EKS managed nodegroups¶

Amazon EKS managed nodegroups is a feature that automates the provisioning and lifecycle management of nodes (EC2 instances) for Amazon EKS Kubernetes clusters. Customers can provision optimized groups of nodes for their clusters and EKS will keep their nodes up to date with the latest Kubernetes and host OS versions. 

An EKS managed node group is an autoscaling group and associated EC2 instances that are managed by AWS for an Amazon EKS cluster. Each node group uses the Amazon EKS-optimized Amazon Linux 2 AMI. Amazon EKS makes it easy to apply bug fixes and security patches to nodes, as well as update them to the latest Kubernetes versions. Each node group launches an autoscaling group for your cluster, which can span multiple AWS VPC availability zones and subnets for high-availability.

NEW Launch Template support for managed nodegroups

Creating managed nodegroups¶

$ eksctl create nodegroup

New clusters¶

To create a new cluster with a managed nodegroup, run

$ eksctl create cluster

To create multiple managed nodegroups and have more control over the configuration, a config file can be used.

# cluster.yaml
# A cluster with two managed nodegroups
---
apiVersion: eksctl.io/v1alpha5
kind: ClusterConfig

metadata:
  name: managed-cluster
  region: us-west-2

managedNodeGroups:
  - name: managed-ng-1
    minSize: 2
    maxSize: 4
    desiredCapacity: 3
    volumeSize: 20
    ssh:
      allow: true
      publicKeyPath: ~/.ssh/ec2_id_rsa.pub
      # new feature for restricting SSH access to certain AWS security group IDs
      sourceSecurityGroupIds: ["sg-00241fbb12c607007"]
    labels: {role: worker}
    tags:
      nodegroup-role: worker
    iam:
      withAddonPolicies:
        externalDNS: true
        certManager: true

  - name: managed-ng-2
    instanceType: t2.large
    minSize: 2
    maxSize: 3

It's possible to have a cluster with both managed and unmanaged nodegroups. Unmanaged nodegroups do not show up in the AWS EKS console but eksctl get nodegroup will list both types of nodegroups.

# cluster.yaml
# A cluster with an unmanaged nodegroup and two managed nodegroups.
---
apiVersion: eksctl.io/v1alpha5
kind: ClusterConfig

metadata:
  name: managed-cluster
  region: us-west-2

nodeGroups:
  - name: ng-1
    minSize: 2

managedNodeGroups:
  - name: managed-ng-1
    minSize: 2
    maxSize: 4
    desiredCapacity: 3
    volumeSize: 20
    ssh:
      allow: true
      publicKeyPath: ~/.ssh/ec2_id_rsa.pub
      # new feature for restricting SSH access to certain AWS security group IDs
      sourceSecurityGroupIds: ["sg-00241fbb12c607007"]
    labels: {role: worker}
    tags:
      nodegroup-role: worker
    iam:
      withAddonPolicies:
        externalDNS: true
        certManager: true

  - name: managed-ng-2
    instanceType: t2.large
    privateNetworking: true
    minSize: 2
    maxSize: 3

NEW Support for custom AMI, security groups, instancePrefix, instanceName, ebsOptimized, volumeType, volumeName, volumeEncrypted, volumeKmsKeyID, volumeIOPS, maxPodsPerNode, preBootstrapCommands, overrideBootstrapCommand, and disableIMDSv1

# cluster.yaml
# A cluster with an unmanaged nodegroup and two managed nodegroups.
---
apiVersion: eksctl.io/v1alpha5
kind: ClusterConfig

metadata:
  name: managed-cluster
  region: us-west-2

managedNodeGroups:
  - name: custom-ng
    ami: ami-0e124de4755b2734d
    securityGroups:
      attachIDs: ["sg-1234"]
    maxPodsPerNode: 80
    ssh:
      allow: true
    volumeSize: 100
    volumeName: /dev/xvda
    volumeEncrypted: true
    # defaults to true, which enforces the use of IMDSv2 tokens
    disableIMDSv1: false  
    overrideBootstrapCommand: |
      #!/bin/bash
      /etc/eks/bootstrap.sh managed-cluster --kubelet-extra-args '--node-labels=eks.amazonaws.com/nodegroup=custom-ng,eks.amazonaws.com/nodegroup-image=ami-0e124de4755b2734d'

If you are requesting an instance type that is only available in one zone (and the eksctl config requires specification of two) make sure to add the availability zone to your node group request:

# cluster.yaml
# A cluster with a managed nodegroup with "availabilityZones"
---

apiVersion: eksctl.io/v1alpha5
kind: ClusterConfig

metadata:
  name: flux-cluster
  region: us-east-2
  version: "1.23"

availabilityZones: ["us-east-2b", "us-east-2c"]
managedNodeGroups:
  - name: workers
    instanceType: hpc6a.48xlarge
    minSize: 64
    maxSize: 64
    labels: { "fluxoperator": "true" }
    availabilityZones: ["us-east-2b"]   
    efaEnabled: true
    placement:
      groupName: eks-efa-testing

This can be true for instance types like the Hpc6 family that are only available in one zone.

