Last updated: July 20, 2019
What is Containerization?
Containerization is something like a middle-ground between the mess of natural computing environments and rigidly segmented virtual machines.
Containerization in Layman Terms
The Docker website is filled with details of its containerization features.
There’s a perfect analogy here to shipping. On the one hand is a giant cargo ship in which each small piece of cargo is packed into the hold and everything can slam into everything else and it all has to be loaded and unloaded by hand.
On the other hand is a multitude of individual boats, one boat for each piece of cargo. The best solution is somewhere between these two: interchangeable, self-contained storage and shipping units which can be loaded easily onto many different types of transportation, from giant cargo ship to railroad.
How Software Containers Work
A software container has a copy of the primary application, as well all dependencies — libraries, languages, frameworks, and everything else. The containerization system provides APIs to the operating system so that the interface between the container and the OS on one machine is the same as the interface between them on another machine.
This means that an app that runs in a container on a local development machine can be deployed easily onto another server by simply copyin
Should You Choose a Container or a Virtual Machine?
The issue of containers vs. virtual machines is a complex one. If you’re working with or developing applications, you may not be sure which to choose. This guide will touch on all those subjects, so read on to find out if Docker is right for your latest project.
Docker is a relatively new containerization technology. It allows web application developers and system admins to deploy apps to web servers inside of isolated virtual containers which provide all needed dependencies and an operating system abstraction layer.
|Allows devs to isolate applications||yes||yes|
|Ability to limit resource access?||yes||not usually|
|Ease of use||newbie-friendly||complex|
|Requires the same OS for all files||yes||no|
How to Get Docker
A Docker container can be installed in a variety of ways. You can get it set up on Linux, Windows 10, Azure, and other systems. Vagrant’s “Docker Provisioner” or sudo apt-get can also install it if you use those programs. Last but not least, Docker Machine will let you run Docker both on cloud platforms and on older versions of Mac and Windows.
What features does Docker offer?
One of the most important things is finding good Docker hosting that supports the platform. You’ll want it either pre-installed or the ability to go in and download programs yourself. There’s no use finding a great host, only to realize that there’s no way to get Docker Engine installed.
How Do You Get a Docker Image?
After you have a host and install Docker Engine, you’ll want to use Docker Hub or a similar repository to find a Docker image. An instance of an image is a container, so one image can create multiple containers — a necessary resource when using this platform.
You can find everything from an Ubuntu container, images from vendors like Red Hat, ora versatile Nginx image for all your web server needs. If you’re proficient with programming, working with these files and commands should be no issue.
Tackling The Environment Problem
No app is an island. Every software application relies on dependencies outside itself — frameworks, libraries, plugins, web servers, databases, are all used when building modern software. These, in turn, rely on other libraries and depend on particular environment settings and configurations.
Each application or dependency might rely on a particular version, or create conflicts if used in conjunction with other software. In short — the complex ecosystem of software on a typical computer running many different applications can create unforeseen problems.
For example — you might find that an app has some bugs when running on one particular version of a web server, but is fine on another. You could track down the source of those bugs (which you may not be able to find or fix), or you could simply choose to use the version that works.
Multiple Apps on the Same Server
Docker has detailed documentation on setting up multiple services in a container.
But what if you are running two apps on the same server that each have a similar problem, but with different versions of the web server software? Or some other dependency, for that matter.
Saying that, when you run multiple apps on the same server, should any of the apps move to a different server, you’ll have some work to do. This would be in the form of redirection or reverse proxying.
Typical Solutions for Software Conflicts
Every computer system has a unique environment. The particular combination of hardware, firmware, operating system (including specific distribution and version), installed languages, particularly specific version of each installed extension, DLL, library, plugin, configuration options. These, along with seemingly-unrelated applications all contribute to this unique environment.
Solutions to Performance Issues
Once an application reaches a sufficient level of complexity, these environmental idiosyncrasies can start to have an effect on performance.
Here are 5 of the more conventional solutions to dealing with this problem:
- Write better software
- Create and maintain duplicate environments
- Segregate apps
- Use virtual machines
- Extensive Research
But, how do these solutions work in practice? Let’s look a bit deeper.
Write Better Software
This seems like a noble direction to head in — trying to write perfect software code that somehow doesn’t conflict or collide with other software. Software that doesn’t rely on outside dependencies, and is backward compatible with older versions of things. The problem is that this is actually impossible in real life.
Maintain Duplicate Environments
Usually, there will be a production environment and then a test and/or development server that is cloned from production.
New versions are tried out in a non-public environment before being deployed to production. Assuming the environments are truly identical, this at least gives developers the chance to see if there are any problems.
Segregate Apps Onto Different (Virtual) Machines
If a company is running multiple web applications, they will often have each one running in its own machine (real or virtual) in order to minimize or eliminate the problem of conflicting needs – two apps needing different versions of the same library, for example.
Virtual Machines for Development
Docker machine and VM guide.
Most developers work locally on their laptops or desktop computers. Since that environment is filled with applications and multiple versions of things (due to g the entire container — moving it like a shipping container from boat to dock — without having to worry about environmental configuration details or installing dependencies.
