What are Containers and Why Do You Need Them?

Containers are a solution that any IT professional can expect to become familiar with in the coming years, if they aren't already. Containerization is often said to be the future of software development, enabling teams to work faster and deploy their solutions more efficiently.

Indeed, some of the world's biggest companies now rely on these to keep their operations moving. Google, for example, notes that containers underpin everything the company does, from Search and Gmail to YouTube, and describes them as a better way of developing and deploying applications.

Other firms seem to be getting the message as well. According to figures from 451 Research, the application container market is set to be worth $2.7 billion by 2020, up from just $495 million in 2015.

Problems arise when the environment where you want to run your software is neither identical nor supportive to the software. For instance, you want to run your tests on Debian but the production is on Red Hat; you want to carry out your test using Python 2.6 but in production, it’s going to run on Python 3. Perhaps you will depend on the behavior of a particular version of an SSL Library but an entirely different one will be installed.

Imagine what the outcome would be.

What could be the cause of this problem? Whatever the problem is, whether it’s the different topology network or different security policies and storage, the fact remains that the software has to run on it.

And this is where containers play a great role.

What are containers?

Simply put, containers make it easier for developers to understand that their software will run reliably, no matter the location it is deployed and this makes the developing of software very fast, and the testing it for likely errors very simple.

Essentially, a container is a lightweight, isolated package that includes an application or applications, along with all the dependencies they need in order to run successfully, regardless of what computing environment they are used in.

This includes everything necessary for it to work:

• An application and all its dependencies
• Libraries
• Utilities and configuration files
• System tools
• A runtime environment.

By bundling everything together into a single package, you end up with a small, portable system that contains only the minimum resources needed for an application to successfully execute. So, by containerizing the software environment and platform as well as its dependencies, the differences in operating system distribution are taken away.

With all the essentials in one place, a container can then be easily moved to wherever it is required, without worrying about the target environment affecting the application. For example, a container can be moved from a physical desktop to a virtual machine, or from a testing to a production environment without any issues being created by the change in location.

Containers vs virtualization

Containers and virtual machines are mutually exclusive as they possess different properties, qualities, and advantages, but for some, containerization may sound as if it has a lot in common with virtualization. Whilst there are a few similarities between the two, containers differ from virtual machines in several key ways.

Like containers, virtualization lets you package applications together with their libraries and dependencies to crate an isolated environment for running software. But containers virtualize at a different level of the stack and offer a much more lightweight approach than virtual machines.

Whereas virtual machines virtualize the hardware stack, with each machine coming with its own complete server stack, including CPU, storage, network adapters, BIOS and operating system in addition to the application itself and all its dependencies.

Containers, on the other hand, virtualize at the operating system level, with each container running directly on top of the host operating system. A virtual machine might be several gigabytes in size, whereas a comparable container can be as small as just a few megabytes. The result of this is that containers can start much faster and have a fraction of the memory requirements of a virtual machine, as they do not have to boot up an entire guest OS in order to work.

When you look at it like this, the differences are clear:

• It is easy and fast to deploy containers while it might take minutes or even days to implement a fully function virtual machine.
• A container requires a small amount of operating system and system infrastructure for deployment and can run in just about any location, or even on bare metal machines or in a virtual machine.
• The scope of a container is smaller while a virtual machine is very heavy.

5 benefits of using containers

Containers may have a number of useful benefits that make them a better choice than tools such as virtual machines when it comes to developing and deploying software. Here are a few key factors that you should take into account.

1. Run anywhere, anytime

As noted above, containers are very small solutions, which means it is easy to run the same applications across a wide variety of different environments. Their portability makes them simple to load and, once they have been built, you can be sure that they will run on any system. This can greatly speed up the development process and mean you don't have to worry about the potential impact of switching to a different cloud platform.

2. Less resource-intensive

The lightweight nature of containers and the fact they don’t require a different operating system for operation also means they use far fewer resources than virtual machines, which means it’s possible to run many more containers from a single server. This lets companies reduce the number of machines needed for their development activities, resulting in fewer overhead costs and more resources freed up for use in other areas. It also makes containers more scalable, as you don't have to dedicate huge resources when you need to increase the number of containers you work with.

3. Better consistency

As containers offer a fully-isolated environment, they provide developers with a much more consistent workspace in which they can work in, safe in the knowledge that any changes they make will not have any unexpected side-effects or create problems. This means less time spent on troubleshooting and more time building new functionality, as developers will know any assumptions made in dev and test environments will translate over to production, so there will be fewer bugs to deal with.

4. More secure

Resource sharing is an integral operation of containers as they run on the same server using the same resources, but they never interact with each other. This isolated nature of containers means it brings with it a range of security benefits.

If one application fails or crashes, the other containers housing the same application will keep on running seamlessly without experiencing any technical hitches along the line. Additionally, if you do happen to fall victim to malware, for example, the nature of containerization means the impact will be restricted only to that particular container. Compromised containers are easy to terminate and reboot from a clean image.

Security software and rules implemented at the container engine level can apply to all of its containers, so there is no need to implement individual requirements for each container.

5. Improved productivity

The end result of many of these benefits is that development teams can work much faster to develop and deploy software. Containers help to remove environmental inconsistencies and make it simple to make changes to applications, quickly apply patches, and reduce the amount of time dealing with technical issues and compatibility problems.

As there will be no inconsistencies between platforms, this makes testing for possible errors smooth and timely as there are smaller differences between running your software in the various environments.

Containers also don’t require operating systems to boot and, as such, start instantly. This means developing and releasing new software is quicker and faster.

Some container tools also offer features such as version control, which makes it easy to roll back any changes that don't work out as intended with no downtime.

The future of software development

The use of containers is only set to increase in the coming years as businesses aim to make software development faster, more agile and cost-effective. While they won't replace virtualization, they do offer a range of benefits that virtual machines cannot replicate.

For many large companies, containerization will be the primary way they develop and deploy applications in the future, so by understanding them now, you'll put your teams in the best position to deliver the best results for years to come.