Terraform manages infrastructure using a <code>state</code> file, which is stored by default as <code>terraform.tfstate</code>. This works fine when working alone, but if multiple people manage the infrastructure simultaneously, conflicts may arise.
<figure class="image"><img src="https://api.reliasoftware.com/uploads/terraform_conflicts_56c78b355b.webp" alt="Terraform's Problem" width="788" height="569">
<figcaption>Terraform's Problem (Source: <a href="https://www.firefly.ai/academy/understanding-state-locking-and-versioning-in-terraform" rel="nofollow noreferrer">Firefly</a>)</figcaption>
</figure>
To solve this issue, Terraform provides the <code>backend</code> block to configure where the <code>state</code> file is stored.
&gt;&gt; Read more:
<ul>
<li>How To <a href="https://reliasoftware.com/blog/provisioning-a-docker-container-with-terraform">Use Terraform for Provisioning A Docker Container</a>?</li>
<li>How to <a href="https://reliasoftware.com/blog/ec2-to-ecs-migration">Migrate Your AWS Workloads from EC2 to ECS</a>?</li>
</ul>
<h2 data-start="0" data-end="32">What is Terraform Backend?</h2>
A Terraform backend defines how and where Terraform stores its state file (<code data-start="139" data-end="158">terraform.tfstate</code>). This state file keeps track of the resources Terraform manages such as AWS instances, Azure services, or any infrastructure created using Terraform. Without it, Terraform won&rsquo;t know what exists or what needs to be changed.
By default, the state is stored locally on your machine, but that becomes problematic when:
<ul>
<li data-start="488" data-end="549">Multiple team members are working on the same infrastructure.</li>
<li data-start="552" data-end="639">You want centralized control, locking, or history/versioning of infrastructure changes.</li>
<li data-start="642" data-end="700">You need the state file to persist beyond a single device.</li>
</ul>
To solve these issues, Terraform supports using remote backends like&nbsp;Amazon S3,&nbsp;Terraform Cloud,&nbsp;Azure Blob Storage,&nbsp;Google Cloud Storage, and more.&nbsp;With a Terraform remote backend, you are allowed:
<ul>
<li data-start="905" data-end="945">Shared access to the same state file</li>
<li data-start="948" data-end="997">State locking to prevent simultaneous updates</li>
<li data-start="1000" data-end="1031">Versioning and audit trails</li>
<li data-start="1034" data-end="1069">Better security and scalability</li>
</ul>
<h2>Terraform Backend Config</h2>
The <code>backend</code> block is placed at the beginning inside the <code>terraform</code> block. For example: Remote backend with Terraform Cloud:
<pre class="language-yaml"><code>terraform {
 backend "remote" {
 organization = "learning-journey"

