Updated:
This page contains notes from my various tests and experiments. It is a raw record of what I did, without correction for errors, or later update for things that I learn. Use at your own risk.
Netplan Apply Failure with tap0 and eno1
While testing Adventures in ROS2 Networking 4 - Complete OpenVPN Cloud Gateway I came across a case where sudo netplan apply failed to add ethernet to the bridge. Let’s see if I can reproduce that.
Remove /etc/netplan/90-rosbridge.yaml from the configuration be renaming it with a “.disabled” suffix. sudo netplan apply. No more bridge, en01 has an IP address. Get OpenVPN running on the Cloud Gateway, and connect using the config file from Adventures in ROS2 Networking 2 - OpenVPN gateway sudo openvpn ros_desktop.ovpn.
Restore again the proper name to /etc/netplan/90-rosbridge.yaml then sudo netplan apply.
kent@ubutower:/etc/netplan$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether d0:17:c2:99:00:a4 brd ff:ff:ff:ff:ff:ff
altname enp0s25
inet 192.168.0.55/24 brd 192.168.0.255 scope global dynamic noprefixroute eno1
valid_lft 7198sec preferred_lft 7198sec
inet6 fe80::4504:135b:d393:8ed3/64 scope link noprefixroute
valid_lft forever preferred_lft forever
5: tap0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN group default qlen 100
link/ether 0e:ae:19:fc:61:b7 brd ff:ff:ff:ff:ff:ff
inet 192.168.255.2/24 brd 192.168.255.255 scope global tap0
valid_lft forever preferred_lft forever
inet6 fe80::cae:19ff:fefc:61b7/64 scope link
valid_lft forever preferred_lft forever
6: rosbridge: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
link/ether fe:25:4c:50:fb:5c brd ff:ff:ff:ff:ff:ff
That is, rosbridge has no IP, eno1 is not under the bridge. Try:
sudo ip link set down eno1
sleep 5
sudo netplan apply
That fixes it.
Reproduce again to the point that sudo netplan apply fails. Now try disconnecting from OpenVPN. tap0 disappears, but problem persists. Moral of the story seems to be to take eno1 down prior to sudo netplan apply. I recall having similar issues trying to change the ip address of eno1. A reboot also fixes it.
I’m not sure what the ramifications of this are. It mostly appears in the middle of config testing.