Proxmox Server freezing

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kadybat

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May 15, 2025
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Hey everyone,

I'm facing an issue with my dedicated server (running Proxmox) hosted by OVH since 4 days. The system randomly freezes, and OVH ends up performing an automatic reboot. This has happened multiple times now, and I'm trying to identify the root cause.

OVH has already conducted three separate hardware investigations and reported no hardware issues.
The NVMe drives were replaced in December, as the previous ones were worn out.
OVH now claims it must be a software issue, but unfortunately there are no clear logs pointing to the root cause.


Interestingly, we had the same issue about two months ago, and what helped back then was reducing the resource limits (CPU/RAM) on the individual containers and VMs. After doing that, the server ran stable for a while – until now.

Here are my server specs:
  • Proxmox Version: 8.4.1
  • CPU: AMD Ryzen 5 3600X - 6c/12t - 3.8 GHz / 4.4 GHz
  • RAM: 64 GB ECC 2666 MHz
  • Storage: 2×500 GB NVMe SSD (Soft RAID)
Here are some logs from /var/log/syslog right before the last freeze:

May 15 14:20:57 mio-network sshd[995589]: Received disconnect from 218.92.0.249 port 31935:11: [preauth]
May 15 14:20:57 mio-network sshd[995589]: Disconnected from authenticating user root 218.92.0.249 port 31935 [preauth]
May 15 14:20:57 mio-network sshd[995589]: PAM 2 more authentication failures; logname= uid=0 euid=0 tty=ssh ruser= rhost=218.92.0.249 user=root
...
May 15 14:21:13 mio-network sshd[996018]: Disconnected from invalid user elena 8.217.43.77 port 49102 [preauth]
May 15 14:21:15 mio-network audit[996161]: NETFILTER_CFG table=filter family=7 entries=0 op=xt_replace pid=996161 subj=unconfined comm="ebtables-restor"
-- Reboot --


As you can see:
  • There were multiple SSH brute-force attempts from random IPs (China, Russia, etc.).
  • SSH logins for invalid or root users were being attempted repeatedly.
  • Around the time of the freeze, ebtables-restore was executed, modifying netfilter rules.
  • Shortly after, the server completely froze and OVH initiated a reboot.

There’s no clear indication of a kernel panic, OOM killer, or disk error in the logs. Just regular cron activity, audit logs, and network rule updates.

Has anyone experienced similar behavior with ebtables-restore or Proxmox freezing with no clear cause?

Additional Info:
  • Root SSH login is still enabled (working on securing it).
  • No monitoring for hardware issues yet (will check with smartctl).
  • Using 4 LXC Containers, 2 Windows VMs
We have already performed several checks ourselves, including:
  • Filesystem check (fsck)
  • RAM tests (memtest)
  • Disk health checks (SMART)
    All of these showed no errors.

Any insights, suggestions, or tools to better trace the next incident would be highly appreciated.
Thanks in advance!
 
May 15 22:36:32 mio-network audit: PROCTITLE proctitle="ebtables-restore"
May 15 22:36:33 mio-network sshd[354590]: Failed password for root from 218.92.0.249 port 35033 ssh2
May 15 22:36:33 mio-network audit[354590]: USER_LOGIN pid=354590 uid=0 auid=4294967295 ses=4294967295 msg='op=login acct="root" addr=218.92.0.249 terminal=sshd res=failed'
May 15 22:36:34 mio-network sshd[354518]: Failed password for root from 218.92.0.249 port 60238 ssh2
May 15 22:36:34 mio-network sshd[354518]: Disconnected from authenticating user root 218.92.0.249 port 60238 [preauth]
May 15 22:36:34 mio-network sshd[354662]: pam_unix(sshd:auth): authentication failure; rhost=218.92.0.249 user=root
May 15 22:36:35 mio-network sshd[354590]: Failed password for root from 218.92.0.249 port 35033 ssh2
May 15 22:36:36 mio-network sshd[354662]: Failed password for root from 218.92.0.249 port 62419 ssh2
May 15 22:36:37 mio-network sshd[354590]: Failed password for root from 218.92.0.249 port 35033 ssh2
May 15 22:36:39 mio-network sshd[354662]: Failed password for root from 218.92.0.249 port 62419 ssh2
May 15 22:36:39 mio-network sshd[354590]: Disconnected from authenticating user root 218.92.0.249 port 35033 [preauth]
May 15 22:36:42 mio-network sshd[354662]: Failed password for root from 218.92.0.249 port 62419 ssh2
-- Reboot --
 
