Route53 Failover Routing for AI Workloads

Question

Pulumi · Accepted Answer

Failover routing in AWS Route 53 allows you to configure active-passive failover, where one resource takes over when the other becomes unavailable, helping ensure high availability of your AI workloads. To implement failover routing, you typically need a primary resource (like an EC2 instance serving your AI application), a secondary resource (a standby instance), and health checks to monitor the health of the primary resource.

Here's a rundown of what we'll do in the Pulumi program for setting up failover routing:

1. Create a new hosted zone in Route 53 or use an existing one if you already have the domain registered.
2. Set up health checks to monitor the endpoint of your primary AI workload.
3. Define the DNS records for both the primary and secondary endpoints with failover routing policy.
4. Associate the health checks with the primary endpoint's DNS record, so Route 53 can automatically route traffic to the secondary in case the health check fails.

Let's go through each step in code. In this program, we'll create a new hosted zone, set up health checks, and configure DNS records for failover routing:

```python
import pulumi
import pulumi_aws as aws

# We are assuming you have a domain name registered outside AWS or a domain you can transfer management to Route53.
domain_name = "myaiworkloads.com"

# Create a new AWS Route53 Hosted Zone for our domain
# Doc: https://www.pulumi.com/docs/reference/pkg/aws/route53/hostedzone/
hosted_zone = aws.route53.HostedZone("myaiworkloadsZone",
    name=domain_name)

# Primary health check for main AI workload
# Doc: https://www.pulumi.com/docs/reference/pkg/aws/route53/healthcheck/
primary_health_check = aws.route53.HealthCheck("primaryHealthCheck",
    fqdn=f"primary.{domain_name}",
    type="HTTP",  # Assuming HTTP for this illustration; adjust as needed
    failure_threshold=3,
    request_interval=30,
    resource_path="/",  # Adjust this path to where health status can be checked
    enable_sni=False)

# Secondary health check for failover AI workload (optional)
# It's not strictly necessary unless you want independent confirmation 
# that your secondary workload is ready to take over
secondary_health_check = aws.route53.HealthCheck("secondaryHealthCheck",
    fqdn=f"secondary.{domain_name}",
    type="HTTP",
    failure_threshold=3,
    request_interval=30,
    resource_path="/",
    enable_sni=False)

# Primary record with failover routing
# Doc: https://www.pulumi.com/docs/reference/pkg/aws/route53/record/
primary_record = aws.route53.Record("primaryRecord",
    zone_id=hosted_zone.id,
    name=f"primary.{domain_name}",
    type="A",
    failover_routing_policies=[aws.route53.RecordFailoverRoutingPolicyArgs(
        type="PRIMARY"
    )],
    set_identifier="primaryEndpoint",  # Distinguishes from other records
    health_check_id=primary_health_check.id,  # Associates health check
    records=["IP_ADDRESS_OF_PRIMARY_RESOURCE"])  # Replace with the actual IP

# Secondary (failover) record
secondary_record = aws.route53.Record("secondaryRecord",
    zone_id=hosted_zone.id,
    name=f"secondary.{domain_name}",
    type="A",
    failover_routing_policies=[aws.route53.RecordFailoverRoutingPolicyArgs(
        type="SECONDARY"
    )],
    set_identifier="secondaryEndpoint",  # Distinguishes from other records
    records=["IP_ADDRESS_OF_SECONDARY_RESOURCE"])  # Replace with the actual IP

# Export hosted zone ID and nameservers
pulumi.export("hosted_zone_id", hosted_zone.id)
pulumi.export("hosted_zone_nameservers", hosted_zone.name_servers)
```

In the above program, replace `IP_ADDRESS_OF_PRIMARY_RESOURCE` and `IP_ADDRESS_OF_SECONDARY_RESOURCE` with the IP addresses of your primary and secondary AI workload instances.

To deploy this Pulumi stack, you'd run `pulumi up` after setting up Pulumi and AWS CLI with appropriate credentials and configurations.

Route 53 will now monitor the primary resource via the health check. If it becomes unavailable (i.e., fails health checks for a threshold period), Route 53 will automatically route traffic to the secondary (failover) resource.