example_cni_attach.sh

# given $netns the the network namespace id. e.g. netns=46165437

# 1st: we create a virtual interface
ip link add name toto_if type ipip local 10.20.30.46 remote 10.30.30.1

# 2nd, we put this interface in the network namespace of our pod
ip link set dev toto_if netns $netns

# 3rd, we can for example change the ip address or routing parameters:
nsenter -t $netns --network ip addr add 1.2.3.4/30 dev toto_if
nsenter -t $netns --network ip route add default via 1.2.3.5