Docker is a container platform, while Kubernetes is a container Orchestration platform, If I tell you this is the difference between Kubernetes and Docker. so did you understand anything? No! Right.
So, to understand the main difference between the 2 technologies, it’s highly suggested to have a fundamental understanding of how docker or containerization works.
What is Docker?
Docker is an open-source platform to develop, ship, and deploy the application along with minimum system dependencies packaged in a container. Imagine containers like a small box inside your EC2 instance containing minimum system libraries. Containers are very lightweight which means they do not have a completed operating system instead have minimum system libraries along with application code and dependencies to run the application.
What is Kubernetes?
Kubernetes has roots connected to Google’s internal Borg legacy system. Due to its core fundamentals of a cloud-native container orchestration platform, the increase in popularity of Containerization and the need for an open-source container orchestration platform led to the existence of Kubernetes. Kubernetes open community project is now the fastest growing open source project with over 2300 contributors and managed by Cloud Native Computing Foundation (CNCF).
In simple words, Kubernetes helps manage the containerized application to ease deployment, scaling, and load balancing of traffic in a cluster of containers. Kubernetes’s auto-deployment, scaling, and healing features allow developers to focus on development, while the DevOps Team takes care of the complex infrastructure management.
Let’s try to simplify it by relating this technology to some real-life practical examples.
Imagine a seaport, what can you see there Ships, shipping Containers, and some machines to handle containers on a high level.
Now think of shipping containers as Docker containers, Ships as your cluster of nodes, and Kubernetes as your seaport.
| Container | Container placement | Container Management | |
| Containers here are placed under cluster nodes like EC2, on-premises | Docker Containers contains a piece of code to run the application | Containers here are placed under cluster nodes like EC2, on premises | Kubernetes manages the container to auto-deploy, scale, and heal. |
| Shipping port | Shipping Container contains material to ship | Shipping Containers are placed on the cargo ships | Sea Port manages the container placement on the ships |
Now you have understood what Docker Containers and Kubernetes are, let’s now go through the main 4 differences between them, although there are other differences as well, these 4 differences are the major limitations of using containers in the production environment.
Difference between Kubernetes and Docker
The 4 major differences between Docker and Kubernetes are the 4 limitations of Docker which Kubernetes solves.
- Single Host – Docker is installed on a single EC2 instance or your laptop and containers are created on top of it, so if you have 100s of containers that all will rely on a single host, and if a host goes down then all your containers are gone. even the data inside the container any logs will not be available since containers are ephemeral. Also if the traffic is increased then the docker container might run out of memory and then the host machine (Linux) will kill the containers running on the old process id.
- Auto Healing – The docker container cannot heal automatically, if a container is dying then the DevOps engineer has to monitor all 1000s of containers and bring up the container manually if the user complains that the application is down.
- Auto Scaling – Docker containers cannot scale up in the event of high traffic volume. for example, if a container has a capacity of 4GB RAM and 4 CPU, which is designed based on the number of current users using the application let’s say 1000, but all of a sudden during the festival season your application received 10,000 user request then, in that case, your application will not be accessible to some user which is not a good user experience since container are not auto-scalable.
- Enterprise-level feature – Container does not support some of the enterprise-level features like load balancing, Firewall, Scaling, Healing, support to API gateway, cluster support, and many more.
Now! we have seen the problems related to Docker and will now check how Kubernetes will solve the problem.
Kubernetes Solution to Docker Limitations
- Cluster Support – By default Kubernetes is installed in a cluster having master-node architecture, having installed in a cluster of nodes, in case where one faulty container is impacting another container, immediately kubernetes will put the container in another node.
- Auto Healing – Kubernetes either controls or heals the damage, mostly it controls the damage. Kubernetes has an API Server that listens to the nodes and whenever there is a container going down Kubernetes rolls out a new container.
- Auto Scaling – Kubernetes has a replicate set controller which is a parameter in your Kubernetes YAML file where you can mention the number of containers required in case the current container receives a load and then a new container is rolled out. Kubernetes also has a feature of Horizontal pod scaling (HPA) which automatically spins up containers when traffic increases.
- Enterprise-level support – Kubernetes is managed by CNCF where the contributor daily enhances Kubernetes to provide enterprise-level support to the companies using it across the globe.
Conclusion
Kubernetes and Docker are not at all rivals to each other but together form a better way to deploy and manage your code on production with high availability, scalability, and robustness.
The combination also helps to deploy solutions quickly and supports in managing and serving microservices to a large number of users.