Understanding Vertical Pod Autoscaler in OpenShift

In modern-day software development, containerization has become a popular way of running applications. OpenShift is one such platform that enables developers to deploy and manage containerized applications at scale. However, with the growing number of containers, managing resources has become a challenge. That's where the Vertical Pod Autoscaler comes into play.

In this article, we'll discuss the Vertical Pod Autoscaler and how it can be used in OpenShift.

What is Vertical Pod Autoscaler?

The Vertical Pod Autoscaler (VPA) is a Kubernetes component that automatically adjusts the resource requests and limits for containers based on their actual usage. VPA can be used to optimize the resource allocation of containers in a Kubernetes cluster. VPA ensures that containers have sufficient resources to operate and avoid resource wastage.

In OpenShift, VPA is enabled by default in the OpenShift Container Platform 4.7 release. VPA can be used for any workload type, such as Deployments, StatefulSets, and DaemonSets.

How does Vertical Pod Autoscaler work?

The VPA controller monitors the resource utilization of the containers in a Kubernetes cluster. Based on the utilization, VPA adjusts the container's resource requests and limits. VPA uses Kubernetes APIs to set the resource requests and limits for the containers. VPA supports CPU, memory, and storage resources.

VPA has two modes of operation:

1. Recommended mode: In this mode, VPA suggests the optimal resource requests and limits based on the actual usage of the containers.

2. Guaranteed mode: In this mode, VPA ensures that containers always have the requested resources, regardless of the actual usage.

How to enable Vertical Pod Autoscaler in OpenShift?

To enable VPA in OpenShift, follow these steps:

1. Log in to the OpenShift cluster using the CLI.

2. Create a new project to host the VPA components:

oc new-project vpa

3. Create a ServiceAccount for the VPA components:

oc create serviceaccount vpa -n vpa

4. Grant the necessary permissions to the ServiceAccount:

oc adm policy add-cluster-role-to-user system:controller:vpa-controller vpa -n vpa
oc adm policy add-scc-to-user anyuid -z vpa -n vpa

5. Deploy the VPA components:

oc apply -f https://raw.githubusercontent.com/openshift/cluster-vpa-operator/master/deploy/vpa-operator.yaml

6. Create a VPA object:

apiVersion: autoscaling.k8s.io/v1
kind: VerticalPodAutoscaler
metadata:
  name: example-vpa
spec:
  targetRef:
    apiVersion: "apps/v1"
    kind:       Deployment
    name:       example-deployment

7. Verify that the VPA object is created:

oc get vpa

That's it! VPA is now enabled in your OpenShift cluster.

So, the Vertical Pod Autoscaler is a valuable tool for managing resources in Kubernetes clusters. In OpenShift, VPA can be used to optimize resource allocation for containers. By following the steps outlined in this article, you can easily enable VPA in your OpenShift cluster and start using it for your containerized workloads.

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That's it for this post. Keep practicing and have fun. Leave your comments if any.