels=my_label1
+   ceph orch host add my_hostname --labels=my_label1,my_label2
+
+To add a label a existing host, run:
+
+.. prompt:: bash #
+
+   ceph orch host label add my_hostname my_label
+
+To remove a label, run:
+
+.. prompt:: bash #
+
+   ceph orch host label rm my_hostname my_label
+
+
+.. _cephadm-special-host-labels:
+
+Special host labels
+-------------------
+
+The following host labels have a special meaning to cephadm.  All start with ``_``.
+
+* ``_no_schedule``: *Do not schedule or deploy daemons on this host*.
+
+  This label prevents cephadm from deploying daemons on this host.  If it is added to
+  an existing host that already contains Ceph daemons, it will cause cephadm to move
+  those daemons elsewhere (except OSDs, which are not removed automatically).
+
+* ``_no_autotune_memory``: *Do not autotune memory on this host*.
+
+  This label will prevent daemon memory from being tuned even when the
+  ``osd_memory_target_autotune`` or similar option is enabled for one or more daemons
+  on that host.
+
+* ``_admin``: *Distribute client.admin and ceph.conf to this host*.
+
+  By default, an ``_admin`` label is applied to the first host in the cluster (where
+  bootstrap was originally run), and the ``client.admin`` key is set to be distributed
+  to that host via the ``ceph orch client-keyring ...`` function.  Adding this label
+  to additional hosts will normally cause cephadm to deploy config and keyring files
+  in ``/etc/ceph``.
+
+Maintenance Mode
+================
+
+Place a host in and out of maintenance mode (stops all Ceph daemons on host):
+
+.. prompt:: bash #
+
+   ceph orch host maintenance enter <hostname> [--force]
+   ceph orch host maintenance exit <hostname>
+
+Where the force flag when entering maintenance allows the user to bypass warnings (but not alerts)
+
+See also :ref:`cephadm-fqdn`
+
+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:
+
+.. prompt:: bash #
+
+   ceph orch host rescan <hostname> [--with-summary]
+
+The ``with-summary`` flag provides a breakdown of the number of HBAs found and scanned, together
+with any that failed:
+
+.. prompt:: bash [ceph:root@rh9-ceph1/]#
+
+   ceph orch host rescan rh9-ceph1 --with-summary
+   
+::
+
+   Ok. 2 adapters detected: 2 rescanned, 0 skipped, 0 failed (0.32s)
+
+Creating many hosts at once
+===========================
+
+Many hosts can be added at once using
+``ceph orch apply -i`` by submitting a multi-document YAML file:
+
+.. code-block:: yaml
+
+    service_type: host
+    hostname: node-00
+    addr: 192.168.0.10
+    labels:
+    - example1
+    - example2
+    ---
+    service_type: host
+    hostname: node-01
+    addr: 192.168.0.11
+    labels:
+    - grafana
+    ---
+    service_type: host
+    hostname: node-02
+    addr: 192.168.0.12
+
+This can be combined with service specifications (below) to create a cluster spec
+file to deploy a whole cluster in one command.  see ``cephadm bootstrap --apply-spec``
+also to do this during bootstrap. Cluster SSH Keys must be copied to hosts prior to adding them.
+
+Setting the initial CRUSH location of host
+==========================================
+
+Hosts can contain a ``location`` identifier which will instruct cephadm to 
+create a new CRUSH host located in the specified hierachy.
+
+.. code-block:: yaml
+
+    service_type: host
+    hostname: node-00
+    addr: 192.168.0.10
+    location:
+      rack: rack1
+
+.. 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 no remove
+  any CRUSH buckets.
+
+See also :ref:`crush_map_default_types`.
+
+SSH Configuration
+=================
+
+Cephadm uses SSH to connect to remote hosts.  SSH uses a key to authenticate
+with those hosts in a secure way.
+
+
+Default behavior
+----------------
+
+Cephadm stores an SSH key in the monitor that is used to
+connect to remote hosts.  When the cluster is bootstrapped, this SSH
+key is generated automatically and no additional configuration
+is necessary.
