GRE tunneling using Open vSwitch

Solution 1:

I got it working. This answer helped me. I had two problems with my config.

First, I should have added an IP address for the nested guests. With tap0 up and connected to the nested guest, I configured a static IP for the nested guest.

Second, I noticed that I have a duplicate MAC address. That was because I had cloned the Guest1 after the installation of the Nested Guest 11, so Nested Guest11 and Nested Guest21 had the same MAC address. I changed the MAC address of Nested Guest21 and tried again.

It didn't worked at first. I was forced to restart Guest1 because of a crash. After that I tried again. This time the nested VMs were able to ping each other.

My configuration:

Guest 1

ovs-vsctl show

Bridge br0
    Port gre0
        Interface gre0
            type: gre
            options: {remote_ip="192.168.239.129"}
    Port tap0
        Interface tap0
    Port br0
        Interface br0
            type: internal
ovs_version: "2.15.0"

ip -br a

lo               UNKNOWN        127.0.0.1/8 ::1/128
ens33            UP             192.168.41.140/24 fe80::4f54:fbff:6d87:b5a7/64
ens34            UP             192.168.239.128/24 fe80::761f:aa88:a28a:aeba/64
virbr2           DOWN           192.168.10.1/24
virbr2-nic       DOWN
virbr1           DOWN           192.168.100.1/24
virbr1-nic       DOWN
virbr0           DOWN           192.168.122.1/24
virbr0-nic       DOWN
vboxnet0         DOWN
ovs-system       DOWN
br0              DOWN
gre0@NONE        DOWN
gretap0@NONE     DOWN
erspan0@NONE     DOWN
gre_sys@NONE     UNKNOWN        fe80::989f:9eff:fe5d:d7ce/64
tap0             UP             fe80::9401:52ff:fe46:86e6/64

Nested Guest11

Guest2

ovs-vsctl show

Bridge br0
    Port tap0
        Interface tap0
    Port gre0
        Interface gre0
            type: gre
            options: {remote_ip="192.168.239.128"}
    Port br0
        Interface br0
            type: internal
ovs_version: "2.15.0"

Nested Guest21

Forgot to add that in this case too, there is no connection between guest and nested guest, which I think is expected.