Kubernetes cluster:
AWS
master: m3.medium
1 minion m3.large

After some time the mount point for the docker file system has become read-only so the containers don't work as expected. Initially it was read-write.

ubuntu@ip-172-20-0-164:~$ grep ephemeral /proc/mounts
/dev/mapper/vg--ephemeral-docker /mnt/ephemeral/docker ext4 ro,noatime,stripe=16,data=ordered 0 0
/dev/mapper/vg--ephemeral-kubernetes /mnt/ephemeral/kubernetes ext4 rw,noatime,data=ordered 0 0