Create a pool. The following example uses the pool name libvirt-pool with 128 placement groups.

cephadm > ceph osd pool create libvirt-pool 128 128

Verify that the pool exists.

cephadm > ceph osd lspools

Create a Ceph User. The following example uses the Ceph user name client.libvirt and references libvirt-pool.

cephadm > ceph auth get-or-create client.libvirt mon 'profile rbd' osd \
 'profile rbd pool=libvirt-pool'

Verify the name exists.

cephadm > ceph auth list

Note

libvirt will access Ceph using the ID libvirt, not the Ceph name client.libvirt. See http://docs.ceph.com/docs/master/rados/operations/user-management/#user for a detailed explanation of the difference between ID and name.

Use QEMU to create an image in your RBD pool. The following example uses the image name new-libvirt-image and references libvirt-pool.

Tip: Keyring File Location

The libvirt user key is stored in a keyring file placed in the /etc/ceph directory. The keyring file needs to have a appropriate name that includes the name of the Ceph cluster it belongs to. For the default cluster name 'ceph', the keyring file name is /etc/ceph/ceph.client.libvirt.keyring.

If the keyring does not exist, create it with:

cephadm > ceph auth get client.libvirt > /etc/ceph/ceph.client.libvirt.keyring

root # qemu-img create -f raw rbd:libvirt-pool/new-libvirt-image:id=libvirt 2G

Verify the image exists.

cephadm > rbd -p libvirt-pool ls

Install a virtual machine manager.

root # zypper in virt-manager

Prepare/download an OS image of the system you want to run virtualized.

Launch the virtual machine manager.

virt-manager

Choose the connection from the list, right-click it, and select New.

Import existing disk image by providing the path to the existing storage. Specify OS type, memory settings, and Name the virtual machine, for example libvirt-virtual-machine.

Finish the configuration and start the VM.

Verify that the newly created domain exists with sudo virsh list. If needed, specify the connection string, such as

virsh -c qemu+ssh://root@vm_host_hostname/system list
Id    Name                           State
-----------------------------------------------
[...]
 9     libvirt-virtual-machine       running

Log in to the VM and stop it before configuring it for use with Ceph.

Open the configuration file with virsh edit vm-domain-name.

root # virsh edit libvirt-virtual-machine

Under <devices> there should be a <disk> entry.

<devices>
    <emulator>/usr/bin/qemu-system-x86_64</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw'/>
      <source file='/path/to/image/recent-linux.img'/>
      <target dev='vda' bus='virtio'/>
      <address type='drive' controller='0' bus='0' unit='0'/>
    </disk>

Replace /path/to/image/recent-linux.img with the path to the OS image.

Important

Use sudo virsh edit instead of a text editor. If you edit the configuration file under /etc/libvirt/qemu with a text editor, libvirt may not recognize the change. If there is a discrepancy between the contents of the XML file under /etc/libvirt/qemu and the result of sudo virsh dumpxml vm-domain-name, then your VM may not work properly.

Add the Ceph RBD image you previously created as a <disk> entry.

<disk type='network' device='disk'>
        <source protocol='rbd' name='libvirt-pool/new-libvirt-image'>
                <host name='monitor-host' port='6789'/>
        </source>
        <target dev='vda' bus='virtio'/>
</disk>

Replace monitor-host with the name of your host, and replace the pool and/or image name as necessary. You may add multiple <host> entries for your Ceph monitors. The dev attribute is the logical device name that will appear under the /dev directory of your VM. The optional bus attribute indicates the type of disk device to emulate. The valid settings are driver specific (for example ide, scsi, virtio, xen, usb or sata). See Disks for details of the <disk> element, and its child elements and attributes.

Save the file.

If your Ceph cluster has authentication enabled (it does by default), you must generate a secret. Open an editor of your choice and create a file called secret.xml with the following content:

<secret ephemeral='no' private='no'>
        <usage type='ceph'>
                <name>client.libvirt secret</name>
        </usage>
</secret>

Define the secret.

root # virsh secret-define --file secret.xml
<uuid of secret is output here>

Get the client.libvirt key and save the key string to a file.

cephadm > ceph auth get-key client.libvirt | sudo tee client.libvirt.key

Set the UUID of the secret.

root # virsh secret-set-value --secret uuid of secret \
--base64 $(cat client.libvirt.key) && rm client.libvirt.key secret.xml

You must also set the secret manually by adding the following <auth> entry to the <disk> element you entered earlier (replacing the uuid value with the result from the command line example above).

root # virsh edit libvirt-virtual-machine

Then, add <auth></auth> element to the domain configuration file:

...
</source>
<auth username='libvirt'>
        <secret type='ceph' uuid='9ec59067-fdbc-a6c0-03ff-df165c0587b8'/>
</auth>
<target ...

Note

The exemplary ID is libvirt, not the Ceph name client.libvirt as generated at step 2 of Section 18.1, “Configuring Ceph”. Ensure you use the ID component of the Ceph name you generated. If for some reason you need to regenerate the secret, you will need to execute sudo virsh secret-undefine uuid before executing sudo virsh secret-set-value again.

Check to see if Ceph is running:

cephadm > ceph health

Check to see if the VM is running:

root # virsh list

Check to see if the VM is communicating with Ceph. Replace vm-domain-name with the name of your VM domain:

root # virsh qemu-monitor-command --hmp vm-domain-name 'info block'

Check to see if the device from &target dev='hdb' bus='ide'/> appears under /dev or under /proc/partitions:

cephadm > ls /dev
cephadm > cat /proc/partitions