 workspaces {
 name = "demo01"
 }
 }
}</code></pre>
Terraform provides multiple <code>backend</code> options, meaning different locations to store the <code>state</code> file, such as <code>local</code>, <code>remote</code>, <code>s3</code>, <code>azurerm</code>, etc. The default storage location is <code>local</code>.
<h2>Backend Types</h2>
As mentioned earlier, Terraform supports multiple backend types, but in this article, we will focus on <code>local</code> and <code>s3</code>.
<h3>Local</h3>
The local backend stores the <code>state</code> file on the user's machine.
Configuration:
<pre class="language-yaml"><code>terraform {
 backend "local" {
 path = "relative/path/to/terraform.tfstate"
 }
}</code></pre>
<code>path</code>: Specifies where the state file is stored. By default, it is <code>terraform.tfstate</code> in the root module.
While easy to set up, the local backend is not recommended for teams. It doesn&rsquo;t support locking, remote access, or version control, so conflicts may arise when multiple users manage infrastructure. Therefore, storing the state file in a shared location helps solve these conflicts, which is where the s3 backend comes in.
<h3>S3</h3>
With this Terraform S3 backend, the&nbsp;<code>state</code> file is stored in an S3 bucket. To ensure consistency, there are two ways to lock the state file:
<ul>
<li>S3 state locking (<code>use_lockfile</code>), available in <code>Terraform 1.10 and later</code>.</li>
<li>DynamoDB (<code>dynamodb_table</code>), where the partition key is <code>LockID</code> with a data type of <code>string</code>.</li>
</ul>
Example: Create an S3 bucket and a DynamoDB table on AWS.
<ul>
<li>Configuration:</li>
</ul>
<pre class="language-yaml"><code>terraform {
 backend "s3" {
 bucket = "mybucket"
 key = "your-state.tfstate"
 region = "us-east-1"
 profile = "Your_Profile"
 dynamodb_table = "states_tb"
 }
}</code></pre>
<ul>
<li>If using an AWS profile with S3 access permissions, no additional S3 permissions are required. Otherwise, you must configure permissions for reading and writing objects in S3:</li>
</ul>
<pre class="language-yaml"><code>{
 "Version": "2012-10-17",
 "Statement": [
 {
 "Effect": "Allow",
 "Action": "s3:ListBucket",
 "Resource": "arn:aws:s3:::mybucket"
 },
 {
 "Effect": "Allow",
 "Action": ["s3:GetObject", "s3:PutObject"],
 "Resource": [
 "arn:aws:s3:::mybucket/path/to/my/key",
 "arn:aws:s3:::mybucket/path/to/my/key.tflock"
 ]
 }
 ]
}</code></pre>
<ul>
<li>If using DynamoDB for state locking, you must also set permissions for DynamoDB on AWS (if the profile lacks necessary permissions):</li>
</ul>
<pre class="language-yaml"><code>{
 "Version": "2012-10-17",
 "Statement": [
 {
 "Effect": "Allow",
 "Action": [
 "dynamodb:DescribeTable",
 "dynamodb:GetItem",
 "dynamodb:PutItem",
 "dynamodb:DeleteItem"
 ],
 "Resource": "arn:aws:dynamodb:*:*:table/mytable"
 }
 ]
}</code></pre>
<h2>Practices</h2>
This section demonstrates how to configure and verify Terraform remote state storage using Amazon S3, and how to enable state locking using either S3-native lockfile or DynamoDB.
<h3>Storing State in S3</h3>
<ul>
<li>Modify <code>main.tf</code> to include the <code>backend</code> block inside the <code>terraform</code> block:</li>
</ul>
<pre class="language-yaml"><code>terraform {
 backend "s3" {
 bucket = "terraform-learning-demo01"
 key = "terraform.tfstate"
 region = "us-east-1"
 profile = "saa"
 }

 ...
}</code></pre>
<ul>
<li>Firstly, create an S3 bucket on AWS with a name matching the bucket field in the backend block. Here, we use <code>terraform-learning-demo01</code>. If not, we will encounter this issue:</li>
</ul>
<img style="display: block; margin-left: auto; margin-right: auto;" src="https://api.reliasoftware.com/uploads/issue_with_creating_an_s3_bucket_ccfbb03687.webp" alt="issue when creating an S3 bucket on AWS" width="1027" height="234">
<ul>
<li>Reinitialize the workspace:</li>
</ul>
<pre class="language-yaml"><code>terraform init</code></pre>
<blockquote data-start="964" data-end="1045">
This initializes the backend and connects Terraform to the specified S3 bucket.
</blockquote>
Expected Output:
<pre class="language-yaml"><code>Initializing the backend...

Successfully configured the backend "s3"! Terraform will automatically
use this backend unless the backend configuration changes.
Initializing modules...
Initializing provider plugins...
- Reusing previous version of hashicorp/aws from the dependency lock file
- Using previously-installed hashicorp/aws v4.67.0

Terraform has been successfully initialized!
...</code></pre>
<ul>
<li>Then, run <code>terraform plan</code> to check for changes, followed by <code>terraform apply</code> to deploy the infrastructure.</li>
<li>After execution, verify in the S3 bucket that the <code>terraform.state</code> (<code>key</code>) file is stored in <code>terraform-learning-demo01</code>&nbsp;(<code>bucket</code>).</li>
</ul>
<img style="display: block; margin-left: auto; margin-right: auto;" src="https://api.reliasoftware.com/uploads/terraform_learning_demo1_eb94605b8d.webp" alt="terraform-learning-demo01" width="923" height="357">
<ul>
<li>In the <code>.terraform/terraform.tfstate</code> directory, you will find the information of backend configuration. This confirms that we have successfully configured state storage on S3.</li>
</ul>
<img style="display: block; margin-left: auto; margin-right: auto;" src="https://api.reliasoftware.com/uploads/information_of_backend_configuration_98e6834e9b.webp" alt="information of backend configuration" width="523" height="945">
<h3>State Locking</h3>
S3 State Locking
<ul>
<li>To enable S3 state locking, add the <code>use_lockfile</code> parameter (only available in Terraform 1.10+) to the <code>backend</code> block. The <code>main.tf</code> file now looks like this:</li>
</ul>
<pre class="language-yaml"><code>terraform {
 backend "s3" {
 bucket = "terraform-learning-demo01"
 key = "terraform.tfstate"
 region = "us-east-1"
 profile = "saa"
 use_lockfile = true
 }

