Ceph Tentacle : Use Block Device2026/04/27 |
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Configure a Client Host [dlp] to use Ceph Storage like follows.
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+--------------------+ |
| [dlp.srv.world] |10.0.0.30 |
| Ceph Client +-----------+
| | |
+--------------------+ |
+----------------------------+----------------------------+
| | |
|10.0.0.51 |10.0.0.52 |10.0.0.53
+-----------+-----------+ +-----------+-----------+ +-----------+-----------+
| [node01.srv.world] | | [node02.srv.world] | | [node03.srv.world] |
| Object Storage +----+ Object Storage +----+ Object Storage |
| Monitor Daemon | | | | |
| Manager Daemon | | | | |
+-----------------------+ +-----------------------+ +-----------------------+
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For example, Create a block device and mount it on a Client Host.
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| [1] | Transfer SSH public key to Client Host and Configure it from Admin Node. |
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# transfer public key root@node01:~# ssh-copy-id dlp # install required packages root@node01:~# ssh dlp "apt -y install ceph-common"
# transfer required files to Client Host root@node01:~# scp /etc/ceph/ceph.conf dlp:/etc/ceph/ ceph.conf 100% 273 150.3KB/s 00:00root@node01:~# scp /etc/ceph/ceph.client.admin.keyring dlp:/etc/ceph/ ceph.client.admin.keyring 100% 151 82.6KB/s 00:00root@node01:~# ssh dlp "chown ceph:ceph /etc/ceph/ceph.*" |
| [2] | Create a Block device and mount it on a Client Host. |
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# create default RBD pool [rbd] root@dlp:~# ceph osd pool create rbd 32 pool 'rbd' created # enable Placement Groups auto scale mode root@dlp:~# ceph osd pool set rbd pg_autoscale_mode on set pool 2 pg_autoscale_mode to on # initialize the pool root@dlp:~# rbd pool init rbd ceph osd pool autoscale-status POOL SIZE TARGET SIZE RATE RAW CAPACITY RATIO TARGET RATIO EFFECTIVE RATIO BIAS PG_NUM NEW PG_NUM AUTOSCALE BULK .mgr 452.0k 3.0 479.9G 0.0000 1.0 1 on False rbd 0 3.0 479.9G 0.0000 1.0 32 on False # create a block device with 10G root@dlp:~# rbd create --size 10G --pool rbd rbd01
# confirm root@dlp:~# rbd ls -l NAME SIZE PARENT FMT PROT LOCK rbd01 10 GiB 2 # map the block device root@dlp:~# rbd map rbd01 /dev/rbd0 # confirm root@dlp:~# rbd showmapped id pool namespace image snap device 0 rbd rbd01 - /dev/rbd0 # format with EXT4 root@dlp:~# mkfs.ext4 /dev/rbd0
mke2fs 1.47.2 (1-Jan-2025)
Discarding device blocks: done
Creating filesystem with 2621440 4k blocks and 655360 inodes
Filesystem UUID: 9095153e-9ab0-41ed-bdd8-23dd8ef830fe
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632
Allocating group tables: done
Writing inode tables: done
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done
root@dlp:~# mount /dev/rbd0 /mnt root@dlp:~# df -hT Filesystem Type Size Used Avail Use% Mounted on tmpfs tmpfs 680M 1.1M 679M 1% /run /dev/mapper/ubuntu--vg-ubuntu--lv ext4 14G 5.8G 7.3G 45% / tmpfs tmpfs 1.7G 0 1.7G 0% /dev/shm none tmpfs 1.0M 0 1.0M 0% /run/credentials/systemd-journald.service none tmpfs 1.0M 0 1.0M 0% /run/credentials/systemd-resolved.service tmpfs tmpfs 1.7G 0 1.7G 0% /tmp /dev/vda2 ext4 2.0G 96M 1.7G 6% /boot none tmpfs 1.0M 0 1.0M 0% /run/credentials/systemd-networkd.service none tmpfs 1.0M 0 1.0M 0% /run/credentials/getty@tty1.service none tmpfs 1.0M 0 1.0M 0% /run/credentials/serial-getty@ttyS0.service tmpfs tmpfs 340M 8.0K 340M 1% /run/user/0 /dev/rbd0 ext4 9.8G 2.1M 9.3G 1% /mnt |
| [3] | For delete Block devices or Pools you created, run commands like follows. For deleting Pools, it needs to set [mon allow pool delete = true] on [Monitor Daemon] configuration. |
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# unmap root@dlp:~# rbd unmap /dev/rbd/rbd/rbd01
# delete a block device root@dlp:~# rbd rm rbd01 -p rbd Removing image: 100% complete...done. # delete a pool # ceph osd pool delete [Pool Name] [Pool Name] *** root@dlp:~# ceph osd pool delete rbd rbd --yes-i-really-really-mean-it pool 'rbd' removed |
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