SOLVED Jail patch level on GUI does not match that reportted by the jail itself.

[SeaFox]

Version: TrueNAS-12.0-U4

I have at least a half-dozen jails operating on my system and so I occasionally go through and run the Update command on the GUI to update the patch level on them to stay on top of security exploits. Right now I have multiple jails I have been updating but the jails themselves claim they are not.

The GUI is showing them as on 12.2-RELEASE-p8, but when I log into them and run uname -mrs I'm being told they are still on p6. These include jails that get rebooted often for unrelated reasons.
Meanwhile, my Syncthing install (which is using the official plugin), also reports itself as FreeBSD 12.2-RELEASE-p6, but the GUI says it's still on 12.1-RELEASE-p13.

 

[Patrick M. Hausen]

uname reports the kernel version of your TrueNAS host, not the version of the jail. Use freebsd-version instead.

 

[SeaFox]

uname reports the kernel version of your TrueNAS host, not the version of the jail. Use freebsd-version instead.

Ah, thank you. I was under the impression when in the jail it would only interface with the jail's system.

I tried freebsd-version earlier, but I had the -k switch on it and was getting an error, so I thought the command was not supported. But now that I tried it by itself it does work.

Code:

root@syncthing-3:/ # freebsd-version
12.1-RELEASE-p13

 

[Patrick M. Hausen]

Jails run on the same kernel as the host system. They are containers, not VMs.

 

[SeaFox]

Jails run on the same kernel as the host system. They are containers, not VMs.

So are jails forwards-compatible with the underlying system? When I upgraded from FreeNAS to TrueNAS I had to redo most of my jails, but my Plex jail (an 11.3 jail) still worked, even though the TrueNAS system was now a 12.x kernel.

 

[Patrick M. Hausen]

You can always run a lower version of a jail on a higher version of the system, but not necessarily the other way round.
If you have OS version > jail version, some tools close to the kernel like sockstat may fail inside the jail.

 

[SeaFox]

Thanks for the explanation.