AWS Load Balancer Operator on ROSA | Tutorials | Red Hat OpenShift Service on AWS

Prerequisites
- Environment
- AWS VPC and subnets
Installation
Validating the deployment
Cleaning up

This content is authored by Red Hat experts, but has not yet been tested on every supported configuration.

Load Balancers created by the AWS Load Balancer Operator cannot be used for OpenShift Routes, and should only be used for individual services or ingress resources that do not need the full layer 7 capabilities of an OpenShift Route.

The AWS Load Balancer Controller manages AWS Elastic Load Balancers for a Red Hat OpenShift Service on AWS (ROSA) cluster. The controller provisions AWS Application Load Balancers (ALB) when you create Kubernetes Ingress resources and AWS Network Load Balancers (NLB) when implementing Kubernetes Service resources with a type of LoadBalancer.

Compared with the default AWS in-tree load balancer provider, this controller is developed with advanced annotations for both ALBs and NLBs. Some advanced use cases are:

Using native Kubernetes Ingress objects with ALBs
Integrate ALBs with the AWS Web Application Firewall (WAF) service
Specify custom NLB source IP ranges
Specify custom NLB internal IP addresses

The AWS Load Balancer Operator is used to used to install, manage and configure an instance of aws-load-balancer-controller in a ROSA cluster.

Prerequisites

AWS ALBs require a multi-AZ cluster, as well as three public subnets split across three AZs in the same VPC as the cluster. This makes ALBs unsuitable for many PrivateLink clusters. AWS NLBs do not have this restriction.

A multi-AZ ROSA classic cluster
BYO VPC cluster
AWS CLI
OC CLI

edit

Environment

Prepare the environment variables:

$ export AWS_PAGER=""
$ export ROSA_CLUSTER_NAME=$(oc get infrastructure cluster -o=jsonpath="{.status.infrastructureName}"  | sed 's/-[a-z0-9]\{5\}$//')
$ export REGION=$(oc get infrastructure cluster -o=jsonpath="{.status.platformStatus.aws.region}")
$ export OIDC_ENDPOINT=$(oc get authentication.config.openshift.io cluster -o jsonpath='{.spec.serviceAccountIssuer}' | sed  's|^https://||')
$ export AWS_ACCOUNT_ID=$(aws sts get-caller-identity --query Account --output text)
$ export SCRATCH="/tmp/${ROSA_CLUSTER_NAME}/alb-operator"
$ mkdir -p ${SCRATCH}
$ echo "Cluster: ${ROSA_CLUSTER_NAME}, Region: ${REGION}, OIDC Endpoint: ${OIDC_ENDPOINT}, AWS Account ID: ${AWS_ACCOUNT_ID}"

AWS VPC and subnets

This section only applies to clusters that were deployed into existing VPCs. If you did not deploy your cluster into an existing VPC, skip this section and proceed to the installation section below.

Set the below variables to the proper values for your ROSA deployment:

$ export VPC_ID=<vpc-id>
$ export PUBLIC_SUBNET_IDS=<public-subnets>
$ export PRIVATE_SUBNET_IDS=<private-subnets>
$ export CLUSTER_NAME=$(oc get infrastructure cluster -o=jsonpath="{.status.infrastructureName}")

Add a tag to your cluster’s VPC with the cluster name:

$ aws ec2 create-tags --resources ${VPC_ID} --tags Key=kubernetes.io/cluster/${CLUSTER_NAME},Value=owned --region ${REGION}

Add a tag to your public subnets:

$ aws ec2 create-tags \
     --resources ${PUBLIC_SUBNET_IDS} \
     --tags Key=kubernetes.io/role/elb,Value='' \
     --region ${REGION}

Add a tag to your private subnets:

$ aws ec2 create-tags \
     --resources "${PRIVATE_SUBNET_IDS}" \
     --tags Key=kubernetes.io/role/internal-elb,Value='' \
     --region ${REGION}

Installation

Create an AWS IAM policy for the AWS Load Balancer Controller:

The policy is sourced from the upstream AWS Load Balancer Controller policy plus permission to create tags on subnets. This is required by the operator to function.

$ oc new-project aws-load-balancer-operator
$ POLICY_ARN=$(aws iam list-policies --query \
     "Policies[?PolicyName=='aws-load-balancer-operator-policy'].{ARN:Arn}" \
     --output text)
$ if [[ -z "${POLICY_ARN}" ]]; then
    wget -O "${SCRATCH}/load-balancer-operator-policy.json" \
       https://raw.githubusercontent.com/rh-mobb/documentation/main/content/docs/rosa/aws-load-balancer-operator/load-balancer-operator-policy.json
     POLICY_ARN=$(aws --region "$REGION" --query Policy.Arn \
     --output text iam create-policy \
     --policy-name aws-load-balancer-operator-policy \
     --policy-document "file://${SCRATCH}/load-balancer-operator-policy.json")
fi
$ echo $POLICY_ARN

Create an AWS IAM trust policy for AWS Load Balancer Operator:

$ cat <<EOF > "${SCRATCH}/trust-policy.json"
{
 "Version": "2012-10-17",
 "Statement": [
 {
 "Effect": "Allow",
 "Condition": {
   "StringEquals" : {
     "${OIDC_ENDPOINT}:sub": ["system:serviceaccount:aws-load-balancer-operator:aws-load-balancer-operator-controller-manager", "system:serviceaccount:aws-load-balancer-operator:aws-load-balancer-controller-cluster"]
   }
 },
 "Principal": {
   "Federated": "arn:aws:iam::$AWS_ACCOUNT_ID:oidc-provider/${OIDC_ENDPOINT}"
 },
 "Action": "sts:AssumeRoleWithWebIdentity"
 }
 ]
}
EOF

