Docker : Use External Storage2021/08/30 |
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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 debian /bin/bash
df -hT Filesystem Type Size Used Avail Use% Mounted on overlay overlay 77G 1.9G 72G 3% / tmpfs tmpfs 64M 0 64M 0% /dev shm tmpfs 64M 0 64M 0% /dev/shm /dev/mapper/debian--vg-root ext4 77G 1.9G 72G 3% /mnt tmpfs tmpfs 7.9G 0 7.9G 0% /proc/acpi tmpfs tmpfs 7.9G 0 7.9G 0% /sys/firmwareroot@ed98ff6b35ef:/# 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": "2021-08-29T19:14:57-05:00",
"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 debian
df -hT /mnt Filesystem Type Size Used Avail Use% Mounted on /dev/mapper/debian--vg-root ext4 77G 1.9G 72G 3% /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 debian 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 - [4cbf4eeb2ef97f916b3c3a1ebf57009c6a82c484f91c9ba74edf87a26e725841, d11c0de4b68f62a45295db78a61d69d8933344583c2a00dc0a2a3a23b698efaa] # 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 4cbf4eeb2ef97f916b3c3a1ebf57009c6a82c484f91c9ba74edf87a26e725841 root@dlp:~# docker rm d11c0de4b68f62a45295db78a61d69d8933344583c2a00dc0a2a3a23b698efaa
docker volume rm volume01 volume01 |
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