title: Multiple replicas of kube-system/ingress controller pods?
body: <p>We have a relatively standard Kubernetes cluster which is hosted in the cloud behind a load balancer. We have found that most of the system pods only run as a single instance, the really concerning thing is that by default our nginx ingress controller will also run as a single instance. This means that in the event of a node failure there is a 1/n chance of every single application going down until the liveness probe kicks in and moves the ingress controller pod.</p>
  
  <p>We have had to increase the number of replicas of our ingress controller because it is a single point of failure. However, I'm not particularly happy about how that makes our network diagram look and I'd imagine that this would cause issues if any of our applications were stateful.</p>
  
  <p>Some pods (like heapster) you can probably only have a single instance of but I was wondering if anyone had any guidelines on what can and can't be scaled up and why this is the default behavior?</p>
  
  <p>Thanks,</p>
  
  <p>Joe</p>