Deploy an AWS Route 53 loadbalancer

Architecture

All Keycloak client requests are routed by a DNS name managed by Route53 records. Route53 is responsibile to ensure that all client requests are routed to the Primary cluster when it is available and healthy, or to the backup cluster in the event of the primary availability-zone or Keycloak deployment failing.

If the primary site fails, the DNS changes will need to propagate to the clients. Depending on the client’s settings, the propagation may take some minutes based on the client’s configuration. When using mobile connections, some internet providers might not respect the TTL of the DNS entries, which can lead to an extended time before the clients can connect to the new site.

Figure 1. AWS Global Accelerator Failover

Two Openshift Routes are exposed on both the Primary and Backup ROSA cluster. The first Route uses the Route53 DNS name to service client requests, whereas the second Route is used by Route53 to monitor the health of the Keycloak cluster.

Prerequisites

Deployment of Keycloak as described in Deploy Keycloak for HA with the Keycloak Operator on a ROSA cluster running OpenShift 4.14 or later in two AWS availability zones in AWS one region.
An owned domain for client requests to be routed through.

Procedure

Create a Route53 Hosted Zone using the root domain name through which you want all Keycloak clients to connect.

Take note of the "Hosted zone ID", because this ID is required in later steps.

Retrieve the "Hosted zone ID" and DNS name associated with each ROSA cluster.

For both the Primary and Backup cluster, perform the following steps:

Log in to the ROSA cluster.

Retrieve the cluster LoadBalancer Hosted Zone ID and DNS hostname

Command:

HOSTNAME=$(oc -n openshift-ingress get svc router-default \
-o jsonpath='{.status.loadBalancer.ingress[].hostname}'
)
aws elbv2 describe-load-balancers \
--query "LoadBalancers[?DNSName=='${HOSTNAME}'].{CanonicalHostedZoneId:CanonicalHostedZoneId,DNSName:DNSName}" \
--region eu-west-1 \(1)
--output json

1	The AWS region hosting your ROSA cluster

Output:

[
    {
        "CanonicalHostedZoneId": "Z2IFOLAFXWLO4F",
        "DNSName": "ad62c8d2fcffa4d54aec7ffff902c925-61f5d3e1cbdc5d42.elb.eu-west-1.amazonaws.com"
    }
]

ROSA clusters running OpenShift 4.13 and earlier use classic load balancers instead of application load balancers. Use the aws elb describe-load-balancers command and an updated query string instead.

Create Route53 health checks

Command:

function createHealthCheck() {
  # Creating a hash of the caller reference to allow for names longer than 64 characters
  REF=($(echo $1 | sha1sum ))
  aws route53 create-health-check \
  --caller-reference "$REF" \
  --query "HealthCheck.Id" \
  --no-cli-pager \
  --output text \
  --health-check-config '
  {
    "Type": "HTTPS",
    "ResourcePath": "/lb-check",
    "FullyQualifiedDomainName": "'$1'",
    "Port": 443,
    "RequestInterval": 30,
    "FailureThreshold": 1,
    "EnableSNI": true
  }
  '
}
CLIENT_DOMAIN="client.keycloak-benchmark.com" (1)
PRIMARY_DOMAIN="primary.${CLIENT_DOMAIN}" (2)
BACKUP_DOMAIN="backup.${CLIENT_DOMAIN}" (3)
createHealthCheck ${PRIMARY_DOMAIN}
createHealthCheck ${BACKUP_DOMAIN}

1	The domain which Keycloak clients should connect to. This should be the same, or a subdomain, of the root domain used to create the Hosted Zone.
2	The subdomain that will be used for health probes on the Primary cluster
3	The subdomain that will be used for health probes on the Backup cluster

Output:

233e180f-f023-45a3-954e-415303f21eab (1)
799e2cbb-43ae-4848-9b72-0d9173f04912 (2)

1	The ID of the Primary Health check
2	The ID of the Backup Health check

Create the Route53 record set

Command:

