Understanding the need for containerization

You may have experienced a conversation like this at your office or school:

Developer: “Here’s the new application. It went through weeks of testing and you are the first to get the new release.”

….. A little while later …..

User: “It’s not working. When I click the submit button, it shows an error about a missing dependency.”

Developer: “That’s weird; it’s working fine on my machine.”

Encountering such issues can be incredibly frustrating for developers when they’re deploying an application. Oftentimes, these problems occur due to a missing library in the final package that the developer had on their own machine. One might think that a simple solution would be to include all the libraries in the release, but what if this release includes a newer version of a library that replaces an older version, which another application may still rely on?

Developers have to carefully consider their new releases and the potential conflicts they may cause with existing software on users’ workstations. It becomes a delicate balancing act that often requires larger deployment teams to thoroughly test the application on various system configurations. This situation can result in additional work for the developer or, in extreme cases, render the application completely incompatible with an existing one.

Over the years, there have been several attempts to simplify application delivery. One solution is VMware’s ThinApp, which aims to virtualize an application (not to be confused with virtualizing the entire operating system (OS)). It allows you to bundle the application and its dependencies into a single executable package. By doing so, all the application’s dependencies are contained within the package, eliminating conflicts with other application dependencies. This not only ensures application isolation but also enhances security and reduces the complexities of OS migrations.

You might not have come across terms like application packaging or application-on-a-stick until now, but it seems like a great solution to the infamous “it worked on my machine” problem. However, there are reasons why it hasn’t gained widespread adoption as anticipated. Firstly, most solutions in this space are paid offerings that require a significant investment. Additionally, they require a “clean PC,” meaning that for each application you want to virtualize, you need to start with a fresh system. The package you create captures the differences between the base installation and any changes made afterward. These differences are then packaged into a distribution file, which can be executed on any workstation.

We’ve mentioned application virtualization to highlight that application issues such as “it works on my machine” have had different solutions over the years. Products such as ThinApp are just one attempt at solving the problem. Other attempts include running the application on a server using Citrix, Remote Desktop, Linux containers, chroot jails, and even virtual machines.