LXC IDmapping host:container. Newlt created files work, old files not visible

fuzzyduck

Member
Jul 14, 2021
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Hey,

I had to reinstall Proxmox 6.4 due to failed upgrade to 7. I pulled the lxc containers from backup and got them running, with proper lxc mappings as before.

NEW LXC containers behave weird.

Inside a fresh LXC ubuntu: (Harro is my name)
groupadd -g 1000 Harro useradd -u 1000 -g Harro Harro passwd Harro

I got this very same user on the host with 1000:1000

then in the conf of the lxc:
lxc.idmap: u 0 100000 1000 lxc.idmap: g 0 100000 1000 lxc.idmap: u 1000 1000 1 lxc.idmap: g 1000 1000 1 lxc.idmap: u 1001 101001 64530 lxc.idmap: g 1001 101001 64530 mp0: /TANK/shares/,mp=/mnt/shares

Then inside the LXC I log in as Harro and change dir to /mnt/shares/
1. I can make a file and it appears as Harro:Harro (so 1000:1000) on both sides and can interact with it
2. I can see the existing dirs but as nobody:nogroup although on the host its Harro:Harro
3. Changing into these existing dirs give me NO files. On host there are files as Harro:Harro

/etc/subuid gives me:
root:100000:65536 Harro:165536:65536 root:1000:1

/etc/subgid gives me:
root:100000:65536 Harro:165536:65536 root:1000:1

Any idea why this happens?
 
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hi,

mp0: /TANK/shares/,mp=/mnt/shares
that's a zfs dataset?

3. Changing into these existing dirs give me NO files. On host there are files as Harro:Harro
that's normal since they aren't mounted recursively because of possible security implications. you can try adding the inner folders as a separate mountpoint and see if that solves your issue
 
Yes its in the zfs list command

In a working running LXC container (those working from backup) and i can browse the mountpoint + subdirs + files just fine. They are all Harro:Harro. In fact i can name the user inside the lxc whatever i want (www-data for nextcloud) as long as the IDs match with the host. In my case 1000:1000.

I have looked for other people with LXC mount problems i posted this due to a similar error on starting a fresh lxc unmodified container. Maybe its not related at all, but errors on a fresh lxc boot is strange to start with.
https://forum.proxmox.com/threads/mountpoint-with-lxc-idmap-no-longer-working.96575/post-418491
 
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