Using NETCONSOLE to debug Linux (and Proxmox) Kernel Panics

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ความคิดเห็น • 19

  • @LampJustin
    @LampJustin 3 หลายเดือนก่อน +14

    Btw the systemd journald also logs kernel messages, which is quite helpful when they get truncated by dmesg or when the system got rebooted as you show the logs from the last boot: journalctl -b -1 -ke

  • @AntranigVartanian
    @AntranigVartanian 3 หลายเดือนก่อน +2

    Somehow doing this on Solaris 10, around 20 years ago, was much simpler and debugging was easier as well. Good to see Linux catching up.

    • @autohmae
      @autohmae 3 หลายเดือนก่อน +1

      This is how easy it has been since 2001, so 'catching up' is a big word, nothing changed.
      BTW Warning this might make you feel old: Solaris 10 was from 1992, 32 years ago.

  • @blevenzon
    @blevenzon 3 หลายเดือนก่อน +3

    Thanks so much, you rock dude. Awesome content as always

  • @drunkbear889
    @drunkbear889 3 หลายเดือนก่อน +2

    Another viewpoint: If using a P2P L3 link to the server (from a router, or L3 switch). I would not see a problem with leaving it on all the time.
    Some switches can can do inbound rules on the interface connected to the server for forwarding packets based on filters to only select destinations (think MT CRS devices). Such that even devices on the same LAN segment, will not receive the broadcast packets destined to ff:ff:ff:ff:ff:ff (switch chip ACL rules). (~port mirroring, but filtered for very specific traffic)

    • @apalrdsadventures
      @apalrdsadventures  3 หลายเดือนก่อน +3

      It's also possible to not use the broadcast mac if you want to leave it on all the time, you then need to set both the unicast IP and unicast MAC since it doesn't do ARP / NDP.
      I also tried using multicast and that works fine on the Netconsole side, but receiving multicast is a lot harder than netcat, so I didn't go down that path. That may be easier to filter depending on your switch.

  • @ws_stelzi79
    @ws_stelzi79 3 หลายเดือนก่อน

    well *someone* "had got" the need to make a video on an advanced Linux/kernel debugging! 😉😇

  • @PCMagikHomeLab
    @PCMagikHomeLab 3 หลายเดือนก่อน

    Thumbs UP! :)

  • @DawidKellerman
    @DawidKellerman 3 หลายเดือนก่อน

    I like your original videos ! The lets do the same vid as some one else is tiresome! Any chance for a video on proxmox offline mirror?

  • @NiHaoMike64
    @NiHaoMike64 3 หลายเดือนก่อน +1

    Wouldn't serial console also be a good option if the machine in question has a serial port?

    • @apalrdsadventures
      @apalrdsadventures  3 หลายเดือนก่อน

      Yes, and I have a video on that too. A lot of machines don't have them, though.

    • @autohmae
      @autohmae 3 หลายเดือนก่อน

      @@apalrdsadventures every Linux VM on KVM/Qemu does of course... what would be a good serial console server software which has the option to log everything ? A quick look around I think I can probably just run a bunch of stty processes to capture the logs.

    • @apalrdsadventures
      @apalrdsadventures  2 หลายเดือนก่อน +2

      For VMs of course, but when you are doing experimental hardware passthrough you tend to crash the host kernel

    • @autohmae
      @autohmae 2 หลายเดือนก่อน

      @@apalrdsadventures ahh, that's sad, that shouldn't really be able to happen.

    • @apalrdsadventures
      @apalrdsadventures  2 หลายเดือนก่อน +1

      Usually it's because the host kernel was already using that device and you took it away improperly to give to the VM. If you do that with the primary GPU, then you have no graphics device to debug from either.

  • @OscarCarlsson1986
    @OscarCarlsson1986 3 หลายเดือนก่อน +1

    The blog entry isn't live yet =)

    • @apalrdsadventures
      @apalrdsadventures  3 หลายเดือนก่อน +1

      fixed it, the timer didn't do it on time for some reason