There's not much left to say about Cluster Autoscaler.

We finished exploring fundamental ways to auto-scale Pods and nodes. Soon we'll dive into more complicated subjects and explore things that are not "baked" into a Kubernetes cluster. We'll go beyond the core project and introduce a few new tools and processes.

This is the moment when you should destroy your cluster if you're not planning to move into the next chapter right away and if your cluster is disposable (for example, not on bare-metal). Otherwise, please delete the go-demo-5 Namespace to remove the resources we created in this chapter.

 1  kubectl delete ns go-demo-5

Before you leave, you might want to go over the main points of this chapter.

• Cluster Autoscaler has a single purpose to adjust the size of the cluster by adding or removing worker nodes. It adds new nodes when Pods cannot be scheduled due to insufficient resources. Similarly, it eliminates nodes when they are underutilized for a period of time and when Pods running on one such node can be rescheduled somewhere else.
• Cluster Autoscaler assumes that the cluster is running on top of some kind of node groups. As an example, in the case of AWS, those groups are Autoscaling Groups (ASGs). When there is a need for additional nodes, Cluster Autoscaler creating a new node by increasing the size of a node group.
• The cluster will be scaled down when the sum of CPU and memory requests of all Pods running on a node is less than 50% of the node's allocatable resources and when all Pods running on the node can be moved to other nodes (DamonSets are the exception).