Scaling a Cluster with Python

Learning Objectives

Successfully complete this lab by achieving the following learning objectives:

Create a cluster with kops.

1. To create a Kubernetes Cluster from the Bastion Host, input the following command:

   $ . ./k8s-create.sh

2. You may view the default YAML templates created by kops with any of the following commands:

   kops edit cluster

   Or to look at the instance group for the nodes:

   kops edit ig nodes

   After looking at the base installation, you may create the cluster by entering:

   kops update cluster --yes

Validate the cluster that was created.

To validate the newly created cluster:

kops validate cluster

And eventually, after the EC2 servers are up:

kubectl get nodes

Use Python to increase the nodes in the instance group.

You may view the files below from the GitHub site, or by simply using cat.

1. The link for the GitHub repo is:

   https://github.com/linuxacademy/content-aiops-essentials

2. To look at the Python source code in scale_cluster.py:

   cat scale_cluster.py

3. Also look at the template YAML for the instance group:

   cat instance.yaml

4. Also, look at the edit_cluster.sh script that edits the instance.yaml file:

   cat edit_cluster.sh

5. Now execute the command to scale the cluster:

   python scale_cluster.py

6. Tell kops to commit the changes to the cluster:

   kops rolling-update cluster --yes

Validate that the cluster was scaled.

You may simply validate the number of worker nodes running by entering:

kubectl get node