What is Immutable Infrastructure? Best Practices with Examples

What is Immutable Infrastructure ? Best Practices with Examples. This concept is extremely popular in the cloud realm as it is transforming the way software is built, shipped and managed. Immutable infrastructure, in fact, is speeding up the software development process.

This article looks at what the concept is and how its benefits the organization and is it going to be a new standard for software development.

What is Immutable Infrastructure

With the rise of cloud services, immutable model infrastructure has come into prominence. The concept refers to servers or VMs that are never amended after deployment.

In immutable environment  model, the servers work differently. Servers are never modified after they’re deployed. If something needs updating the new server is built from an image with the appropriate changes replacing the old one. 

Immutable Infrastructure model

Steps you take when servers that are never are changed after deployment but need updating:

  • Validate the server.


  • Build a new server from the standard image, with changes and packages.


  • Facilitate the new server to replace the existing one .


  • Decommission the existing or old server.

Every server update is exact, timestamped and redeployed. The old servers are still available for rolling back your environment. With this change, you almost remove troubleshooting for broken instances. Moreover, thanks to the OS level virtualization in computing, the new servers are swift in deploying.

This concept helps to speed up deployment. But is the actual performance augmented? Actually, yes. Performance in this infrastructure can occasionally be slower than the mutable infrastructure. However, the chances are very rare. What is important is horizontal scaling becomes easier, supporting rapid environment building with faster deployments and more VM machines.

Benefits of Immutable Infrastructure

One of the most significant benefits of this infrastructure is that it helps engineers to replace servers that are problematic with ease. It can be done by keeping all the applications running with minimal effort.

The other benefits of immutable infrastructure include:

  • Instead of logging in via SSH into the server and updating the software version, every change in the application starts with a software push to the Git code repository.
  • Simplified and reliable deployments. Cloud services make auto scaling effortless
  • Fault tolerance. Deployment offers fast rollback and recovery processes in case needed.
  • Testing and quality analysis are very consistent, from development to test to production.


  • It gives a compatible environment to the servers.
  • Resolve issues faster. All you need to do is delete the instance that is creating the fallacy. It thus leads to fewer support calls.
  • No scope for configuration drift, snowflakes and errors. You will know the exact state of the server as long as it is running. This helps in avoiding unexpected events.
  • It takes the most advantage of the cloud, hence it is legitimate DevOps functions.
  • Simplified toolchain.

When you improve efficiency, consistency and reliability in a deployed environment and recreate the environment within minutes, it becomes invaluable. With mutable servers, it is not possible. Mutable servers increase operation time and cost, delaying your time to market severely. Immutable servers encourage simple development.

Pros of immutable infrastructure:

  • There are no server updates which can be problematic at times. That means lower IT complexity and failures.
  • Reduces support calls: it resolves the issues by deleting the instance that causes the problem.
  • Improves security and incident resolution: incident becomes an exception. The exception problem is solved by machine learning (Weka)from manual rules to automatic.
  • Cost savings by encouraging reduced hardware usage.
  • Configuration management can run faster than manual system.
  • Less dependency on third party resources at deployment.
  • Requires a learning curve due to new tools. It can make the initial adoption challenging  at first. The learning challenges are due to learning the new technology.

Best Practices for Immutable Infra

To take all the benefits of immutable infrastructure, you will have to use the tools and processes more efficiently. The best practices include:

Examples of Immutable Infrastructure Tools

Below are some examples of using the tools and services for accomplishing immutable infrastructure. However, the list is only includes few. There is many more.

Why is it DevOps tool?

DevOps adopt this infrastructure concept as it makes creating new servers affordable and accessible. If there is a requirement for improvements or updates, you have to replace the entire server and not change a part of it.

Immutable infrastructure is very much in tune with the idea of infrastructure as a code. You can do all the planning of components like networking, instances and security with infrastructure as a code. Once done, you can push it into your dev ecosystem. It becomes easy to test and prod as you promote them in the dev environment and consistently repeat these steps.

It ensures that whatever the ecosystem the developers work in, there will always be a consistent environment. As a result, they will not have to worry about it while they are deploying applications.

DevOps tools and culture is to work together to achieve supply development with continuous delivery. And you know continuous delivery drives immutable infrastructure.

Implementation Details

Immutable infrastructure has some requirements while it is implemented. To implement it without automation, software design, or tooling principles by simply following the critical principles of immutability is possible, however, the components mentioned below are always recommended for practicality:

Servers in a cloud computing ecosystem: It could be other virtualized environments like containers, but that would change some of the requirements below. The main point here is to have isolated instances with rapid provisioning from custom images as well as automated management for creation and destruction through an API or similar.

Total automation of the entire deployment pipeline: It includes post creation image validation. Setting up this automation significantly adds to the upfront cost of implementing the infrastructure. However, it is a one time cost that settles down quickly.

Service oriented architecture: This separates your infrastructure into modular and logically distinct units that communicate over a network. This component allows you to take full advantage of cloud computing’s features that are service oriented (e.g. IaaS, PaaS).

Stateless, volatile application layer: This includes your immutable servers. Everything here can be destroyed and re built quickly at any time (volatile) and without any data loss (stateless)

Persistent data layer: This includes two components:

  1. Centralized logging includes additional details about a server’s deployment, like image identification via Git commit SHA or via a version. Since servers are disposable in immutable infrastructure, storing metrics and logs externally allows debugging even when shell access is restricted, or the server has been destroyed.


2. External data stores are for databases and other stateful data, like cloud databases and block storage. When your server is volatile, you cannot rely on local storage. You would need to store the data elsewhere.

Immutable infrastructure, together with containers, can provide the flexible elastic infrastructures needed for for DevOps work schedules..

There are many ways to implement this concept. Choosing one option depends on familiarity, personal preference, how much of your infrastructure you want to build on your own and how much you want to rely on paid service.

What is Immutable Infrastructure ? Best Practices with Examples Conclusion

This column covered what immutable infrastructure is and what are the best practices. Immutable infrastructure tools brings many security benefits, less errors or error discovery at the beginning, reduced attacks and less opportunities for human error in scripts. It will make you think in terms of automation and stateless servers and apps.


Knowing when to consider moving to immutable infrastructure is not easy, and there can be no one clearly defined inflection point.

One way to start is by implementing some of the design practices recommended above in this article if you work primarily in a mutable infrastructure environment. This will make the transition to immutable infrastructure simple in the future.

If you are already working in an immutable infrastructure environment, this can be an excellent time to evaluate how immutability can enhance your infrastructure.

If you have a mutable infrastructure and you find yourself hitting scaling issues or feeling frustrated with the clumsiness of your deployment process, that can be a good time to start evaluating how an immutability could improve your infrastructure.

Avatar for Hitesh Jethva
Hitesh Jethva

I am a fan of open source technology and have more than 10 years of experience working with Linux and Open Source technologies. I am one of the Linux technical writers for Cloud Infrastructure Services.

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