 ...
}
...</code></pre>
<ul>
<li>Modify a resource value (e.g., the subnet CIDR block) and run <code>terraform apply</code> simultaneously. You will see an error in the console:</li>
</ul>
<img src="https://api.reliasoftware.com/uploads/error_in_the_console_081bbe292e.webp" alt="error in the console" width="1184" height="337">
<ul>
<li>A lock file <code>{key}.tflock</code> appears in the S3 bucket, preventing simultaneous apply operations:</li>
</ul>
<img style="display: block; margin-left: auto; margin-right: auto;" src="https://api.reliasoftware.com/uploads/a_lock_file_in_the_s3_bucket_aa64a851ff.webp" alt="A lock file {key}.tflock appears in the S3 bucket" width="1019" height="216">
<ul>
<li>Once the apply operation completes, the lock file is deleted, and the state file will be added in S3:</li>
</ul>
<img style="display: block; margin-left: auto; margin-right: auto;" src="https://api.reliasoftware.com/uploads/the_state_file_will_be_added_in_s3_cbb45e46fe.webp" alt="the state file will be added in S3" width="1011" height="200">
<h3>DynamoDB State Locking</h3>
<ul>
<li>Create a DynamoDB table named <code>terraform-tfstate</code> with <code>LockID</code> as the partition key of type <code>string</code>.</li>
</ul>
<img style="display: block; margin-left: auto; margin-right: auto;" src="https://api.reliasoftware.com/uploads/create_a_dynamodb_table_714b407032.webp" alt="Create a DynamoDB table" width="1111" height="395">
<ul>
<li>If not, this issue will appear:&nbsp;</li>
</ul>
<img style="display: block; margin-left: auto; margin-right: auto;" src="https://api.reliasoftware.com/uploads/error_when_creating_a_dynamodb_table_7a26961c39.webp" alt="error when creating a DynamoDB table " width="803" height="216">
<ul>
<li>Configure DynamoDB in <code>main.tf</code>:</li>
</ul>
<pre class="language-yaml"><code>terraform {
 backend "s3" {
 bucket = "terraform-learning-demo01"
 key = "terraform.tfstate"
 region = "us-east-1"
 profile = "saa"
 dynamodb_table = "terraform-tfstate"
 }
}</code></pre>
<ul>
<li>Running <code>terraform apply</code> simultaneously will result in an error:</li>
</ul>
<img style="display: block; margin-left: auto; margin-right: auto;" src="https://api.reliasoftware.com/uploads/error_when_running_terraform_apply_simultaneously_55547e32fa.webp" alt="Running terraform apply simultaneously will cause error" width="1112" height="320">
<ul>
<li>The DynamoDB table contains a record with <code>LockID</code> formatted as <code>{bucket}/{key}</code>.</li>
</ul>
<img style="display: block; margin-left: auto; margin-right: auto;" src="https://api.reliasoftware.com/uploads/the_dynamodb_table_contains_a_record_with_lockid_fdce0fffad.webp" alt="The DynamoDB table contains a record with LockID" width="1200" height="186">
<ul>
<li>Once apply excecuted, file <code>state</code> will be created in <code>S3</code>:</li>
</ul>
<img style="display: block; margin-left: auto; margin-right: auto;" src="https://api.reliasoftware.com/uploads/file_state_will_be_created_in_s3_a80e0d1a0c.webp" alt="file state will be created in S3" width="1102" height="302">
<ul>
<li>Once the process completes, the lock record is deleted, but a <code>{bucket}/{key}-md5</code> file is created:</li>
</ul>
<img style="display: block; margin-left: auto; margin-right: auto;" src="https://api.reliasoftware.com/uploads/a_bucket_key_md5_file_is_created_574e777434.webp" alt="a {bucket}/{key}-md5 file is created" width="755" height="153">
&gt;&gt; Explore: Top 20&nbsp;<a href="https://reliasoftware.com/blog/infrastructure-as-code-tools">Infrastructure as Code (IaC) Tools</a> For Businesses
<h2>Conclusion</h2>
<ul>
<li>Terraform provides the <code>backend</code> block to define state file storage locations.</li>
<li>Multiple backend options are available: <code>local</code>, <code>remote</code>, <code>s3</code>, etc.</li>
<li>The <code>s3</code> backend supports state locking via S3 native (Terraform 1.10+) or DynamoDB:
<ul>
<li>When applying changes, a <code>.lock</code> file is created in S3 or DynamoDB.</li>
<li>Once the process completes, the lock file is removed, and the state file is updated in S3.</li>
</ul>
</li>
</ul>
<div id="article_content" class="inner_article__entries__X3PKd">
&gt;&gt;&gt; Follow and Contact&nbsp;<a href="https://reliasoftware.com/">Relia Software</a> for more information!
</div>

