Fedora 41
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Podman : Use External Storage2024/11/06

 

When a Container is removed, data in it are also lost, so it's necessary to use external storage on Containers if you'd like to save your data.

[1] It's possible to mount a directory on Podman Host into Containers.
# create a directory for containers data

[root@dlp ~]#
mkdir /var/lib/containers/disk01

[root@dlp ~]#
echo "persistent storage" >> /var/lib/containers/disk01/testfile.txt

# run a Container with mounting the directory above on [/mnt]
# if SELinux is [Enforcing], it needs to add [--privileged] option

[root@dlp ~]#
podman run --privileged -it -v /var/lib/containers/disk01:/mnt fedora /bin/bash
[root@586cac343aff /]#
df -hT /mnt

Filesystem              Type  Size  Used Avail Use% Mounted on
/dev/mapper/fedora-root xfs    77G  4.0G   74G   6% /mnt

[root@586cac343aff /]#
cat /mnt/testfile.txt

persistent storage
[2] It's also possible to configure external storage by Podman Data Volume command.
# create [volume01] volume

[root@dlp ~]#
podman volume create volume01

volume01
# display volume list

[root@dlp ~]#
podman volume ls

DRIVER      VOLUME NAME
local       volume01

# display details of [volume01]

[root@dlp ~]#
podman volume inspect volume01

[
     {
          "Name": "volume01",
          "Driver": "local",
          "Mountpoint": "/var/lib/containers/storage/volumes/volume01/_data",
          "CreatedAt": "2024-11-06T09:15:38.791519569+09:00",
          "Labels": {},
          "Scope": "local",
          "Options": {},
          "MountCount": 0,
          "NeedsCopyUp": true,
          "NeedsChown": true,
          "LockNumber": 8
     }
]

# run a container with mounting [volume01] to [/mnt] on container

[root@dlp ~]#
podman run -it -v volume01:/mnt fedora
[root@d17431a32cdb /]#
df -hT /mnt

Filesystem              Type  Size  Used Avail Use% Mounted on
/dev/mapper/fedora-root xfs    77G  4.0G   74G   6% /mnt

[root@d17431a32cdb /]#
echo "Podman Volume test" > /mnt/testfile.txt

[root@d17431a32cdb /]#
exit
[root@dlp ~]#
cat /var/lib/containers/storage/volumes/volume01/_data/testfile.txt

Podman Volume test
# possible to mount from other containers

[root@dlp ~]#
podman run -v volume01:/var/volume01 fedora /usr/bin/cat /var/volume01/testfile.txt

Podman Volume test
# to remove volumes, do like follows

[root@dlp ~]#
podman volume rm volume01

Error: volume volume01 is being used by the following container(s): d17431a32cdbaed4afdf97ef4fe14da1e60d4aa7da30761c5324a1c11b4db791, 16d16b3d63922bfc42bc33566064e325dc5c04296598f9e3e67f1f7c09350e7b: volume is being used

# 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 ~]#
podman rm d17431a32cdbaed4afdf97ef4fe14da1e60d4aa7da30761c5324a1c11b4db791

[root@dlp ~]#
podman rm 16d16b3d63922bfc42bc33566064e325dc5c04296598f9e3e67f1f7c09350e7b
[root@dlp ~]#
podman volume rm volume01

volume01
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