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Version: 3.0

Sleep Mode

Loft provides two powerful features to reduce Kubernetes cost:

  • Sleep Mode which puts virtual clusters to sleep when nobody is using them, i.e. purging all pods while keeping all resources inside the virtual clusters during periods of inactivity
  • Auto-Delete which deletes virtual clusters that have been idle for a while

Both of these feature typically rely on Loft's inactivity detection.

Working with Sleep Mode​

With sleep mode, you can put virtual clusters to sleep which means that Loft will set replicas: 0 for all replica-controlled resources such as Deployments and StatefulSets inside the virtual cluster. This means that Kubernetes will delete all pods but the entire configuration of resources within the virtual cluster is still there.

Sleep mode can be:

  • Invoked manually
  • Triggered by an inactivity timeout (no one has ran a kubectl command or accessed an ingress in this virtual cluster for X minutes)
  • Scheduled using a CRON syntax

Manual + Automatic Sleep / Wake-up​

Start Sleep (manual)
  1. In the Projects > Virtual Clusters view, hover over the row of the virtual cluster that you want to put to sleep
  2. Click on the button to put the virtual cluster to Sleep
  3. Notice how the Status column shows that the virtual cluster is now sleeping.
Automatic Wakeup
Note that the virtual cluster will automatically wake up again, once you run a kubectl command or send a Kubernetes request via another tool to the virtual cluster.
Automatic Sleep Mode (individual virtual cluster)
  1. In the Projects > Virtual Clusters view, hover over the virtual cluster that you want to configure automatic sleep mode for
  2. Click on the Edit button to Edit the virtual cluster
  3. In the drawer that appears on the right, expand the Sleep Mode section. This only works for virtual clusters without a template, if you want to change the sleep mode configuration for a virtual cluster created by a template, please do the changes in the Templates view
  4. Use the Sleep After Inactivity field to specify the time to wait before putting the virtual cluster to sleep if there is no more user activity in this virtual cluster
  5. On the very bottom, click on the button to save the changes
Wake up virtual cluster
  1. In the Projects > Virtual Clusters view, hover over the Status column of the virtual cluster that you want to wake up
  2. While hovering over the row, you will see a tooltip appear that provide information about the sleep state of this virtual cluster
  3. Click on the button to wakeup the virtual cluster
  4. Notice how the Status column shows that the virtual cluster is now running again.

Scheduled Sleep / Wake-up​

Scheduled Sleep & Wake-Up (individual space)
  1. In the Projects > Virtual Clusters view, hover over virtual cluster that you want to configure automatic sleep mode for
  2. Click on the Edit button to Edit the virtual cluster
  3. In the drawer that appears on the right, expand the Sleep Mode virtual cluster. This only works for virtual clusters without a template, if you want to change the sleep mode configuration for a virtual cluster created by a template, please do the changes in the Templates view
  4. Expand the Sleep & Wake-Up Schedule section
  5. Use the Sleep Schedule field and/or the Wake-Up Schedule field to specify the Cronjob Times when the respective virtual cluster should be put to sleep or woken up
  6. On the very bottom, click on the button to save the changes

Working with Auto-Delete​

Loft lets you configure an auto-delete for virtual clusters that have not been used for a certain period of time (inactivity).

Configure Auto-Delete Timeout
  1. In the Projects > Virtual Clusters view, hover over the virtual cluster that you want to configure auto-delete for
  2. Click on the Edit button to Edit the virtual cluster
  3. In the drawer that appears on the right, expand the Sleep Mode section. This only works for virtual clusters without a template, if you want to change the auto delete configuration for a virtual cluster created by a template, please do the changes in the Templates view
  4. Use the Delete After Inactivity field to specify the time to wait before deleting the virtual cluster if there was no more user activity within this virtual cluster
  5. On the very bottom, click on the button to save the changes

Inactivity Detection​

All requests that are made through Loft count as activity in the virtual cluster.

If your kube-context points to Loft's API server as a proxy before the actual connected cluster's API server, every kubectl request will be an activity and reset the inactivity timeout.

Ingress Requests​

For ingress-nginx based ingresses, activity detection also works automatically. Other ingress controllers are currently not supported. For nginx based ingresses, Loft will add a special annotation to each ingress that will track activity and reset the timer as soon as a request is made to that ingress.

Ingress Wakeup
Loft supports waking up a virtual cluster through an ingress independent of the underlying ingress controller. Just navigate to the ingress host and you should see a Loft wakeup page for the virtual cluster.

Advanced Configuration​

Exclude Resources From Sleep​

Loft allows you to specify resources that should not sleep within a space by providing the annotation sleepmode.loft.sh/exclude: 'true' on either a Deployment, StatefulSet, ReplicaSet or Pod. For example the following Deployment would not sleep if the space is sleeping:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: test
  annotations:
    sleepmode.loft.sh/exclude: 'true'
spec:
  replicas: 2
  selector:
    matchLabels:
      app: test
  template:
    metadata:
      labels:
        app: test
    spec:
      containers:
        - name: busybox
          image: busybox
          command:
            - sleep
            - '3600'

Long-Living Connections​

It's possible that certain requests such as kubectl exec or kubectl port-forward keep an active connection open to the virtual cluster that prevents it from sleeping. This is in most cases wanted since the virtual cluster shouldn't start sleeping when someone is still clearly using it, however there are cases where the connection might be idle (someone left the laptop open, but is not using it anymore) in which you want to terminate such connections and put the virtual cluster to sleep.

There are multiple ways to approach this problem of active connections preventing a virtual cluster from sleeping:

  1. You can tell loft to timeout idle streaming connections (such as kubectl exec, kubectl port-forward etc.) after a certain time period with the annotation loft.sh/streaming-connection-idle-timeout: '3600' on a **cluster**. With this annotation set, loft will close connections automatically that are idle after the given seconds. By default, Loft will not timeout any connections. This will only apply to new opened connections to that cluster and not affect already running connections.
    2. Display Sleep Mode Information
    Set annotation on cluster
  2. Tell loft to ignore all active connections for determining virtual cluster activity via the annotation sleepmode.loft.sh/ignore-active-conntections: 'true'. This will put a virtual cluster to sleep even though there still might be open connections such as kubectl exec or kubectl port-forward.
  3. Configure your kubelets with the flag --streaming-connection-idle-timeout duration(see docs). This behaves essentially as option 1, however this configuration is Loft independent.