A Terraform backend defines how and where Terraform stores its state file (<code data-start="139" data-end="158">terraform.tfstate</code>). Terraform remote backends like S3 are used to solve conflicts.

What is Terraform Backend? Dive into Terraform Backend S3 | Relia Software

What is Terraform Backend? Dive into Terraform Backend S3

large_terraform-backend.webp

medium_terraform-backend.webp

small_terraform-backend.webp

thumbnail_terraform-backend.webp

terraform-backend.webp

featured

software-development.webp

Software Development

outsourcing.webp

Outsourcing

software-as-service-business.webp

Business

automation.webp

Automation

artificial-intelligence.webp

AI/ML

Relia Software is an AI-driven custom software development company with 10+ years of experience in delivering 300+ web and mobile solutions for global businesses.

Relia Software | Custom & AI-Driven Software Development Company

relia-software-company.webp

At Relia Software, we believe in the power of design thinking &ndash; a human-centered approach to problem-solving. It's about understanding your users' needs, brainstorming innovative solutions, and iterating on ideas to create exceptional software experiences.&nbsp;
Our Design Thinking Services empower you to uncover deep user needs, turn ideas into action, and create intuitive UX/UI. Are you ready to develop software that delights your users?

Stop guessing, start understanding. We use design thinking to crack user needs, craft intuitive interfaces, and build apps that win hearts.

thumbnail_design-thinking.webp

design-thinking.webp

Design Thinking

large_design-thinking-services.webp

medium_design-thinking-services.webp

small_design-thinking-services.webp

thumbnail_design-thinking-services.webp

design-thinking-services.webp

UX/UI Design Services

Relia Software is a top UX/UI Design Company that stands by to a design-driven approach. Checkout for our Web and Mobile Application UX/UI Design Services here!

UX/UI Design Agency | Web & Mobile App Design | Relia Software

MVP Development Services

Relia Software offers Minimum Viable Product (MVP) development services for businesses of all sizes. Our leading criteria are: agile, cost-effective, and value-loaded.

Relia Software offers Minimum Viable Product (MVP) development services for businesses of all sizes with criteria that are agile, cost-saving, and value-loaded.

MVP Development Company | Relia Software

Full-Stack Web Development Services

Relia Software offers a full-stack website development service to ensure a solid online presence of your business in the evolving digital landscape.

Web Development Company | Relia Software

Mobile apps are increasingly crucial in today's fast-paced society. They allow us to stay in touch, get the news, and get things done on the go.&nbsp;
At Relia Software, we understand the immense potential mobile apps hold for businesses like yours. Therefore, we offer comprehensive Mobile App Development Services to realize your vision. Our expert developers, designers, and strategists work with you to build a stunning mobile app with exceptional features and user experience.
Don't miss out on the mobile potential for your business growth. Let's chat about your app vision and see how we can help!

We build scalable, responsive applications that grow with you. Our experts handle everything, from user-friendly interfaces to robust back-end systems.

small_app-development.webp

thumbnail_app-development.webp

app-development.webp

Mobile App Development

large_mobile-app-development-services.webp

medium_mobile-app-development-services.webp

small_mobile-app-development-services.webp

thumbnail_mobile-app-development-services.webp

mobile-app-development-services.webp

Custom Mobile App Development Services

Relia Software specializes in custom mobile app development, creating holistic solutions that align with your unique business goals and target audience.

