How to update base of my pot ?

[eleutherius]

Hello.
I have pot with base 11.1, but I want update base to 11.2 of my pot. How can I do that?

[pizzamig]

Hi.
It's a nice use case. The solution is a bit tricky and I cannot guarantee that everything will work, but it's easy to rollback.
Let's say that I have a pot called mypot111 based on FreeBSD 11.1 and I want upgrade it to FreeBSD 11.2.
First of all, I need an 11.2 base (if not yet available)

pot create-base -r 11.2

Then, that's what I did:

pot mypot111 stop
pot snap -p mypot111
cd /opt/pot/jails/mypot111/conf/

NOTE: /opt/pot is my POT_FS_ROOT configuration value. Check yours via pot config -g fs_root
In the /opt/pot/jails/mypot111/conf/pot.conf file

pot.level=1
pot.type=multi
pot.base=11.1
pot.potbase=
pot.dns=inherit
pot.cmd=sh /etc/rc
host.hostname="mypot111.pizzamig"
osrelease="11.1-RELEASE"
ip4=inherit
vnet=false

I changed pot.base=11.1 in pot.base=11.2 and osrelease="11.1-RELEASE" in osrelease="11.2-RELEASE"
Then, in the /opt/pot/jails/mypot111/conf/pot.conf file

zroot/pot/bases/11.1 /opt/pot/jails/mypot111/m ro
zroot/pot/jails/mypot111/usr.local /opt/pot/jails/mypot111/m/usr/local zfs-remount
zroot/pot/jails/mypot111/custom /opt/pot/jails/mypot111/m/opt/custom zfs-remount

I changed the first line to use the new base:

zroot/pot/bases/11.2 /opt/pot/jails/mypot111/m ro

Now you can restart your pot:

pot run mypot111
uname -r

If you're not happy with the upgrade or the upgrade failed you can revert the changes via:

pot stop mypot111
pot revert -p mypot111

[OPTIONAL] you can also rename your pot via

pot stop mypot111
pot rename -p mypot111 -n mypot112
pot start mypot112

IMPORTANT NOTE: The folders /etc and /var are not updated, because they're a copy of the 11.1 ones. If you're using some new 11.2 features that needs updated configuration files or tree layouts in /etc or /var you have to merge those files manually