Container orchestration is fast evolving and Kubernetes and Docker Swarm are the two major players in this field. Both Kubernetes and Docker Swarm are important tools that are used to deploy containers inside a cluster. Kubernetes and Docker Swarm has many their prominent niche USPs and Pros in the field and they are here to stay. Though both of them have quite a different and unique way to meet the goals, at the end of the day their endpoint remains quite near.
Overview of Kubernetes
Kubernetes is based on years of Google’s experience of running workloads at a huge scale in production. As per Kubernetes website, “Kubernetes is an open-source system for automating deployment, scaling, and management of containerized applications.”
It groups containers that make up an application into logical units for easy management and discovery. Kubernetes builds upon 15 years of experience of running production workloads at Google, combined with best-of-breed ideas and practices from the community.
Overview of Docker Swarm:
Docker swarm is Docker’s own container’s orchestration system. It uses the standard Docker API and networking, making it easy to drop into an environment where you’re already working with the Docker containers. Docker Swarm is designed to work around four key principles:
- Less cluttered/heavy and with just working methodology
- No Single Point of Failure option for Docker Swarm
- Secure due to auto-generation of security certificates.
- Compatibility with Backward versions easily.
If both are same, which one to use?
Although both of the orchestration tools are quite similar there are some technical and functional variations and differences which make them different and also good or bad in their own niches. Some of those points are listed below.
- Installation and set-up
In Kubernetes, installation is manual and it takes serious planning to make Kubernetes up and running. Installation instructions differ from OS to OS. Cluster configuration like IP addresses of a node or which node takes what role is needed to know in advance in Kubernetes. Various 3rd party packages like minikube/microk8s and kubectl/kubeadm are needed to be installed for the working and development of kubernetes.
Whereas; Docker Swarm is simple to install as compared to Kubernetes. With Docker, only one set of tools is required to learn to build upon environment and configuration. Docker Swarm also provides flexibility by allowing any new node to join an existing cluster as either a manager or a worker. Docker swarm moreover has the added advantage of using Docker API and common commands and underlying architecture remains the same.
- Working on two systems
It requires knowing CLI (Command Line Interface) to run Kubernetes on top of Docker. You should know Docker CLI to navigate within a structure and then supplemental Kubernetes common language infrastructure to run for those programs.
Since Docker Swarm is a tool of Docker, a same common language is used to navigate within a structure. This provides variability and speed to this tool and gives Docker a significant usability edge.
- Logging and monitoring
Kubernetes supports multiple versions of logging and monitoring when the services are deployed within the cluster:
- ELK Stack — ElasticSearch, Logstash, Kibana.
- Heapster/Grafana/ Influx for monitoring in the container
Docker Swarm is supported for only monitoring with third-party applications. It is recommended to use Docker with Reimann for monitoring, however since Docker Swarm has an open API, it makes easier to connect with plenty of apps.
Kubernetes is more of an all-in-one framework for distributed systems. It is a complex system as it offers a unified set of APIs and strong guarantees about the cluster state, which slows down container deployment and scaling.
As compared to Kubernetes, Docker Swarm can deploy containers faster; this allows fast reaction times to scale on demand.
Kubernetes network is flat, as it enables all pods to communicate with one another. In Kubernetes, the model requires two CIDRs( Classless Inter-Domain Routing). The first one requires pods to get an IP address, the other is for services.
In a Docker Swarm, a node joining a cluster creates an overlay network of services that span all of the hosts in the Swarm and a host only Docker bridge network for containers. In Docker Swarm, users have the option to encrypt container data traffic when creating an overlay network by on their own.
Benefits & drawbacks of Kubernetes
Benefits of Kubernetes:
- Kubernetes is backed by the Cloud Native Computing Foundation (CNCF).
- Kubernetes has an impressively huge community among container orchestration tools. Over 50,000 commits and 1200 contributors.
- Kubernetes is an open source and modular tool that works with most OS.
- Kubernetes provides easy service organization with pods
Drawbacks of Kubernetes
- When doing it yourself, Kubernetes installation can be quite complex with steep learning curve. An option to solve this issue is to opt for a managed Kubernetes-as-a-service such as ours.
- In Kubernetes, it is required to have a separate set of tools for management, including kubectl CLI.
- It is incompatible with existing Docker CLI and Compose tools
Benefits & drawbacks of Docker Swarm
Benefits of Docker Swarm
- Docker Swarm is easy to install with a fast setup
- Docker Swarm is a lightweight installation. It is simpler to deploy and Swarm mode is included in the Docker engine.
- Docker Swarm has an easier learning curve.
- Docker Swarm smoothly integrates with Docker Compose and Docker CLI. That’s because these are native Docker tools. Most of the Docker CLI commands will work with Swarm.
Drawbacks of Docker Swarm
- Docker Swarm provides limited functionality.
- Docker Swarm has limited fault tolerance.
- Docker Swarm have smaller community and project as compared to Kubernetes community
- In Docker Swarm, services can be scaled manually.
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