CephFS

CephFS provides a common filesystem that can be shared amongst multiple OpenStack VM hosts. Access to the service is granted via requests to cloud@tech.alliancecan.ca.

This is a fairly technical procedure that assumes basic Linux skills for creating/editing files, setting permissions, and creating mount points. For assistance in setting up this service, write to cloud@tech.alliancecan.ca.

Procedure

Request access to shares

If you do not already have a quota for the service, you will need to request this through cloud@tech.alliancecan.ca. In your request please provide the following:

• OpenStack project name
• amount of quota required in GB
• number of shares required

Create share

1. Create the share.
   • In Project --> Share --> Shares, click on +Create Share.
   • Share Name = enter a name that identifies your project (e.g. project-name-shareName)
   • Share Protocol = CephFS
   • Size = size you need for this share
   • Share Type = cephfs
   • Availability Zone = nova
   • Do not check Make visible for all, otherwise the share will be accessible by all users in all projects.
   • Click on the Create button.
2. Create an access rule to generate an access key.
   • In Project --> Share --> Shares --> Actions column, select Manage Rules from the drop-down menu.
   • Click on the +Add Rule button (right of page).
   • Access Type = cephx
   • Access Level = select read-write or read-only (you can create multiple rules for either access level if required)
   • Access To = select a key name that describes the key (e.g. def-project-shareName-read-write)
3. Note the share details which you will need later.
   • In Project --> Share --> Shares, click on the name of the share.
   • In the Share Overview, note the Path.
   • Under Access Rules, note the Access Key (the access key is approximately 40 characters and ends with the = sign; if you do not see an access key, you probably didn't add an access rule of type cephx.

Configure host

1. Install the required packages.

   • Red Hat family (RHEL, CentOS, Fedora, Scientific Linux, SUSE, etc.):

     1. Install relevant repositories for access to ceph client packages:

        ceph-stable (nautilus is current as of this writting)
            https://docs.ceph.com/en/nautilus/install/get-packages/
        epel (sudo yum install epel-release)
        
        

     2. Install packages to enable the ceph client on all the instances where you plan on mounting the share:

        libcephfs2
        python3-cephfs
        ceph-common
        python3-ceph-argparse
        ceph-fuse (only if you intend a fuse mount)
        

     • Debian family (Debian, Ubuntu, Mint, etc.):

         https://docs.ceph.com/en/nautilus/install/get-packages/
     

2. Configure Keys:

   • Create two files in your instance, each containing the access key. This key can be found in the rule definition, or in the Access Rules section of your share definition.

   • File 1: /etc/ceph/client.fullkey.shareName (e.g. client.fullkey.def-project-shareName-read-write)

     • contents:

       [client.shareName]
           key = AccessKey
       

   • File 2: /etc/ceph/client.keyonly.shareName (e.g client.keyonly.def-project-shareName-read-write)

     • contents:

       AccessKey
       

     • This file only contains the access key.

   • Own these files correctly to protect the key information:

     • Each file should be own to root

     sudo chown root.root filename
     

     • Each file should be only readable by root

     sudo chmod 600 filename
     

3. Create /etc/ceph/ceph.conf with contents:

   [client]
       client quota = true
       mon host = 10.30.201.3:6789,10.30.202.3:6789,10.30.203.3:6789
       keyring = /etc/ceph/client.keyonly.def-project-sharename-read-write
   

   • Note: these are the monitors for the Arbutus cluster. If connecting to a different cluster, you will need the monitor information specific to that cluster.
     • You can find the monitor information in the share details for your share in the Path field.

4. Retrieve the connection information from the share page for your connection:

   • Open up the share details by clicking the name of the share in the Shares page.
   • Copy the entire path of the share for mounting the filesystem.

5. Mount the filesystem

   • Create a mount point directory somewhere in your host (likely under /mnt/ - e.g. /mnt/ShareName)
   • Via kernel mount using the ceph driver:
     • Syntax: sudo mount -t ceph <path information> <mountPoint> -o name=<shareKeyName>, secretfile=</path/to/keyringfileOnlyFile>
     • sudo mount -t ceph mon1:6789,mon2:6789,mon3:6789:/volumes/_nogroup/share_instance_id
       • e.g sudo mount -t ceph 192.168.17.13:6789,192.168.17.14:6789,192.168.17.15:6789:/volumes/_nogroup/a87b5ef3-b266-4664-a5ed-026cddfdcdb7 /mnt/WebServerShare -o name=def-project-shareName-read-write,secretfile=/etc/ceph/client.keyonly.def-project-sharename-read-write
   • Via ceph-fuse
     • Need to install ceph-fuse
     • Syntax: sudo ceph-fuse <mountPoint> --id=<shareKeyName> --conf=<pathtoCeph.conf> --keyring=<fullKeyringLocation> --client-mountpoint=pathFromShareDetails
       • e.g. sudo ceph-fuse /mnt/WebServerShare --id=def-project-shareName-read-write --conf=/etc/ceph/ceph.conf --keyring=/etc/ceph/client.fullkey.def-project-shareName-read-write --client-mountpoint=/volumes/_nogroup/a87b5ef3-b266-4664-a5ed-026cddfdcdb7

Notes

• A particular share can have more than one user key provisioned for it.
  • This allows a more granular access to the filesystem, for example if you needed some hosts to only access the filesystem in a read-only capacity.
  • If you have multiple keys for a share, you can add the extra keys to your host and modify the above mounting procedure.
• This service is not available to hosts outside of the OpenStack cluster.