AWS Big Data Blog

Externalize Amazon MSK Connect configurations with Terraform

Managing configurations for Amazon MSK Connect, a feature of Amazon Managed Streaming for Apache Kafka (Amazon MSK), can become challenging, especially as the number of topics and configurations grows. In this post, we address this complexity by using Terraform to optimize the configuration of the Kafka topic to Amazon S3 Sink connector. By adopting this strategic approach, you can establish a robust and automated mechanism for handling MSK Connect configurations, eliminating the need for manual intervention or connector restarts. This efficient solution will save time, reduce errors, and provide better control over your Kafka data streaming processes. Let’s explore how Terraform can simplify and enhance the management of MSK Connect configurations for seamless integration with your infrastructure.

Solution overview

At a well-known AWS customer, the management of their constantly growing MSK Connect S3 Sink connector topics has become a significant challenge. The challenges lie in the overhead of managing configurations, as well as dealing with patching and upgrades. Manually handling Kubernetes (K8s) configs and restarting connectors can be cumbersome and error-prone, making it difficult to keep track of changes and updates. At the time of writing this post, MSK Connect does not offer native mechanisms to easily externalize the Kafka topic to S3 Sink configuration.

To address these challenges, we introduce Terraform, an infrastructure as code (IaC) tool. Terraform’s declarative approach and extensive ecosystem make it an ideal choice for managing MSK Connect configurations.

By externalizing Kafka topic to S3 configurations, organizations can achieve the following:

  • Scalability – Effortlessly manage a growing number of topics, ensuring the system can handle increasing data volumes without difficulty
  • Flexibility – Seamlessly integrate MSK Connect configurations with other infrastructure components and services, enabling adaptability to changing business needs
  • Automation – Automate the deployment and management of MSK Connect configurations, reducing manual intervention and streamlining operational tasks
  • Centralized management – Achieve improved governance with centralized management, version control, auditing, and change tracking, ensuring better control and visibility over the configurations

In the following sections, we provide a detailed guide on establishing Terraform for MSK Connect configuration management, defining and decentralizing Topic configurations, and deploying and updating configurations using Terraform.


Before proceeding with the solution, ensure you have the following resources and access:

  • You need access to an AWS account with sufficient permissions to create and manage resources, including AWS Identity and Access Management (IAM) roles and MSK clusters.
  • To simplify the setup, use the provided AWS CloudFormation template. This template will create the necessary MSK cluster and required resources for this post.
  • For this post, we are using the latest Terraform version (1.5.6).

By ensuring you have these prerequisites in place, you will be ready to follow the instructions and streamline your MSK Connect configurations with Terraform. Let’s get started!


Setting up Terraform for MSK Connect configuration management includes the following:

  • Installation of Terraform and setting up the environment
  • Setting up the necessary authentication and permissions

Defining and decentralizing topic configurations using Terraform includes the following:

  • Understanding the structure of Terraform configuration files
  • Determining the required variables and resources
  • Utilizing Terraform’s modules and interpolation for flexibility

The decision to externalize the configuration was primarily driven by the customer’s business requirement. They anticipated the need to add topics periodically and wanted to avoid the need to bring down and write specific code each time. Given the limitations of MSK Connect (as of this writing), it’s important to note that MSK Connect can handle up to 300 workers. For this proof of concept (POC), we opted for a configuration with 100 topics directed to a single Amazon Simple Storage Service (Amazon S3) bucket. To ensure compatibility within the 300-worker limit, we set the MCU count to 1 and configured auto scaling with a maximum of 2 workers. This ensures that the configuration remains within the bounds of the 300-worker maximum.

To make the configuration more flexible, we specify the variables that can be utilized in the code.(

variable "aws_region" {
description = "The AWS region to deploy resources in."
type = string

variable "s3_bucket_name" {
description = "s3_bucket_name."
type = string

variable "topics" {
description = "topics"
type = string

variable "msk_connect_name" {
description = "Name of the MSK Connect instance."
type = string

variable "msk_connect_description" {
description = "Description of the MSK Connect instance."
type = string

# Rest of the variables...

To set up the AWS MSK Connector for the S3 Sink, we need to provide various configurations. Let’s examine the connector_configuration block in the code snippet provided in the file in more detail:

connector_configuration = {
"connector.class" = "io.confluent.connect.s3.S3SinkConnector"
"s3.region" = "us-east-1"
"flush.size" = "5"
"schema.compatibility" = "NONE"
"tasks.max" = "1"
"topics" = var.topics
"format.class" = "io.confluent.connect.s3.format.json.JsonFormat"
"partitioner.class" = ""
"value.converter.schemas.enable" = "false"
"value.converter" = "org.apache.kafka.connect.json.JsonConverter"
"storage.class" = ""
"key.converter" = ""
"" = var.s3_bucket_name
"topics.dir" = "cxdl-data/KairosTelemetry"

The kafka_cluster block in the code snippet defines the Kafka cluster details, including the bootstrap servers and VPC settings. You can reference the variables to specify the appropriate values:

kafka_cluster {
apache_kafka_cluster {
bootstrap_servers = var.bootstrap_servers

vpc {
security_groups = [var.security_groups]
subnets = [var.aws_subnet_example1_id, var.aws_subnet_example2_id, var.aws_subnet_example3_id]

