3 minutes

You don’t use immutable infrastructure in your DevOps development yet? In this article, we will explain to you what is precisely immutable infrastructure and why you should implement it to master your DevOps environment and deployments!

Immutable infrastructure: a simple definition

Mutable or immutable infrastructure? That is the question. Both can be used to manage your project infrastructure. And we couldn’t speak of one without talking about the other. So we explain the properties of the two of them!

Mutable infrastructure

The word mutable describes anything that is capable of change. By extension, your infrastructure is mutable if you can update it, for example modify in-place its properties, and still use it to run your application. 

Mutable infrastructure - Definition

Immutable infrastructure

In opposition, you can’t modify an immutable infrastructure. To put it simply, once your services are in-place, you can’t update them! If you want to apply changes to your server, you need to use a new version of it.

Immutable infrastructure - Definition

Why mutable infrastructure isn’t the right choice? 

When you look only at the definition of mutable and immutable infrastructure, it seems easier to use the mutable one. And sure, it is easier to implement a mutable infrastructure! Changes can be added more quickly. But it is so much harder to maintain

For example, if your project has several servers, each one of them will have its own configuration. When you will add the changes you need on those servers, you might not have the same final solution on all of them! This is called a “configuration drift”. It makes it really hard for your team to know the state of your servers and the behavior of each of them.

If we look at our drawing of mutable infrastructure, this is what really happens when you apply changes on your servers:

Comparison of mutable and immutable infrastructure

Once you have this configuration, you can’t affirm your application will act the way it should. You will also have a hard time to find the technical issues and reproduce them, because each one of your servers has its own behavior. More complications and work for your teams while the trust in your system falls… This is not really great, don’t you think?

Immutable infrastructure in DevOps

Now that we can differentiate mutable and immutable infrastructures, let’s see how the second one can improve your deployments and help you boost your DevOps processes!

Why using this server’s structure in DevOps?

Immutable infrastructure is a must-have for your DevOps’ team. Actually, it works well with clouds deployments, from which it can pull as many benefits as possible. And its performances are optimum paired with containerization

Containerization (with Docker if I can only name one) is a basis of DevOps, as well as the automatization of process!

The benefits of immutable infrastructure

While using immutable infrastructure, you will gain many benefits for your DevOps projects.

📌 Because you are using a new service every time you need to apply changes, you will completely avoid configuration drift. And in case of issue in your new server, you only have to delete the instance causing the error and redirect your application to your old servers. On top of that: it can be automated!

📌 You will increase your scalability and finally be sure what you have in production. This way, you’ll ensure a better control of your application and its deployments.

📌 The tests for quality are more reliable at all your project’s steps: development, test and production!

📌 Finally, immutable infrastructure is affordable, and your team can easily create new servers using modern DevOps!

Some prerequisites before getting started

As you understand it, immutable infrastructure will ensure a better deployment for your application. But to certify the proper functioning of this infrastructure, they are some steps that should be thought ahead of your development. For example, your application must be stateless if you want your shift from one server to another to go smoothly!