I think storage volumes will work fine for shared data for your Docker applications. There are drawbacks, like not being able to drill down the tree to access it easily. Once it’s imported into Incus, it goes dark in the UI and you can’t cd down the path to the files. Since you can’t see the volumes, you can’t mount them in the Web UI either. It should essentially work similarly to host mount points.
On the other hand, it’s managed within Incus, so permissions should work, if we get an image running with the Incus Web UI, it would probably be easy to manage the storage and volumes within Incus easily since it’s using the ZFS driver to handle datasets, volumes, snapshots, etc.
This was just a quick setup and test and there are probably some best practices I’m likely missing as well. This should persist as it’s being created in the default profile. Thoughts, suggestions?
Create volume:
incus storage volume create default docker size=50GiB zfs.block_mode=true block.filesystem=ext4
Default storage info:
incus storage show default
config:
source: sol/.ix-virt
zfs.pool_name: sol/.ix-virt
description: ""
name: default
driver: zfs
used_by:
- /1.0/images/d500c0445c2514fc514add9df99e433e208e3d4102fed497c807f24ab5a09146
- /1.0/instances/docker1
- /1.0/instances/docker2
- /1.0/profiles/default
- /1.0/storage-pools/default/volumes/custom/docker
status: Created
locations:
- none
Volume info:
incus storage volume show default docker
config:
block.filesystem: ext4
block.mount_options: discard
size: 50GiB
volatile.idmap.last: '[{"Isuid":true,"Isgid":false,"Hostid":2147000001,"Nsid":0,"Maprange":458752},{"Isuid":false,"Isgid":true,"Hostid":2147000001,"Nsid":0,"Maprange":458752}]'
volatile.idmap.next: '[{"Isuid":true,"Isgid":false,"Hostid":2147000001,"Nsid":0,"Maprange":458752},{"Isuid":false,"Isgid":true,"Hostid":2147000001,"Nsid":0,"Maprange":458752}]'
zfs.block_mode: "true"
description: ""
name: docker
type: custom
used_by:
- /1.0/instances/docker1
- /1.0/instances/docker2
location: none
content_type: filesystem
project: default
created_at: 2025-02-25T20:18:29.231566987Z
ZFS datasets:
zfs list|grep ^sol/.ix-virt
sol/.ix-virt 1.88G 1.02T 96K legacy
sol/.ix-virt/buckets 96K 1.02T 96K legacy
sol/.ix-virt/containers 1.38G 1.02T 96K legacy
sol/.ix-virt/containers/docker1 708M 1.02T 960M legacy
sol/.ix-virt/containers/docker2 708M 1.02T 960M legacy
sol/.ix-virt/custom 1.84M 1.02T 96K legacy
sol/.ix-virt/custom/default_docker 1.75M 1.02T 1.75M -
sol/.ix-virt/deleted 255M 1.02T 96K legacy
sol/.ix-virt/deleted/buckets 96K 1.02T 96K legacy
sol/.ix-virt/deleted/containers 96K 1.02T 96K legacy
sol/.ix-virt/deleted/custom 96K 1.02T 96K legacy
sol/.ix-virt/deleted/images 254M 1.02T 96K legacy
sol/.ix-virt/deleted/images/d3d195e18e3f6ad0ec8b8c69adfa46e46074410e10a214173536f37c18c33e92 254M 1.02T 254M legacy
sol/.ix-virt/deleted/virtual-machines 96K 1.02T 96K legacy
sol/.ix-virt/images 254M 1.02T 96K legacy
sol/.ix-virt/images/d500c0445c2514fc514add9df99e433e208e3d4102fed497c807f24ab5a09146 254M 1.02T 254M legacy
sol/.ix-virt/virtual-machines
Attach to instances:
incus config device add docker1 docker disk source=docker pool=default path=/mnt/foo
incus config device add docker2 docker disk source=docker pool=default path=/mnt/foo
Instance configuration:
volatile.idmap.base: "0"
volatile.idmap.current: '[{"Isuid":true,"Isgid":false,"Hostid":2147000001,"Nsid":0,"Maprange":458752},{"Isuid":false,"Isgid":true,"Hostid":2147000001,"Nsid":0,"Maprange":458752}]'
volatile.idmap.next: '[{"Isuid":true,"Isgid":false,"Hostid":2147000001,"Nsid":0,"Maprange":458752},{"Isuid":false,"Isgid":true,"Hostid":2147000001,"Nsid":0,"Maprange":458752}]'
docker:
path: /mnt/foo
pool: default
source: docker
type: disk
Touch files:
root@docker1:~# cd /mnt/foo && touch docker1
root@docker2:~# cd /mnt/foo && touch docker2
List files in volume:
ls -l /mnt/foo/
total 16
-rw-r--r-- 1 root root 0 Feb 25 15:52 docker1
-rw-r--r-- 1 root root 0 Feb 25 15:52 docker2
drwx------ 2 root root 16384 Feb 25 15:18 lost+found
Disk usage:
df -h /mnt/foo
Filesystem Size Used Avail Use% Mounted on
/dev/zvol/sol/.ix-virt/custom/default_docker 49G 24K 47G 1% /mnt/foo
Screenshot of volume added in UI:
Also, when adding a volume this way, it breaks the Web UI when attempting to upload images.
