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…
In my previous 101 posts on Kubernetes Storage on vSphere, we saw how to create “static” persistent volumes (PVs) by mapping an existing virtual machine disk (VMDK) directly into a persistent volume (PV) manifest YAML file. We also saw that we could dynamically instantiate PVs through the use of a StorageClass. We saw how a StorageClass can also be used to apply features of the underlying vSphere storage, such as a storage policy, to a PV and how Pods can consume both static or dynamic PVs through the use of persistent volume claims (PVCs). However in both previous exercises, we…
In the first 101 post, we talked about persistent volumes (PVs), persistent volumes claims (PVCs) and PODs (a group of one or more containers). In particular, we saw how with Kubernetes on vSphere, a persistent volume is essentially a VMDK (virtual machine disk) on a datastore. In that first post, we created a static VMDK on a vSAN datastore, then built manifest files (in our case YAML) for a PV, a persistent volume claim (PVC) and finally a Pod, and showed how to map that static preexisting VMDK directly to the Pod, so that it could be mounted. We saw…
I’ve just returned from KubeCon 2019 in Barcelona, and was surprised to see such a keen interest in how Kubernetes consumed infrastructure related resources, especially storage. Although I have been writing about a lot of Kubernetes related items recently, I wanted to put together a primer on some storage concepts that might be useful as a stepping stone or even on-boarding process to some of you who are quite new to Kubernetes. I am going to talk about this from the point of view of vSphere and vSphere storage. Thus I will try to map vSphere storage constructs such as…
Last week, the Velero team announced the availability of release candidate (RC) version 1.0.0. I was eager to get my hands on it and try it out. Since it is RC (and not GA), I thought I would just deploy a fresh environment for testing. The guidance from the Velero team is to test it out in your non-critical environments! On a number of Velero github sites, the links to download the binaries do not appear to be working, plus some of the install guidance is a little sparse. Anyhow, after some trial and error, I decided it might be…
I’ve been spending a bit of time lately look at our Heptio Velero product, and how it works with various cloud native applications. Next application on my list is MongoDB, another NoSQL database. I looked at various deployment mechanisms for MongoDB, and it seems that using Helm Charts is the most popular approach. This led me to the Bitnami MongoDB Stack Chart GitHub Repo. At this point, I did spin my wheels a little trying to get MongoDB stood up. In this post, I’ll talk through some of the gotchas I encountered. Once again, my environment is vSphere 6.7 and…