This page provides an overview of preemptible VMs support in Kubernetes Engine.
Preemptible VMs are Google Compute Engine VM instances that last a maximum of 24 hours and provide no availability guarantees. Preemptible VMs are priced lower than standard Compute Engine VMs and offer the same machine types and options.
You can use preemptible VMs in your Kubernetes Engine clusters or node pools to run batch or fault-tolerant jobs that are less sensitive to the ephemeral, non-guaranteed nature of preemptible VMs.
To learn more about preemptible VMs, refer to Preemptible VMs in the Compute Engine documentation.
gcloud to use the
To use this feature with
gcloud, you must enable the
v1beta1 API surface for
which allows you to run
gcloud beta container clusters commands.
To configure the
gcloud command-line tool to use the
v1beta1 API, run one of
the following commands in your shell or terminal window:
gcloud config set container/use_v1_api false
How preemptible VMs work
When Kubernetes Engine clusters or node pools create Compute Engine VMs, the VMs behave like a managed instance group. Preemptible VMs in Kubernetes Engine are subject to the same limitations as preemptible instances in a managed instance group.
Here is an example selector for filtering preemptible VMs:
apiVersion: v1 kind: Pod spec: nodeSelector: cloud.google.com/gke-preemptible: "true"
Creating a cluster or node pool with preemptible VMs
You can use GCP Console or
gcloud beta container clusters create to
create a cluster or node pool with preemptible VMs.
Visit the Kubernetes Engine menu in GCP Console.
Click Create cluster.
- Configure your cluster as desired. Then, click More.
- From the Preemptible nodes drop-down menu, select Enabled.
- Click Create.
You can create a cluster or node pool with preemptible VMs by specifying the
To create a cluster with preemptible VMs, run the following command:
gcloud beta container clusters create [CLUSTER_NAME] --preemptible \ [--zone [COMPUTE_ZONE] --project [PROJECT_ID]]
[COMPUTE_ZONE] is the cluster's compute zone.
To create a node pool with preemptible VMs:
gcloud beta container node-pools create [POOL_NAME] --preemptible \ --cluster [CLUSTER_NAME] [--zone [COMPUTE_ZONE] --project [PROJECT_ID]]
Using node taints to avoid scheduling to preemptible VM nodes
Depending on your use case, you might want to avoid having critical Pods scheduled on a preemptible VM node. In such cases, you can use a node taint and toleration to avoid scheduling Pods to nodes with preemptible VMs.
To add a node taint for a node with preemptible VMs, run the following command:
kubectl taint nodes [NODE_NAME] cloud.google.com/gke-preemptible="true":NoSchedule
Now, only Pods that tolerate the node taint are scheduled to the node.
To add the relevant toleration to your Pods, add the following to your Pod's specification or your object's Pod template specification:
tolerations: - key: cloud.google.com/gke-preemptible operator: Equal value: "true" effect: NoSchedule
Because preemptible VMs have no availability guarantees, you should design your system under the assumption that any or all of your Compute Engine instances might be preempted and become unavailable. There are no guarantees as to when new instances become available.
If you want to ensure that your jobs or workloads are processed even if no preemptible VMs are available, you can create both non-preemptible and preemptible node pools in your cluster.
- Currently, preemptible VMs do not support shutdown scripts.
- Preemptible instances terminate after 30 seconds upon receiving a preemption notice.