HOSTED_ZONE_ID="Z09084361B6LKQQRCVBEY" (1)
PRIMARY_LB_HOSTED_ZONE_ID="Z2IFOLAFXWLO4F"
PRIMARY_LB_DNS=ad62c8d2fcffa4d54aec7ffff902c925-61f5d3e1cbdc5d42.elb.eu-west-1.amazonaws.com
PRIMARY_HEALTH_ID=233e180f-f023-45a3-954e-415303f21eab
BACKUP_LB_HOSTED_ZONE_ID="Z2IFOLAFXWLO4F"
BACKUP_LB_DNS=a184a0e02a5d44a9194e517c12c2b0ec-1203036292.elb.eu-west-1.amazonaws.com
BACKUP_HEALTH_ID=799e2cbb-43ae-4848-9b72-0d9173f04912
aws route53 change-resource-record-sets \
  --hosted-zone-id Z09084361B6LKQQRCVBEY \
  --query "ChangeInfo.Id" \
  --output text \
  --change-batch '
  {
    "Comment": "Creating Record Set for '${CLIENT_DOMAIN}'",
  	"Changes": [{
  		"Action": "CREATE",
  		"ResourceRecordSet": {
  			"Name": "'${PRIMARY_DOMAIN}'",
  			"Type": "A",
        "AliasTarget": {
          "HostedZoneId": "'${PRIMARY_LB_HOSTED_ZONE_ID}'",
          "DNSName": "'${PRIMARY_LB_DNS}'",
          "EvaluateTargetHealth": true
        }
  		}
  	}, {
  		"Action": "CREATE",
  		"ResourceRecordSet": {
  			"Name": "'${BACKUP_DOMAIN}'",
  			"Type": "A",
        "AliasTarget": {
          "HostedZoneId": "'${BACKUP_LB_HOSTED_ZONE_ID}'",
          "DNSName": "'${BACKUP_LB_DNS}'",
          "EvaluateTargetHealth": true
        }
  		}
  	}, {
  		"Action": "CREATE",
  		"ResourceRecordSet": {
  			"Name": "'${CLIENT_DOMAIN}'",
  			"Type": "A",
        "SetIdentifier": "client-failover-primary-'${SUBDOMAIN}'",
        "Failover": "PRIMARY",
        "HealthCheckId": "'${PRIMARY_HEALTH_ID}'",
        "AliasTarget": {
          "HostedZoneId": "'${HOSTED_ZONE_ID}'",
          "DNSName": "'${PRIMARY_DOMAIN}'",
          "EvaluateTargetHealth": true
        }
  		}
  	}, {
  		"Action": "CREATE",
  		"ResourceRecordSet": {
  			"Name": "'${CLIENT_DOMAIN}'",
  			"Type": "A",
        "SetIdentifier": "client-failover-backup-'${SUBDOMAIN}'",
        "Failover": "SECONDARY",
        "HealthCheckId": "'${BACKUP_HEALTH_ID}'",
        "AliasTarget": {
          "HostedZoneId": "'${HOSTED_ZONE_ID}'",
          "DNSName": "'${BACKUP_DOMAIN}'",
          "EvaluateTargetHealth": true
        }
  		}
  	}]
  }
  '

1	The ID of the Hosted Zone created earlier

Output:

/change/C053410633T95FR9WN3YI

Wait for the Route53 records to be updated

Command:

aws route53 wait resource-record-sets-changed --id /change/C053410633T95FR9WN3YI

Update or create the Keycloak deployment

For both the Primary and Backup cluster, perform the following steps:

Log in to the ROSA cluster
Ensure the Keycloak CR has the following configuration
```
apiVersion: k8s.keycloak.org/v2alpha1
kind: Keycloak
metadata:
  name: keycloak
spec:
  hostname:
    hostname: ${CLIENT_DOMAIN} (1)
```
1 The domain clients used to connect to Keycloak

To ensure that request forwarding works, edit the Keycloak CR to specify the hostname through which clients will access the Keycloak instances. This hostname must be the $CLIENT_DOMAIN used in the Route53 configuration.

Create health check Route

Command:

cat <<EOF | kubectl apply -n $NAMESPACE -f - (1)
apiVersion: route.openshift.io/v1
kind: Route
metadata:
  name: aws-health-route
spec:
  host: $DOMAIN (2)
  port:
    targetPort: https
  tls:
    insecureEdgeTerminationPolicy: Redirect
    termination: passthrough
  to:
    kind: Service
    name: keycloak-service
    weight: 100
  wildcardPolicy: None

EOF

1	`$NAMESPACE` should be replaced with the namespace of your Keycloak deployment
2	`$DOMAIN` should be replaced with either the `PRIMARY_DOMAIN` or `BACKUP_DOMAIN`, if the current cluster is the Primary of Backup cluster, respectively.

Verify

Navigate to the chosen CLIENT_DOMAIN in your local browser and log in to the Keycloak console.

To test failover works as expected, log in to the Primary cluster and scale the Keycloak deployment to zero Pods. Scaling will cause the Primary’s health checks to fail and Route53 should start routing traffic to the Keycloak Pods on the Backup cluster.