Kernel update, reboot required?

heutger

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Apr 25, 2018
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Fulda, Hessen, Germany
www.heutger.net
There was a recent kernel update from PMG. I try to keep the system clean and use pvekclean to remove old kernels. I expected, I need to reboot first and then be able to remove the old kernel, but it seems to have been used already. So my question is: Is there no reboot required? Are new kernels used directly? May it break then at next reboot?
 
You need to reboot to activate a new kernel.
 
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Reactions: Stoiko Ivanov
In addition to what @tom said
and use pvekclean to remove old kernels.
since PMG 7.2 you should be fine by just updating and running `apt autoremove` afterwards
(This has been the case for PVE since 6.4 IIRC, but a config-file was preventing the autmatic removal in PMG until recently)
 
I'm a bit confused. I use the unattended-updates, which should remove old kernels, but it doesn't. I tried pvekclean and it removed two kernels without reboot. I did a uname -a and it showed me the .15 kernel, after your message I rebooted and it still showed me the .15 kernel?

.15 in full: Linux pmg 5.15.74-1-pve #1 SMP PVE 5.15.74-1 (Mon, 14 Nov 2022 20:17:15 +0100) x86_64
 
Last edited:
I'm a bit confused. I use the unattended-updates, which should remove old kernels, but it doesn't.
the logs from unattended-upgrades might provide an idea why something was/was not removed

did a uname -a and it showed me the .15 kernel, after your message I rebooted and it still showed me the .15 kernel?
which kernel version did uname -a show exactly?
* 5.15.XX-Y-pve (XX is the patch version Y the abi version of a particular kernel package, and then there is the version of an actual kernel package) e.g.
Code:
 pve-kernel-5.15.30-2-pve              5.15.30-3
the package name (pve-kernel-5.15.30-2-pve) contains major (5), minor (15), patch level (30) and abi-version (2) - the package version is 5.15.30-3, since there were 3 packages of kernel version 5.15.30

see:
https://kernel-team.pages.debian.net/kernel-handbook/ch-versions.html
and
https://wiki.debian.org/DebianKernelABIChanges

I hope this explains it
 
Thanks, however it showed 5.15.74-1 before reboot as well as after reboot?
* Check in /var/log/apt/history.log (and term.log) what exactly got installed
* Check with `pmgversion -v` which kernel packages are installed
* make sure to not have pinned a particular version (`proxmox-boot-tool kernel unpin`)
 
I got a mail from apticron, next hours the kernel will be updated. I currently have this output:

root@pmg:~# uname -a
Linux pmg 5.15.74-1-pve #1 SMP PVE 5.15.74-1 (Mon, 14 Nov 2022 20:17:15 +0100) x86_64 GNU/Linux
root@pmg:~# pmgversion -v
proxmox-mailgateway: 7.2-1 (API: 7.2-2/fe97dfd3, running kernel: 5.15.74-1-pve)
pmg-api: 7.2-2
pmg-gui: 3.2-2
pve-kernel-helper: 7.3-1
pve-kernel-5.15: 7.2-14
pve-kernel-5.15.74-1-pve: 5.15.74-1
clamav-daemon: 0.103.7+dfsg-0+deb11u1
ifupdown2: 3.1.0-1+pmx3
libarchive-perl: 3.4.0-1
libjs-extjs: 7.0.0-1
libjs-framework7: 4.4.7-1
libproxmox-acme-perl: 1.4.3
libproxmox-acme-plugins: 1.4.3
libpve-apiclient-perl: 3.2-1
libpve-common-perl: 7.3-1
libpve-http-server-perl: 4.1-5
libxdgmime-perl: 1.0-1
lvm2: 2.03.11-2.1
pmg-docs: 7.2-1
pmg-i18n: 2.8-1
pmg-log-tracker: 2.3.2-1
postgresql-13: 13.9-0+deb11u1
proxmox-mini-journalreader: 1.3-1
proxmox-offline-mirror-helper: 0.5.0-1
proxmox-spamassassin: 3.4.6-5
proxmox-widget-toolkit: 3.5.3
pve-firmware: 3.6-1
pve-xtermjs: 4.16.0-1
zfsutils-linux: 2.1.6-pve1
root@pmg:~# uptime
16:37:18 up 7 days, 1:57, 1 user, load average: 0.00, 0.05, 0.07

I will then post again after update and before reboot.
 
