OpenShift Container Platform

Handling ingress in a hosted cluster on bare metal

Every OpenShift Container Platform cluster has a default application Ingress Controller that typically has an external DNS record associated with it.

For example, if you create a hosted cluster named example with the base domain krnl.es, you can expect the wildcard domain *.apps.example.krnl.es to be routable.

To set up a load balancer and wildcard DNS record for the *.apps domain, perform the following actions on your hosted cluster.

Procedure

Deploy MetalLB by creating a YAML file that has the configuration for the MetalLB Operator:

apiVersion: v1
kind: Namespace
metadata:
  name: metallb
  labels:
    openshift.io/cluster-monitoring: "true"
  annotations:
    workload.openshift.io/allowed: management
---
apiVersion: operators.coreos.com/v1
kind: OperatorGroup
metadata:
  name: metallb-operator-operatorgroup
  namespace: metallb
---
apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  name: metallb-operator
  namespace: metallb
spec:
  channel: "stable"
  name: metallb-operator
  source: redhat-operators
  sourceNamespace: openshift-marketplace

Save the file as metallb-operator-config.yaml.
Enter the following command to apply the configuration:
```
$ oc apply -f metallb-operator-config.yaml
```
After the Operator is running, create the MetalLB instance:
1. Create a YAML file that has the configuration for the MetalLB instance:
  apiVersion: metallb.io/v1beta1 kind: MetalLB metadata: name: metallb namespace: metallb
2. Save the file as metallb-instance-config.yaml.
3. Create the MetalLB instance by entering this command:
  $ oc apply -f metallb-instance-config.yaml
Create an IPAddressPool resource with a single IP address. This IP address must be on the same subnet as the network that the cluster nodes use.
1. Create a file, such as ipaddresspool.yaml, with content similar to the following example:
  apiVersion: metallb.io/v1beta1 kind: IPAddressPool metadata: namespace: metallb name: <ip_address_pool_name> spec: addresses: - <ingress_ip>-<ingress_ip> autoAssign: false
  - metadata.name specifies the IPAddressPool resource name.
  - spec.addresses specifies the IP address for your environment. For example, 192.168.122.23.
2. Apply the configuration for the IP address pool by entering the following command:
  $ oc apply -f ipaddresspool.yaml
Create a L2 advertisement.
1. Create a file, such as l2advertisement.yaml, with content similar to the following example:
  apiVersion: metallb.io/v1beta1 kind: L2Advertisement metadata: name: <l2_advertisement_name> namespace: metallb spec: ipAddressPools: - <ip_address_pool_name>
  - metadata.name specifies the L2Advertisement resource name.
  - spec.ipAddressPools specifies the IPAddressPool resource name.
2. Apply the configuration by entering the following command:
  $ oc apply -f l2advertisement.yaml

After creating a service of the LoadBalancer type, MetalLB adds an external IP address for the service.

Configure a new load balancer service that routes ingress traffic to the ingress deployment by creating a YAML file named metallb-loadbalancer-service.yaml:

kind: Service
apiVersion: v1
metadata:
  annotations:
   metallb.io/address-pool: ingress-public-ip
  name: metallb-ingress
  namespace: openshift-ingress
spec:
  ports:
    - name: http
      protocol: TCP
      port: 80
      targetPort: 80
    - name: https
      protocol: TCP
      port: 443
      targetPort: 443
  selector:
    ingresscontroller.operator.openshift.io/deployment-ingresscontroller: default
  type: LoadBalancer

Save the metallb-loadbalancer-service.yaml file.
Enter the following command to apply the YAML configuration:
```
$ oc apply -f metallb-loadbalancer-service.yaml
```
Enter the following command to reach the OpenShift Container Platform console:
```
$ curl -kI https://console-openshift-console.apps.example.krnl.es
```
Example output
```
HTTP/1.1 200 OK
```

Check the clusterversion and clusteroperator values to verify that everything is running. Enter the following command:

$ oc --kubeconfig <hosted_cluster_name>.kubeconfig get clusterversion,co

Example output

NAME                                         VERSION   AVAILABLE   PROGRESSING   SINCE   STATUS
clusterversion.config.openshift.io/version   4.x.y      True        False        3m32s   Cluster version is 4.x.y

NAME                                                                             VERSION   AVAILABLE   PROGRESSING   DEGRADED   SINCE   MESSAGE
clusteroperator.config.openshift.io/console                                      4.x.y     True        False         False      3m50s
clusteroperator.config.openshift.io/ingress                                      4.x.y     True        False         False      53m

Replace <4.x.y> with the supported OpenShift Container Platform version that you want to use, for example, 4.22.0-multi.