CNS – not just for vSAN

After a very eventful VMworld, we received lots of questions about CNS, the Cloud Native Storage feature that was released with vSphere 6.7U3. Whilst most of the demonstrations and blog articles around CNS focused on vSAN, what may have been missed is that this feature also works with both VMFS and NFS datastores. For that reason, I decided to create some examples of how CNS can also bubble up information in vSphere about Kubernetes Persistent Volumes (PVs) created on both VMFS and NFS datastores. Let’s begin by creating some simple policies to tag my VMFS datastore and my NFS datastore.…

Safekeeping – a useful tool for interacting with First Class Disks/Improved Virtual Disks

I have been doing quite a bit of work on First Class Disks (FCD), also known as Improved Virtual Disks (IVD) over the past number of months. One tool that has been extremely useful in improving my understanding of FCDs has been safekeeping, a tool developed by Max Daneri of VMware and which is now available to download on GitHub. If you did not know, FCDs are used extensively in VMware’s new Cloud Native Storage (CNS) offering that is currently available with vSphere/vSAN 6.7U3. Now, whilst the primary aim of this tool is to help backup vendors become familiar with…

A first look at Octant – Visualizing your K8s clusters

In my lab, I run a number of different flavors of Kubernetes. Some of them I deploy via kubeadm. Others I have provisioned by VMware PKS. Some of these can access the outside world, while others are secured. Sometimes it is difficult to figure out the relationship between various K8s objects – which services, endpoints,  PVs and PVCs are used by different Pods or StatefulSets. In the past I have used the K8s dashboard, but more often than not, I have to start kube proxy and then run some sort of tunnel (via PuTTY or similar) in order to be…

Kubernetes Storage on vSphere 101 – NFS revisited

In my most recent 101 post on ReadWriteMany volumes, I shared an example whereby we created an NFS server in a Pod which automatically exported a File Share. We then mounted the File Share to multiple NFS client Pods deployed in the same namespace. We saw how multiple Pods were able to write to the same ReadWriteMany volume, which was the purpose of the exercise. I received a few questions on the back on that post relating to the use of Services. In particular, could an external NFS client, even one outside of the K8s cluster, access a volume from…

Kubernetes Storage on vSphere 101 – ReadWriteMany NFS

Over the last number of posts, we have spent a lot of time looking at persistent volumes (PVs) instantiated on some vSphere back-end block storage. These PVs were always ReadWriteOnce, meaning they could only be accessed by a single Pod at any one time.  In this post, we will take a look at how to create a ReadWriteMany volume, based on an NFS share, which can be accessed by multiple Pods. To begin, we will use a useful NFS server image running in a Pod, and show how to mount the exported file share to another Pod, simply to get…

Kubernetes Storage on vSphere 101 – Failure Scenarios

We have looked at quite a few scenarios when Kubernetes is running on vSphere, and what that means for storage. We looked at PVs, PVC, PODs, Storage Classes, Deployments and ReplicaSets, and most recently we looked at StatefulSets. In a few of the posts we looked at some controlled failures, for example, when we deleted a Pod from a Deployment or from a StatefulSet. In this post, I wanted to look a bit closer at an uncontrolled failure, say when a node crashes. However, before getting into this in too much details, it is worth highlighting a few of the…

Kubernetes Storage on vSphere 101 – StatefulSet

In my last post we looked at creating a highly available application that used multiple Pods in Kubernetes with Deployments and ReplicaSets. However, this was only focused on Pods.  In this post, we will look at another way of creating highly available applications through the use of StatefulSets. The first question you will probably have is what is the difference between a Deployment (with ReplicaSets) and a StatefulSet. From a high level perspective, conceptually we can consider that the major difference is that a Deployment is involved in maintaining the desired number of Pods available for an application, whereas a…