.. _cephadm_deploying_new_cluster: ========================================== Using cephadm to Deploy a New Ceph Cluster ========================================== Cephadm creates a new Ceph cluster by bootstrapping a single host, expanding the cluster to encompass any additional hosts, and then deploying the needed services. .. highlight:: console .. _cephadm-host-requirements: Requirements ============ - Python 3 - Systemd - Podman or Docker for running containers - Time synchronization (such as Chrony or the legacy ``ntpd``) - LVM2 for provisioning storage devices Any modern Linux distribution should be sufficient. Dependencies are installed automatically by the bootstrap process below. See `Docker Live Restore `_ for an optional feature that allows restarting Docker Engine without restarting all running containers. See the section :ref:`Compatibility With Podman Versions` for a table of Ceph versions that are compatible with Podman. Not every version of Podman is compatible with Ceph. .. _get-cephadm: Install cephadm =============== When installing cephadm there are two key steps: first you need to acquire an initial copy of cephadm, then the second step is to ensure you have an up-to-date cephadm. There are two ways to get the initial ``cephadm``: #. :ref:`distribution-specific installation methods` #. a :ref:`curl-based installation` method .. important:: These methods of installing ``cephadm`` are mutually exclusive. Choose either the distribution-specific method or the curl-based method. Do not attempt to use both these methods on one system. .. note:: Recent versions of cephadm are distributed as an executable compiled from source code. Unlike for earlier versions of Ceph it is no longer sufficient to copy a single script from Ceph's git tree and run it. If you wish to run cephadm using a development version you should create your own build of cephadm. See :ref:`compiling-cephadm` for details on how to create your own standalone cephadm executable. .. _cephadm_install_distros: distribution-specific installations ----------------------------------- Some Linux distributions may already include up-to-date Ceph packages. In that case, you can install cephadm directly. For example: In Ubuntu: .. prompt:: bash # apt install -y cephadm In CentOS Stream: .. prompt:: bash # :substitutions: dnf search release-ceph dnf install --assumeyes centos-release-ceph-|stable-release| dnf install --assumeyes cephadm In Fedora: .. prompt:: bash # dnf -y install cephadm In SUSE: .. prompt:: bash # zypper install -y cephadm .. _cephadm_install_curl: Using curl to install cephadm ----------------------------- #. Determine which version of Ceph you will install. Use the releases page to find the `latest active releases `_. For example, you might find that ``18.2.1`` is the latest active release. #. Use ``curl`` to fetch a build of cephadm for that release. .. prompt:: bash # :substitutions: CEPH_RELEASE=18.2.0 # replace this with the active release curl --silent --remote-name --location https://download.ceph.com/rpm-${CEPH_RELEASE}/el9/noarch/cephadm #. Use ``chmod`` to make the ``cephadm`` file executable: .. prompt:: bash # chmod +x cephadm After ``chmod`` has been run on cephadm, it can be run from the current directory: .. prompt:: bash # ./cephadm cephadm Requires Python 3.6 or Later ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ * ``cephadm`` requires Python 3.6 or later. If you encounter difficulties running ``cephadm``, then you may not have Python or the correct version of Python installed. This includes any errors that include the message ``bad interpreter``. You can manually run cephadm with a particular version of Python by prefixing the command with your installed Python version. For example: .. prompt:: bash # python3.8 ./cephadm Installing cephadm on the Host ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Although the standalone ``cephadm`` is sufficient to bootstrap a cluster, it is best to have the ``cephadm`` command installed on the host. To install the packages that provide the ``cephadm`` command, run the following commands: #. Add the repository: .. prompt:: bash # ./cephadm add-repo --release |stable-release| #. Run ``cephadm install``: .. prompt:: bash # ./cephadm install #. Confirm that ``cephadm`` is now in your PATH by running ``which``: .. prompt:: bash # which cephadm A successful ``which cephadm`` command will return this: .. code-block:: bash /usr/sbin/cephadm Bootstrap a new cluster ======================= What to know before you bootstrap --------------------------------- The first step in creating a new Ceph cluster is running the ``cephadm bootstrap`` command on the Ceph cluster's first host. The act of running the ``cephadm bootstrap`` command on the Ceph cluster's first host creates the Ceph cluster's first Monitor daemon. You must pass the IP address of the Ceph cluster's first host to the ``ceph bootstrap`` command, so you'll need to know the IP address of that