With the rise of the containerization technology and increased attention from enterprises and technologists in general, more and more containerized applications have been deployed to the cloud. Moreover, research conducted by 451 Research predicts that the application container market will grow dramatically through 2020, which will continue to expand the number of containerized applications in the cloud.
When the scale and complexity of production-critical containers rises, container orchestration tools step into the picture and fill an important gap in the container management toolbox. Kubernetes and Docker Swarm are two well-known, leading players in the container orchestration market that are an essential part of container story for many enterprises.
Kubernetes is an open-source, community-driven Container Orchestration Engine (COE) inspired by a Google project called Borg. Kubernetes is used to orchestrate fleets of containers representing instances of applications decoupled from the machines they run on. As the number of containers in a cluster increases to hundreds or thousands, with application components deployed as separate containers, Kubernetes comes to the rescue by providing a framework for deployment, management, auto-scaling, high availability, and related tasks.
Kubernetes allows you to handle various container orchestration-related tasks such as scaling containers up or down, automatic failover, distributing workloads among containers hosted on different machines.
Kubernetes follows a traditional client-server architecture where the Master node has the global view of the cluster and is responsible for decision making, allocating resources, and scheduling containers. Users can interact with the Master node through the REST API, the web UI, and the command line interface (CLI). The Master node interacts with the Worker nodes that host the containerized applications.
Some of the common terminology used within the Kubernetes ecosystem are:
Docker Swarm is an alternative, Docker-native Container Orchestration Engine that coordinates container placement and management among multiple Docker Engine hosts. Docker Swarm allows you to communicate directly with swarm instead of communicating with each Docker Engine individually. Docker Swarm architecturally is comprised of two types of nodes called Managers and Workers.
Below are some the common terms used in the Docker Swarm ecosystem:
Both Kubernetes and Docker Swarm COEs have advantages and disadvantages and the best fit will largely depend on your requirements. Below, we compare a few features they share.
In summary, both Kubernetes and Docker Swarm have advantages and disadvantages.
If you require a quick setup and have simple configuration requirements, Docker Swarm may be a good option due to its simplicity and shallow learning curve.
If your application is complex and utilize dozens to thousands of containers in production, Kubernetes, with its auto scaling capabilities and high availability policies, is almost certainly the right choice. Its steep learning curve and longer setup and configuration time can be a bad fit for some users, but with additional tooling, like Rancher, some of these administration and maintenance pain points can be mitigated, making the platform more accessible.