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Installing OpenShift Serverless

This guide walks cluster administrators through installing the OpenShift Serverless Operator to an OpenShift Container Platform cluster.

OpenShift Serverless is supported for installation in a restricted network environment. For more information, see Using Operator Lifecycle Manager on restricted networks.

Before upgrading to the latest Serverless release, you must remove the community Knative Eventing Operator if you have previously installed it. Having the Knative Eventing Operator installed will prevent you from being able to install the latest version of Knative Eventing using the OpenShift Serverless Operator.

Defining cluster size requirements for an OpenShift Serverless installation

To install and use OpenShift Serverless, the OpenShift Container Platform cluster must be sized correctly. The minimum requirement for OpenShift Serverless is a cluster with 10 CPUs and 40GB memory. The total size requirements to run OpenShift Serverless are dependent on the applications deployed. By default, each pod requests approximately 400m of CPU, so the minimum requirements are based on this value. In the size requirement provided, an application can scale up to 10 replicas. Lowering the actual CPU request of applications can increase the number of possible replicas.

The requirements provided relate only to the pool of worker machines of the OpenShift Container Platform cluster. Master nodes are not used for general scheduling and are omitted from the requirements.

The following limitations apply to all OpenShift Serverless deployments:

  • Maximum number of Knative services: 1000

  • Maximum number of Knative revisions: 1000

Additional requirements for advanced use cases

For more advanced use cases such as logging or metering on OpenShift Container Platform, you must deploy more resources. Recommended requirements for such use cases are 24 CPUs and 96GB of memory.

If you have high availability (HA) enabled on your cluster, this requires between 0.5 - 1.5 cores and between 200MB - 2GB of memory for each replica of the Knative Serving control plane. HA is enabled for some Knative Serving components by default. You can disable HA by following the documentation on Configuring high availability replicas on OpenShift Serverless.

Scaling your cluster using machine sets

You can use the OpenShift Container Platform MachineSet API to manually scale your cluster up to the desired size. The minimum requirements usually mean that you must scale up one of the default machine sets by two additional machines. See Manually scaling a machine set.

Installing the OpenShift Serverless Operator

This procedure describes how to install and subscribe to the OpenShift Serverless Operator from the OperatorHub using the OpenShift Container Platform web console.

Procedure

  1. In the OpenShift Container Platform web console, navigate to the Operators → OperatorHub page.

  2. Scroll, or type they keyword Serverless into the Filter by keyword box to find the OpenShift Serverless Operator.

    OpenShift Serverless Operator in the OpenShift Container Platform web console

  3. Review the information about the Operator and click Install.

    OpenShift Serverless Operator information

  4. On the Create Operator Subscription page:

    Create Operator Subscription page

    1. The Installation Mode is All namespaces on the cluster (default). This mode installs the Operator in the default openshift-operators namespace to watch and be made available to all namespaces in the cluster.

    2. The Installed Namespace will be openshift-operators.

    3. Select the 4.4 channel as the Update Channel. The 4.4 channel will enable installation of the latest stable release of the OpenShift Serverless Operator.

    4. Select Automatic or Manual approval strategy.

  5. Click Subscribe to make the Operator available to the selected namespaces on this OpenShift Container Platform cluster.

  6. From the Catalog → Operator Management page, you can monitor the OpenShift Serverless Operator subscription’s installation and upgrade progress.

    1. If you selected a Manual approval strategy, the subscription’s upgrade status will remain Upgrading until you review and approve its install plan. After approving on the Install Plan page, the subscription upgrade status moves to Up to date.

    2. If you selected an Automatic approval strategy, the upgrade status should resolve to Up to date without intervention.

Verification steps

After the Subscription’s upgrade status is Up to date, select Catalog → Installed Operators to verify that the OpenShift Serverless Operator eventually shows up and its Status ultimately resolves to InstallSucceeded in the relevant namespace.

Installed Operators page

If it does not:

  1. Switch to the Catalog → Operator Management page and inspect the Operator Subscriptions and Install Plans tabs for any failure or errors under Status.

  2. Check the logs in any pods in the openshift-operators project on the Workloads → Pods page that are reporting issues to troubleshoot further.

Additional resources

  • For more information on installing Operators, see the OpenShift Container Platform documentation on Adding Operators to a cluster.

Next steps

  • After the OpenShift Serverless Operator is installed, you can install the Knative Serving component. See the documentation on Installing Knative Serving.

  • After the OpenShift Serverless Operator is installed, you can install the Knative Eventing component. See the documentation on Installing Knative Eventing.