creating-and-managing-node-pools.md

Creating and Managing Node Pools

In Kubernetes, a Node

In this lab you will:

• Use labels and nodeSelectors to assign Pods to specific Nodes
• Set up a Node Pool to manage multiple types of Nodes in one Cluster

Tutorial: Assign a Pod to a Specific Node

kubectl get nodes --show-labels

kubectl label nodes <node-name> nodeclass=high-mem

Now that we have labeled Node, we can use that to assign our Pods to the node by adding a nodeSelector to deployments/persistent-db.yaml:

Explore our deployment and examine the nodeSelector field:

cat deployments/persistent-db.yaml

Exercise: Verify that our node was assigned properly

kubectl create -f deployments/persistent-db.yaml

kubectl get pods -o wide

Tutorial: Create a High Memory NodePool

The first thing we need to do is create a cluster for use during this workshop.

gcloud container clusters create workshop

Now if we look at our node pools we'll see we have 'default' nodes set up.

gcloud container node-pools list --cluster=workshop

The next step is to create our 'high memory' Node as part of our cluster.

gcloud container node-pools create high-mem --cluster=workshop --machine-type=custom-2-12288 --disk-size=200 --num-nodes=1

If we view all of our Nodes now, we'll see the high memory ones, too.

kubectl get nodes

It is now possible to delete the default-pool, leaving only the high memory nodes.

gcloud container node-pools delete default-pool --cluster=workshop

kubectl get nodes

Exercise: Create a new node pool to replace the deleted default pool.

Use gcloud container node-pools help to learn the proper command syntax

Exercise: Assign the dbd pod to our high-mem node.

When this node is created it gets a label, we'll use that label in our NodeSelector field to assign our DB pod to this node.

View the labels on our 'high-mem' node

kubectl get nodes --show-labels

You'll see a label that looks like cloud.google.com/gke-nodepool=. Update our deployment to assign our pod to this Node:

nano deployments/persistent-db.yaml

kubectl apply -f deployments/persistent-db.yaml