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Chapter 3. Installing OpenShift Serverless
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.
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.
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 withcluster-admin
permission.
Procedure
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>
.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.
ImportantBy 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.
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.
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
Autoscaling is disabled in this version. This release is not intended for production use.
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
- Log in to your OpenShift Container Platform installation as a cluster administrator.
Run the following command to create the
istio-system
namespace:$ oc new-project istio-system
-
Copy the sample YAML file into a
smcp.yaml
file. Apply the YAML file using the command:
$ oc apply -f smcp.yaml
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
- Create a YAML file that replicates the ServiceMeshMemberRoll Custom Resource sample.
Configure the YAML file to include relevant namespaces.
NoteAdd all namespaces to which you want to deploy serverless applications. Ensure you retain the
knative-serving
namespace in the member roll.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.
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.
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
Copy the sample YAML file into
serving.yaml
and apply it using:$ oc apply -f serving.yaml
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
To remove Knative Serving, use the following command:
$ oc delete knativeserving knative-serving -n knative-serving
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
Run the following command to delete the remaining Knative Serving CRDs:
$ oc delete crd knativeservings.serving.knative.dev