To ease the burden of deploying and managing complex applications, many development teams rely on the benefits of container technology. Containers group all necessary dependencies within one package. They are portable, fast, secure, scalable, and easy to manage, making them the primary choice over traditional VMs. But to scale containers, you need a container orchestration tool like Docker Swarm or Kubernetes. Both these tools provide a framework for managing multiple containers. Both have advantages and disadvantages, and each has a different focus, or purpose. In this article, we examine Docker Swarm and Kubernetes to help you identify which container orchestration tool is best for your organization.
Docker Swarm is an open-source container orchestration platform built and maintained by Docker. Under the hood, Docker Swarm converts multiple Docker instances into a single virtual host. A Docker Swarm cluster generally contains three items:
- Services and tasks
- Load balancers
Nodes are individual instances of the Docker engine that control your cluster and manage the containers used to run your services and tasks. Docker Swarm clusters also include load balancing to route requests across nodes.
Advantages of Docker Swarm
Docker Swam is straightforward to install, especially for those just jumping into the container orchestration world. It is lightweight and easy to use. Also, Docker Swarm takes less time to understand than more complex orchestration tools. It provides automated load balancing within the Docker containers, whereas other container orchestration tools require manual efforts.
Docker Swarm works with the Docker CLI, so there is no need to run or install the entire new CLI. Plus, it works seamlessly with existing Docker tools such as Docker Compose.
Docker Swarm does not require configuration changes if your system is already running inside Docker.
Disadvantages of Docker Swarm
Despite its benefits, there are a few disadvantages of using Docker Swarm that you should be aware of.
First, it is lightweight and tied to the Docker API, which limits functionality in Docker Swarm, compared to Kubernetes. Likewise, Docker Swarm’s automation capabilities are not as robust as those offered by Kubernetes.
Kubernetes is an open source container orchestration platform that was initially designed by Google to manage their containers. Kubernetes has a more complex cluster structure than Docker Swarm. It usually has a builder and worker nodes architecture divided further into pods, namespaces, config maps, and so on.
Advantages of Kubernetes
Kubernetes offers a wide range of benefits to teams looking for a robust container orchestration tool:
- It has a large open-source community, and Google backs it.
- It supports every operating system.
- It can sustain and manage large architectures and complex workloads.
- It is automated and has a self-healing capacity that supports automatic scaling.
- It has built-in monitoring and a wide range of available integrations.
- It is offered by all three key cloud providers: Google, Azure, and AWS.
Because of its broad community support and ability to handle even the most complex deployment scenarios, Kubernetes is often the number one choice for enterprise development teams managing microservice-based applications.
Disadvantages of Kubernetes
Despite its comprehensive feature set, Kubernetes also has a few drawbacks:
- It has a complex installation process and a steep learning curve.
- It requires you to install separate CLI tools and learn each of them.
- The transition from Docker Swarm to Kubernetes can be complicated and difficult to manage.
In some situations, Kubernetes can be overly complicated and lead to a loss of productivity.
Docker Swarm vs Kubernetes: similarities and differences
So far, we have discussed the pros and cons of each platform in general. Now, let’s analyze their key differences and similarities. We will compare the two platforms in terms of their setup requirements, app deployment capabilities, availability and scaling, monitoring features, security, and load balancing.
Installation, configuration, and learning curve
Docker Swarm is simple to install compared to Kubernetes, and instances are usually consistent across the OS. Configuring a cluster in Docker Swarm is easier than configuring Kubernetes. It is easy to learn compared to its counterpart and works with the existing CLI.
Compared to Docker Swarm, Kubernetes has a more complex installation and requires manual effort. The installation instructions can differ for each OS. It is challenging to learn and has a separate CLI tool.
Docker Swarm applications are services or microservices you can deploy using YAML files or Docker Compose.
Kubernetes provides a broader range of options, such as a combination of namespaces, pods, and deployments.
Availability and scaling
Docker Swarm provides high availability as you can easily duplicate the microservices in Docker Swarm. Moreover, Docker Swarm has a faster deployment time. On the other hand, it doesn’t provide automatic scaling.
Kubernetes is by nature highly available, fault tolerant, and self-healing. It also provides automatic scaling and can replace faulty pods if required.
Docker Swarm supports monitoring only through third-party applications. There are no in-built monitoring mechanisms.
In contrast, Kubernetes has built-in monitoring and supports integration with third-party monitoring tools.
Docker Swarm relies on transport layer security (TLS) to carry out security and access control-related tasks.
Kubernetes supports multiple security protocols such as RBAC, SSL/TLS, secrets management, policies, and so on.
Docker Swarm supports automatic load balancing and uses DNS under the hood.
Kubernetes does not have an auto load-balancing mechanism. However, Nginx Ingress can serve as the load balancer for each service within the cluster.
K3s as an alternative
In summary, the main difference between both platforms is that Docker Swarm is lightweight and more beginner-friendly, while Kubernetes is heavy and complex. Developers looking for a middle ground might want to consider a new platform, K3s. K3s eliminates the complexity of Kubernetes and provides a lighter, more accessible experience.
K3s is a tiny binary that implements the complete Kubernetes API. It’s small because the binary does not have unnecessary packages. You can add functionality quickly by using third-party add-ons. It is lightweight, easy to use, and Cloud Native Computing Foundation (CNCF) certified.
K3s is more friendly to Docker Swarm users who are not sure if they are ready for full-on Kubernetes. It could be an ideal alternative to the bulky Kubernetes.
Which platform should you use?
Both Kubernetes and Docker Swarm serve specific use cases. Which one is best for you depends on your organization’s needs.
For beginners, Docker Swarm is an easy-to-use and simple solution to manage your containers at scale. If your company is moving to the container world and does not have complex workloads to manage, then Docker Swarm is the right choice.
If your applications are tricky and you are looking for a complete package that includes monitoring, security features, self-healing, high availability, and absolute flexibility, then Kubernetes is the right choice.
If you need all the capabilities of Kubernetes but are put off by its learning curve, then K3s is a good alternative.
In this article, we explored the two primary orchestrators of the container world, Kubernetes and Docker Swarm. Docker Swarm is a lightweight, easy-to-use orchestration tool with limited offerings compared to Kubernetes. In contrast, Kubernetes is complex but powerful and provides self-healing, auto-scaling capabilities out of the box. K3s, a lightweight form of Kubernetes certified by CNCF, can be the right choice if you want the benefits of Kubernetes without all of the learning overhead.
Which orchestration tool is best for you depends on your business needs. Consider your team’s objectives and experience carefully before making a choice. No matter which platform you choose, you will be well-positioned to scale and manage your containerized applications. Sign up for a free CircleCI plan to start exploring container orchestration for your projects.