Serial console for NetBSD

Written at lunch time in English • Tags: , ,

I’ve been switching my NetBSD machines to using a serial console lately, as it is easier to copy output from it (no more screen shots). I would still need to figure out how to setup rtty1 to log console output, so unexpected output could also be inspected later (hello, panic).

On the NetBSD VM its bootblocks must be reinstalled to select a serial port as the console. I’ve been using the auto option, so I can easily switch between the VGA and serial consoles. I set speed to zero, which will use the speed configured in BIOS. The only available “speed” with qemu is 115200 bps.

installboot -v -o console=auto,speed=0 /dev/rsd0a /usr/mdec/bootxx_ffsv2

In Proxmox a serial port must be added to the VM on the Hardware tab. It is important to leave the Display setting at Default (or VGA) — for some reason input from the serial console will not work in the boot menu otherwise. (It will work in BIOS and at the login prompt.)

  1. Also known as remote-tty in Debian. 


  • 1

    how about trying Conserver?

    pkgin install conserver8

    Also, though I don’t know about plain qemu, or proxmox, I use conserver with Xen using the following script:

    (Xen does log serial console output and allows local root to connect to consoles, but conserver adds sharing, non-root access, remote access, etc.)

    Greg A. Woods — 23.4.20 @ 2:15

  • 2

    Thank you for the pointers, Greg! I will definitely have a look.

    Proxmox does not log serial console output, and like Xen it allows local root to connect (using qm terminal). Ideally I would like to have logging from the moment the VM starts. Having non-root access is also highly desirable — sharing is a nice bonus.

    Kimmo Suominen — 23.4.20 @ 10:41

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