============================= Storage Cluster Quick Start ============================= If you haven't completed your `Preflight Checklist`_, do that first. This **Quick Start** sets up a :term:`Ceph Storage Cluster` using ``ceph-deploy`` on your admin node. Create a three Ceph Node cluster so you can explore Ceph functionality. .. ditaa:: /------------------\ /----------------\ | Admin Node | | ceph–node1 | | +-------->+ cCCC | | ceph–deploy | | mon.ceph–node1 | \---------+--------/ \----------------/ | | /----------------\ | | ceph–node2 | +----------------->+ cCCC | | | osd.0 | | \----------------/ | | /----------------\ | | ceph–node3 | +----------------->| cCCC | | osd.1 | \----------------/ For best results, create a directory on your admin node node for maintaining the configuration that ``ceph-deploy`` generates for your cluster. :: mkdir my-cluster cd my-cluster .. tip:: The ``ceph-deploy`` utility will output files to the current directory. Ensure you are in this directory when executing ``ceph-deploy``. As a first exercise, create a Ceph Storage Cluster with one Ceph Monitor and two Ceph OSD Daemons. Once the cluster reaches a ``active + clean`` state, expand it by adding a third Ceph OSD Daemon, a Metadata Server and two more Ceph Monitors. .. important:: Do not call ``ceph-deploy`` with ``sudo`` or run it as ``root`` if you are logged in as a different user, because it will not issue ``sudo`` commands needed on the remote host. Create a Cluster ================ If at any point you run into trouble and you want to start over, execute the following:: ceph-deploy purgedata {ceph-node} [{ceph-node}] ceph-deploy forgetkeys On your admin node, perform the following steps using ``ceph-deploy``. #. Create the cluster. :: ceph-deploy new {ceph-node} ceph-deploy new ceph-node1 Check the output of ``ceph-deploy`` with ``ls`` and ``cat`` in the current directory. You should see a Ceph configuration file, a keyring, and a log file for the new cluster. See `ceph-deploy new -h`_ for additional details. #. Install Ceph. :: ceph-deploy install {ceph-node}[{ceph-node} ...] ceph-deploy install ceph-node1 ceph-node2 ceph-node3 #. Add a Ceph Monitor. :: ceph-deploy mon create {ceph-node} ceph-deploy mon create ceph-node1 #. Gather keys. :: ceph-deploy gatherkeys {ceph-node} ceph-deploy gatherkeys ceph-node1 Once you have gathered keys, your local directory should have the following keyrings: - ``{cluster-name}.client.admin.keyring`` - ``{cluster-name}.bootstrap-osd.keyring`` - ``{cluster-name}.bootstrap-mds.keyring`` #. Add two OSDs. For fast setup, this quick start uses a directory rather than an entire disk per Ceph OSD Daemon. See `ceph-deploy osd`_ for details on using separate disks/partitions for OSDs and journals. Login to the Ceph Nodes and create a directory for the Ceph OSD Daemon. :: ssh ceph-node2 sudo mkdir /tmp/osd0 exit ssh ceph-node3 sudo mkdir /tmp/osd1 exit Then, from your admin node, use ``ceph-deploy`` to prepare the OSDs. :: ceph-deploy osd prepare {ceph-node}:/path/to/directory ceph-deploy osd prepare ceph-node2:/tmp/osd0 ceph-node3:/tmp/osd1 Finally, activate the OSDs. :: ceph-deploy osd activate {ceph-node}:/path/to/directory ceph-deploy osd activate ceph-node2:/tmp/osd0 ceph-node3:/tmp/osd1 #. Use ``ceph-deploy`` to copy the configuration file and admin key to your admin node and your Ceph Nodes so that you can use the ``ceph`` CLI without having to specify the monitor address and ``ceph.client.admin.keyring`` each time you execute a command. :: ceph-deploy admin {ceph-node} ceph-deploy admin admin-node ceph-node1 ceph-node2 ceph-node3 **Note:** Since you are using ``ceph-deploy`` to talk to the local host, your host must be reachable by its hostname (e.g., you can modify ``/etc/hosts`` if necessary). Ensure that you have the correct permissions for the ``ceph.client.admin.keyring``. #. Check your cluster's health. :: ceph health Your cluster should return an ``active + clean`` state when it has finished peering. Operating Your Cluster ====================== Deploying a Ceph cluster with ``ceph-deploy`` automatically starts the cluster. To operate the cluster daemons with Debian/Ubuntu distributions, see `Running Ceph with Upstart`_. To operate the cluster daemons with CentOS, Red Hat, Fedora, and SLES distributions, see `Running Ceph with sysvinit`_. To learn more about peering and cluster health, see `Monitoring a Cluster`_. To learn more about Ceph OSD Daemon and placement group health, see `Monitoring OSDs and PGs`_. Once you deploy a Ceph cluster, you can try out some of the administration functionality, the ``rados`` object store command line, and then proceed to Quick Start guides for Ceph Block Device, Ceph Filesystem, and the Ceph Object Gateway. Expanding Your Cluster ====================== Once you have a basic cluster up and running, the next