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Create Custom Labels

In this tutorial you will learn how to use custom labels with Ocean Launch Specifications.

Relevance​

This tutorial is relevant for Kubernetes users.

Label Definition​

Labels are key and value pairs that are attached to objects such as pods. Labels enable you to constrain a pod to run only on particular nodes or have a preference for a particular node.

Ocean supports custom label selectors, built-in node labels, and affinity/anti-affinity for pods and nodes.

Once configured, Ocean considers the constraints and launches capacity only when pods that have the predefined labels are waiting to be scheduled.

Step 1: Label the Pods​

Ensure that your pods are labeled properly. See the Kubernetes documentation for more information.

Step 2: Define the Custom Labels in Ocean​

  1. In your Ocean cluster, go to Actions and click Launch Specifications.

  2. Click Add Launch Specification. This will add a new Launch Specification to your Ocean Cluster.

  3. In the Launch Specification, add a key and value pair for the custom label and click Add.

Step 3: Add Labels to the Nodes​

Add Labels to EKS​

Add labels to the nodes by using the user data:

--kubelet-extra-args --node-labels=mykey=myvalue,mykey2=myvalue2

For example:

#!/bin/bash
set -o xtrace
/etc/eks/bootstrap.sh Ocean_Cluster --kubelet-extra-args --node-labels=mykey=myvalue,mykey2=myvalue2
For all of the above, new nodes will be launched with new labels.

Add Labels to kOps Clusters​

These are clusters that were created by kOps natively.

  1. Recognize the IG name you originally created (nodes in the following example):

  2. Run kops edit ig nodes and add the relevant label.

  3. Run kops update cluster.