Scalable AI Workloads with Custom DNS via Route53 ResolverRules

Question

Pulumi · Accepted Answer

To handle scalable AI workloads with custom DNS routing, we'll utilize AWS Route 53 Resolver Rules. This service allows you to configure custom DNS rules that can direct your DNS queries to specific endpoints. This is particularly useful for AI workloads that are distributed across different geographical locations, environments, or need special routing for optimal performance and lower latency.

Resolver Rules can specify how you want the DNS queries for a particular domain (or subdomain) to be handled. For example, you might send queries to an internal service, or across AWS accounts and VPCs, or even to an on-premises environment with hybrid cloud settings.

Below is a Pulumi program in Python that sets up two Route 53 Resolver Rules. One directs traffic for `ai.internal.example.com` to a specific IP, which could represent an internal load balancer for your AI services. The second rule directs all other DNS queries to use AWS's default DNS resolver (using the rule type `'SYSTEM'`).

It's important to note that `ResolverRule` refers to the rule that defines the DNS query behavior and `ResolverRuleAssociation` links that rule to a specific VPC. This association is necessary because the resolver rule must know where to apply the DNS query routing rules.

Here's how you can set it up with Pulumi:

```python
import pulumi
import pulumi_aws as aws

# Input parameters for the resolver rule
domain_name = "ai.internal.example.com"
target_ip = "10.0.0.5"  # An example IP address for your AI service.
resolver_endpoint_id = "rslvr-out-xxxxxxxxxxxxxx"  # Change this to your resolver endpoint ID.
vpc_id = "vpc-xxxxxxxxxxxxxxxxx"  # Change this to your VPC ID where the rule should apply.

# Create a Route 53 resolver rule for specific domain name to be routed to a specific IP
ai_resolver_rule = aws.route53.ResolverRule("aiResolverRule",
    domain_name=domain_name,
    rule_type="FORWARD",
    target_ips=[aws.route53.ResolverRuleTargetIpArgs(
        ip=target_ip,
    )],
    resolver_endpoint_id=resolver_endpoint_id,
    # Optional: Add additional rule parameters such as tags, rule_action, etc.
)

# Associate the resolver rule with a specific VPC
ai_resolver_rule_association = aws.route53.ResolverRuleAssociation("aiResolverRuleAssociation",
    resolver_rule_id=ai_resolver_rule.id,
    vpc_id=vpc_id,
)

# Create a Route 53 resolver rule to forward all other DNS queries to use AWS's default resolver
default_resolver_rule = aws.route53.ResolverRule("defaultResolverRule",
    domain_name="example.com",  # Change this to your domain if needed.
    rule_type="SYSTEM",
    # Optional: Add additional rule parameters such as tags, rule_action, etc.
)

# Associate the default resolver rule with the same VPC
default_resolver_rule_association = aws.route53.ResolverRuleAssociation("defaultResolverRuleAssociation",
    resolver_rule_id=default_resolver_rule.id,
    vpc_id=vpc_id,
)

# Export the IDs of the resolver rules and associations
pulumi.export("ai_resolver_rule_id", ai_resolver_rule.id)
pulumi.export("ai_resolver_rule_association_id", ai_resolver_rule_association.id)
pulumi.export("default_resolver_rule_id", default_resolver_rule.id)
pulumi.export("default_resolver_rule_association_id", default_resolver_rule_association.id)
```

The program sets up DNS routing for scalable AI workloads via the following steps:

1. Defines the domain name for which the custom DNS routing will apply.
2. Creates a Route 53 Resolver Rule (`aiResolverRule`) to forward DNS queries for `ai.internal.example.com` to a specific IP address.
3. Associates the `aiResolverRule` with a VPC, which is necessary for the rule to take effect in that VPC network context.
4. Sets up a default Resolver Rule (`defaultResolverRule`) for all other DNS queries to be routed normally using AWS's default resolver.
5. Associates the default resolver rule with the same VPC as well.
6. Exports the IDs as stack outputs for easy reference.

For the above code to work, replace `target_ip`, `resolver_endpoint_id`, and `vpc_id` with your actual target IP, resolver endpoint ID, and VPC ID, respectively. The target IP should represent the IP of your internal endpoint for the AI workload.

By creating these resolver rules, you ensure that DNS routing is appropriately configured for your scalable AI workloads, improving both performance and reliability.