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What Is Immutable Infrastructure?
Immutable infrastructure is a model of software management where components are replaced rather than updated. In simpler terms, once an instance is deployed, it is never modified. If an update or change is required, a new instance is created from a common image, and the old instance is destroyed.
The idea behind this approach is to eliminate the inconsistencies that can arise from updating existing components. By treating infrastructure as code, we can ensure that our environments are consistent, reliable, and easily replicable. This reduces the risk of unexpected issues cropping up due to changes in the environment, and makes it easier to manage and scale our infrastructure.
This concept is not entirely new and has its roots in the manufacturing industry, which transitioned from mutable assembly lines to immutable, single-use molds to increase efficiency, reduce errors, and simplify the production process. Similarly, in the world of IT, immutable infrastructure provides a way to manage our servers with the same efficiency and reliability.
Mutable vs. Immutable Infrastructure: What’s the Difference?
Change Management
In a mutable infrastructure, change is constant. Servers are continuously updated and modified to accommodate new features, fix bugs, or enhance performance. While this allows for flexibility, it also introduces a certain level of unpredictability as each change can potentially introduce new issues or conflicts.
On the contrary, in an immutable infrastructure, changes are handled differently. Instead of modifying existing servers, new ones are spun up to incorporate the required changes. The old servers are then phased out and replaced with the new ones. This approach ensures that the system remains in a known, stable state, reducing the risk of unforeseen issues and facilitating easier troubleshooting.
Configuration Drift
Configuration drift refers to the phenomenon where servers in an environment become more and more different over time due to updates, changes, and manual intervention. This is a common issue in mutable infrastructure, leading to inconsistencies that can cause failures and other unforeseen issues.
Immutable infrastructure, on the other hand, prevents configuration drift by design. Since servers are replaced instead of modified, the environment remains consistent. This simplifies management and maintenance, and reduces the chances of unexpected issues.
Maintenance Overhead
Managing a mutable infrastructure can be complex and time-consuming as it requires continuous monitoring, troubleshooting, and manual intervention. Additionally, it demands a high level of expertise to handle the complexities and challenges that come with constant change.
Immutable infrastructure significantly reduces maintenance overhead. Since servers are replaced instead of modified, there is less need for manual intervention. Moreover, because the infrastructure remains in a known state, troubleshooting becomes easier and more straightforward.
4 Benefits of Immutable Infrastructure
Let’s summarize the key benefits of immutable infrastructure:
- Consistency and reliability: Since servers are replaced instead of modified, the infrastructure remains in a known, stable state. This eliminates the risk of unexpected issues arising from changes or inconsistencies in the environment.
- Enhanced security: Since the servers are not modified after deployment, the attack surface remains constant and predictable. This makes it easier to secure the infrastructure and detect any anomalies or breaches. In the event of a security incident, a new, clean instance can be deployed quickly and easily, minimizing the impact.
- Simplified management and debugging: Since the infrastructure remains in a known state, troubleshooting becomes easier and more straightforward. Errors can be isolated and rectified more efficiently, reducing downtime and improving service availability.
- Scalability and performance: Since new instances can be spun up quickly and easily, it’s possible to scale up or down to meet demand. Additionally, by eliminating the unpredictability associated with changes and updates, performance can be optimized and maintained at a consistent level.
Learn more in our detailed guide to IaC security (coming soon)
Key Components of Immutable Infrastructure
Infrastructure as Code (IaC)
One of the pillars of immutable infrastructure is Infrastructure as Code (IaC). IaC is the process of managing and provisioning data center resources through machine-readable definition files, rather than physical hardware configuration or interactive configuration tools. It is essentially a way to automate your infrastructure setup.
IaC offers several benefits that make it an essential component of immutable infrastructure. First, it enables version control for your infrastructure setup. This allows you to track changes, roll back to previous configurations, and keep your infrastructure consistent across different environments.
Moreover, IaC allows for better collaboration among team members. Everyone can see the infrastructure setup and make changes if necessary. It also eliminates the risk of manual errors, as everything is automated.
Containers and Orchestration
Another key component of immutable infrastructure is the use of containers and orchestration. Containers are lightweight, standalone, executable software packages that include everything needed to run a piece of software, including the code, runtime, system tools, libraries, and settings.
