The cluster is running fine. The grid jobs are reaching the workers, but are stuck there in a waiting state. I was looking into those pods, but the warning message in the description of those pods was not very conclusive/helpful. 
I also see that there is one calico pod (in calico-system namespace), which is running but is not showing healthy. Though overall the internal network provided by calico is working fine, there seems to be some configuration issue. That issue must be the source of the problem with stuck pods.