Ubuntu EKS Platform Images for k8s 1.19


This article originally appeared on Cody Shepherd’s blog.

1.19 Platform Images Now Live

Following the GA of Kubernetes 1.19 support in AWS, EKS-optimized Ubuntu images for 1.19 node groups have been released. The ami-id of this image for each region can be found on the official site for Ubuntu EKS images.

Like the 1.18 platform AMIs, these images are minimized 20.04 Focal Fossa server cloud images that include a couple of extra customized utilities for interacting with EKS, namely the kubectl-eks snap, which simply pins kubectl to a platform version-appropriate channel, as well as pinned versions of cni and auth tools.

These packages are all pinned because, although unattended-upgrades is enabled for EKS-optimized Ubuntu images, the recommended upgrade path for Kubernetes compatibility is via launching the latest AMI, rather than trying to update in place.

Launch Paths for Ubuntu in EKS

It might be worth taking this opportunity to describe the methods for launching
EKS clusters and nodegroups using the Ubuntu images identified above that are
currently the best-supported. One of my previous posts described in detail
how to use CloudFormation to launch Self-Managed nodegroups under an EKS
cluster, and although I’ve tried my best to keep those instructions up to date,
there are a couple of far easier ways to use Ubuntu with EKS.

eksctl

While not an AWS product, eksctl
is a tool that appears in AWS EKS Docs
and is well-supported, open-source, and under active development. It removes
a huge portion of the manual config and tedium of launching EKS clusters and
nodegroups via any other method.

Using eksctl to launch a 1.19 cluster that uses the EKS-optimized Ubuntu
image, and enables key-based ssh access to the node instances, is as simple as
the following example command:

eksctl  
  --profile <profile> create cluster 
  --name <cluster name> 
  --version 1.19 
  --nodegroup-name <nodegroup name> 
  --node-type <instance type, e.g. m5.large> 
  --nodes <number of nodes, e.g. 10> 
  --nodes-min <number of nodes, e.g. 5> 
  --nodes-max < number of nodes, e.g. 15> 
  --node-ami <relevant Ubuntu ami id for your region, e.g. ami-0fc3ca5b2c5e1fb11> 
  --node-ami-family Ubuntu2004 
  --region <aws region, e.g. us-west-2> 
  --ssh-access 
  --ssh-public-key <ec2 public key name>

eksctl will take care of creating both cluster and nodegroup, as well as
VPCs and security groups, and will also update your kubeconfig file. The tool
also produces helpful logging and error messages in the event that something
goes amiss.

Managed Nodegroups with Launch Templates

Using managed nodegroups is a nice middle ground between the full-on-manual
self-managed nodegroups method described in my previous post, and the almost
totally hands-free use of eksctl described above. And, judging by the results
of end-to-end tests performed with the kubernetes-test-eks snap, this method
also produces a nodegroup with the best Conformance characteristics of any
method I’ve described thus far.

Launching a managed nodegroup requires the following steps; these steps assume
you’ve already created a cluster, VPC, and security group, following the steps
detailed in my previous post:

  1. In your AWS web console, navigate to the EC2 service, then to ‘Launch Templates’ under the Instances submenu in the sidebar. Click ‘Create Launch Template’ and use the following key configuration options:
    1. AMI: choose the ami id of the EKS-optimized Ubuntu image for your region
    2. Instance type: choose the shape you want for your nodes
    3. Key pair: this will enable SSH’ing to the node instance if necessary
    4. Under Advanced Settings, for ‘User Data,’ add the following, making sure to use the actual name of the cluster you’ve created:#!/usr/bin/bash sudo /etc/eks/bootstrap.sh <cluster name>
  2. Navigate to the IAM service, click Roles, and create a new IAM role with the following AWS-Managed policies, naming the role whatever you like:
    • AmazonEKSWorkerNodePolicy
    • AmazonEC2ContainerRegistryReadOnly
    • AmazonEKS_CNI_Policy
  3. Navigate to the EKS service, click Clusters, click the cluster you’ve created, and under the Compute tab click ‘Add Node Group’, using the following configurations:
    1. Choose the newly-created IAM role
    2. Enable the ‘Use launch template’ toggle and select the template you’ve created above; click Next
    3. Set the options for the number of nodes to whatever you like; click Next
    4. Use the default subnets for your VPC; click Next; click Create
  4. Viola! The nodegroup will have a status of “Creating” that will likely last several minutes. Once it is finished, if you’ve updated your kubeconfig to point to your cluster, you can verify your nodes are ready via kubectl get nodes.

Happy piloting!



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