I put together a few starter notes on things you should delve into and understand before working with infrastructure related tooling, like Ansible, Terraform, or similar tools. If you think I've missed any do ping me @Adron and let me know your thoughts on other additions. The first starter items I'd list as the following.

• Computer Networking - Basic understanding of what an IP number is, how they're assigned via DHCP vs. static, and related basic TCP/IP knowledge. Also, it is helpful, yet not necessary to understand the idea behind CIDR ranges and related network concepts about addressing also.
• Basic Linux or Unix CLI Commands - Commands like; ls, mv, rm, cp, mkdir, rmdir, wget, curl, ping, traceroute, ifconfig, nslookup, vi, kill, chown, whoami, su, chmod, chown, chroot, cat, env, echo or tail. All these commands aren't used in the course, but they're fundamental for building and troubleshooting any infrastructure and related environments and systems in the future.
• Basic Scripting and Language Constructs - Things like if-then-else, while loops, and related programming constructs for use in scripting languages like Bash or Powershell.

With those basics covered, here are some of the things that help shape one getting a good understanding of what Terraform, Ansible, Chef, Puppet, and related tooling is.

• Ansible - https://www.ansible.com/ - Ansible is a tool that helps provision, deploy, and apply compliance of infrastructure through configuration management. It was purchased by Red Hat and is now in their stable of tools.
• Puppet - https://puppet.com - Puppet provides discovery, management of infrastructure, and mutable updates and changes to that infrastructure. It's also important to note that Puppet is made up of a number of individual tools.
• Chef - https://www.chef.io - Chef is one of the leading companies that helped to start and push the DevOps narrative in the industry. It is a tool that provides a programmatic DSL, configuration, and related ways to create and manage one's infrastructure. Chef, similarly to Puppet, is also made up of a number of individual tools, and the company itself continues to develop a number of tools within the space.
• CloudFormation - https://aws.amazon.com/cloudformation/ - AWS CloudFormation provides a way to describe and provision infrastructure resources in AWS. This is used as the single source of truth for all the cloud resources when used.

I talk about and use Terraform a LOT so let's talk comparisons with these tools and Terraform for a moment. Terraform compares with configuration management tools like Chef and Puppet in it's abstract use of provisioners to setup resources such as the network, instances, and other things within the cloud platform being deployed to. Terraform operates at a higher level abstraction of to where the platform's resources are deployed. By doing this Terraform can be used with, or even similar to, Chef and Puppet. These tools can complement each other or work independently.

In comparison to CloudFormation, the differences start out with the cross-platform and multi-cloud platform capabilities of Terraform versus CloudFormation being limited to only AWS. Terraform also draws out a more stage based approach for each execution. This gives more control over where, when, and why Terraform can replace or be used in conjunction with CloudFormation or any of the tooling mentioned.

These Tools, Immutable Infrastructure?

With these tools, one key ideal among them is the pattern of immutable infrastructure. Defining immutable infrastructure, in short, is the idea you create and operate your infrastructure using the programming concept of immutability. Once you instantiate something it is never changed. It is replaced with another instance of making changes or ensuring proper behavior.

The effect of immutable infrastructure is that it provides stability, efficiency, and fidelity to your applications through automation and the use of successful patterns from software development.

• Increasing operational complexity can be dealt with. With the complexity of distributed systems like Cassandra, Kubernetes, and others immutable infrastructure practices have become the defacto way to manage this extra complexity and volume of resources.
• Snowflake components are removed. Mutable maintenance methods enable this idea of snowflake components like bespoke, handcrafted, and artisanal servers and infrastructure. Immutable infrastructure eliminates the possibility of these outliers and increases repeatability within systems and infrastructure.
• Increased threat identification and mitigation of harm. With immutable infrastructure the number of knowns, at the start and completion of infrastructure usage, increases as needed. Need debugging information, a single way to gather that can be provided, set by policy, and enforced with immutable infrastructure in a way that simply can't be with artisanal infrastructure.
• Integration and seamless continuous integration and deployment. With immutable infrastructure, the enforcement and enablement of integration, and deployment of solutions, is largely self-fulfilled. To deploy through automation requires integration and deployment, for immutable infrastructure automation for integration and deployment is needed, and, in turn, enables the other.
• Reproducibility is inherent in the system. The ability to take an environment and all of its nuances, recreate that environment among complex orchestrations that is flawless with immutable infrastructure. This gives us the ability to set audit points, track, and log data accordingly to the entire environment.

That's my wrap up for getting into and gaining a more holistic idea of what immutable infrastructure is and what tools work to help attain this level of infrastructure development and usage. Until next time.

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