stable/cluster-overprovisioner/README.md
With upcoming deprecation of helm/charts repository, the cluster-overprovisioner Helm Chart has moved to Delivery Hero's Helm Repository: https://github.com/deliveryhero/helm-charts
You can use this new Helm repository by doing:
helm repo add deliveryhero https://charts.deliveryhero.io/public
helm search repo deliveryhero
You can now use deliveryhero/cluster-overprovisioner instead of stable/cluster-overprovisioner in all your Helm commands, e.g.:
# New installation
helm install --name <RELEASE_NAME> deliveryhero/cluster-overprovisioner
# Upgrade existing installation
helm upgrade --name <RELEASE_NAME> deliveryhero/cluster-overprovisioner
This chart provide a buffer for cluster autoscaling to allow overprovisioning of cluster nodes. This is desired when you have work loads that need to scale up quickly without waiting for the new cluster nodes to be created and join the cluster.
It works but creating a deployment that creates pods of a lower than default PriorityClass. These pods request resources from the cluster but don't actually consume any resources. These pods are then evicted allowing other normal pods are created while also triggering a scale-up by the cluster-autoscaler.
This approach is the current recommended method to achieve overprovisioning.
cluster-autoscaler installed in your cluster with --expendable-pods-priority-cutoff=-10 . Priority cutoff has a default of -10 in cluster-autoscaler >= 1.12.To install the chart with the release name my-release and default configuration:
$ helm install --name my-release stable/cluster-overprovisioner
To delete the chart:
$ helm delete my-release
Some thought or experimentation is required to set deployment.resources and deployment.replicaCount correctly. Aspects such as cluster size, costs and size of buffer required should be considered.
The following table lists the configurable parameters for this chart and their default values.
| Parameter | Description | Default |
|---|---|---|
podSecurityContext | Pod security context object | {} |
priorityClassOverprovision.name | Name of the overprovision priorityClass | overprovision |
priorityClassOverprovision.value | Priority value of the overprovision priorityClass | -1 |
priorityClassDefault.enabled | If true, enable default priorityClass | true |
priorityClassDefault.name | Name of the default priorityClass | default |
priorityClassDefault.value | Priority value of the default priorityClass | 0 |
image.repository | Image repository | k8s.gcr.io/pause |
image.tag | Image tag | 3.1 |
image.pullSecrets | Image pull secrets | [] |
image.pullPolicy | Container pull policy | IfNotPresent |
fullnameOverride | Override the fullname of the chart | nil |
nameOverride | Override the name of the chart | nil |
deployments | Define optional additional deployments | [] |
deployments[].name | Name for additional deployments (will be added as label cluster-over-provisioner-name, so you can match it with affinity rules) | `` |
deployments[].replicaCount | Number of replicas | 1 |
deployments[].annotations | Annotations to add to the deployment | {} |
deployments[].resources | Resources for the overprovision pods | {} |
deployments[].affinity | Map of node/pod affinities | {} |
deployments[].nodeSelector | Node labels for pod assignment | {} |
deployments[].tolerations | Optional deployment tolerations | [] |
deployments[].labels | Optional labels tolerations | {} |
Specify each parameter using the --set key=value[,key=value] argument to helm install or provide a YAML file containing the values for the above parameters:
$ helm install --name my-release stable/cluster-overprovisioner --values values.yaml