This script updates the Amazon EKS node groups associated with a given EKS cluster to use the latest version of the launch template.

update_node_group_launch_template.sh

#!/bin/bash

# ----------------------------------------------
# This script updates the Amazon EKS node groups
# associated with a given EKS cluster to use the
# latest version of the launch template.
#
# Usage:
#   ./update_node_group_launch_template.sh <AWS_PROFILE> <AWS_REGION> <CLUSTER_NAME>
#
# Parameters:
#   AWS_PROFILE - The AWS profile to use
#   AWS_REGION - The AWS region of the cluster
#   CLUSTER_NAME - The name of the EKS cluster
# ----------------------------------------------

# Ensure that exactly 3 arguments are provided
if [ "$#" -ne 3 ]; then
    echo "Usage: ./update_nodegroups.sh <AWS_PROFILE> <AWS_REGION> <CLUSTER_NAME>"
    exit 1
fi

# Assign command line arguments to variables
AWS_PROFILE=$1
AWS_REGION=$2
CLUSTER_NAME=$3

# Export AWS_PROFILE and AWS_REGION as environment variables
export AWS_PROFILE
export AWS_REGION

# List the node groups associated with the specified EKS cluster
NODEGROUPS=$(aws eks list-nodegroups --cluster-name "${CLUSTER_NAME}" --query 'nodegroups' --output text)

# Iterate through each node group in the cluster
for NODE_GROUP_NAME in ${NODEGROUPS}; do
    echo "----------------------------------------------------------"
    echo "Processing Node Group: ${NODE_GROUP_NAME}"

    # Get the launch template ID and version associated with the node group
    LAUNCH_TEMPLATE_ID=$(aws eks describe-nodegroup --cluster-name "${CLUSTER_NAME}" --nodegroup-name "${NODE_GROUP_NAME}" --query 'nodegroup.launchTemplate.id' --output text)
    LAUNCH_TEMPLATE_VERSION=$(aws eks describe-nodegroup --cluster-name "${CLUSTER_NAME}" --nodegroup-name "${NODE_GROUP_NAME}" --query 'nodegroup.launchTemplate.version' --output text)

    # Get the latest version number of the launch template
    LATEST_VERSION=$(aws ec2 describe-launch-templates --launch-template-ids ${LAUNCH_TEMPLATE_ID} --query 'LaunchTemplates[0].LatestVersionNumber' --output text)

    # Output launch template details
    echo "Launch Template ID: ${LAUNCH_TEMPLATE_ID}"
    echo "Node Group's Launch Template Version: ${LAUNCH_TEMPLATE_VERSION}"
    echo "Latest Launch Template Version: ${LATEST_VERSION}"

    # Compare the version numbers and decide whether to update the node group
    if [ "$LAUNCH_TEMPLATE_VERSION" == "$LATEST_VERSION" ]; then
        echo "The node group ${NODE_GROUP_NAME} is already using the latest launch template version (${LATEST_VERSION})."
    else
        echo "The node group ${NODE_GROUP_NAME} is using version ${LAUNCH_TEMPLATE_VERSION}, but a newer version (${LATEST_VERSION}) is available."
        echo "Initiating update for the node group..."

        # Update the node group to use the latest launch template version
        aws eks update-nodegroup-version --cluster-name "${CLUSTER_NAME}" --nodegroup-name "${NODE_GROUP_NAME}" --launch-template "{\"id\": \"${LAUNCH_TEMPLATE_ID}\", \"version\": \"${LATEST_VERSION}\"}"

        # Monitor the status of the node group update
        while true; do
            STATUS=$(aws eks describe-nodegroup --cluster-name "${CLUSTER_NAME}" --nodegroup-name "${NODE_GROUP_NAME}" --query 'nodegroup.status' --output text)
            echo "Current status: ${STATUS}"

            # Break the loop if the update is complete or has failed
            if [ "$STATUS" = "ACTIVE" ]; then
                echo "Node group update completed successfully."
                break
            elif [ "$STATUS" = "CREATE_FAILED" ] || [ "$STATUS" = "DELETE_FAILED" ]; then
                echo "Node group update failed."
                exit 1
            else
                # Wait for 30 seconds before checking the status again
                sleep 30
            fi
        done
    fi
done

unset AWS_PROFILE
unset AWS_REGION