Access the cluster using rbd client
This guide shows you how to access your cluster using rbd client.
Last update 22th June 2022
Objective
There are different ways to use your Ceph cluster. We'll describe how to map your cluster using rbd client.
Requirements
You must first ensure that you have done those steps :
- Create a pool
- Create a user
- Add rights to a user on a pool
- Add an IP ACL to allow your server to contact the cluster
Ceph installation
For deb based distributions:
ubuntu@server:~$ sudo apt-get -y install ceph ceph-common
[...]
Setting up ceph-common (10.2.0-0ubuntu0.16.04.2) ...
Setting up ceph (10.2.0-0ubuntu0.16.04.2) ...
For rpm based distributions:
[centos@server ~]$ sudo yum install -y ceph-common
[...]
Installed:
ceph-common.x86_64 1:0.80.7-3.el7
Ceph configuration
Create file /etc/ceph/ceph.conf
[global]
mon_host = <mon_1_IP>,<mon_2_IP>,<mon_3_IP>
Create the file /etc/ceph/ceph.client.<ceph_user_name>.keyring
[client.<ceph_user_name>]
key = <my_user_key>
<mon_X_IP> has to be replaced by monitors IP you can find on your Ceph as a Service manager..
<my_user_key> has to be replaced by the users's key you can find on your Ceph as a Service manager..
Configuration check
You can check the configuration by listing the images inside your pool.
ubuntu@server:~$ rbd -n client.myuser list mypool
In this case, the result is empty because we have not have created an image yet. If you have an error, please double check your configuration.
Image creation
You can't directly mount a pool, you have to mount an image that exists on the pool.
ubuntu@server:~$ rbd -n client.myuser create mypool/myimage -s $((10*1024*1024)) --image-format 2 --image-feature layering
ubuntu@server:~$ rbd -n client.myuser list mypool
myimage
We make sure that the image was created correctly by listing the pool content.
Map the image
ubuntu@server:~$ sudo rbd -n client.myuser map mypool/myimage
/dev/rbd0
My rbd image is not mapped to /dev/rbd0, it's a block storage. Therefore we have to setup a filesystem.
Setup the filesystem
ubuntu@server:~$ sudo mkfs.xfs /dev/rbd0
meta-data=/dev/rbd0 isize=512 agcount=33, agsize=83885056 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=1, sparse=0
data = bsize=4096 blocks=2684354560, imaxpct=5
= sunit=1024 swidth=1024 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=521728, version=2
= sectsz=512 sunit=8 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
Mount the filesystem
ubuntu@server:~$ sudo mkdir /mnt/rbd
ubuntu@server:~$ sudo mount /dev/rbd0 /mnt/rbd
ubuntu@server:~$ df -h /mnt/rbd
Filesystem Size Used Avail Use% Mounted on
/dev/rbd0 10T 34M 10T 1% /mnt/rbd
You can now use your Ceph cluster!
Go further
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