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Posted June 23, 2015

Immutable Infrastructure


Server hugging is a disease

In the dark days before immutable servers, people clung to servers and treated them as untouchable gold. These people still exist, and hang onto their servers instead of moving into the Cloud. They are server huggers. What does the term “server hugger” mean? Its the desire to “touch” servers, “reboot” them on a regular basis, constantly upgrading really old software and hardware needed, etc. Before anyone can help cure the problem, server huggers have to admit it. They struggle to let go and embrace the Cloud. The thought of trashing servers and disposable components is absolutely frightening to server huggers, especially the (unfounded) fear of losing control. Server virtualization and Cloud computing will make these types extinct in the near future. Let’s start unshackling your servers!

Unshackle your servers

It’s all within reach. Start the transition today! Before the unshackling can begin, you need to build a Cloud architecture strategy for predictability, scalability, and automated recovery. The next step is huge: getting buy-in from development and operation teams. It starts by presenting your strategy and demonstrating the importance of virtual servers and containers to make it possible. Let’s start setting your dedicated servers free! Start small and expand slowly! Always look for ways to simplify your infrastructure — build, measure, and learn. Some people like to learn by jumping directly into writing their own code and others may seek experts. Choose your own adventure! You are making giant leaps towards immutable servers. Do not treat virtual machines in a static way.

Make infrastructure part of the application

What is an immutable infrastructure? It is made up of immutable components that are replaced at every build and deployment, with changes made only by modifying a versioned definition, rather than being updated in place. So when building infrastructure as part of the application, the following three words immediately come to mind:

  • Predictable - Promote the exact same artifact that you tested into your production system.

  • Scalable - Meet user demand so the application can automatically grow or shrink your servers.

  • Recoverable - Using Auto Scaling Group (ASG) should detect the instance termination and automatically bring up a new, identically configured instance. Netflix has taken this a step further with its Chaos Monkey, a service which randomly knocks out production services, forcing developers to build easily recoverable infrastructure.

Why is this important? Without this infrastructure, you can spend hours each week manually maintaining and modifying network configurations and the problems will still continue to grow. It's just not a smart use of employee resources. There are many benefits and advantages to moving your infrastructure to the Cloud. Let’s start with the possible cost savings — You can pay for how much you consume, instead of having to invest heavily in data centers and servers. Next, stop guessing your infrastructure capacity and speed needs. You can access as much or as little as you need, and scale up and down as required in only a few minutes. Another plus — Where it matters the most, you can easily deploy your application in multiple regions around the world in a few minutes. This means you can provide a lower latency and better experience for your customers. To ease the management of your Cloud infrastructure, you will benefit from many available Cloud infrastructure automation tools. When all is said and done, you can release the entire stack faster to market with greater test coverage since you’ve helped the server huggers move on.


The Cloud! Start turning your infrastructure into code. Enable developers to build, test and deploy applications on highly scalable and reliable infrastructure. Think about what you want the servers to run, not how to run them. When starting the shift to immutable infrastructure, consider these steps:

  • Start small

  • Get buy-in

  • Implementation

  • Reinforce best practices and automate the deployment

  • Adopt automation across the deployment process

  • Build on your successes, so you can begin to reap the benefits of immutable servers

The takeaway:

  • Get over static servers, and treat servers as a commodity.

  • Treat all our virtual servers as immutable.

  • The deployment model is to terminate the instance/container and start over from step one: build a new image and throw old instances away.

  • Script your orchestration, and expand your ability to test more and build more comprehensive grids.

  • When designing your Cloud infrastructure from scratch, it makes sense to start small and expanded slowly — don’t try to “boil the ocean.”

  • The Cloud has made immutable infrastructure possible.

Greg Sypolt (@gregsypolt) is a senior engineer at Gannett and co-founder of Quality Element. He is a passionate automation engineer seeking to optimize software development quality, coaching team members how to write great automation scripts, and helping testing community become better testers. Greg has spent most of his career working on software quality - concentrating on web browsers, APIs, and mobile. For the past 5 years he has focused on the creation and deployment of automated test strategies, frameworks, tools, and platforms.

Jun 23, 2015
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