Custom Mobile App Development Company | Relia Software

Enterprise App Development Services

We design our project-based end-to-end development services for the enterprise. Relia holds the experience to deliver mobile products that are successful and consistent in results.

Enterprise App Development | Relia Software

Flutter App Development Services

Relia Software is a Flutter app development company with 10+ years of experience in mobile app development. We build robust Flutter solutions for clients.

Flutter App Development Company | Relia Software

iOS App Development Services

Over the last decade, Relia Software has built a reputation as a go-to iOS app development company, serving clients in various industries. Explore our services here!

iOS App Development Company | Relia Software

Android App Development Services

Relia Software offers a full spectrum of Android app development services to cater to your unique needs. We will help you launch your project on Apple platforms.

Android App Development Company | Relia Software

Cross-Platform App Development Services

Relia Software specializes in cross-platform app development, creating high-quality apps for Android and iOS devices. We use frameworks like React Native and Flutter.

Cross-Platform App Development Company | Relia Software

React Native App Development Services

At the forefront of React Native development, Relia Software delivers cutting-edge mobile apps for both Android and iOS platforms. Check out our React Native services!

React Native App Development Company | Relia Software

The future is intelligent, and artificial intelligence (AI) is at the forefront of innovation. At Relia Software, we help businesses leverage the power of AI to solve complex problems, automate tasks, and gain valuable insights. Our team of experienced developers, data scientists, and strategists collaborate closely with you to create intelligent solutions tailored to your unique needs.
Embrace the future with AI. Let's collaborate to bring your groundbreaking ideas to life and set your business on the path to success!

AI isn't sci-fi anymore. We build intelligent solutions that automate tasks, gain insights, and unlock new chances. Let's make your business smarter!

small_ai-development-icon.webp

thumbnail_ai-development-icon.webp

ai-development-icon.webp

AI Development

large_ai-development.webp

medium_ai-development.webp

small_ai-development.webp

thumbnail_ai-development.webp

ai-development.webp

Digital Transformation Consulting Services

At Relia Software, we offer comprehensive digital transformation consulting services, giving clients a technology-powered plan to improve business processes.

Digital Transformation Consulting Company | Relia Software

AI/ML Consulting & Development Services

Our AI/ML services can automate operations, improve customer interactions, use analytics, and future-proof business processes to stay relevant to the market and client needs.

AI/ML Consulting & Development Company | Relia Software

Chatbot Development Services

Relia Software creates smart chatbot that help businesses engage customers, save time, and automate support. Our solutions are designed to give smooth, human-like interactions across platforms.

Chatbot Development Company | Relia Software

With over a decade of experience, Relia empowers you with DevOps as a Service (DaaS) to streamline your software development lifecycle. We automate the entire delivery pipeline across top cloud platforms, enabling continuous integration and development (CI/CD) for faster deployments and smoother workflows.&nbsp;
Integrate your development and operations teams with cloud-based DevOps automation to achieve peak performance and effortless application onboarding. Partner with Relia and unlock the power of DevOps for your business!

Let&rsquo;s unleash the power of DevOps. We automate your software pipeline, smash deployment times, and keep your teams in sync &ndash; all on the cloud.

thumbnail_devops-service.webp

devops-service.webp

DevOps Services

large_devops-services.webp

medium_devops-services.webp

small_devops-services.webp

thumbnail_devops-services.webp

devops-services.webp

DevOps Automation Services

As a DevOps services company with over 11 years of experience, Relia may bring value to your product from start to finish.

DevOps Services And Solutions

Relia Software understands that building a top-notch development team can be challenging. Our Software Development Outsourcing Services offer a cost-effective and flexible solution to fulfill your project needs. We connect you with a pool of talented developers worldwide, optimize your development process, and achieve your business goals.
Need a full development crew? We've got you covered. Looking for specific expertise? We can source it. Our range of engagement models, from outsourcing to dedicated teams, gives you the perfect fit. Contact us today!