To secure the connection between Kafka and the connector, the code snippet includes configurations for authentication and encryption:

  • The kafka_cluster_client_authentication block sets the authentication type to IAM, enabling the use of IAM for authentication
  • The kafka_cluster_encryption_in_transit block enables TLS encryption for data transfer between Kafka and the connector
  kafka_cluster_client_authentication {
    authentication_type = "IAM"

  kafka_cluster_encryption_in_transit {
    encryption_type = "TLS"

You can externalize the variables and provide dynamic values using a var.tfvars file. Let’s assume the content of the var.tfvars file is as follows:

aws_region = "us-east-1"
msk_connect_name = "confluentinc-MSK-connect-s3-2"
msk_connect_description = "My MSK Connect instance"
s3_bucket_name = "msk-lab-xxxxxxxxxxxx-target-bucket"
topics = "salesdb.salesdb.CUSTOMER,salesdb.salesdb.CUSTOMER_SITE,salesdb.salesdb.PRODUCT,salesdb.salesdb.PRODUCT_CATEGORY,salesdb.salesdb.SALES_ORDER,salesdb.salesdb.SALES_ORDER_ALL,salesdb.salesdb.SALES_ORDER_DETAIL,salesdb.salesdb.SALES_ORDER_DETAIL_DS,salesdb.salesdb.SUPPLIER"
bootstrap_servers = ",,“
aws_subnet_example1_id = "subnet-016ef7bb5f5db5759"
aws_subnet_example2_id = "subnet-0114c390d379134fa"
aws_subnet_example3_id = "subnet-0f6352ad89a1454f2"
security_groups = "sg-07eb8f8e4559334e7"
aws_mskconnect_custom_plugin_example_arn = "arn:aws:kafkaconnect:us-east-1:xxxxxxxxxxxx:custom-plugin/confluentinc-kafka-connect-s3-10-0-3/e9aeb52e-d172-4dba-9de5-f5cf73f1cb9e-2"
aws_mskconnect_custom_plugin_example_latest_revision = "1"
aws_iam_role_example_arn = "arn:aws:iam::xxxxxxxxxxxx:role/msk-connect-lab-S3ConnectorIAMRole-3LBTU7YAV9CM"

Deploy and update configurations using Terraform

Once you’ve defined your MSK Connect infrastructure using Terraform, applying these configurations is a straightforward process for creating or updating your infrastructure. This becomes particularly convenient when a new topic needs to be added. Thanks to the externalized configuration, incorporating this change is now a seamless task. The steps are as follows:

  1. Download and install Terraform from the official website ( for your operating system.
  2. Confirm the installation by running the terraform version command on your command line interface.
  3. Ensure that you have configured your AWS credentials using the AWS Command Line Interface (AWS CLI) or by setting environment variables. You can use the aws configure command to configure your credentials if you’re using the AWS CLI.
  4. Place the,, and var.tfvars files in the same Terraform directory.
  5. Open a command line interface, navigate to the directory containing the Terraform files, and run the command terraform init to initialize Terraform and download the required providers.
  6. Run the command terraform plan -var-file="var.tfvars" to review the run plan.

This command shows the changes that Terraform will make to the infrastructure based on the provided variables. This step is optional but is often used as a preview of the changes Terraform will make.

  1. If the plan looks correct, run the command terraform apply -var-file="var.tfvars" to apply the configuration.

Terraform will create the MSK_Connect in your AWS account. This will prompt you for confirmation before proceeding.

  1. After the terraform apply command is complete, verify the infrastructure has been created or updated on the console.
  2. For any changes or updates, modify your Terraform files (,, var.tfvars) as needed, and then rerun the terraform plan and terraform apply commands.
  3. When you no longer need the infrastructure, you can use terraform destroy -var-file="var.tfvars" to remove all resources created by your Terraform files.

Be careful with this command because it will delete all the resources defined in your Terraform files.


In this post, we addressed the challenges faced by a customer in managing MSK Connect configurations and described a Terraform-based solution. By externalizing Kafka topic to Amazon S3 configurations, you can streamline your configuration management processes, achieve scalability, enhance flexibility, automate deployments, and centralize management. We encourage you to use Terraform to optimize your MSK Connect configurations and explore further possibilities in managing your streaming data pipelines efficiently.

To get started with externalizing MSK Connect configurations using Terraform, refer to the provided implementation steps and the Getting Started with Terraform guide, MSK Connect documentation, Terraform documentation, and example GitHub repository.

Using Terraform to externalize the Kafka topic to Amazon S3 Sink configuration in MSK Connect offers a powerful solution for managing and scaling your streaming data pipelines. By automating the deployment, updating, and central management of configurations, you can ensure efficiency, flexibility, and scalability in your data processing workflows.

About the Author

RamC Venkatasamy is a Solutions Architect based in Bloomington, Illinois. He helps AWS Strategic customers transform their businesses in the cloud. With a fervent enthusiasm for Serverless, Event-Driven Architecture and GenAI.