Docker : Use External Storage2024/06/13 |
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. |
# 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 ubuntu /bin/bash
df -hT Filesystem Type Size Used Avail Use% Mounted on overlay overlay 77G 7.6G 65G 11% / tmpfs tmpfs 64M 0 64M 0% /dev shm tmpfs 64M 0 64M 0% /dev/shm /dev/mapper/ubuntu--vg-ubuntu--lv ext4 77G 7.6G 65G 11% /mnt tmpfs tmpfs 7.9G 0 7.9G 0% /proc/acpi tmpfs tmpfs 7.9G 0 7.9G 0% /proc/scsi tmpfs tmpfs 7.9G 0 7.9G 0% /sys/firmwareroot@55c3e6fe614d:/# cat /mnt/testfile.txt persistent storage |
[2] | It's also possible to configure external storage by Docker Data Volume command. |
# 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": "2024-06-13T00:40:57Z", "Driver": "local", "Labels": null, "Mountpoint": "/var/lib/docker/volumes/volume01/_data", "Name": "volume01", "Options": null, "Scope": "local" } ] # run a container with mounting [volume01] to [/mnt] on container root@dlp:~# docker run -it -v volume01:/mnt ubuntu
df -hT /mnt Filesystem Type Size Used Avail Use% Mounted on /dev/mapper/ubuntu--vg-ubuntu--lv ext4 77G 7.6G 65G 11% /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 ubuntu /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 - [4d651899ed4e4b047c550f03b64b626d3699c4ad504d3d11cd6e6f97e687b49d, bf943ba6a51bd3b820f74b336328d55eff4d6330df3c96efbaf6b875101911bb] # 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 4d651899ed4e4b047c550f03b64b626d3699c4ad504d3d11cd6e6f97e687b49d root@dlp:~# docker rm bf943ba6a51bd3b820f74b336328d55eff4d6330df3c96efbaf6b875101911bb
docker volume rm volume01 volume01 |
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