You want to build a top tech team? We will help you access global talent, optimize workflows, and achieve your goals &ndash; all under your budget.

thumbnail_offshore-team.webp

offshore-team.webp

Software Development Outsourcing

large_software-development-outsourcing.webp

medium_software-development-outsourcing.webp

small_software-development-outsourcing.webp

thumbnail_software-development-outsourcing.webp

software-development-outsourcing.webp

Offshore Development Center Services

For over a decade, Relia Software has been empowering businesses of all sizes and fields with robust and scalable Offshore Development Center (ODC) solutions.

Offshore Development Center Services | Viet Nam | Relia Software

Software Support & Maintenance Services

Relia Software offers superior software maintenance and support services for optimal efficiency, security, performance, and better user experience. Contact us!

Software Support & Maintenance Services | Relia Software

Dedicated Software Development Team Services

Relia Software specializes in building dedicated development teams that seamlessly integrate into your project, becoming a true extension of your in-house force.

Dedicated Software Development Team Services | Relia Software

IT Staff Augmentation Services

Relia has been a trusted partner in Staff Augmentation for 10+ years. We've a streamlined process to seamlessly integrate skilled experts into your existing team.

IT Staff Augmentation Services | Relia Software

Build-Operate-Transfer (BOT) Services

The Build-Operate-Transfer model (BOT model) lets you stay competitive and successful in the market. Your ODC team should be reliable to work with.

Build-Operate-Transfer (BOT) Services | Relia Software

Software Development Outsourcing Services

At Relia, we've spent over a decade cultivating a reputation for excellence in outsourced software development. Our weapon is a dream team of skilled developers.

Software Development Outsourcing Company | Relia Software

Software Quality Assurance & Testing Services

Relia Software is a dedicated Software QA & Testing Services provider with a proven track record of ensuring exceptional quality in our clients' applications.

Software Quality Assurance & Testing Services | Relia Software

Website is not only a digital brochure, but also the heart of modern businesses. Relia Software understands the critical role of web applications in connecting you to your customers and achieving your goals.&nbsp;
That's why we're your one-stop shop for web app development. Whether you need a custom application or a streamlined web presence, we have the expertise to deliver.&nbsp;
Don't settle for a website gathering dust &ndash; Let Relia turn your vision into a vibrant digital space, converting browsers into brand loyalists.

We build powerful web apps that connect you with customers, drive results, and launch your digital strategy into overdrive.

thumbnail_data-transformation.webp

data-transformation.webp

Web App Development

large_web-app-development.webp

medium_web-app-development.webp

small_web-app-development.webp

thumbnail_web-app-development.webp

web-app-development.webp

Custom Web App Development Services

Relia Software is the top web app development company. We offer great services for building robust web applications. Check out for our detailed services here!

Custom Web App Development Company | Relia Software

Ruby On Rails (RoR) Development Services

Relia Software develops Ruby On Rails custom web applications using cutting-edge custom setups and pre-designed technologies. Contact us!

Ruby On Rails (RoR) Development Company | Relia Software

.NET Development Services

Relia Software - Leading Dot Net Development Company in the USA & Vietnam. Offers the best .net development services. Hire our top Dot Net Developers!

.NET Development Company | .Net Services | Relia Software

NEXT.JS Development Services

Relia Software is your one-stop shop for powerful Next.js development services. Our elite Next.js developers craft web apps that propel your business forward.

Next.js Development Company | Relia Software

Angular Development Services

Relia Software is a top software development company in Vietnam with recognized Angular expertise. We use Angular to deliver innovative products for businesses.

Angular Development Company | Relia Software

Golang Development Services

Relia is a reputed Golang Development Company that promises to ensure a scalable, sound and user-friendly development of your application with quality and performance guaranteed.

Golang Development Company | Relia Software

Node.js Development Services

Relia is the best Node.js development company in Vietnam. Learn about our expertise, custom solutions, full-cycle development services, and more. Transform your web development with our top-notch Node.js services.

Node.js Development Services | Relia Software

React Development Services

Relia Software is a leading ReactJS Development Company based in the USA & Vietnam offers the best react development services. Hire Top ReactJS Developers!

React.js Development Company | Hire Top React.js Developers

Python App Development Services

Relia Software boasts over 10 years of combined experience and a proven track record of delivering a wide range of successful Python projects for clients worldwide.

Solutions We Provide

Solutions We Provide

Luong Xuan Tri

About Luong Xuan Tri

Articles by Luong Xuan Tri