Different Versions of the Same Libraries
Several different contained apps on the same machine might be using different versions of the same libraries, or might have other conflicting dependencies. That’s okay because they are separated from each other.
This does end up potentially using up more storage space (because of the need of having multiple copies of some things on the same machine). Even so, this is a negligible cost in comparison to the benefits.
Docker Hosting – Things to Know
Docker is one of the leading containerization technologies. It is Open Source and can run on any Linux environment with a modern kernel. In other words, all you need is a host that will let you in the areas necessary to get the program running. That is to say, a majority of VPS and dedicated servers (if you’re not sure, ask!).
Before we look at some options, let’s summarize a few benefits of using Docker with your hosting plan:
- Simplicity and configuration with ease
- Reduced deployment time
- Security and isolation
- Multi-cloud platforms
- Saving costs
In the meantime, I’ll talk you through a few options that would make sense to dig into further.
Shared Hosting for Docker
If you’re dealing with shared hosting, things might get a bit more complicated. Some shared servers come with Docker pre-installed or as part of a one-click install. But this seems to be rare, so you may be better off upgrading to VPS should you wish to use containers.
Linux Hosts for Docker
Other than that, your focus should be simply on finding a great Linux host that suits the needs of your project. Developer-friendliness (obviously) and a fair bit of resources at a low price are the general qualities of a perfect Docker host.
Docker is Taking Over the Virtual Machine World
Docker has done well for itself, essentially creating a mini virtual machine. Before containers, you might have needed to wait for a virtual machine to boot. Running virtual machines requires a lot of resources, driving up your hosting fees.
And don’t forget trying to develop an application while dealing with the variety of bugs even the tiniest difference in software can cause. Virtual machines softened this issue, but their weight on servers cause even more problems.
Are Containers the Future?
But that’s all a thing of the past. Virtual machines, of course, are still invaluable tools, but no longer do they need to be applied in situations where they don’t belong. Docker is a much more fitting tool to use.
While it does have its own problems, the avid community has done its best to minimize them and provide even more functionality to a program already so versatile. Plugins can run the gamut from image/container management to volume plugins to networking and connections.
Alternatives to Docker
If even then Docker doesn’t seem right, there are other options out there. Vagrant, a software that works with many virtual machines, can run a Windows environment on Mac or Linux. While none have quite the same popularity, Docker alternatives are everywhere.
Whether you choose a container, a virtual machine, or maybe even both, you’re going to need a powerful Linux server to host it on — one that has lots of options available and even more developer tools to work with.
Containers VS Virtual Machines: Who Wins?
While Docker runs flawlessly for many apps, virtualization software like VirtualBox VM competes with it in many aspects. Though they fill many of the same niches, containers do some things a virtual machine can’t, and vice versa. To be short, if you need to run many applications and operating systems, sticking with the time-honored VM is best.
- Allows for app development and testing in a controlled environment
- Faster and more lightweight than VMs by a mile
- Often easier to set up than an entirely virtual environment
- A server can host more docker images than virtual machines, reducing workload and cost of extra servers
- Community support; dedicated coders have crafted programs that address issues from the difficulty setting up networking to the limited OS support.
- Though generally easier to work with than VMs, can still be difficult to use
- Not great at running multiple applications (use a virtual machine)
- Limited support for non-Linux applications
- Difficulty using containers of different operating systems on one server
- VMs present fewer security issues as they are more isolated
Top 3 Hosts for Docker
What host is the right choice if you want to use, Docker? As always, it depends on your unique needs. The tool above will allow you to filter hosts by specific needs. However, if you are overwhelmed by all the choices, we’ve chosen three hosts we think are your best bet when using Docker.
DigitalOcean is a popular host, but is it right for Docker? Let’s dig deeper.
The big winner is fairly clear: DigitalOcean seamlessly provides cloud hosting that spares developers any hassle. Make use of a simple API, create a new server in seconds, and scale up resources whenever you need them.
Not only does DigitalOcean provide extensive tutorials on how to set up and manage a container, but Docker itself provides its own guide. It’s clear these two work seamlessly together, and the affordability and elegance of DigitalOcean’s services make it a top candidate.
LiquidWeb could be the right host for your Docker-powered project.
Though it’s a lot more expensive, LiquidWeb is worth a look as well. This host runs primarily in the cloud, but it has many options ranging from cloud VPS to a physical dedicated server.
Extensive Docker documentation is available here as well. With its helpful support and powerful servers, LiquidWeb makes a great choice for those in need of maximum power.
Atlantic.net is a good option for hosting Docker.
Last is Atlantic.net, a professional host made especially for larger businesses. But if you’re not part of a huge company, don’t despair — this host’s scalable public cloud service is affordable enough.
You can select from certain server optimizations (storage, memory, and computer), which is super nifty. Atlantic.net has reliable, redundant infrastructure along with knowledgeable support and a powerful API. For a trustworthy, professional host that has the latest technology, Atlantic.Net is the way to go.