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Chapter 3. Installing OpenShift Serverless

Note

OpenShift Serverless is not tested or supported for installation in a restricted network environment.

3.1. Cluster size requirements

The cluster must be sized appropriately to ensure that OpenShift Serverless can run correctly. You can use the MachineSet API to manually scale your cluster up to the desired size.

An OpenShift cluster with 10 CPUs and 40 GB memory is the minimum requirement for getting started with your first serverless application. This usually means you must scale up one of the default MachineSets by two additional machines.

Note

For this configuration, the requirements depend on the deployed applications. By default, each pod requests ~400m of CPU and recommendations are based on this value. In the given recommendation, an application can scale up to 10 replicas. Lowering the actual CPU request of the application further pushes the boundary.

Note

The numbers given only relate to the pool of worker machines of the OpenShift cluster. Master nodes are not used for general scheduling and are omitted.

For more advanced use-cases, such as using OpenShift logging, monitoring, metering, and tracing, you must deploy more resources. Recommended requirements for such use-cases are 24 vCPUs and 96GB of memory.

Additional resources

For more information on using the MachineSet API, see Creating MachineSets.

3.1.1. Scaling a MachineSet manually

If you must add or remove an instance of a machine in a MachineSet, you can manually scale the MachineSet.

Prerequisites

  • Install an OpenShift Container Platform cluster and the oc command line.
  • Log in to oc as a user with cluster-admin permission.

Procedure

  1. View the MachineSets that are in the cluster: 

    $ oc get machinesets -n openshift-machine-api

    The MachineSets are listed in the form of <clusterid>-worker-<aws-region-az>.

  2. Scale the MachineSet: 

    $ oc scale --replicas=2 machineset <machineset> -n openshift-machine-api

    Or: 

    $ oc edit machineset <machineset> -n openshift-machine-api

    You can scale the MachineSet up or down. It takes several minutes for the new machines to be available.

    Important

    By default, the OpenShift Container Platform router pods are deployed on workers. Because the router is required to access some cluster resources, including the web console, do not scale the worker MachineSet to 0 unless you first relocate the router pods.

3.2. Installing Service Mesh

An installed version of Service Mesh is required for the installation of OpenShift Serverless. For details, see the OpenShift Container Platform documentation on Installing Service Mesh.

Note

Use the Service Mesh documentation for Operator installation only. Once you install the Operators, use the documentation below to install the Service Mesh Control Plane and Member Roll.

3.2.1. Installing the ServiceMeshControlPlane

Service Mesh is comprised of a data plane and a control plane. After you install the ServiceMesh operator, you can install the control plane. The control plane manages and configures the sidecar proxies to enforce policies and collect telemetry. The following procedure installs a version of the ServiceMesh control plane that acts as an ingress to your applications.

Note

You must install the control plane into the istio-system namespace. Other namespaces are currently not supported.

Sample YAML file

apiVersion: maistra.io/v1
kind: ServiceMeshControlPlane
metadata:
  name: basic-install
  namespace: istio-system
spec:
  istio:
    global:
      multitenant: true
      proxy:
        autoInject: disabled
      omitSidecarInjectorConfigMap: true
      disablePolicyChecks: false
      defaultPodDisruptionBudget:
        enabled: false
    istio_cni:
      enabled: true
    gateways:
      istio-ingressgateway:
        autoscaleEnabled: false
        type: LoadBalancer
      istio-egressgateway:
        enabled: false
      cluster-local-gateway:
        autoscaleEnabled: false
        enabled: true
        labels:
          app: cluster-local-gateway
          istio: cluster-local-gateway
        ports:
          - name: status-port
            port: 15020
          - name: http2
            port: 80
            targetPort: 8080
          - name: https
            port: 443
    mixer:
      enabled: false
      policy:
        enabled: false
      telemetry:
        enabled: false
    pilot:
      autoscaleEnabled: false
      sidecar: false
    kiali:
      enabled: false
    tracing:
      enabled: false
    prometheus:
      enabled: false
    grafana:
      enabled: false
    sidecarInjectorWebhook:
      enabled: false

Note

Autoscaling is disabled in this version. This release is not intended for production use.

Note

Running ServiceMesh with a sidecar injection enabled with OpenShift Serverless is currently not recommended.

Prerequisite

  • An account with cluster administrator access.
  • The ServiceMesh operator must be installed.

