nerdctl requires CNI to be installed when running containers with network_mode host

[vosdev]

Description

Running containers with network_mode: host, nerdctl still tries to create a default network even when no containers require one.

Steps to reproduce the issue

1. Do not have a CNI installed on your host
2. Try to start a container with network_mode: host (nerdctl run --rm -it --network host alpine sh or nerdctl compose up -d with a compose file with network_mode: host)

FATA[0000] failed to create default network: needs CNI plugin "bridge" to be installed in CNI_PATH ("/opt/cni/bin"), see https://github.com/containernetworking/plugins/releases: exec: "/opt/cni/bin/bridge": stat /opt/cni/bin/bridge: no such file or directory

Describe the results you received and expected

I expected nerdctl to not try to create a default network when none of my containers need one.

Docker is able to start these containers without creating a docker bridge/network

What version of nerdctl are you using?

v2.1.3 (latest)

Are you using a variant of nerdctl? (e.g., Rancher Desktop)

None

Host information

Client:
Namespace: default
Debug Mode: false

Server:
Server Version: 1.7.27
Storage Driver: overlayfs
Logging Driver: json-file
Cgroup Driver: systemd
Cgroup Version: 2
Plugins:
Log: fluentd journald json-file none syslog
Storage: native overlayfs
Security Options:
apparmor
seccomp
Profile: builtin
cgroupns
Kernel Version: 6.14.0-27-generic
Operating System: Ubuntu 25.04
OSType: linux
Architecture: x86_64
CPUs: 6
Total Memory: 3GiB
Name: grafana
ID: 6890ed18-5623-4145-9125-84c57aaed5ae