This repo is based 99% of the
estafette-gke-preemptible-killer
repo.
This small Kubernetes application loop through a given preemptibles node pool and kill a node before the regular 24h life time of a preemptible VM.
When creating a cluster, all the node are created at the same time and should be deleted after 24h of activity. To prevent large disruption, the estafette-gke-preemptible-killer can be used to kill instances during a random period of time between 12 and 24h. It makes use of the node annotation to store the time to kill value.
At a given interval, the application get the list of preemptible nodes and check weither the node should be deleted or not. If the annotation doesn't exist, a time to kill value is added to the node annotation with a random range between 12h and 24h based on the node creation time stamp. When the time to kill time is passed, the Kubernetes node is marked as unschedulable, drained and the instance deleted on GCloud.
- Pods in selected nodes are deleted, not evicted.
- Selecting node pool is not supported yet, the code is processing ALL preemptible nodes attached to the cluster, and there is no way to limit it even via taints nor annotations
- This tool increases the chances to have many small disruptions instead of one major disruption.
- This tool does not guarantee that major disruption is avoided - GCP can trigger large disruption because the way preemptible instances are managed. Ensure your have PDB and enough of replicas, so for better safety just use non-preemptible nodes in different zones. You may also be interested in estafette-gke-node-pool-shifter
You can either use environment variables or flags to configure the following settings:
| Environment variable | Flag | Default | Description |
|---|---|---|---|
| DRAIN_TIMEOUT | --drain-timeout | 300 | Max time in second to wait before deleting a node |
| FILTERS | --filters (-f) | Label filters in the form of key1: value1[, value2[, ...]][; key2: value3[, value4[, ...]], ...] |
|
| INTERVAL | --interval (-i) | 600 | Time in second to wait between each node check |
| KUBECONFIG | --kubeconfig | Provide the path to the kube config path, usually located in ~/.kube/config. This argument is only needed if you're running the killer outside of your k8s cluster | |
| METRICS_LISTEN_ADDRESS | --metrics-listen-address | :9001 | The address to listen on for Prometheus metrics requests |
| METRICS_PATH | --metrics-path | /metrics | The path to listen for Prometheus metrics requests |
In order to have the estafette-gke-preemptible-killer instance delete nodes, create a service account and give the compute.instances.delete permissions.
You can either create the service account and associate the role using the GCloud web console or the cli:
$ export project_id=<PROJECT>
$ gcloud iam --project=$project_id service-accounts create preemptible-killer \
--display-name preemptible-killer
$ gcloud iam --project=$project_id roles create preemptible_killer \
--project $project_id \
--title preemptible-killer \
--description "Delete compute instances" \
--permissions compute.instances.delete
$ export service_account_email=$(gcloud iam --project=$project_id service-accounts list --filter preemptible-killer --format 'value([email])')
$ gcloud projects add-iam-policy-binding $project_id \
--member=serviceAccount:${service_account_email} \
--role=projects/${project_id}/roles/preemptible_killer
$ gcloud iam --project=$project_id service-accounts keys create \
--iam-account $service_account_email \
google_service_account.jsonPrepare using Helm:
brew install kubernetes-helm
kubectl -n kube-system create serviceaccount tiller
kubectl create clusterrolebinding tiller --clusterrole=cluster-admin --serviceaccount=kube-system:tiller
helm init --service-account tiller --wait
Then install or upgrade with Helm:
helm repo add softonic-public https://charts.softonic.io
helm upgrade --install preemptible-killer --namespace preemptible-killer softonic-public/preemptible-killer