My PBS is currently hosed after 3 to 4 upgrade.
I had a similar error to you, but I am slightly different.
I am running PBS inside LXC on TrueNAS Scale 25.04.2, so definitely an unsupported setup.
Code:
= CHECKING VERSION INFORMATION FOR PBS PACKAGES =
INFO: Checking for package updates..
PASS: all packages up-to-date
INFO: Checking proxmox backup server package version..
FAIL: could not match the 'proxmox-backup' package version, is it installed?
INFO: Check running kernel version..
WARN: unexpected running and installed kernel '6.12.15-production+truenas'.
I fully acknowledge my setup is unsupported.
This is a homelab situation, the backups storage box is a TrueNAS box.
I referenced this guide originally for the Bookworm install
https://forum.proxmox.com/threads/pbs-on-truenas-have-your-cake-and-eat-it-too.162860/
The dist upgrade went fine and it is now a Trixie LXC container upgraded from originally a Bookworm LXC container, it is just the kernel is the TrueNAS kernel.
proxmox-backup-proxy and proxmox-backup services are running, and the logs look normal, but when I try to access the web interface I get connection reset error and it doesn't load.
Nothing helpful in the logs, doesn't even show my attempt to load the web page in any log I have found so no error I can really troubleshoot.
Code:
openssl s_client -connect localhost:8007
CONNECTED(00000004)
Can't use SSL_get_servername
depth=0 O = Proxmox Backup Server, OU = 81F45FD4-ED16-4A0B-A2AE-635EE9081313, CN = mypbs.HOME.local
verify error:num=18:self-signed certificate
verify return:1
depth=0 O = Proxmox Backup Server, OU = 81F45FD4-ED16-4A0B-A2AE-635EE9081313, CN = mypbs.HOME.local
verify return:1
---
******** redacted cert data here ********
Verify return code: 18 (self-signed certificate)
Extended master secret: no
Max Early Data: 0
---
---
read R BLOCK
40E7D131B4720000:error:0A000126:SSL routines:ssl3_read_n:unexpected eof while reading:../ssl/record/rec_layer_s3.c:322:
I dunno what the cause is.
Not had the chance to properly troubleshoot this yet however.
Out of curiosity I decided to start with a fresh Trixie LXC container and then installed PBS 4 on top of that.
It worked fine, no issues accessing web interface.
So it is not an outright incompatibility running PBS4 inside LXC on top of TrueNAS Scale, something just went south with the upgrade process from 3 to 4.
Just interesting that the upgrade hosed the original PBS.
I am reckon there is some minor bug there brought on because I am running it inside LXC on top of TrueNAS Scale which is not a supported way of doing it. (I did it this way so the container could have direct access to an underlying ZFS dataset in TrueNAS BTW)
No matter, seeing that it looks like it is going to work OK with a fresh install in a fresh Trixie LXC container, I will just go with that and migrate my datastore over to the new PBS instance, minor annoyance.
I will note however, I have now upgraded 2 bare metal PBS hosts at work from version 3 to version 4, and both of them went smoothly without a single problem.
Next step is to upgrade our PVE hosts from 8 to 9.
