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Kubernetes vs Docker Swarm: Which is better?

You may be looking into the pros and cons of Kubernetes vs Docker Swarm. Both platforms are excellent, but they both have qualities that are unique to each other. One business or user may be better off with Docker Swarm over Kubernetes and vice-versa.

But what exactly are Kubernetes and Docker Swarm, and what are their benefits? Let’s dive in and learn a bit more.

What is Kubernetes?

KubernetesKubernetes, also known as K8s, is an open-source container orchestration system. It was originally created and maintained by Google.

Outside of Google Cloud, major cloud providers and operating system vendors offer support for Kubernetes. These include Amazon Web Services (AWS), IBM, and Microsoft.

Pros of Kubernetes

Kubernetes has an auto-scaling feature and can scale up to thousands of nodes with different containers per node, up to 5,000.

Kubernetes uses raft consensus for management failover and requires several management nodes and health checks to automatically create containers when nodes or applications fail. For service discovery, Kubernetes requires users to define containers as services by hand or manually. This can be seen as a pro and a con, depending on the control the developer wishes to have.

The platform itself is also highly customizable and offers various possibilities for personalization, though the learning curve for this can be steep.

Kubernetes offers built-in logging and monitoring. One can also use outside monitoring tools as well, such as Prometheus or AppDynamics in order to keep an eye on metrics and logs. It also has excellent rolling updates that progressively update pods in order and also offers rollback automation in the event of a system or host failure. This platform also has excellent community support.

Cons of Kubernetes

Kubernetes can take a significant amount of planning and work to set up. TLS (Transport Layer Security) authentication for security requires manual configuration within Kubernetes, which can be a bit of a pain.

Kubernetes’ learning curve doesn’t get easier throughout the use of the product, though it is highly customizable.

Kubernetes also lacks compatibility with Docker CLI and Compose tools, which can be inconvenient for integrations.

What is Docker Swarm?

Docker SwarmDocker Swarm{: target="_blank"} is also a container orchestration system similar to Kubernetes as well as the native clustering engine for Docker. Docker Swarm is also open-source and quite simple for developers to work with since elements and features that work for Docker services also work for Docker Swarm.

Pros of Docker Swarm

Docker Swarm is very easy to install. One only needs to understand a small number of commands to set up clusters in Swarm, and setting up Docker across various multiple operating systems is pretty much the same. When it comes to TLS authentication and container networking, Docker Swarm automatically configures these networking features.

Like Kubernetes, Docker Swarm uses Raft consensus for management failover and requires several management nodes and health checks to automatically create containers when nodes or applications fail.

Docker’s Swarm API is customizable, though it isn’t very easy to perform operations that aren’t under the Swarm API.

Cons of Docker Swarm

Docker Swarm is quite scalable but does not offer auto-scaling, though developers can find workarounds for this. Docker Swarm is scalable up to 4,700 nodes which is less than Kubernetes.

While Docker Swarm has some useful monitoring tools, including Docker Service Logs and Docker Events, they overall fall flat. It is recommended to install secondary logging and monitoring tools.

Docker Swarm lacks rollback functions when compared to Kubernetes. While one can use the scheduler for updates, automated rollbacks are not available right after installation. You can definitely get full automatic rollback support with some coding, but it is a bit inconvenient.

Docker’s limited functionality and fault tolerance can also be off-putting to many developers. Compared to Kubernetes, Docker Swarm has a noticeably smaller and less helpful community for ongoing support.

Kubernetes vs Docker Swarm: Which is Better?

Both Kubernetes and Docker Swarm are open source and have similar service discovery and fault tolerance. Both Docker Swarm and Kubernetes also have similar load-balancing– both solutions are highly available and improve redundancy by running the same container on multiple nodes. This is helpful because, in the event of a host failure, the services therein can heal on their own. Both platforms are also highly customizable, though both are not very easy to customize.

Kubernetes does have a slight advantage over Docker Swarm because it can scale up to around 5,000 nodes, while Docker Swarm can scale up to 4,700 nodes. Kubernetes is also a bit more popular and has been adopted across DevOps and wider software development groups. Docker Swarm also lacks in the monitoring department and it is recommended to use additional third-party tools for logging and metrics. Docker Swarm also isn’t the best when it comes to rolling updates and rollbacks, especially when compared to Kubernetes automatic functions for this.

However, Kubernetes is not as easy to install as Docker Swarm by any stretch, especially when using the platform on-premises. It also lacks compatibility with Docker CLI and other tools, which is inconvenient. Docker Swarm’s learning curve is also gentler, compared to Kubernetes and it works perfectly with current Docker tools.

When it comes down to it, Kubernetes is indeed complex but has entered the market regardless and has been widely adopted. While the learning curve is challenging and installation is a pain, the massive Kubernetes community offers extensive support for working around the few faults of this platform.

Most developers would benefit more from Kubernetes than Docker Swarm. However, since both are open-source and free, it may be worth trying out the functions of both platforms before adopting Kubernetes exclusively.

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March 19, 2020
5 min read

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About the author

Austin Parker

Austin Parker

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