Category Archives: Kubernetes

Setting Up Cluster Autoscaler In EKS

Unlike GKE, EKS does not come with Cluster Autoscaler. We’ll have to configure it ourselves. We’ll need to add a few tags to the Autoscaling Group dedicated to worker nodes, to put additional permissions to the Role we’re using, and to install Cluster Autoscaler.
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To Replicas Or Not To Replicas In Kubernetes Deployments And StatefulSets?

Knowing that HorizontalPodAutoscaler (HPA) manages auto-scaling of our applications, the question might arise regarding replicas. Should we define them in our Deployments and StatefulSets, or should we rely solely on HPA to manage them? Instead of answering that question directly, we’ll explore different combinations and, based on results, define the strategy.

First, let’s see how many Pods we have in our cluster right now.

You might not be able to use the same commands since they assume that go-demo-5 application is already running, that the cluster has HPA enabled, that you cloned the code, and a few other things. I presented the outputs so that you can follow the logic without running the same commands.

kubectl -n go-demo-5 get pods

The output is as follows.

NAME    READY STATUS  RESTARTS AGE
api-... 1/1   Running 0        27m
api-... 1/1   Running 2        31m
db-0    2/2   Running 0        20m
db-1    2/2   Running 0        20m
db-2    2/2   Running 0        21m

We can see that there are two replicas of the api Deployment, and three replicas of the db StatefulSets.
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Four Phases Of Kubernetes Adoption

Kubernetes is probably the biggest project we know. It is vast, and yet many think that after a few weeks or months of reading and practice they know all there is to know about it. It’s much bigger than that, and it is growing faster than most of us can follow. How far did you get in Kubernetes adoption?

From my experience, there are four main phases in Kubernetes adoption.

In the first phase, we create a cluster and learn intricacies of Kube API and different types of resources (e.g., Pods, Ingress, Deployments, StatefulSets, and so on). Once we are comfortable with the way Kubernetes works, we start deploying and managing our applications. By the end of this phase, we can shout “look at me, I have things running in my production Kubernetes cluster, and nothing blew up!” I explained most of this phase in The DevOps 2.3 Toolkit: Kubernetes.
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Deploying Jenkins To A Kubernetes Cluster Using Helm

This article is an excerpt from The DevOps 2.4 Toolkit: Continuous Deployment To Kubernetes. It assumes that you already have a Kubernetes cluster with nginx Ingress. The article was tested with minikube, minishift, Docker for Mac/Windows, AWS with kops, and GKE. Furthermore, I will assume that you already installed Helm. Finally, I expect you to clone vfarcic/k8s-specs and execute the commands from inside it.

First things first… We need to find out the IP of our cluster or external LB if available. The commands that follow will differ from one cluster type to another.
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Defining Continuous Deployment Goals

The difference between continuous integration, delivery, and deployment is not in processes, but in the level of confidence we have in them.

The continuous deployment process is relatively easy to explain, even though implementation might get tricky. We’ll split our requirements into two groups. We’ll start with a discussion about the overall goals that should be applied to the whole process. To be more precise, we’ll talk about what I consider non-negotiable requirements.
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The DevOps Toolkit Series Explores Continuous Deployment To Kubernetes

Soon after I started working on The DevOps 2.3 Toolkit: Kubernetes, I realized that a single book could only scratch the surface. Kubernetes is vast, and no single book can envelop even all the core components. If we add community projects, the scope becomes even more extensive. Then we need to include hosting vendors and different ways to set up and manage Kubernetes. That would inevitably lead us to third-party solutions like OpenShift, Rancher, and DockerEE, to name a few. It doesn’t end there. We’d need to explore other types of community and third-party additions like those related to networking and storage. And don’t forget the processes like, for example, continuous delivery and deployment. All those things could not be explored in a single book so The DevOps 2.3 Toolkit: Kubernetes ended up being an introduction to Kubernetes. It can serve as the base for exploring everything else.

The moment I published the last chapter of The DevOps 2.3 Toolkit: Kubernetes, I started working on the next material. A lot of ideas and tryouts came out of it. It took me a while until the subject and the form of the forthcoming book materialized. After a lot of consultation with the readers of the previous book, the decision was made to explore continuous delivery and deployment processes in a Kubernetes cluster. The high-level scope of the book you are reading right now was born.
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“The DevOps 2.3 Toolkit: Kubernetes” is available!

The DevOps 2.2 Toolkit: Kubernetes is available through Amazon.com (and other worldwide sites) as well as through LeanPub.com. Soon it will be available through other retailers as well.

The goal of this book is not to convince you to adopt Kubernetes but to provide a detailed overview of its features. I want you to become confident in your Kubernetes knowledge and only then choose whether to embrace it. That is, unless you already made up your mind and stumbled upon this book in search of Kubernetes guidance.
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