<p>Is it worth using SSD as boot disk? I'm not planning to access local disks <a href="https://cloud.google.com/container-engine/docs/local-ssd" rel="nofollow noreferrer">within pods</a>.</p>

<p>Also, GCP by default creates 100GB disk. If I use 20GB disk, will it cripple the cluster or it's OK to use smaller sized disks?</p>

<p>I would always recommend SSD considering the small difference in price and large difference in performance. Even if it just speeds up the deployment/upgrade of containers. </p>

<p>Reducing the disk size to what is required for running your PODs should save you more. I cannot give a general recommendation for disk size since it depends on the OS you are using and how many PODs you will end up on each node as well as how big each POD is going to be. To give an example: When I run coreOS based images with staging deployments for nginx, php and some application servers I can reduce the disk size to 10gb with ample free room (both for master and worker nodes). On the extreme side - If I run self-contained golang application containers without storage need, each POD will only require a few MB space.</p>