Create an AWS IAM role for the AWS Load Balancer Operator:

$ ROLE_ARN=$(aws iam create-role --role-name "${ROSA_CLUSTER_NAME}-alb-operator" \
   --assume-role-policy-document "file://${SCRATCH}/trust-policy.json" \
   --query Role.Arn --output text)
$ echo $ROLE_ARN

$ aws iam attach-role-policy --role-name "${ROSA_CLUSTER_NAME}-alb-operator" \
     --policy-arn $POLICY_ARN

Create a secret for the AWS Load Balancer Operator to assume our newly created AWS IAM role:

$ cat << EOF | oc apply -f -
apiVersion: v1
kind: Secret
metadata:
  name: aws-load-balancer-operator
  namespace: aws-load-balancer-operator
stringData:
  credentials: |
    [default]
    role_arn = $ROLE_ARN
    web_identity_token_file = /var/run/secrets/openshift/serviceaccount/token
EOF

Install the Red Hat AWS Load Balancer Operator:

$ cat << EOF | oc apply -f -
apiVersion: operators.coreos.com/v1
kind: OperatorGroup
metadata:
  name: aws-load-balancer-operator
  namespace: aws-load-balancer-operator
spec:
  upgradeStrategy: Default
---
apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  name: aws-load-balancer-operator
  namespace: aws-load-balancer-operator
spec:
  channel: stable-v1.0
  installPlanApproval: Automatic
  name: aws-load-balancer-operator
  source: redhat-operators
  sourceNamespace: openshift-marketplace
  startingCSV: aws-load-balancer-operator.v1.0.0
EOF

Deploy an instance of the AWS Load Balancer Controller using the operator:

If you get an error here wait a minute and try again, it means the Operator has not completed installing yet.

$ cat << EOF | oc apply -f -
apiVersion: networking.olm.openshift.io/v1
kind: AWSLoadBalancerController
metadata:
  name: cluster
spec:
  credentials:
    name: aws-load-balancer-operator
EOF

Check the that the operator and controller pods are both running:

$ oc -n aws-load-balancer-operator get pods

You should see the following, if not wait a moment and retry:

NAME                                                             READY   STATUS    RESTARTS   AGE
aws-load-balancer-controller-cluster-6ddf658785-pdp5d            1/1     Running   0          99s
aws-load-balancer-operator-controller-manager-577d9ffcb9-w6zqn   2/2     Running   0          2m4s

Validating the deployment

Create a new project:
```
$ oc new-project hello-world
```

Deploy a hello world application:

$ oc new-app -n hello-world --image=docker.io/openshift/hello-openshift

Configure a NodePort service for the AWS ALB to connect to:

$ cat << EOF | oc apply -f -
apiVersion: v1
kind: Service
metadata:
  name: hello-openshift-nodeport
  namespace: hello-world
spec:
  ports:
    - port: 80
      targetPort: 8080
      protocol: TCP
  type: NodePort
  selector:
    deployment: hello-openshift
EOF

Deploy an AWS ALB using the AWS Load Balancer Operator:

$ cat << EOF | oc apply -f -
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: hello-openshift-alb
  namespace: hello-world
  annotations:
    alb.ingress.kubernetes.io/scheme: internet-facing
spec:
  ingressClassName: alb
  rules:
    - http:
        paths:
          - path: /
            pathType: Exact
            backend:
              service:
                name: hello-openshift-nodeport
                port:
                  number: 80
EOF

Curl the AWS ALB Ingress endpoint to verify the hello world application is accessible:

AWS ALB provisioning takes a few minutes. If you receive an error that says curl: (6) Could not resolve host, please wait and try again.
```
$ INGRESS=$(oc -n hello-world get ingress hello-openshift-alb \
    -o jsonpath='{.status.loadBalancer.ingress[0].hostname}')
$ curl "http://${INGRESS}"
```
Example output
```
Hello OpenShift!
```

Deploy an AWS NLB for your hello world application:

$ cat << EOF | oc apply -f -
apiVersion: v1
kind: Service
metadata:
  name: hello-openshift-nlb
  namespace: hello-world
  annotations:
    service.beta.kubernetes.io/aws-load-balancer-type: external
    service.beta.kubernetes.io/aws-load-balancer-nlb-target-type: instance
    service.beta.kubernetes.io/aws-load-balancer-scheme: internet-facing
spec:
  ports:
    - port: 80
      targetPort: 8080
      protocol: TCP
  type: LoadBalancer
  selector:
    deployment: hello-openshift
EOF

Test the AWS NLB endpoint:

NLB provisioning takes a few minutes. If you receive an error that says curl: (6) Could not resolve host, please wait and try again.
```
$ NLB=$(oc -n hello-world get service hello-openshift-nlb \
  -o jsonpath='{.status.loadBalancer.ingress[0].hostname}')
$ curl "http://${NLB}"
```
Example output
```
Hello OpenShift!
```

Cleaning up

Delete the hello world application namespace (and all the resources in the namespace):
```
$ oc delete project hello-world
```

Delete the AWS Load Balancer Operator and the AWS IAM roles:

$ oc delete subscription aws-load-balancer-operator -n aws-load-balancer-operator
$ aws iam detach-role-policy \
  --role-name "${ROSA_CLUSTER_NAME}-alb-operator" \
  --policy-arn $POLICY_ARN
$ aws iam delete-role \
  --role-name "${ROSA_CLUSTER_NAME}-alb-operator"

Delete the AWS IAM policy:

$ aws iam delete-policy --policy-arn $POLICY_ARN

Tutorial: AWS Load Balancer Operator on ROSA

Prerequisites

Environment

AWS VPC and subnets

Installation

Validating the deployment

Cleaning up