+
+A *new* SSH key can be generated with:
+
+.. prompt:: bash #
+
+   ceph cephadm generate-key
+
+The public portion of the SSH key can be retrieved with:
+
+.. prompt:: bash #
+
+   ceph cephadm get-pub-key
+
+The currently stored SSH key can be deleted with:
+
+.. prompt:: bash #
+
+   ceph cephadm clear-key
+
+You can make use of an existing key by directly importing it with:
+
+.. prompt:: bash #
+
+   ceph config-key set mgr/cephadm/ssh_identity_key -i <key>
+   ceph config-key set mgr/cephadm/ssh_identity_pub -i <pub>
+
+You will then need to restart the mgr daemon to reload the configuration with:
+
+.. prompt:: bash #
+
+   ceph mgr fail
+
+.. _cephadm-ssh-user:
+
+Configuring a different SSH user
+----------------------------------
+
+Cephadm must be able to log into all the Ceph cluster nodes as an user
+that has enough privileges to download container images, start containers
+and execute commands without prompting for a password. If you do not want
+to use the "root" user (default option in cephadm), you must provide
+cephadm the name of the user that is going to be used to perform all the
+cephadm operations. Use the command:
+
+.. prompt:: bash #
+
+   ceph cephadm set-user <user>
+
+Prior to running this the cluster SSH key needs to be added to this users
+authorized_keys file and non-root users must have passwordless sudo access.
+
+
+Customizing the SSH configuration
+---------------------------------
+
+Cephadm generates an appropriate ``ssh_config`` file that is
+used for connecting to remote hosts.  This configuration looks
+something like this::
+
+  Host *
+  User root
+  StrictHostKeyChecking no
+  UserKnownHostsFile /dev/null
+
+There are two ways to customize this configuration for your environment:
+
+#. Import a customized configuration file that will be stored
+   by the monitor with:
+
+   .. prompt:: bash #
+
+      ceph cephadm set-ssh-config -i <ssh_config_file>
+
+   To remove a customized SSH config and revert back to the default behavior:
+
+   .. prompt:: bash #
+
+      ceph cephadm clear-ssh-config
+
+#. You can configure a file location for the SSH configuration file with:
+
+   .. prompt:: bash #
+
+      ceph config set mgr mgr/cephadm/ssh_config_file <path>
+
+   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
+   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
+   ``/var/lib/ceph/mgr/ceph-<id>`` from inside the container).
+   
+.. _cephadm-fqdn:
+
+Fully qualified domain names vs bare host names
+===============================================
+
+.. note::
+
+  cephadm demands that the name of the host given via ``ceph orch host add`` 
+  equals the output of ``hostname`` on remote hosts.
+
+Otherwise cephadm can't be sure that names returned by
+``ceph * metadata`` match the hosts known to cephadm. This might result
+in a :ref:`cephadm-stray-host` warning.
+
+When configuring new hosts, there are two **valid** ways to set the 
+``hostname`` of a host:
+
+1. Using the bare host name. In this case:
+
+-  ``hostname`` returns the bare host name.
+-  ``hostname -f`` returns the FQDN.
+
+2. Using the fully qualified domain name as the host name. In this case:
+
+-  ``hostname`` returns the FQDN
+-  ``hostname -s`` return the bare host name
+
+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
+    domain name (the part after the first dot). You can check the FQDN
+    using ``hostname --fqdn`` or the domain name using ``dnsdomainname``.
+
+    .. code-block:: none
+
+          You cannot change the FQDN with hostname or dnsdomainname.
+
+          The recommended method of setting the FQDN is to make the hostname
+          be an alias for the fully qualified name using /etc/hosts, DNS, or
+          NIS. For example, if the hostname was "ursula", one might have
+          a line in /etc/hosts which reads
+
+                 127.0.1.1    ursula.example.com ursula
+
+Which means, ``man hostname`` recommends ``hostname`` to return the bare
+host name. This in turn means that Ceph will return the bare host names
+when executing ``ceph * metadata``. This in turn means cephadm also
+requires the bare host name when adding a host to the cluster: 
+``ceph orch host add <bare-name>``.
+
+..
+  TODO: This chapter needs to provide way for users to configure
+  Grafana in the dashboard, as this is right now very hard to do.
-- 
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