Containers are in vogue lately and for excellent reason. They solve the computer architecture’s most critical problem – running reliable, distributed software with near-infinite scalability in any computing environment.
They have enabled an entirely new discipline in software engineering – microservices. They have also introduced the package once deploy anywhere concept in technology. Combined with the cloud and distributed applications, containers with container orchestration technology have led to a new buzzword in the industry – cloud-native – changing the IT ecosystem like never before.
Before we delve into more technical details, let’s understand containers in plain and simple words.
Containers derive their name from shipping containers. I will explain containers using a shipping container analogy for better understanding. Historically, because of transportation improvements, a lot of stuff moved across multiple geographies. With various goods being transported in different modes, loading and unloading goods was a massive issue at every transportation point. In addition, with rising labor costs, it was impractical for shipping companies to operate at scale while keeping prices low.
Also, it resulted in frequent damage to items, and goods used to get misplaced or mixed up with other consignments because there was no isolation. There was a need for a standard way of transporting goods that provided the necessary isolation between consignments and allowed for easy loading and unloading of goods. The shipping industry came up with shipping containers as an elegant solution to this problem.
Now, shipping containers have simplified a lot of things in the shipping industry. With a standard container, we can ship goods from one place to another by only moving the container. The same container can be used on roads, loaded on trains, and transported via ships. The operators of these vehicles don’t need to worry about what is inside the container most of the time. The following figure depicts the entire workflow graphically for ease of understanding:
Figure 1.2 – Shipping container workflow
Similarly, there have been issues with software portability and compute resource management in the software industry. In a standard software development life cycle, a piece of software moves through multiple environments, and sometimes, numerous applications share the same OS. There may be differences in the configuration between environments, so software that may have worked in a development environment may not work in a test environment. Something that worked in test may also not work in production.
Also, when you have multiple applications running within a single machine, there is no isolation between them. One application can drain compute resources from another application, and that may lead to runtime issues.
Repackaging and reconfiguring applications is required in every step of deployment, so it takes a lot of time and effort and is sometimes error-prone.
In the software industry, containers solve these problems by providing isolation between application and compute resource management, which provides an optimal solution to these issues.
The software industry’s biggest challenge is to provide application isolation and manage external dependencies elegantly so that they can run on any platform, irrespective of the OS or the infrastructure. Software is written in numerous programming languages and uses various dependencies and frameworks. This leads to a scenario called thematrix of hell.