host. .. important:: ``ssh`` must be installed and running in order for the bootstrapping procedure to succeed. .. note:: If there are multiple networks and interfaces, be sure to choose one that will be accessible by any host accessing the Ceph cluster. Running the bootstrap command ----------------------------- Run the ``ceph bootstrap`` command: .. prompt:: bash # cephadm bootstrap --mon-ip ** This command will: * Create a Monitor and a Manager daemon for the new cluster on the local host. * Generate a new SSH key for the Ceph cluster and add it to the root user's ``/root/.ssh/authorized_keys`` file. * Write a copy of the public key to ``/etc/ceph/ceph.pub``. * Write a minimal configuration file to ``/etc/ceph/ceph.conf``. This file is needed to communicate with Ceph daemons. * Write a copy of the ``client.admin`` administrative (privileged!) secret key to ``/etc/ceph/ceph.client.admin.keyring``. * Add the ``_admin`` label to the bootstrap host. By default, any host with this label will (also) get a copy of ``/etc/ceph/ceph.conf`` and ``/etc/ceph/ceph.client.admin.keyring``. .. _cephadm-bootstrap-further-info: Further information about cephadm bootstrap ------------------------------------------- The default bootstrap process will work for most users. But if you'd like immediately to know more about ``cephadm bootstrap``, read the list below. Also, you can run ``cephadm bootstrap -h`` to see all of ``cephadm``'s available options. * By default, Ceph daemons send their log output to stdout/stderr, which is picked up by the container runtime (docker or podman) and (on most systems) sent to journald. If you want Ceph to write traditional log files to ``/var/log/ceph/$fsid``, use the ``--log-to-file`` option during bootstrap. * Larger Ceph clusters perform best when (external to the Ceph cluster) public network traffic is separated from (internal to the Ceph cluster) cluster traffic. The internal cluster traffic handles replication, recovery, and heartbeats between OSD daemons. You can define the :ref:`cluster network` by supplying the ``--cluster-network`` option to the ``bootstrap`` subcommand. This parameter must be a subnet in CIDR notation (for example ``10.90.90.0/24`` or ``fe80::/64``). * ``cephadm bootstrap`` writes to ``/etc/ceph`` files needed to access the new cluster. This central location makes it possible for Ceph packages installed on the host (e.g., packages that give access to the cephadm command line interface) to find these files. Daemon containers deployed with cephadm, however, do not need ``/etc/ceph`` at all. Use the ``--output-dir **`` option to put them in a different directory (for example, ``.``). This may help avoid conflicts with an existing Ceph configuration (cephadm or otherwise) on the same host. * You can pass any initial Ceph configuration options to the new cluster by putting them in a standard ini-style configuration file and using the ``--config **`` option. For example:: $ cat < initial-ceph.conf [global] osd crush chooseleaf type = 0 EOF $ ./cephadm bootstrap --config initial-ceph.conf ... * The ``--ssh-user **`` option makes it possible to designate which SSH user cephadm will use to connect to hosts. The associated SSH key will be added to ``/home/**/.ssh/authorized_keys``. The user that you designate with this option must have passwordless sudo access. * If you are using a container image from a registry that requires login, you may add the argument: * ``--registry-json `` example contents of JSON file with login info:: {"url":"REGISTRY_URL", "username":"REGISTRY_USERNAME", "password":"REGISTRY_PASSWORD"} Cephadm will attempt to log in to this registry so it can pull your container and then store the login info in its config database. Other hosts added to the cluster will then also be able to make use of the authenticated container registry. * See :ref:`cephadm-deployment-scenarios` for additional examples for using ``cephadm bootstrap``. .. _cephadm-enable-cli: Enable Ceph CLI =============== Cephadm does not require any Ceph packages to be installed on the host. However, we recommend enabling easy access to the ``ceph`` command. There are several ways to do this: * The ``cephadm shell`` command launches a bash shell in a container with all of the Ceph packages installed. By default, if configuration and keyring files are found in ``/etc/ceph`` on the host, they are passed into the container environment so that the shell is fully functional. Note that when executed on a MON host, ``cephadm shell`` will infer the ``config`` from the MON container instead of using the default configuration. If ``--mount `` is given, then the host ```` (file or directory) will appear under ``/mnt`` inside the container: .. prompt:: bash # cephadm shell * To execute ``ceph`` commands, you can also run commands like this: .. prompt:: bash # cephadm shell -- ceph -s * You can install the ``ceph-common`` package, which contains all of the ceph commands, including ``ceph``, ``rbd``, ``mount.ceph`` (for