In addition to what @tom said

since PMG 7.2 you should be fine by just updating and running `apt autoremove` afterwards
(This has been the case for PVE since 6.4 IIRC, but a config-file was preventing the autmatic removal in PMG until recently)
This kernel update I was required to reboot. Will keep an eye on. However, apt(-get) autoremove doesn’t show anything for removal, but pvekclean does and sure, after rebooting, I switched the kernel and there is something to remove? Will keep trying what unattendedupgrades will do on old kernel removal with next kernel update.
 
please post `pmgversion -v` else it's just guesswork what is working and what is not working

additionally post the output of `ls -l /etc/apt/apt.conf.d`
 
root@pmg:~# pmgversion -v
proxmox-mailgateway: 7.2-1 (API: 7.2-2/fe97dfd3, running kernel: 5.15.83-1-pve)
pmg-api: 7.2-2
pmg-gui: 3.2-2
pve-kernel-5.15: 7.3-1
pve-kernel-helper: 7.3-1
pve-kernel-5.15.83-1-pve: 5.15.83-1
pve-kernel-5.15.74-1-pve: 5.15.74-1
clamav-daemon: 0.103.7+dfsg-0+deb11u1
ifupdown2: 3.1.0-1+pmx3
libarchive-perl: 3.4.0-1
libjs-extjs: 7.0.0-1
libjs-framework7: 4.4.7-1
libproxmox-acme-perl: 1.4.3
libproxmox-acme-plugins: 1.4.3
libpve-apiclient-perl: 3.2-1
libpve-common-perl: 7.3-1
libpve-http-server-perl: 4.1-5
libxdgmime-perl: 1.0-1
lvm2: 2.03.11-2.1
pmg-docs: 7.2-1
pmg-i18n: 2.8-1
pmg-log-tracker: 2.3.2-1
postgresql-13: 13.9-0+deb11u1
proxmox-mini-journalreader: 1.3-1
proxmox-offline-mirror-helper: 0.5.0-1
proxmox-spamassassin: 3.4.6-5
proxmox-widget-toolkit: 3.5.3
pve-firmware: 3.6-2
pve-xtermjs: 4.16.0-1
zfsutils-linux: 2.1.7-pve1
root@pmg:~# ls -l /etc/apt/apt.conf.d
total 48
drwxr-xr-x 2 root root 4096 Dec 23 06:51 .
drwxr-xr-x 8 root root 4096 Dec 22 11:16 ..
-rw-r--r-- 1 root root 630 Jun 10 2021 01autoremove
-r--r--r-- 1 root root 120 Dec 23 06:50 01autoremove-kernels
-r--r--r-- 1 root root 496 Dec 7 21:17 01autoremove-postgresql
-rw-r--r-- 1 root root 80 Feb 19 2021 20auto-upgrades
-rw-r--r-- 1 root root 307 Mar 28 2021 20listchanges
-rw-r--r-- 1 root root 7392 Dec 11 11:49 50unattended-upgrades
-rw-r--r-- 1 root root 182 Jun 10 2021 70debconf
-rw-r--r-- 1 root root 23 Dec 23 01:09 76pmgproxy
-r--r--r-- 1 root root 203 Dec 23 06:51 76pveconf
root@pmg:~
 
pve-kernel-helper: 7.3-1
pve-kernel-5.15.83-1-pve: 5.15.83-1
pve-kernel-5.15.74-1-pve: 5.15.74-1
seems ok - proxmox-boot-tool (which handles the flagging of kernel for keeping and autoremoving, from the pve-kernel-helper package) keeps the last 2 installed kernels, and a kernel from each series (e.g. pve-kernel-5.15 and maybe later a pve-kernel-6.1)
see https://pve.proxmox.com/pve-docs/chapter-sysadmin.html#sysboot "Kernel Versions considered by proxmox-boot-tool"
(the docs are for PVE, but the code is shared with PMG )
 

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