Procedure

  1. Log in to your OpenShift Container Platform installation as a cluster administrator.

  2. Run the following command to create the istio-system namespace: 

    $ oc new-project istio-system
  3. Copy the sample YAML file into a smcp.yaml file.

  4. Apply the YAML file using the command: 

    $ oc apply -f smcp.yaml

  5. Run this command to watch the progress of the pods during the installation process: 

    $ oc get pods -n istio-system -w

3.2.2. Installing a ServiceMeshMemberRoll

You must have a Service Mesh Member Roll for the control plane namespace, if the Service Mesh is configured for multi-tenancy. For applications to use the deployed control plane and ingress, their namespaces must be part of a member roll.

A multi-tenant control plane installation only affects namespaces configured as part of the Service Mesh. You must specify the namespaces associated with the Service Mesh in a ServiceMeshMemberRoll resource located in the same namespace as the ServiceMeshControlPlane resource and name it default.

ServiceMeshMemberRoll Custom Resource Example

apiVersion: maistra.io/v1
kind: ServiceMeshMemberRoll
metadata:
  name: default
  namespace: istio-system
spec:
  members:
  - knative-serving
  - mynamespace

Prerequisites

  • Installed Service Mesh Operator.
  • A custom resource file that defines the parameters of your Red Hat OpenShift Service Mesh control plane.

Procedure

  1. Create a YAML file that replicates the ServiceMeshMemberRoll Custom Resource sample.

  2. Configure the YAML file to include relevant namespaces.

    Note

    Add all namespaces to which you want to deploy serverless applications. Ensure you retain the knative-serving namespace in the member roll.

  3. Copy the configured YAML into a file smmr.yaml and apply it using: 

    $ oc apply -f smmr.yaml

3.3. Installing the OpenShift Serverless Operator

The OpenShift Serverless Operator can be installed using the OpenShift Container Platform instructions for installing Operators.

You can install the OpenShift Serverless Operator in the host cluster by following the OpenShift Container Platform instructions on installing an Operator.

Note

The OpenShift Serverless Operator only works for OpenShift Container Platform versions 4.1.13 and later.

For details, see the OpenShift Container Platform documentation on adding Operators to a cluster.

3.4. Installing Knative Serving

You must create a KnativeServing object to install Knative Serving using the OpenShift Serverless Operator.

Important

You must create the KnativeServing object in the knative-serving namespace, as shown in the sample YAML, or it is ignored.

Sample serving.yaml

apiVersion: v1
kind: Namespace
metadata:
 name: knative-serving
---
apiVersion: serving.knative.dev/v1alpha1
kind: KnativeServing
metadata:
 name: knative-serving
 namespace: knative-serving

Prerequisite

  • An account with cluster administrator access.
  • Installed OpenShift Serverless Operator.

Procedure

  1. Copy the sample YAML file into serving.yaml and apply it using: 

    $ oc apply -f serving.yaml

  2. Verify the installation is complete by using the command: 

    $ oc get knativeserving/knative-serving -n knative-serving --template='{{range .status.conditions}}{{printf "%s=%s\n" .type .status}}{{end}}'

    Results should be similar to: 

    DeploymentsAvailable=True
InstallSucceeded=True
Ready=True

3.5. Uninstalling Knative Serving

To uninstall Knative Serving, you must remove its custom resource and delete the knative-serving namespace.

Prerequisite

  • Installed Knative Serving

Procedure

  1. To remove Knative Serving, use the following command: 

    $ oc delete knativeserving knative-serving -n knative-serving

  2. After the command has completed and all pods have been removed from the knative-serving namespace, delete the namespace by using the command: 

    $ oc delete namespace knative-serving

3.6. Deleting the OpenShift Serverless Operator

You can remove the OpenShift Serverless Operator from the host cluster by following the OpenShift Container Platform instructions on deleting an Operator.

For details, see the OpenShift Container Platform documentation on deleting Operators from a cluster.

3.7. Deleting Knative Serving CRDs from the Operator

After uninstalling the OpenShift Serverless Operator, the Operator CRDs and API services remain on the cluster. Use this procedure to completely uninstall the remaining components.

Prerequisite

  • You have uninstalled Knative Serving and removed the OpenShift Serverless Operator using the previous procedure.

Procedure

  1. Run the following command to delete the remaining Knative Serving CRDs: 

    $ oc delete crd knativeservings.serving.knative.dev
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