Kubernetes vs. Docker Swarm: What’s the Difference?

Since Linux first introduced containerization more than a decade ago, many teams have made the switch to using containers over traditional VM (virtual machine) infrastructure setups. Containerization tools like Docker have made application deployment much more simple, allowing teams to easily manage all of their microservices. However, as you increase the number of containers within a system, you’ll need something to help orchestrate these Docker containers. Enter Docker Swarm and Kubernetes.

The Google-created Kubernetes (or K8s) and Docker’s own Docker Swarm are the two powerhouse tools for container orchestration. And, as with many other great debates – Jordan or LeBron, The Office or Friends, paper or plastic – we often see teams questioning whether Kubernetes or Docker Swarm is the better option. Both are great for managing multiple containers and work seamlessly with Docker, but the best choice for you will depend on what your needs and preferences are.

What is Kubernetes?

Kubernetes –referred to as K8s by its vast developer community – is a powerful open-source platform released in 2014 by Google. Since then, Kubernetes has quickly become one of the top container orchestration tools, known for its ability to manage complex system architectures, automate across host clusters (scaling up or down, rollbacks, and more), and log/monitor system performance using its built-in GUI.

Kubernetes is also modular and compatible with all architecture deployments. It works by grouping containers and naming them as logistical units which can then be used and communicated with individually. By distributing the load amongst containers, Kubernetes allows for increased portability across the system, while dramatically improving scalability and growth.

What is Docker Swarm?

Docker Swarm – or just Swarm – is Docker’s open-source platform for container orchestration. Created and maintained by the same company behind the beloved Docker containers, Swarm gained popularity for its quick setup, ease of use, and quick scalability.

Docker Swarm excels within simple or smaller architectures with less containers. It is used for compiling separate Docker hosts into a single, easy-to-manage host that allows for automated load balancing and rolling updates.

But wait, what is the difference between Docker and Docker Swarm? Not to be confused with Docker, which is used for containerization, Docker Swarm is the tool for managing and orchestrating these dockerized containers. After all, when the container and container orchestration tools are made by the same company, you know they’ll play very well with one another.

Kubernetes vs. Docker Swarm: The Showdown

Because both Kubernetes and Docker Swarm are container orchestration tools, they have many of the same features. However, each tends to shine in different aspects, which can mean one or the other might be the best fit depending on your needs and preferences.

Let’s see how Kubernetes and Docker Swarm face off in key areas…

Setup/Installation & Cluster Strength

Hands down, Docker Swarm is known to have the more quick and simple setup and installation process. Swarm is also easier to pick up, even with less technical knowledge. Kubernetes on the other hand is much more complex to install and has a steeper learning curve. However, because of this, Kubernetes is also able to handle far larger or more complicated deployments. Once you’re past the initial install and get the hang of how it works, Kubernetes offers stronger clusters that are faster and more secure—golden in large production environments.

Winner: It depends on your system needs! Smaller, simpler infrastructures can thrive with Docker Swarm. But if you’re looking for flexible growth and the ability to handle extremely complex systems, Kubernetes is the way to go.

GUI (Graphical User Interface)

Kubernetes comes with its own GUI built right in. The Kubernetes Dashboard allows you to easily scale and deploy individual applications, as well as control and monitor your different clusters. Docker Swarm does not have a built-in GUI. However, there are several third party tools available to supplement this as needed.

Winner: Kubernetes

Scalability

Both Kubernetes and Docker Swarm allow you to more easily scale your infrastructure up or down depending on your needs. While Kubernetes does add automated scaling which can adjust based on traffic, Swarm requires all scaling to be done manually. However! Container scaling and deployment is slowed down by Kubernetes’ more complex framework.

Winner: Again, this depends on what matters more to you when it comes to scalability. If you’re looking for automation, then Kubernetes might be your best bet. But if speed when scaling up or down is more important to your team, then you may prefer Docker Swarm.

Load Balancing

Docker Swarm shines when it comes to load balancing because of how it is easily automated within Docker containers. Kubernetes requires manual configuration of load balancing within the different nodes.

Winner: Docker Swarm

Logging & Monitoring

With the Kubernetes dashboard, logging and monitoring is built-in and readily available. There are also many additional third party monitoring tools that can be added to track additional key metrics. While Docker Swarm does come with some basic server log and event tools from Docker, third party apps are a must to really get the most out of your monitoring.

Winner: Kubernetes

Future Outlook

Docker was acquired in November 2019 by Mirantis, which has caused some concern among Docker Swarm users. Mirantis has stated they will continue support for Docker Swarm without any implied end date, though many are left feeling unsure about the future of Docker Swarm. Because of this, many Swarm users are beginning to start planning a migration to Kubernetes, which due to its ties to Google and large community, shows no signs of slowing down any time soon.

Winner: Kubernetes

The Case for Kubernetes

Pros:

  • Trusted, open-source platform backed by Google with a large community of users
  • Works smoothly on all operating systems
  • Able to manage large and complex infrastructures
  • Highly scalable with flexible room for growth
  • Automated, self-healing features
  • Large community of users

Cons:

  • Installation is complex and set up has a steeper learning curve
  • Requires separate Compose and Command Line Interface (CLI) tools

The Case for Docker Swarm

Pros:

  • Open-source platform that works perfectly with all existing Docker products
  • Installation is quick and simple
  • Great for smaller and less complex systems

Cons:

  • Can be limited in functionality as it’s tied to Docker’s API
  • Future of Docker Swarm is unsure following the Mirantis acquisition

Kubernetes or Docker Swarm: Which will you choose?

So, Kubernetes or Docker Swarm – which is the right choice? The fact is that both Kubernetes and Docker Swarm are great options for container orchestration. Docker Swarm integrates seamlessly with all existing Docker tools, is easy to set up and use, and is excellent when paired with smaller infrastructures. However, after the acquisition of Docker by Mirantis, many Swarm users feel now is the time to begin planning a move to Kubernetes. Kubernetes works excellently on all operating systems and is backed by years of industry-leading expertise. It is extremely flexible and powerful, and can manage larger, more complex infrastructures.

Which will you choose?