Hello,

which kernel version are you using?

  • There were multiple SSH brute-force attempts from random IPs (China, Russia, etc.).
Click to expand...
I would highly recommend to not have the Proxmox VE accessible through the public internet. On top of that it should also be firewalled so that port 22 is only accessible from within the local network.
 
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Reactions: gfngfn256
Maximiliano said:
Hello,

which kernel version are you using?


I would highly recommend to not have the Proxmox VE accessible through the public internet. On top of that it should also be firewalled so that port 22 is only accessible from within the local network.
Click to expand...

Hello, i am using: 6.2.16-20-pve

And good point. I will disable access to public.
But the issue is still ongoing.
 
Below you can see some data.
Before the gaps, the server freezed - then OVH rebooted automatically
 

Attachments

  • image.png
    image.png
    70.4 KB · Views: 9
How are you upgrading your host? Proxmox VE 8.4 was released with kernel 6.8 so any system upgrade should have had updated your kernel to 6.8. Did you use `apt upgrade`?

We generally recommend to run

```
apt update && apt full-upgrade
```

when upgrading the host, the `apt upgrade` command is known to cause issues. Is it possible that kernel 6.2 was pinned in the past?


The issues you have look like a kernel bug, so I would highly suggest to

1. Try if upgrading to the latest kernel in the 6.8 series improves the situation
2. If that does not improve the situation, try out the opt-in 6.14 kernel, see [1]. As of today this kernel should be available in all of our repositories for Proxmox VE 8.

Note that kernel upgrades require a reboot of the host to take into effect.

[1] https://forum.proxmox.com/threads/o...e-8-available-on-test-no-subscription.164497/
 
Maximiliano said:
How are you upgrading your host? Proxmox VE 8.4 was released with kernel 6.8 so any system upgrade should have had updated your kernel to 6.8. Did you use `apt upgrade`?

We generally recommend to run

```
apt update && apt full-upgrade
```

when upgrading the host, the `apt upgrade` command is known to cause issues. Is it possible that kernel 6.2 was pinned in the past?


The issues you have look like a kernel bug, so I would highly suggest to

1. Try if upgrading to the latest kernel in the 6.8 series improves the situation
2. If that does not improve the situation, try out the opt-in 6.14 kernel, see [1]. As of today this kernel should be available in all of our repositories for Proxmox VE 8.

Note that kernel upgrades require a reboot of the host to take into effect.

[1] https://forum.proxmox.com/threads/o...e-8-available-on-test-no-subscription.164497/
Click to expand...

Thank you for your reply.
I will do it, but I don't think it is causing the freezes.

I noticed that i'm ballooning on 2 windows guests.
Someone told me to disable it, because it can cause the freezes.

I did now and will test if it's solving my issue
 
I will do it, but I don't think it is causing the freezes.
Click to expand...

The kernel is literally the only piece of software that can cause a host to freeze, the other alternative is faulty hardware.
 
Hello @Maximiliano
I disabled the auto hard reboot which was triggered by OVH after every freeze.

Now I can see this kernel panic message in my KVM console.
Do you know the issue?

uJUPSfq.png
 
From what I gather from your screenshot, you have a hardware problem. Unfortunately, you'll be spending a lot of time on the phone with OVH.
 
Last edited:
Would it be possible to get more output before and after? A crash in the kernel generally contains more information.
 
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