step is to expand cluster. Add a Ceph OSD Daemon and a Ceph Metadata Server to ``ceph-node1``. Then add a Ceph Monitor to ``ceph-node2`` and ``ceph-node3`` to establish a quorum of Ceph Monitors. .. ditaa:: /------------------\ /----------------\ | ceph–deploy | | ceph–node1 | | Admin Node | | cCCC | | +-------->+ mon.ceph–node1 | | | | osd.2 | | | | mds.ceph–node1 | \---------+--------/ \----------------/ | | /----------------\ | | ceph–node2 | | | cCCC | +----------------->+ | | | osd.0 | | | mon.ceph–node2 | | \----------------/ | | /----------------\ | | ceph–node3 | | | cCCC | +----------------->+ | | osd.1 | | mon.ceph–node3 | \----------------/ Adding an OSD ------------- Since you are running a 3-node cluster for demonstration purposes, add the OSD to the monitor node. :: ssh ceph-node1 sudo mkdir /tmp/osd2 exit Then, from your ``ceph-deploy`` node, prepare the OSD. :: ceph-deploy osd prepare {ceph-node}:/path/to/directory ceph-deploy osd prepare ceph-node1:/tmp/osd2 Finally, activate the OSDs. :: ceph-deploy osd activate {ceph-node}:/path/to/directory ceph-deploy osd activate ceph-node1:/tmp/osd2 Once you have added your new OSD, Ceph will begin rebalancing the cluster by migrating placement groups to your new OSD. You can observe this process with the ``ceph`` CLI. :: ceph -w You should see the placement group states change from ``active+clean`` to active with some degraded objects, and finally ``active+clean`` when migration completes. (Control-c to exit.) Add a Metadata Server --------------------- To use CephFS, you need at least one metadata server. Execute the following to create a metadata server:: ceph-deploy mds create {ceph-node} ceph-deploy mds create ceph-node1 .. note:: Currently Ceph runs in production with one metadata server only. You may use more, but there is currently no commercial support for a cluster with multiple metadata servers. Adding Monitors --------------- A Ceph Storage Cluster requires at least one Ceph Monitor to run. For high availability, Ceph Storage Clusters typically run multiple Ceph Monitors so that the failure of a single Ceph Monitor will not bring down the Ceph Storage Cluster. Ceph uses the Paxos algorithm, which requires a majority of monitors (i.e., 1, 2:3, 3:4, 3:5, 4:6, etc.) to form a quorum. Add two Ceph Monitors to your cluster. :: ceph-deploy mon create {ceph-node} ceph-deploy mon create ceph-node2 ceph-node3 Once you have added your new Ceph Monitors, Ceph will begin synchronizing the monitors and form a quorum. You can check the quorum status by executing the following:: ceph quorum_status Storing/Retrieving Object Data ============================== To store object data in the Ceph Storage Cluster, a Ceph client must: #. Set an object name #. Specify a `pool`_ The Ceph Client retrieves the latest cluster map and the CRUSH algorithm calculates how to map the object to a `placement group`_, and then calculates how to assign the placement group to a Ceph OSD Daemon dynamically. To find the object location, all you need is the object name and the pool name. For example:: ceph osd map {poolname} {object-name} .. topic:: Exercise: Locate an Object As an exercise, lets create an object. Specify an object name, a path to a test file containing some object data and a pool name using the ``rados put`` command on the command line. For example:: rados put {object-name} {file-path} --pool=data rados put test-object-1 testfile.txt --pool=data To verify that the Ceph Storage Cluster stored the object, execute the following:: rados -p data ls Now, identify the object location:: ceph osd map {pool-name} {object-name} ceph osd map data test-object-1 Ceph should output the object's location. For example:: osdmap e537 pool 'data' (0) object 'test-object-1' -> pg 0.d1743484 (0.4) -> up [1,0] acting [1,0] To remove the test object, simply delete it using the ``rados rm`` command. For example:: rados rm test-object-1 --pool=data As the cluster evolves, the object location may change dynamically. One benefit of Ceph's dynamic rebalancing is that Ceph relieves you from having to perform the migration manually. .. _Preflight Checklist: ../quick-start-preflight .. _Ceph Deploy: ../../rados/deployment .. _ceph-deploy install -h: ../../rados/deployment/ceph-deploy-install .. _ceph-deploy new -h: ../../rados/deployment/ceph-deploy-new .. _ceph-deploy osd: ../../rados/deployment/ceph-deploy-osd .. _Running Ceph with Upstart: ../../rados/operations/operating#running-ceph-with-upstart .. _Running Ceph with sysvinit: ../../rados/operations/operating#running-ceph-with-sysvinit .. _CRUSH Map: ../../rados/operations/crush-map .. _pool: ../../rados/operations/pools .. _placement group: ../../rados/operations/placement-groups .. _Monitoring a Cluster: ../../rados/operations/monitoring .. _Monitoring OSDs and PGs: ../../rados/operations/monitoring-osd-pg