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Elektrobit / flake-pilot

Registration/Control utility for applications launched through a runtime-engine, e.g containers
MIT License
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FireCracker: Command output intermix with kernel log #75

Closed schaefi closed 1 year ago

schaefi commented 1 year ago

Description

As we plan to use firecracker as the launcher for applications, the process to run commands involves the startup of the VM through firecracker and next to it the startup of the application. As of today the output of the command is captured through the console setting of the VM console=ttyS0 which transfers all output to the caller. This works but also includes other messages not related to the actual command call. To keep the bootup of the VM as silent as possible we currently use the kernel options loglevel=0 quiet which eliminates most of the unwanted messages but surely not all of them and it also depends on the used kernel image if there might be more unrelated messages.

This opens the question how we can separate the command output from the VM startup messages in a generic way

schaefi commented 1 year ago

My findings on this one ( mostly reading /sys/module/printk/parameters/)

boot_args:
    - "printk.time=N"
    - "printk.ignore_loglevel=N"
    - "loglevel=0"
    - "quiet"
    - "console=ttyS0"

removes most of the messages. But all [ T1] are still there. I guess they are not printed through printk but through printf and I have no idea how we could prevent them

@m-kat I'm eager to see your findings. Thanks much

m-kat commented 1 year ago

My findings:

boot_args:
    - 'pci=off"
    - "acpi=off"
    - "quiet"
    - "loglevel=0"
    - "i8042.nokbd"
    - "i8042.noaux"
    - "i8042.nomux"
    - "i8042.nopnp"
    - "i8042.dumbkbd"
    - "console=ttyS0"

removes all kernel messages but there is still " sysrq: Resetting" message, tried to turn it off by kernel parameters and sysrq-trigger interface but no luck there. Tried also to switch logs into some other console but this message is not treated as a pure kernel message and still is on the main console shown.

schaefi commented 1 year ago

I added a doc hint regarding this