openshift 3.11 install fails - Unable to update cni config: No networks found in /etc/cni/net.d",

Question

I'm trying to install Openshift 3.11 on a one master, one worker node setup.

The installation fails, and I can see in journalctl -r:

2730 kubelet.go:2101] Container runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:docker: network plugin is not ready: cni config uninitialized
2730 cni.go:172] Unable to update cni config: No networks found in /etc/cni/net.d

Things I've tried:

1. reboot master node
2. Ensure that hostname is the same as hostname -f on all nodes
3. Disable IP forwarding on master node as described on https://github.com/openshift/openshift-ansible/issues/7967#issuecomment-405196238 and https://linuxconfig.org/how-to-turn-on-off-ip-forwarding-in-linux
4. Applying kube-flannel, on master node as described on https://stackoverflow.com/a/54779881/265119
5. unset http_proxy https_proxy on master node as described on https://github.com/kubernetes/kubernetes/issues/54918#issuecomment-385162637
6. modify /etc/resolve.conf to have nameserver 8.8.8.8, as described on https://github.com/kubernetes/kubernetes/issues/48798#issuecomment-452172710
7. created a file /etc/cni/net.d/80-openshift-network.conf with content { "cniVersion": "0.2.0", "name": "openshift-sdn", "type": "openshift-sdn" }, as described on https://stackoverflow.com/a/55743756/265119

The last step does appear to have allowed the master node to become ready, however the ansible openshift installer still fails with Control plane pods didn't come up.

For a more detailed description of the problem see https://github.com/openshift/openshift-ansible/issues/11874

Answer 1

Along with Step 6: make sure that hostname and hostname -f bot return the FQDN for your hosts.

https://github.com/openshift/openshift-ansible/issues/10798

Answer 2

The error was using a too recent version of Ansible.

Downgrading to Ansible 2.6 fixed the problem.