When utilising Azure Container Service (Kubernetes provider) I am seeing a number of my pods randomly restart at exactly the same time?

Randomly, it seems to affect all pods apart from a daemonset pod I have and the kube proxy. All other pods restart including the kube-system pods such as DNS, Heapster and dashboard.

Can anyone point me in the right direction for understanding why the pods are restarting? Nothing seems to jump out on the syslog file and I couldn't find the kubelet log on Azure?