Tip: Calico BGP IP AUTODETECTION Issue and Troubleshoot in OKE

Symptoms:

  We follow Calico doc to deploy a Calico instance.  After that,  Calico Nodes are always not ready though the pods are up and running.

Error in logs:
Unable to open configuration file /etc/calico/confd/config/bird6.cfg: No such file or directory 

Verify commands
# ./calico-node -bird-ready
2020-02-13 20:27:38.757 [INFO][5132] health.go 114: Number of node(s) with BGP peering established = 0
calico/node is not ready: BIRD is not ready: BGP not established with 10.244.16.1,10.244.15.1

Solutions:

     One possible reason is there are a few network interfaces in the host. Calico may choose the wrong interface with the auto-detection method. Details refer
https://docs.projectcalico.org/networking/ip-autodetection#change-the-autodetection-method
     It can be solved by setting an environment variable for calico node daemonset.  In OKE VMs with Oracle Linux, the primary network interface is ens*  ie, ens3.
     kubectl set env daemonset/calico-node -n kube-system IP_AUTODETECTION_METHOD=interface=ens*