File System Guide | Basic Ceph Administration

Lab Environment:

Prerequisites:

Basic Administration:

1. Deploy Metadata Servers

[root@ceph-01 ~]# ceph orch apply mds my-mds --placement="ceph-01,ceph-02,ceph-03"
Scheduled mds.my-mds update...
[root@ceph-01 ~]# ceph orch ps | grep mds
mds.my-mds.ceph-01.eqhwax ceph-01 running (28s) 19s ago 28s 11.8M - 16.2.6 02a72919e474 f815be961426
mds.my-mds.ceph-02.vskgwt ceph-02 running (26s) 20s ago 26s 15.8M - 16.2.6 02a72919e474 74e1da7386d0
mds.my-mds.ceph-03.oadfmh ceph-03 running (24s) 20s ago 24s 12.6M - 16.2.6 02a72919e474 c9568108123f
[root@ceph-01 ~]# for i in {01..03}; do mkdir -p /var/lib/ceph/mds/ceph-$i; done
[root@ceph-01 ~]# ceph-authtool --create-keyring /var/lib/ceph/mds/ceph-01/keyring --gen-key -n mds.ceph-01
creating /var/lib/ceph/mds/ceph-01/keyring
[root@ceph-01 ~]# chown -R ceph. /var/lib/ceph/mds/ceph-01
[root@ceph-01 ~]# ceph auth add mds.ceph-01 osd "allow rwx" mds "allow" mon "allow profile mds" -i /var/lib/ceph/mds/ceph-01/keyring
added key for mds.ceph-01

2. Create Ceph File System

[root@ceph-01 ~]# ceph osd pool create cephfs_data 64
pool 'cephfs_data' created
[root@ceph-01 ~]# ceph osd pool create cephfs_metadata 64
pool 'cephfs_metadata' created
[root@ceph-01 ~]# ceph fs new cephfs cephfs_metadata cephfs_data
new fs with metadata pool 4 and data pool 3
[root@ceph-01 ~]# ceph fs ls
name: cephfs, metadata pool: cephfs_metadata, data pools: [cephfs_data ]
[root@ceph-01 ~]# ceph mds stat
cephfs:1 {0=my-mds.ceph-03.pryhgc=up:active} 2 up:standby
[root@ceph-01 ~]# ceph fs status cephfs
cephfs - 0 clients
======
RANK STATE MDS ACTIVITY DNS INOS DIRS CAPS
0 active my-mds.ceph-03.pryhgc Reqs: 0 /s 10 13 12 0
POOL TYPE USED AVAIL
cephfs_metadata metadata 96.0k 28.4G
cephfs_data data 0 28.4G
STANDBY MDS
my-mds.ceph-01.lgdxeq
my-mds.ceph-02.djhpmd
MDS version: ceph version 16.2.6 (ee28fb57e47e9f88813e24bbf4c14496ca299d31) pacific (stable)

3. Mount CephFS on a Ceph client

[root@ceph-01 ~]# ssh ceph-client
[root@ceph-client ~]# dnf -y install centos-release-ceph-pacific epel-release
[root@ceph-client ~]# dnf -y install ceph-fuse
[root@ceph-client ~]# scp ceph-01:/etc/ceph/ceph.conf /etc/ceph/
ceph.conf 100% 277 506.8KB/s 00:00
[root@ceph-client ~]# scp ceph-01:/etc/ceph/ceph.client.admin.keyring /etc/ceph/
ceph.client.admin.keyring 100% 151 330.5KB/s 00:00
[root@ceph-client ~]# chown ceph. /etc/ceph/ceph.*
[root@ceph-client ~]# ceph-authtool -p /etc/ceph/ceph.client.admin.keyring > admin.key
[root@ceph-client ~]# chmod 600 admin.key
[root@ceph-client ~]# mount -t ceph ceph-01:6789:/ /mnt -o name=admin,secretfile=admin.key
[root@ceph-client ~]# df -hT
[root@ceph-client ~]# curl https://cloud-images.ubuntu.com/focal/current/focal-server-cloudimg-amd64.img -o /mnt/Ubuntu-Focal.img
[root@ceph-client ~]# df -hT /mnt
[root@ceph-client ~]# ls -lh /mnt
total 542M
-rw-r — r — . 1 root root 542M Oct 25 15:30 Ubuntu-Focal.img

4. Removing CephFS and Pools

[root@ceph-client ~]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
devtmpfs devtmpfs 891M 0 891M 0% /dev
tmpfs tmpfs 909M 0 909M 0% /dev/shm
tmpfs tmpfs 909M 8.6M 900M 1% /run
tmpfs tmpfs 909M 0 909M 0% /sys/fs/cgroup
/dev/mapper/cl-root xfs 35G 2.1G 33G 6% /
/dev/sda2 ext4 976M 198M 712M 22% /boot
/dev/sda1 vfat 599M 7.3M 592M 2% /boot/efi
tmpfs tmpfs 182M 0 182M 0% /run/user/0
tmpfs tmpfs 182M 0 182M 0% /run/user/1000
192.168.1.231:6789:/ ceph 29G 544M 28G 2% /mnt
[root@ceph-client ~]# umount /mnt
[root@ceph-01 ~]# ceph orch ls | grep mds
mds.my-mds 3/3 3m ago 64m ceph-01;ceph-02;ceph-03
[root@ceph-01 ~]# ceph orch stop mds.my-mds
Scheduled to stop mds.my-mds.ceph-01.lgdxeq on host 'ceph-01'
Scheduled to stop mds.my-mds.ceph-02.djhpmd on host 'ceph-02'
Scheduled to stop mds.my-mds.ceph-03.pryhgc on host 'ceph-03'
[root@ceph-01 ~]# ceph fs rm cephfs --yes-i-really-mean-it
[root@ceph-01 ~]# ceph osd pool rm cephfs_data cephfs_data --yes-i-really-really-mean-it
Error EPERM: pool deletion is disabled; you must first set the mon_allow_pool_delete config option to true before you can destroy a pool
[root@ceph-01 ~]# ceph osd pool ls | grep cephfs
cephfs_data
cephfs_metadata
[root@ceph-01 ~]# ceph osd pool rm cephfs_data cephfs_data --yes-i-really-really-mean-it
pool 'cephfs_data' removed
[root@ceph-01 ~]# ceph osd pool rm cephfs_metadata cephfs_metadata --yes-i-really-really-mean-it
pool 'cephfs_metadata' removed

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Ach.Chusnul Chikam

Ach.Chusnul Chikam

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Cloud Consultant | RHCSA | RHCE in Red Hat OpenStack | Google Cloud ACE | AWS SAA | LinkedIn: https://www.linkedin.com/in/achchusnulchikam