# Ceph commands usage

###### tags: `ceph`

### some commands

# get Ceph quorum status
ceph quorum_status -f json-pretty
   
# get ceph usage
ceph df
ceph df detail

# get radosgw user info
radosgw-admin user info --uid=testuser

# list buckets
radosgw-admin bucket list

# remove shadow objects
rados --pool=.rgw.buckets ls
rados --pool=.rgw.buckets rm <object name>
rados --pool=.rgw.buckets ls | grep __shadow_ | xargs rados --pool=.rgw.buckets rm

### remove all objects in a Ceph pool
!!! But it is not good to use in a large number of object pool.

Create a script with following to remove all objects in a Ceph pool.
#!/usr/bin/bash
pool_name=rbd

for i in `rados -p $pool_name ls`
  do echo $i
  rados -p $pool_name rm $i
done

rados -p rbd ls

### ronfigure VM to use Ceph RBD as disk

[ On Ceph monitor node ]
1. create pool
ceph osd pool create <pool name> <number of pg> <number of pgp>
ceph osd lspools

2. create a ceph user name as "client.libvirt" and references it to the <pool name>
ceph auth get-or-create client.libvirt mon 'allow r' osd 'allow class-read object_prefix rbd_children, allow rwx pool=<pool name>'
ceph auth list

3. get the key of the user "client.libvirt" and save it to a file called "client.libvirt.key"
ceph auth get-key client.libvirt | tee client.libvirt.key

4. copy the key file "client.libvirt.key" to VM Computer node
scp -pr ./client.libvirt.key root@computer:/root/

5. create 2GB size image file
qemu-img create -f rbd rbd:<pool name>/<image name> 2G
rbd -p <pool name> ls


[ On VM Computer node ]
1. create an VM via virt-manager

2. edit the VM xml file. Add or modify xml as following disk defination, change {monitor-host} to ceph monitor node IP

<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>

3. generate a secret
cat > secret.xml <<EOF
<secret ephemeral='no' private='no'>
        <usage type='ceph'>
                <name>client.libvirt secret</name>
        </usage>
</secret>
EOF

4. define the secret, this will output a uuid of the secret. copy that uuid.
virsh secret-define --file secret.xml

5. set the uuid of the secret value
virsh secret-set-value --secret <uuid of secret> --base64 $(cat /root/client.libvirt.key)
rm -rf ./secret.xml /root/client.libvirt.key

6. edit the secret in VM xml file. add <auth></auth>
<disk type='network' device='disk'>
  <driver name='qemu'/>
  <auth username='libvirt'>
    <secret type='ceph' uuid='628f1d68-efa9-494f-b00d-f67b92933395'/>
  </auth>
  <source protocol='rbd' name='libvirt-pool/new-libvirt-image'>
    <host name='192.168.124.11' port='6789'/>
  </source>
  <target dev='vda' bus='virtio'/>
  <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
</disk>