Docker : Use External Storage2021/04/06 |
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When containers are removed, data in them are also lost, so it's necessary to use external filesystem in containers as persistent storages if you need.
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| [1] | It's possible to mount a directory on Docker Host into containers. |
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# create a directory for containers data [root@dlp ~]# mkdir -p /var/lib/docker/disk01 [root@dlp ~]# echo "persistent storage" >> /var/lib/docker/disk01/testfile.txt
# run a container with mounting the directory above on [/mnt] [root@dlp ~]# docker run -it -v /var/lib/docker/disk01:/mnt centos /bin/bash
df -hT Filesystem Type Size Used Avail Use% Mounted on overlay overlay 71G 3.4G 68G 5% / tmpfs tmpfs 64M 0 64M 0% /dev tmpfs tmpfs 7.8G 0 7.8G 0% /sys/fs/cgroup shm tmpfs 64M 0 64M 0% /dev/shm /dev/mapper/cs-root xfs 71G 3.4G 68G 5% /mnt tmpfs tmpfs 7.8G 0 7.8G 0% /proc/acpi tmpfs tmpfs 7.8G 0 7.8G 0% /proc/scsi tmpfs tmpfs 7.8G 0 7.8G 0% /sys/firmware[root@81396e59ba03 /]# cat /mnt/testfile.txt persistent storage |
| [2] | It's also possible to configure external storage by Docker Data Volume command. |
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# create [volume01] volume [root@dlp ~]# docker volume create volume01 volume01 # display volume list [root@dlp ~]# docker volume ls DRIVER VOLUME NAME local volume01 # display details of [volume01] [root@dlp ~]# docker volume inspect volume01
[
{
"CreatedAt": "2021-04-06T00:25:10-06:00",
"Driver": "local",
"Labels": {},
"Mountpoint": "/var/lib/docker/volumes/volume01/_data",
"Name": "volume01",
"Options": {},
"Scope": "local"
}
]
# run a container with mounting [volume01] to [/mnt] on container [root@dlp ~]# docker run -it -v volume01:/mnt centos
df -hT /mnt Filesystem Type Size Used Avail Use% Mounted on /dev/mapper/cs-root xfs 71G 3.4G 68G 5% /mnt
[root@dlp ~]#
cat /var/lib/docker/volumes/volume01/_data/testfile.txt Docker Volume test # possible to mount from other containers [root@dlp ~]# docker run -v volume01:/var/volume01 centos /usr/bin/cat /var/volume01/testfile.txt Docker Volume test # to remove volumes, do like follows [root@dlp ~]# docker volume rm volume01 Error response from daemon: remove volume01: volume is in use - [18c6165c9ded7f0774ea39c391dd49860c1fcd720bf744d557069c758cb7eaf2, e6ee46179535325d325e866ca10d6420816f0baa6a7803ef46d989637ddcb98e] # if some containers are using the volume you'd like to remove like above, # it needs to remove target containers before removing a volume [root@dlp ~]# docker rm 18c6165c9ded7f0774ea39c391dd49860c1fcd720bf744d557069c758cb7eaf2 [root@dlp ~]# docker rm e6ee46179535325d325e866ca10d6420816f0baa6a7803ef46d989637ddcb98e
docker volume rm volume01 volume01 |
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