Existing clusters¶

$ eksctl create nodegroup --managed

Tip : if you are using a ClusterConfig file to describe your whole cluster, describe your new managed node group in the managedNodeGroups field and run:

$ eksctl create nodegroup --config-file=YOUR_CLUSTER.yaml

Upgrading managed nodegroups¶

You can update a nodegroup to the latest EKS-optimized AMI release version for the AMI type you are using at any time.

If your nodegroup is the same Kubernetes version as the cluster, you can update to the latest AMI release version for that Kubernetes version of the AMI type you are using. If your nodegroup is the previous Kubernetes version from the cluster’s Kubernetes version, you can update the nodegroup to the latest AMI release version that matches the nodegroup’s Kubernetes version, or update to the latest AMI release version that matches the clusters Kubernetes version. You cannot roll back a nodegroup to an earlier Kubernetes version.

To upgrade a managed nodegroup to the latest AMI release version:

eksctl upgrade nodegroup --name=managed-ng-1 --cluster=managed-cluster

If a nodegroup is on Kubernetes 1.14, and the cluster's Kubernetes version is 1.15, the nodegroup can be upgraded to the latest AMI release for Kubernetes 1.15 using:

eksctl upgrade nodegroup --name=managed-ng-1 --cluster=managed-cluster --kubernetes-version=1.15

To upgrade to a specific AMI release version instead of the latest version, pass --release-version:

eksctl upgrade nodegroup --name=managed-ng-1 --cluster=managed-cluster --release-version=1.19.6-20210310

Handling parallel upgrades for nodes¶

Multiple managed nodes can be upgraded simultaneously. To configure parallel upgrades, define the updateConfig of a nodegroup when creating the nodegroup. An example updateConfig can be found here.

To avoid any downtime to your workloads due to upgrading multiple nodes at once, you can limit the number of nodes that can become unavailable during an upgrade by specifying this in the maxUnavailable field of an updateConfig. Alternatively, use maxUnavailablePercentage, which defines the maximum number of unavailable nodes as a percentage of the total number of nodes.

Note that maxUnavailable cannot be higher than maxSize. Also, maxUnavailable and maxUnavailablePercentage cannot be used simultaneously.

This feature is only available for managed nodes.

Updating managed nodegroups¶

eksctl allows updating the UpdateConfig section of a managed nodegroup. This section defines two fields. MaxUnavailable and MaxUnavailablePercentage. Your nodegroups are unaffected during the update, thus downtime shouldn't be expected.

The command update nodegroup should be used with a config file using the --config-file flag. The nodegroup should contain an nodeGroup.updateConfig section. More information can be found here.

Nodegroup Health issues¶

EKS Managed Nodegroups automatically checks the configuration of your nodegroup and nodes for health issues and reports them through the EKS API and console. To view health issues for a nodegroup:

eksctl utils nodegroup-health --name=managed-ng-1 --cluster=managed-cluster

Managing Labels¶

EKS Managed Nodegroups supports attaching labels that are applied to the Kubernetes nodes in the nodegroup. This is specified via the labels field in eksctl during cluster or nodegroup creation.

To set new labels or updating existing labels on a nodegroup:

eksctl set labels --cluster managed-cluster --nodegroup managed-ng-1 --labels kubernetes.io/managed-by=eks,kubernetes.io/role=worker

To unset or remove labels from a nodegroup:

eksctl unset labels --cluster managed-cluster --nodegroup managed-ng-1 --labels kubernetes.io/managed-by,kubernetes.io/role

To view all labels set on a nodegroup:

eksctl get labels --cluster managed-cluster --nodegroup managed-ng-1

Scaling Managed Nodegroups¶

eksctl scale nodegroup also supports managed nodegroups. The syntax for scaling a managed or unmanaged nodegroup is the same.

eksctl scale nodegroup --name=managed-ng-1 --cluster=managed-cluster --nodes=4 --nodes-min=3 --nodes-max=5

Feature parity with unmanaged nodegroups¶

EKS Managed Nodegroups are managed by AWS EKS and do not offer the same level of configuration as unmanaged nodegroups. The unsupported options are noted below.

• iam.instanceProfileARN is not supported for managed nodegroups.
• instancesDistribution field is not supported
• Full control over the node bootstrapping process and customization of the kubelet are not supported. This includes the following fields: classicLoadBalancerNames, targetGroupARNs, clusterDNS and kubeletExtraConfig.
• No support for enabling metrics on AutoScalingGroups using asgMetricsCollection

Further information¶

• EKS Managed Nodegroups