Run a lean VM without containerd/nerdctl

[chenxiaoqino]

Description

I am trying to run a lightweight VM on hardware-constrained laptops, and want to minimize the VM's unnecessary CPU/Memory footprint. In my use case, I run single pre-built Linux binaries in the VM, and do not need containerd/nerdctl. However, a bare-bone default VM with nothing running costs 5-10% CPU and close to 1GB host memory (~300MB resident as seen inside the VM), mostly due to many containerd-related processes.

Since I don't run containers I want to remove these background processes in the VM. However, seems like there is no option to avoid adding containerd-related stuff when launching the VM. The launch script always attempt to download and install nerdctl -- it appears that even if I delete everything, it gets installed again in the next reboot. (I believe the "sticky" logic is here:

lima/pkg/cidata/cidata.TEMPLATE.d/boot/40-install-containerd.sh

Line 11 in 67e465e

if [ ! -x /usr/local/bin/nerdctl ]; then

)

I can open a pull-request myself if the authors can advise on where to change the logic. Is start.go the best place to change?

[jandubois]

However, seems like there is no option to avoid adding containerd-related stuff when launching the VM.

You can disable installation of nerdctl and containerd by editing your lima.yaml file:

lima/pkg/limayaml/default.yaml

Lines 90 to 92 in f24302b

	# Enable user-scoped (aka rootless) containerd and its dependencies
	# Default: true
	user: null

The default for containerd.user is true, so set it to false to disable:

containerd:
  system: false
  user: false

This is done in the Alpine example, which is also generally the smallest instance you can use.