README.md

AWS Node Termination Handler

AWS Node Termination Handler Helm chart for Kubernetes. For more information on this project see the project repo at https://github.com/aws/aws-node-termination-handler.

Prerequisites

• Kubernetes >= 1.11

Installing the Chart

Add the EKS repository to Helm:

helm repo add eks https://aws.github.io/eks-charts

Install AWS Node Termination Handler: To install the chart with the release name aws-node-termination-handler and default configuration:

helm install --name aws-node-termination-handler \
  --namespace kube-system eks/aws-node-termination-handler

To install into an EKS cluster where the Node Termination Handler is already installed, you can run:

helm upgrade --install --recreate-pods --force \
  aws-node-termination-handler --namespace kube-system eks/aws-node-termination-handler

If you receive an error similar to Error: release aws-node-termination-handler failed: <resource> "aws-node-termination-handler" already exists, simply rerun the above command.

The configuration section lists the parameters that can be configured during installation.

Uninstalling the Chart

To uninstall/delete the aws-node-termination-handler deployment:

helm delete --purge aws-node-termination-handler

The command removes all the Kubernetes components associated with the chart and deletes the release.

Configuration

The following tables lists the configurable parameters of the chart and their default values.

Parameter	Description	Default
image.repository	image repository	amazon/aws-node-termination-handler
image.tag	image tag	<VERSION>
image.pullPolicy	image pull policy	IfNotPresent
image.pullSecrets	image pull secrets (for private docker registries)	[]
deleteLocalData	Tells kubectl to continue even if there are pods using emptyDir (local data that will be deleted when the node is drained).	false
gracePeriod	(DEPRECATED: Renamed to podTerminationGracePeriod) The time in seconds given to each pod to terminate gracefully. If negative, the default value specified in the pod will be used.	30
podTerminationGracePeriod	The time in seconds given to each pod to terminate gracefully. If negative, the default value specified in the pod will be used.	30
nodeTerminationGracePeriod	Period of time in seconds given to each NODE to terminate gracefully. Node draining will be scheduled based on this value to optimize the amount of compute time, but still safely drain the node before an event.	120
ignoreDaemonsSets	Causes kubectl to skip daemon set managed pods	true
instanceMetadataURL	The URL of EC2 instance metadata. This shouldn't need to be changed unless you are testing.	http://169.254.169.254:80
webhookURL	Posts event data to URL upon instance interruption action	``
webhookProxy	Uses the specified HTTP(S) proxy for sending webhooks	``
webhookHeaders	Replaces the default webhook headers.	{"Content-type":"application/json"}
webhookTemplate	Replaces the default webhook message template.	{"text":"[NTH][Instance Interruption] EventID: {{ .EventID }} - Kind: {{ .Kind }} - Description: {{ .Description }} - State: {{ .State }} - Start Time: {{ .StartTime }}"}
dryRun	If true, only log if a node would be drained	false
enableScheduledEventDraining	[EXPERIMENTAL] If true, drain nodes before the maintenance window starts for an EC2 instance scheduled event	false
enableSpotInterruptionDraining	If true, drain nodes when the spot interruption termination notice is received	true
metadataTries	The number of times to try requesting metadata. If you would like 2 retries, set metadata-tries to 3.	3
cordonOnly	If true, nodes will be cordoned but not drained when an interruption event occurs.	false
taintNode	If true, nodes will be tainted when an interruption event occurs. Currently used taint keys are aws-node-termination-handler/scheduled-maintenance and aws-node-termination-handler/spot-itn	false
jsonLogging	If true, use JSON-formatted logs instead of human readable logs.	false
affinity	node/pod affinities	None
podAnnotations	annotations to add to each pod	{}
priorityClassName	Name of the priorityClass	system-node-critical
resources	Resources for the pods	requests.cpu: 50m, requests.memory: 64Mi, limits.cpu: 100m, limits.memory: 128Mi
dnsPolicy	DaemonSet DNS policy	ClusterFirstWithHostNet
nodeSelector	Tells the daemon set where to place the node-termination-handler pods. For example: lifecycle: "Ec2Spot", on-demand: "false", aws.amazon.com/purchaseType: "spot", etc. Value must be a valid yaml expression.	{}
tolerations	list of node taints to tolerate	[ {"operator": "Exists"} ]
rbac.create	if true, create and use RBAC resources	true
rbac.pspEnabled	If true, create and use a restricted pod security policy	false
serviceAccount.create	If true, create a new service account	true
serviceAccount.name	Service account to be used	None
serviceAccount.annotations	Specifies the annotations for ServiceAccount	{}
procUptimeFile	(Used for Testing) Specify the uptime file	/proc/uptime
securityContext.runAsUserID	User ID to run the container	1000
securityContext.runAsGroupID	Group ID to run the container	1000
nodeSelectorTermsOs	Operating System Node Selector Key	beta.kubernetes.io/os
nodeSelectorTermsArch	CPU Architecture Node Selector Key	beta.kubernetes.io/arch
enablePrometheusServer	If true, start an http server exposing /metrics endpoint for prometheus.	false
prometheusServerPort	Replaces the default HTTP port for exposing prometheus metrics.	9092

Metrics endpoint consideration

If prometheus server is enabled and since NTH is a daemonset with host_networking=true, nothing else will be able to bind to :9092 (or the port configured) in the root network namespace since it's listening on all interfaces. Therefore, it will need to have a firewall/security group configured on the nodes to block access to the /metrics endpoint.