Earlier in the workshop, in the Add EKS managed Spot workers chapter, we created node groups that run a diversified set of Spot Instances to run our applications. Let’s create a new eksctl nodegroup configuration file called
The Jenkins default resource requirements (Request and Limit CPU/Memory) are 512m (~0.5 vCPU) and 512Mi (~0.5 GB RAM), and since we are not going to perform any large build jobs in this workshop, we can stick to the defaults and also choose relatively small instance types that can accommodate the Jenkins agent pods.
cat <<EoF > ~/environment/add-mng-spot-jenkins.yml apiVersion: eksctl.io/v1alpha5 kind: ClusterConfig metadata: name: eksworkshop-eksctl region: $AWS_REGION managedNodeGroups: - name: jenkins-agents-mng-spot-2vcpu-8gb amiFamily: AmazonLinux2 desiredCapacity: 1 minSize: 0 maxSize: 3 spot: true instanceTypes: - m4.large - m5.large - m5a.large - m5ad.large - m5d.large - t2.large - t3.large - t3a.large iam: withAddonPolicies: autoScaler: true cloudWatch: true albIngress: true privateNetworking: true labels: alpha.eksctl.io/cluster-name: eksworkshop-eksctl alpha.eksctl.io/nodegroup-name: jenkins-agents-mng-spot-2vcpu-8gb intent: jenkins-agents tags: alpha.eksctl.io/nodegroup-name: jenkins-agents-mng-spot-2vcpu-8gb alpha.eksctl.io/nodegroup-type: managed k8s.io/cluster-autoscaler/node-template/label/intent: jenkins-agents EoF
Create new EKS managed node groups with Spot capacity for Jenkins Agents.
eksctl create nodegroup -f add-mng-spot-jenkins.yml
The creation of the workers will take about 3 minutes.
Since eksctl 0.41, integrates with the instance selector ! This can create more convenient configurations that apply diversification of instances in a concise way. As an exercise, read eks instance selector documentation and figure out which changes you may need to apply the configuration changes using instance selector. At the time of writing this workshop, we have not included this functionality as there is a pending feature we’d need to deny a few instances Read more about this here
There are a few things to note in the configuration that we just used to create these node groups.
Node groups configurations are set under the managedNodeGroups section, this indicates that the node groups are managed by EKS.
The node group has large (2 vCPU and 8 GB) instance types with minSize 0, maxSize 3 and desiredCapacity 1.
The configuration spot: true indicates that the node group being created is a EKS managed node group with Spot capacity.
Notice that the we added 3 node labels per node:
alpha.eksctl.io/cluster-name, to indicate the nodes belong to eksworkshop-eksctl cluster.
alpha.eksctl.io/nodegroup-name, to indicate the nodes belong to jenkins-agents-mng-spot-2vcpu-8gb node group.
intent, to allow you to deploy jenkins agents on nodes that have been labeled with value jenkins-agents.
Notice that the we added 1 cluster autoscaler related tag to node groups:
k8s.io/cluster-autoscaler/node-template/label/intent is used by cluster autoscaler when node groups scale down to 0 (and scale up from 0). Cluster autoscaler acts on Auto Scaling groups belonging to node groups, therefore it requires same tags on ASG as well. Currently managed node groups do not auto propagate tags to ASG, see this open issue. Therefore, we will be adding these tags to ASG manually.
Let’s add these tags to Auto Scaling groups of each node group using AWS cli.
ASG_JENKINS_2VCPU_8GB=$(eksctl get nodegroup -n jenkins-agents-mng-spot-2vcpu-8gb --cluster eksworkshop-eksctl -o json | jq -r '..AutoScalingGroupName') aws autoscaling create-or-update-tags --tags \ ResourceId=$ASG_JENKINS_2VCPU_8GB,ResourceType=auto-scaling-group,Key=k8s.io/cluster-autoscaler/node-template/label/intent,Value=jenkins-agents,PropagateAtLaunch=true