Orchestration, on the other hand, involves managing the life cycles of containers, especially in large, dynamic environments. Kubernetes is a popular tool for container orchestration, and it automates the deployment, scaling, and management of containerized applications.
The use of containers and orchestration in immutable infrastructure provides several advantages. Firstly, containers are isolated and consistent, ensuring that the software runs the same way in any environment. Secondly, containers are lightweight and start quickly, making them ideal for scaling applications. Lastly, orchestration tools like Kubernetes automate the management of containers, making it easier to manage large-scale applications.
CI/CD
Continuous Integration/Continuous Deployment (CI/CD) is a vital part of immutable infrastructure. CI/CD is a method to frequently deliver apps to customers by introducing automation into the stages of app development. The main practices that make up CI/CD are continuous integration, continuous delivery, and continuous deployment.
CI/CD bridges the gaps between development and operation activities and teams by enforcing automation in building, testing, and deployment of applications. It lets developers automate tests and build processes to quickly find and identify bugs and improve software quality.
In the context of immutable infrastructure, CI/CD allows for rapid and reliable delivery of new software releases. Developers can easily integrate new code and features, test them, and deploy them to production as immutable artifacts, all in an automated fashion.
Learn more in our detailed guide to IaC tools (coming soon)
4 Tips for Immutable Infrastructure Success
Here are a few tips for success when running immutable infrastructure.
1. Version Everything
In an immutable infrastructure, it’s crucial to version everything. This includes your infrastructure code, your application code, and even your data.
Versioning your infrastructure code allows you to track changes over time, roll back to previous configurations if necessary, and ensure consistency across different environments. This is a fundamental aspect of Infrastructure as Code.
Versioning your application code allows you to keep track of different versions of your application, roll back to previous versions if necessary, and manage dependencies effectively.
Versioning your data, on the other hand, can be more challenging, but it’s equally important. This could involve implementing a data versioning system, using a database that supports versioning, or simply keeping backups of your data.
2. Keep Data Separate from Application and Infrastructure
Another best practice for implementing immutable infrastructure is to keep your data separate from your application and infrastructure. This is because your data is mutable—it changes over time—while your application and infrastructure should be immutable and should not change after they are deployed.
Keeping your data separate from your applications and infrastructure allows you to update and scale each component independently. It also makes it easier to back up and restore your data, as you don’t have to worry about the state of your application or infrastructure.
You can achieve this separation by using different storage solutions for your data, such as databases, data warehouses, or cloud storage services. You should also implement data access controls to ensure that only authorized applications and services can access your data.
3. Implement Strong Access Controls
When your infrastructure is defined as code and stored in a version control system, it’s crucial to control who has access to it. Unauthorized access to immutable infrastructure tooling can be catastrophic, because attackers can use it to tamper with your entire environment.
You should implement role-based access control (RBAC) to ensure that only authorized individuals can make changes to your infrastructure. This can help prevent unauthorized access and reduce the risk of accidental or malicious changes to your infrastructure.
You should also regularly review and audit your access controls to ensure they are still appropriate and effective. This can help you identify any potential weaknesses and address them promptly.
4. Plan for Rollbacks
Finally, it’s crucial to plan for rollbacks when implementing immutable infrastructure. Even with careful planning and testing, things can still go wrong, and you need to be able to quickly revert to a previous state if necessary.
You should have a rollback strategy in place that allows you to quickly and easily revert to a previous version of your application or infrastructure. This could involve keeping backups of your previous versions, using a version control system, or using a tool that supports automated rollbacks.
You should also regularly test your rollback process to ensure it works as expected. This can help you identify any potential issues and address them before they become a problem.
Immutable Infrastructure with Codefresh
Codefresh is built for modern tools with support for flexible frameworks. Most infrastructure as code tools are available as docker images and can be seamlessly integrated into Codefresh pipelines – this happens to be a very common pattern for many of our customers. Learn more about how you can easily execute a custom freestyle step with any of these images here.
If you are interested in managing Codefresh resources with Terraform, we also have you covered there! The Codefresh Terraform provider can manage the creation, updates, and removal of Codefresh resources allowing you to utilize your current infrastructure as code workflows without compromises.