Docker : Use External Storage2020/12/14 |
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When Container is removed, data in it 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 [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 75G 3.0G 73G 4% / 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/cl-root xfs 75G 3.0G 73G 4% /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@3af5df55cbcc /]# 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": "2020-12-11T10:33:36+09:00",
"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/cl-root xfs 75G 3.0G 73G 4% /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 - [d97446251ba6ca6adeecbed6cb4d7e94a77cbc83bfb2ee6a15ba5b1e7d918d6b, 35f196402ba86aa873cabda59ada3d80c98e022db2f69b70365be43b5e43299c] # 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 35f196402ba86aa873cabda59ada3d80c98e022db2f69b70365be43b5e43299c [root@dlp ~]# docker rm d97446251ba6ca6adeecbed6cb4d7e94a77cbc83bfb2ee6a15ba5b1e7d918d6b
docker volume rm volume01 volume01 |
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