Why Pulumi Might Outshine Terraform for Infrastructure as Code

Why Some Dislike Terraform

Terraform uses its own domain‑specific language (HCL), which many developers find unfamiliar and hard to learn, leading to a steep learning curve. It also complicates testing, secret management, and team productivity because teams must adopt a language separate from their application code.

What Pulumi Can Do

Pulumi offers a more intuitive way to write infrastructure code using familiar programming languages. Below is a Java example that creates a VPC, a subnet group, and an AWS DocumentDB cluster, then exports the cluster endpoint.

import com.pulumi.pulumi;
import com.pulumi.pulumi.aws.ec2;
import com.pulumi.pulumi.aws.rds;
import com.pulumi.pulumi.aws.vpc;

public class Main {
    public static void main(String[] args) {
        // Create a VPC
        Vpc myVpc = new Vpc("myVpc", VpcArgs.builder()
            .cidrBlock("10.0.0.0/16")
            .build());

        // Create a subnet group
        SubnetGroup dbSubnetGroup = new SubnetGroup("myDbSubnetGroup", SubnetGroupArgs.builder()
            .subnetIds(myVpc.getPrivateSubnetIds())
            .build());

        // Create an AWS DocumentDB cluster
        Cluster documentDbCluster = new Cluster("myDocumentDBCluster", ClusterArgs.builder()
            .clusterIdentifier("my-docdb-cluster")
            .availabilityZones("us-east-1a", "us-east-1b")
            .dbSubnetGroupName(dbSubnetGroup.getId())
            .masterUsername("admin")
            .masterPassword("mysecretpassword")
            .skipFinalSnapshot(true)
            .storageEncrypted(true)
            .applyImmediately(true)
            .engine("docdb")
            .engineVersion("4.0")
            .instanceType("db.r5.large")
            .build());

        pulumi.export("clusterEndpoint", documentDbCluster.getEndpoint());
    }
}

Language Support

Pulumi works with multiple programming languages and cloud providers, allowing developers to use the same language they use for application code, which improves abstraction and enables testing infrastructure before incurring cloud costs.

Pulumi Secret Store

Pulumi includes an integrated secret store that automatically encrypts sensitive data for each stack, whether using the managed Pulumi service or a self‑hosted backend such as AWS S3 or Google Cloud Storage.

Team Productivity

When a team uses the same language for both application and infrastructure code, the cognitive load drops, developers can focus on building features, and overall development time and cost are reduced.

Using Terraform State

Pulumi can import and reference existing local or remote Terraform state, making migration smoother. Resources like VPC IDs and subnet IDs created by Terraform can be reused directly in Pulumi projects.

Testing

Developers can choose any testing framework to write unit and integration tests for their infrastructure. The following Spock (Groovy) test demonstrates how to mock Pulumi and verify an AWS S3 bucket creation.

import spock.lang.Specification
import io.pulumi.pulumi
import io.pulumi.pulumi.aws.s3.Bucket
import io.pulumi.pulumi.runtime.Mocks
import org.mockito.Mockito

class PulumiIntegrationTest extends Specification {
    def setup() {
        // Configure Pulumi mocks
        pulumi.runtime.setMocks(new Mocks())
    }

    def cleanup() {
        // Restore Pulumi mocks
        pulumi.runtime.setMocks(null)
    }

    def "test AWS S3 bucket creation"() {
        given:
        // Set up the environment for the Pulumi program
        def program = new pulumi.Stack("mystack")

        when:
        // Execute the Pulumi program that creates the S3 bucket
        program.apply()

        then:
        // Verify that the S3 bucket was created successfully
        def bucketName = program.getOutput(Bucket.BucketName)
        assert bucketName != null && bucketName != ""

        cleanup:
        // Perform additional cleanup tasks if necessary
    }
}

TL;DR

Although Terraform has a strong community, many teams find its HCL language and steep learning curve cumbersome for IaC. Pulumi lets developers use familiar programming languages, improving efficiency and productivity. If you are undecided about an IaC tool, consider the potential impact of Terraform’s complexity on your organization.