[OCP3.X] OCP install/test server (ansible-host) is not part of SDN.

[jmencak]

OCP install/test server (ansible-host) is not part of OpenShift SDN, which complicates tests that require SDN connectivity, for example fio testing (@ekuric has more detail).

root@ansible-host: ~ # ip route|grep tun 
root@ansible-host: ~ #

Current workaround is to test from one of the masters.

[openshift@master-0 ~]$ ip route show dev tun0
10.128.0.0/10 scope link 
172.30.0.0/16 

Possible solutions 1) Create an ipip or gre (both tested and worked) tunnel to a "ramp" node and use 2 IP addresses which must not be allocated within the SDN (10.191.255.253 and 10.191.255.254 in this example).

On the RAMP node (that has access to the SDN, e.g. master)

ansible_host_ip=192.168.0.10
ip tunnel add tun1 mode ipip remote $ansible_host_ip
ip link set tun1 up
ip addr add 10.191.255.254 dev tun1
ip route add 10.191.255.253/32 dev tun1

On the install/test server (ansible-host)

ramp_ip=192.168.0.9     # for example master IP
ip tunnel add tun1 mode ipip remote $ramp_ip
ip link set tun1 up
ip addr add 10.191.255.253 dev tun1
ip route add 10.128.0.0/10 dev tun1

2) Add ansible-host to the OCP cluster after installation and make it unschedulable. I believe this solution is easier to automate, doesn't create potential IP conflicts addresses, but installs a lot of software "unnecessarily" on the ansible-host.

3) Add only SDN? Not sure how to do this apart from using only parts of the installer, probably unnecessarily complicated.