Installation (cephadm)

    The following example installs a basic three-node cluster. Eachnode will be identified by its prompt. For example, “[monitor 1]”identifies the first monitor, “[monitor 2]” identifies the secondmonitor, and “[monitor 3]” identifies the third monitor. Thisinformation is provided in order to make clear which commandsshould be issued on which systems.

    “[any node]” identifies any Ceph node, and in the contextof this installation guide means that the associated commandcan be run on any node.

    The utility is used to bootstrap a new Ceph Cluster.

    Use curl to fetch the standalone script:

    You can also get the utility by installing a package provided byyour Linux distribution:

    1. [monitor 1] # apt install -y cephadm   # or
    2. [monitor 1] # yum install -y cephadm   # or
    3. [monitor 1] # zypper install -y cephadm

    Bootstrap a new cluster

    To create a new cluster, you need to know:

    • Which IP address to use for the cluster’s first monitor. This isnormally just the IP for the first cluster node. If there aremultiple networks and interfaces, be sure to choose one that will beaccessible by any hosts accessing the Ceph cluster.

    To bootstrap the cluster run the following command:

    1. [node 1] $ sudo cephadm bootstrap --mon-ip *<mon-ip>*

    • Creates a monitor and manager daemon for the new cluster on thelocal host. A minimal configuration file needed to communicate withthe new cluster is written to ceph.conf in the local directory.

    • A copy of the client.admin administrative (privileged!) secretkey is written to ceph.client.admin.keyring in the local directory.

    • Generates a new SSH key, and adds the public key to the local root user’s file. A copy of the public key is writtento ceph.pub in the local directory.

    To interact with your cluster, start up a container that has all ofthe Ceph packages installed:

    1. [any node] $ sudo cephadm shell --config ceph.conf --keyring ceph.keyring

    The —config and —keyring arguments will bind those localfiles to the default locations in inside the containerto allow the ceph CLI utility to work without additionalarguments. Inside the container, you can check the cluster status with:

    In order to interact with the Ceph cluster outside of a container(that is, from the command line), install the Cephclient packages and install the configuration and privilegedadministrator key in a global location:

    1. [any node] $ sudo apt install -y ceph-common   # or,
    2. [any node] $ sudo yum install -y ceph-common
    3.  
    4. [any node] $ sudo install -m 0644 ceph.conf /etc/ceph/ceph.conf
    5. [any node] $ sudo install -m 0600 ceph.keyring /etc/ceph/ceph.keyring

    Adding hosts to the cluster

    For each new host you’d like to add to the cluster, you need to do two things:

    • Install the cluster’s public SSH key in the new host’s root user’sauthorized_keys file. For example,:
    1. [monitor 1] # cat ceph.pub | ssh root@*newhost* tee -a /root/.ssh/authorized_keys
    • Tell Ceph that the new node is part of the cluster:
    1. [monitor 1] # ceph orchestrator host add *newhost*

    To deploy additional monitors,:

    For example, to deploy a second monitor on newhost using an IPaddress in network ,:

    1. [monitor 1] # ceph orchestrator mon update 2 newhost:10.1.2.0/24

    Deploying OSDs

    To add an OSD to the cluster, you need to know the device name for theblock device (hard disk or SSD) that will be used. Then,:

      For example, to deploy an OSD on host newhost’s SSD,:

      1. [monitor 1] # ceph orchestrator osd create newhost:/dev/disk/by-id/ata-WDC_WDS200T2B0A-00SM50_182294800028

      It is a good idea to have at least one backup manager daemon. Todeploy one or more new manager daemons,:

      Deploying MDSs

      In order to use the CephFS file system, one or more MDS daemons is needed.

      TBD