mounting CephFS file systems), etc.: .. prompt:: bash # :substitutions: cephadm add-repo --release |stable-release| cephadm install ceph-common Confirm that the ``ceph`` command is accessible with: .. prompt:: bash # ceph -v Confirm that the ``ceph`` command can connect to the cluster and also its status with: .. prompt:: bash # ceph status Adding Hosts ============ Add all hosts to the cluster by following the instructions in :ref:`cephadm-adding-hosts`. By default, a ``ceph.conf`` file and a copy of the ``client.admin`` keyring are maintained in ``/etc/ceph`` on all hosts that have the ``_admin`` label. This label is initially applied only to the bootstrap host. We recommend that one or more other hosts be given the ``_admin`` label so that the Ceph CLI (for example, via ``cephadm shell``) is easily accessible on multiple hosts. To add the ``_admin`` label to additional host(s), run a command of the following form: .. prompt:: bash # ceph orch host label add ** _admin Adding additional MONs ====================== A typical Ceph cluster has three or five Monitor daemons spread across different hosts. We recommend deploying five Monitors if there are five or more nodes in your cluster. Most clusters do not benefit from seven or more Monitors. Please follow :ref:`deploy_additional_monitors` to deploy additional MONs. Adding Storage ============== To add storage to the cluster, you can tell Ceph to consume any available and unused device(s): .. prompt:: bash # ceph orch apply osd --all-available-devices See :ref:`cephadm-deploy-osds` for more detailed instructions. Enabling OSD memory autotuning ------------------------------ .. warning:: By default, cephadm enables ``osd_memory_target_autotune`` on bootstrap, with ``mgr/cephadm/autotune_memory_target_ratio`` set to ``.7`` of total host memory. See :ref:`osd_autotune`. To deploy hyperconverged Ceph with TripleO, please refer to the TripleO documentation: `Scenario: Deploy Hyperconverged Ceph `_ In other cases where the cluster hardware is not exclusively used by Ceph (converged infrastructure), reduce the memory consumption of Ceph like so: .. prompt:: bash # # converged only: ceph config set mgr mgr/cephadm/autotune_memory_target_ratio 0.2 Then enable memory autotuning: .. prompt:: bash # ceph config set osd osd_memory_target_autotune true Using Ceph ========== To use the *Ceph Filesystem*, follow :ref:`orchestrator-cli-cephfs`. To use the *Ceph Object Gateway*, follow :ref:`cephadm-deploy-rgw`. To use *NFS*, follow :ref:`deploy-cephadm-nfs-ganesha` To use *iSCSI*, follow :ref:`cephadm-iscsi` .. _cephadm-deployment-scenarios: Different deployment scenarios ============================== Single host ----------- To deploy a Ceph cluster running on a single host, use the ``--single-host-defaults`` flag when bootstrapping. For use cases, see :ref:`one-node-cluster`. Such clusters are generally not suitable for production. The ``--single-host-defaults`` flag sets the following configuration options:: global/osd_crush_chooseleaf_type = 0 global/osd_pool_default_size = 2 mgr/mgr_standby_modules = False For more information on these options, see :ref:`one-node-cluster` and ``mgr_standby_modules`` in :ref:`mgr-administrator-guide`. .. _cephadm-airgap: Deployment in an isolated environment ------------------------------------- You might need to install cephadm in an environment that is not connected directly to the Internet (an "isolated" or "airgapped" environment). This requires the use of a custom container registry. Either of two kinds of custom container registry can be used in this scenario: (1) a Podman-based or Docker-based insecure registry, or (2) a secure registry. The practice of installing software on systems that are not connected directly to the internet is called "airgapping" and registries that are not connected directly to the internet are referred to as "airgapped". Make sure that your container image is inside the registry. Make sure that you have access to all hosts that you plan to add to the cluster. #. Run a local container registry: .. prompt:: bash # podman run --privileged -d --name registry -p 5000:5000 -v /var/lib/registry:/var/lib/registry --restart=always registry:2 #. If you are using an insecure registry, configure Podman or Docker with the hostname and port where the registry is running. .. note:: You must repeat this step for every host that accesses the local insecure registry. #. Push your container image to your local registry. Here are some acceptable kinds of container images: * Ceph container image. See :ref:`containers`. * Prometheus container image * Node exporter container image * Grafana container image * Alertmanager container image #. Create a temporary configuration file to store the names of the monitoring images. (See :ref:`cephadm_monitoring-images`): .. prompt:: bash $ cat < initial-ceph.conf :: [mgr] mgr/cephadm/container_image_prometheus = **:5000/prometheus mgr/cephadm/container_image_node_exporter = **:5000/node_exporter mgr/cephadm/container_image_grafana = **:5000/grafana mgr/cephadm/container_image_alertmanager = **:5000/alertmanger #. Run bootstrap using the ``--image`` flag and pass the name of your container image as the argument of the image flag. For example: .. prompt:: bash # cephadm --image **:5000/ceph/ceph bootstrap --mon-ip ** .. _cluster network: ../rados/configuration/network-config-ref#cluster-network .. _cephadm-bootstrap-custom-ssh-keys: Deployment with custom SSH keys ------------------------------- Bootstrap allows users to create their own private/public SSH key pair rather than having cephadm generate them automatically. To use custom SSH keys, pass the ``--ssh-private-key`` and ``--ssh-public-key`` fields to bootstrap. Both parameters require a path to the file where the keys are stored: .. prompt:: bash # cephadm bootstrap --mon-ip --ssh-private-key --ssh-public-key This setup allows users to use a key that has already been distributed to hosts the user wants in the cluster before bootstrap. .. note:: In order for cephadm to connect to other hosts you'd like to add to the cluster, make sure the public key of the key pair provided is set up as an authorized key for the ssh user being used, typically root. If you'd like more info on using a non-root user as the ssh user, see :ref:`cephadm-bootstrap-further-info` .. _cephadm-bootstrap-ca-signed-keys: Deployment with CA signed SSH keys ---------------------------------- As an alternative to standard public key authentication, cephadm also supports deployment using CA signed keys. Before bootstrapping it's recommended to set up the CA public key as a trusted CA key on hosts you'd like to eventually add to the cluster. For example: .. prompt:: bash # we will act as our own CA, therefore we'll need to make a CA key [root@host1 ~]# ssh-keygen -t rsa -f ca-key -N "" # make the ca key trusted on the host we've generated it on # this requires adding in a line in our /etc/sshd_config # to mark this key as trusted [root@host1 ~]# cp ca-key.pub /etc/ssh [root@host1 ~]# vi /etc/ssh/sshd_config [root@host1 ~]# cat /etc/ssh/sshd_config | grep ca-key TrustedUserCAKeys /etc/ssh/ca-key.pub # now restart sshd so it picks up the config change [root@host1 ~]# systemctl restart sshd # now, on all other hosts we want in the cluster, also install the CA key [root@host1 ~]# scp /etc/ssh/ca-key.pub host2:/etc/ssh/ # on other hosts, make the same changes to the sshd_config [root@host2 ~]# vi /etc/ssh/sshd_config [root@host2 ~]# cat /etc/ssh/sshd_config | grep ca-key TrustedUserCAKeys /etc/ssh/ca-key.pub # and restart sshd so it picks up the config change [root@host2 ~]# systemctl restart sshd Once the CA key has been installed and marked as a trusted key, you are ready to use a private key/CA signed cert combination for SSH. Continuing with our current example, we will create a new key-pair for for host access and then sign it with our CA key .. prompt:: bash # make a new key pair [root@host1 ~]# ssh-keygen -t rsa -f cephadm-ssh-key -N "" # sign the private key. This will create a new cephadm-ssh-key-cert.pub # note here we're using user "root". If you'd like to use a non-root # user the arguments to the -I and -n params would need to be adjusted # Additionally, note the -V param indicates how long until the cert # this creates will expire [root@host1 ~]# ssh-keygen -s ca-key -I user_root -n root -V +52w cephadm-ssh-key [root@host1 ~]# ls ca-key ca-key.pub cephadm-ssh-key cephadm-ssh-key-cert.pub cephadm-ssh-key.pub # verify our signed key is working. To do this, make sure the generated private # key ("cephadm-ssh-key" in our example) and the newly signed cert are stored # in the same directory. Then try to ssh using the private key [root@host1 ~]# ssh -i cephadm-ssh-key host2 Once you have your private key and corresponding CA signed cert and have tested SSH authentication using that key works, you can pass those keys to bootstrap in order to have cephadm use them for SSHing between cluster hosts .. prompt:: bash [root@host1 ~]# cephadm bootstrap --mon-ip --ssh-private-key cephadm-ssh-key --ssh-signed-cert cephadm-ssh-key-cert.pub Note that this setup does not require installing the corresponding public key from the private key passed to bootstrap on other nodes. In fact, cephadm will reject the ``--ssh-public-key`` argument when passed along with ``--ssh-signed-cert``. This is not because having the public key breaks anything, but rather because it is not at all needed and helps the bootstrap command differentiate if the user wants the CA signed keys setup or standard pubkey encryption. What this means is that SSH key rotation would simply be a matter of getting another key signed by the same CA and providing cephadm with the new private key and signed cert. No additional distribution of keys to cluster nodes is needed after the initial setup of the CA key as a trusted key, no matter how many new private key/signed cert pairs are rotated in.