Accelerating rootless networking with bypass4netns

bypass4netns is an experimental accelerator for rootless networking.

On macOS hosts, it is highly recommended to use the vzNAT networking in conjunction to reduce the overhead of Lima’s user-mode networking:

limactl start --network vzNAT

To enable bypass4netns, the daemon process (bypass4netnsd) has to be installed in the VM as follows:

lima containerd-rootless-setuptool.sh install-bypass4netnsd

Then run a container with an annotation nerdctl/bypass4netns=true:

# 192.168.64.1 is the IP address of the "bridge100" interface on the macOS host
lima nerdctl run --annotation nerdctl/bypass4netns=true alpine \
  sh -euc 'apk add iperf3 && iperf3 -c 192.168.64.1'

Benchmark result: