How can high availability services be provisioned using Oracle Cloud Infrastructure for enterprise cloud infrastructure in TypeScript

Question

Pulumi · Accepted Answer

In Oracle Cloud Infrastructure (OCI), the provisioning of high availability services often involves multiple components, including instance pools for scalable and redundant compute resources, load balancers to distribute traffic and ensure uptime, and possibly database services configured for high availability. To ensure enterprise-level cloud infrastructure's high availability, it's important to have redundancy across different availability domains and fault-tolerant systems.

I'll demonstrate how to use Pulumi to create an infrastructure with high availability in OCI using TypeScript.

The following program will use an OCI Instance Pool which allows you to create and manage a pool of identical instances within your OCI environment. The instance pool ensures that you have a specified number of instances running in different fault domains, which improves the availability of your application.

Moreover, we'll include a Load Balancer, which distributes incoming application traffic across multiple instances in your instance pool, enhancing the performance and fault tolerance of your application.

Here's a Pulumi program using TypeScript that sets up this high availability scenario:

```typescript
import * as pulumi from "@pulumi/pulumi";
import * as oci from "@pulumi/oci";

// Create a new instance configuration for the instance pool
const instanceConfiguration = new oci.core.InstanceConfiguration("instanceConfiguration", {
    // Here you would define the specifics of your instance configuration,
    // like compute shape, image source details, and other configuration details.
});

// Provision an instance pool with high availability across different availability domains
const instancePool = new oci.core.InstancePool("instancePool", {
    compartmentId: "your-compartment-id", // Replace with your compartment ID
    instanceConfigurationId: instanceConfiguration.id,
    size: 2, // Desired number of instances to maintain in the pool
    placementConfigurations: [
        // This array allows you to specify placement configurations in different availability domains
        // and fault domains for high availability and fault tolerance.
    ],
    // Additional instance pool configuration...
});

// Create a Load Balancer to distribute traffic among the instances
const loadBalancer = new oci.loadbalancer.LoadBalancer("loadBalancer", {
    compartmentId: "your-compartment-id", // Replace with your compartment ID
    shapeName: "flexible", // Change to a different shape if necessary
    subnetIds: /* array of subnet IDs */, // Place the Load Balancer in subnets that can reach the instance pool
    // Additional load balancer configuration...
});

// Create Load Balancer BackendSet
const backendSet = new oci.loadbalancer.BackendSet("backendSet", {
    loadBalancerId: loadBalancer.id,
    policy: "ROUND_ROBIN",
    backends: [
        {
            instancePoolId: instancePool.id,
            // Configuring port and other parameters for each backend member of the pool
            // ...
        },
        // You can add additional backends if necessary
    ],
    healthChecker: {
        // Define health check policy for the Backend Set
        // ...
    },
    // Additional backend set configuration...
});

// Outputs
export const instancePoolId = instancePool.id;
export const loadBalancerId = loadBalancer.id;
```

This code is a high-level overview and uses placeholders where specific details about your environment and configuration would be needed. Each section marked with `// ...` should be replaced with your specific configuration details. For example, you would need to replace the `your-compartment-id` placeholder with your actual OCI compartment ID and so forth for subnets, instance configurations, etc.

Detailed explanation of the resources being used:

- `InstanceConfiguration`: A template that provides the settings for the instances in the pool. These settings include the image, shape, attached block volumes, networking, and so on.

- `InstancePool`: Maintains a specified number of instances which are created based on the instance configuration. The instance pool helps in providing high availability by ensuring the desired number of instances are always running.

- `LoadBalancer`: Distributes incoming traffic to instances within the backend set, ensuring high availability and fault tolerance for your application.

- `BackendSet`: A logical entity within a Load Balancer that groups backend servers, against which the Load Balancer can route requests based on a specified Load Balancer policy (e.g., round-robin, least connections).

Ensure you have the proper OCI setup, including having your compartment ID and networking configured before deploying this Pulumi stack.

To execute this program, save it in a file (e.g., `main.ts`), run `pulumi up` in the terminal, and follow the prompts to provision the resources detailed in the code. This will set up a highly available service within Oracle Cloud Infrastructure.