Setting up the Vertical Pod Autoscaler

3 min read

To be able take advantage of using a Cluster Autoscaler (same applies to AWS Karpenter) we need make sure we properly set the resources any scheduled Pod is requesting to Kubernetes:

• If we are requesting too much resources, we will be wasting resources
• If we are requesting too few, the application might end up on a node where it needs to constantly share resources with other Pods

When we are not use the resources a given Pod or container is going to use, we can use the Vertical Pod Autoscaler to help us define them

14/02/2022

Installing and configuring AWS Karpenter

7 min read

Starting November 29th 2021, AWS is considering that Karpenter is ready for production: It is a cluster autoscaler alternative intended to improve the efficiency and cost of running workloads on Kubernetes clusters

03/12/2021

Prevent a Pod being evicted by the cluster autoscaler

2 min read

The cluster autoscaler takes into consideration several factors when it chooses a node to remove (evicting it's Pods)

28/10/2021

How to avoid pods of the same Deployment to be scheduled on the same node

2 min read

For some applications we might want to avoid having two or more Pods belonging to the same Deployment to be scheduled on different nodes, yet we don't need them to be a DaemonSet. Let's use as an example the cluster autoscaler: We would like to have two replicas but not on the same node, since if we are draining the node an there's not enough capacity on the other nodes with both Pods offline a manual intervention would be required to spawn a new node

$ kubectl get pods -n autoscaler -o wide
NAME                                                 READY   STATUS    RESTARTS   AGE     IP              NODE                                           NOMINATED NODE   READINESS GATES
autoscaler-aws-cluster-autoscaler-585cc546dd-jc46d   1/1     Running   0          16h     10.103.195.47   ip-10-12-16-10.eu-west-1.compute.internal    <none>           <none>
autoscaler-aws-cluster-autoscaler-585cc546dd-s4j2r   1/1     Running   0          16h     10.103.195.147  ip-10-12-16-10.eu-west-1.compute.internal    <none>           <none>

To do so we will have to configure affinity

11/08/2021