Isolated Network for Large Language Model API Access

Question

Pulumi · Accepted Answer

Setting up an isolated network for accessing a Large Language Model (LLM) API typically involves creating a cloud network infrastructure that provides a secure and controlled environment for API communication. This network would typically consist of a virtual private cloud (VPC), subnets, network access control lists (ACLs), security groups, and possibly NAT gateways or private endpoints, depending on your design.

The goal is to set up a network that allows VMs or containers within the VPC to reach out to the LLM API, while ensuring that access is restricted and controlled.

Here's an example of how you could set up such an environment using Pulumi with AWS as the cloud provider:

1. **Virtual Private Cloud (VPC)**: Create a VPC to provide an isolated network environment.
2. **Subnets**: Create public and private subnets. You typically place your resources, such as API client instances or containers, in the private subnet to restrict incoming traffic from the internet.
3. **Internet Gateway (IGW)** and **NAT Gateway**: The IGW enables resources in your public subnet to access the internet, whereas the NAT Gateway allows instances in your private subnet to send requests to the LLM API over the internet without receiving unsolicited inbound connections.
4. **Security Groups**: Security groups act as a virtual firewall for your instances, controlling both inbound and outbound traffic at the instance level.
5. **Network ACLs**: Network ACLs provide an additional layer of security, controlling traffic to and from the subnets.

Now, let's write the Pulumi program that creates this infrastructure:

```python
import pulumi
import pulumi_aws as aws

# Create a new VPC for our isolated network
vpc = aws.ec2.Vpc("vpc",
                  cidr_block="10.0.0.0/16")

# Create internet gateway for the VPC
igw = aws.ec2.InternetGateway("igw",
                              vpc_id=vpc.id)

# Create public and private subnets within the VPC
public_subnet = aws.ec2.Subnet("public-subnet",
                               vpc_id=vpc.id,
                               cidr_block="10.0.1.0/24",
                               map_public_ip_on_launch=True)

private_subnet = aws.ec2.Subnet("private-subnet",
                                vpc_id=vpc.id,
                                cidr_block="10.0.2.0/24")

# Associate route table to the public subnet that directs internet-bound traffic to the IGW
route_table = aws.ec2.RouteTable("route-table",
                                 vpc_id=vpc.id,
                                 routes=[
                                     aws.ec2.RouteTableRouteArgs(
                                         cidr_block="0.0.0.0/0",
                                         gateway_id=igw.id
                                     )
                                 ])

route_table_association = aws.ec2.RouteTableAssociation("route-table-association",
                                                        subnet_id=public_subnet.id,
                                                        route_table_id=route_table.id)

# Create a NAT Gateway in the public subnet to enable internet access for the private subnet
elastic_ip = aws.ec2.Eip("eip", vpc=True)
nat_gateway = aws.ec2.NatGateway("nat-gateway",
                                 subnet_id=public_subnet.id,
                                 allocation_id=elastic_ip.id)

# Security Group for instances that will be accessing the LLM API
security_group = aws.ec2.SecurityGroup("security-group",
                                       vpc_id=vpc.id,
                                       description="Allow outbound access to LLM API",
                                       egress=[
                                           aws.ec2.SecurityGroupEgressArgs(
                                               description="Allow outbound access to LLM API",
                                               from_port=443,
                                               to_port=443,
                                               protocol="tcp",
                                               cidr_blocks=["0.0.0.0/0"] # Only allowing outbound access on HTTPS
                                           )
                                       ])

# Export the VPC information
pulumi.export('vpc_id', vpc.id)
pulumi.export('public_subnet_id', public_subnet.id)
pulumi.export('private_subnet_id', private_subnet.id)
pulumi.export('security_group_id', security_group.id)
```

In this program:
- We create a new VPC with a `/16` CIDR block, providing a large private network space.
- We add an Internet Gateway to enable traffic from the VPC to the internet.
- We configure both a public and private subnet. The public subnet includes a route to the Internet Gateway, while the private subnet's outbound traffic is routed through the NAT Gateway.
- We create a dedicated security group allowing outbound access on HTTPS (port 443) to LLM API, implying that the API is accessed over the secure HTTP protocol.

Ensure that the LLM API you wish to connect to allows incoming connections from the network you have just defined or that you set up appropriate routes and gateway configurations to reach it.

Remember, this program assumes that you've already set up your AWS environment and Pulumi CLI. When you run this program with `pulumi up`, it will provision the resources as per the code above in your AWS account.