{"id":91413,"date":"2019-09-06T13:05:32","date_gmt":"2019-09-06T18:05:32","guid":{"rendered":"https:\/\/wpengine.com\/?p=91413"},"modified":"2020-02-12T20:50:03","modified_gmt":"2020-02-13T02:50:03","slug":"a-high-level-guide-to-containerization","status":"publish","type":"post","link":"https:\/\/wpengine.com\/case-studies\/a-high-level-guide-to-containerization\/","title":{"rendered":"A High-Level Guide to Containerization"},"content":{"rendered":"\n

The concept of small, lightweight execution environments, known as containers, has been a phenomenon in computer science for more than a decade. Over the past ten years, this technology has grown rapidly in popularity, and software such as Docker<\/a> and Kubernetes<\/a> have arrived on the scene to support the \u201ccontainer revolution.\u201d Still, even with its increase in adoption and popularity, containerization remains a mystery to many. In this guide, we\u2019ll walk you through containers at a high level. Armed with this knowledge, you can approach the actual implementation of containers with more confidence and clarity.  <\/p>\n\n\n\n

Containers: An Overview <\/strong><\/h2>\n\n\n\n

Within an operating system (OS), let\u2019s say Linux<\/a>, users have the ability to run processes. These processes share a number of qualities associated with the space they take up in the operating system: address space, identification numbers, etc. Operating systems are designed to allow a number of processes to run concurrently. That\u2019s all fine and well, but what if you\u2019d like to isolate certain processes? In the most basic sense, a container creates an environment where an isolated process can run. Now, within that isolated space, you can own process space, own network interference, install packages, run services, and tinker with routing. <\/p>\n\n\n\n

That Sounds Like a VM, What\u2019s the Difference? <\/strong> <\/h2>\n\n\n\n

While working with containers can have the feeling of working in a separate VM, it\u2019s important to know the difference. While containers enable a way to virtualize an OS so that multiple workloads can run on a single OS instance, VMs allow the hardware to virtualize to run multiple OS instances. A container uses the host kernel, can\u2019t run multiple OSes, and can\u2019t have its own modules. Once applications are containerized, they are able to be deployed on any infrastructure (virtual machines, public cloud infrastructure, bare metal, etc.). <\/p>\n\n\n\n

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Virtual Machines vs. Containerization. Image Source: Docker Blog<\/a>. <\/figcaption><\/figure>\n\n\n\n

What Does That Look Like? <\/strong><\/h2>\n\n\n\n

If you were to put a shell on that process, you\u2019d find a process with its own unique namespace<\/strong>. Therefore, you\u2019re only seeing the processes that run in that specific container. In addition to the namespace, containers allow you to add cgroups<\/strong> that restrict the capabilities of the process. Cgroups can do a number of things including limit the amount of CPU your process can use or restrict the system calls the process can make. <\/p>\n\n\n\n

Diving Deeper: Types of Cgroups and Namespaces <\/strong><\/h3>\n\n\n\n

Namespaces:<\/strong><\/h4>\n\n\n\n