How do I execute a shell command on an AWS EC2 instance?

In this guide, we will walk through the steps to execute a shell command on an AWS EC2 instance using Pulumi. We will define an EC2 instance and use the user_data parameter to run the desired shell commands at the instance startup.

Here’s a detailed explanation of what will be done:

1. AWS Provider: Set up the AWS provider to manage resources on AWS.
2. VPC and Security Group: Create a VPC and a security group to use for our EC2 instance.
3. EC2 Instance: Define the EC2 instance resource.
4. User Data: Pass shell commands using the user_data parameter which executes upon instance startup.
5. Outputs: Export essential details such as instance ID, public IP for reference.

Here’s the complete program:

import * as pulumi from "@pulumi/pulumi";
import * as aws from "@pulumi/aws";

const exampleVpc = new aws.ec2.Vpc("example_vpc", {cidrBlock: "10.0.0.0/16"});
const exampleSg = new aws.ec2.SecurityGroup("example_sg", {
    vpcId: exampleVpc.id,
    ingress: [{
        fromPort: 22,
        toPort: 22,
        protocol: "tcp",
        cidrBlocks: ["0.0.0.0/0"],
    }],
    egress: [{
        fromPort: 0,
        toPort: 0,
        protocol: "-1",
        cidrBlocks: ["0.0.0.0/0"],
    }],
});
const exampleInstance = new aws.ec2.Instance("example_instance", {
    ami: "ami-0c55b159cbfafe1f0",
    instanceType: aws.ec2.InstanceType.T2_Micro,
    securityGroups: [exampleSg.name],
    userData: `#!/bin/bash
echo "Hello, Pulumi!" > /home/ec2-user/welcome.txt
`,
    tags: {
        Name: "example-instance",
    },
});
export const instanceId = exampleInstance.id;
export const publicIp = exampleInstance.publicIp;

Summary

In this example, we’ve set up an AWS environment with a VPC and a security group, and provisioned an EC2 instance. Using the user_data parameter, we executed a shell command to create a file with a welcome message. This file will be created once the instance starts up. Finally, we exported the instance ID and public IP for easy reference.