Recommended OS for cluster?

We are getting a lot of node failures lately. we switched from ubuntu to redhat 7.5 because ubuntu nodes were crashing but not indicating why, and now on redhat 7.5 we are getting “kubelet not responding” or “pleg not responding” and I basically have to replace the node to fix the issue. it seems to happen anytime resource usage goes about 50%.

I can’t help but wonder if there isn’t an ideal OS or ami image we should be using that would enable us to get more than 50% usage from an instance before the node dies.