Implementing a scalable secure and reliable DevOps ecosystem has become a DeFacto for all kinds of tech-oriented businesses and so has become a container orchestration tool that helps developers build, package, test, and deploy applications independently across all the servers and OS platforms.
Having said that the selection of the right containerization tools has also become a bigger question that a solution architect/CTO of any organization has to decide while finalizing their system architecture after all it is going to impact the technology budget and also the business of the company overall.
Some of the strong contenders in this race are:
- Docker(docker desktop, compose, swarm, etc)
Today we will discuss two of the popular orchestration tools Docker and Podman and compare the same to see which one can help you to plan your DevOps implementation strategy better. So let’s start with defining Docker Container first
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What is Docker?
Well, I always like to call Docker a mammoth cargo ship that has the ability to hold big boxes (containers) having their distinct objectives and id. These boxes contain items that are unique is required to make that particular box useful for the company/person who has asked for it to be shipped. These items are first manufactured in the factories that have templates to reproduce such items(I see the images) . These items(images) are packaged into the boxes(dockerized/containerized)in such a manner that they are useful for someone who has asked them to be shipped.
If you are finding this analogy hard to digest, let me define it by keeping its technical aesthetics in place
Docker is open-source, virtualization software created to make developer’s life easy. It is a kind of PaaS (platform-as-a-service) product whose core objective is to isolate virtual environments to deploy, build, and test applications that are usually incompatible or not meant to work with the current OS.
Docker is almost a synonym for containerization amongst the developer fraternity. Docker has grown to a full-blown container solution offering everything from orchestration, to load-balancing, networking, etc
Docker helps developers get rid of boring, repetitive configuration tasks and makes development fast, easy and portable across all the platforms. Docker’s complete ecosystem includes UIs, CLIs, APIs and security that are engineered to work together across the entire application delivery lifecycle.
Docker’s subsidiary tools handle all the tasks related to container orchestration, from load balancing to networking, making it the industry’s primary choice, besides being the established reference technology.
Now that we have the fundamentals of the What and Why of Docker? It’s time to define Podman and try to understand its basics before we jump into decoding which tool can be apt for your use case.
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Why Docker? : What Are Docker Benefits?
Docker offers the following key benefits that make it an extremely reliable and useful tool for developers.
- Improved and seamless portability:
Docker containers run without modification across any desktop, data center, and cloud environment.
- Even lighter weight and more granular updates:
With Docker containers, only one process can run in each container. This makes it possible to build an application that can continue running while one of its parts is taken down for an update or repair.
- Automated container creation:
Docker can easily leverage code templates to craft and build a container automatically
- Container versioning:
Docker helps you track each version of any container images and if you have to roll back any changes you can do it seamlessly due to smart versioning support. It can even upload only the changes(delta) between an existing version and a new one.
- Docker Container reuse:
If you have built a docker container, the same can be used as as base images — essentially like templates for building new containers.
- Shared container libraries:
Docker allows developers to create their custom docker images that can be submitted to the public registry. This has helped docker to build a large public registry repo in the form of an open-source Docker hub. Developers can leverage this open-source registry to quickly get started building and deploying containerized apps.
What is PodMan?
Podman (an abbreviation of Pod Manager) is linux-native container orchestration tool that uses a deamon-less architecture to create , build and run your application. Podman containerization process is fully complaint to Open container initiatives (OCI) which it leverages tio deploy your app container images and containers.
Podman container ecosystem is almost equivalent to Docker. Podman has got all the CLI and functions like docker, faciltitating developers to create, maintain, modify, and run container and their associated images in a production-ready environment
In a nutshell:
Podman: Is a tool for managing OCI containers and pods and it levaerge libpod library that provides APIs for managing containers, pods, container images, and volumes.
What are some of the key benefits which make Podman Special?
To understand why Podman is so powerful, we need to look into the offerings which Podman and libpod provide
- Podman supports all kinds of container image formats like OCI and Docker images and helps you to fully manage the same
- It provides a full container management lifecycle right from creation to running, checkpointing and restoring (via CRIU), and removal.
- Podman enables full container networking management using CNI, Netavark, and slirp4netns
- Podman supports pods, and container groups sharing the resources and also allows Resource isolation of containers and pods.
- It has all the support for docker compatible CLI that can run containers both locally and remotely
- unlike docker, It doesn’t have a daemon manager and this choice has been made to enhance security and low resoourc utilization when Podman is not running.
- Podman also extends support for REST API which can be leveraged by third party tool to adopt Podman capabilties.
- It supports multiple OS and can run on Windows and Mac via virtual machines
- One more concept that makes Podman special is that it is “Rootless”. This helps Podman to allow user a container access to without asking uswr to have a supr admin or root level priveliages specifically. IT manages the permission level stuff by using the concept of user namespaces
Now that we covered the fundamentals of both Podman and Docker, its time to decode the differentiating factors between the two
Difference Between Docker and Podman
In this section we will try to find out some key differences between the two, having said that the intent is not to decide the winner or loser as both of them exist for a common reason but to help you make a conscious decision while keeping your requirement into the consideration
- Architectural Differences
- Podman is a deamonless system which is not the case with Docker. Docker uses a deamon thread called containerd. Containerd is used by docker to pull any docker images that is lying in any public or private repositories. Unlike docker Podman uses conman
Conman has a smaller memory requirement compared to containerd even though they both delegate container creation to a low-level container runtime such as runc.
Docker daemon runs with elevated root access which is a security loophole. Rootless containers avoid this by allowing non-privileged users to run containers through the use of user namespaces. Podman enables running and managing rootless containers which makes it more reliable.
Do you know?
Docker recently added rootless mode to its daemon configuration following the footstep of Podman
One key concept that differentiates Podman from Docker is “fork-exec”. By fork exec model, it means that Podman runs as a process initially and when the container is created it process forks and forms a separate process that constitutes what is required for the running container.
Podman leverages fork-exec to perfrom in-depth user audit log in the system
Docker uses a client-server model (using deamon process)to create containers, where the container is spawned as a child of the deamon , this makes daemon a single point of failure. Podman does behave like this as it is deamonless.
- Building images:
Docker is self-sufficient when it comes to building container images whereas Podman relies on Buildah, which expresses its specialized nature
Podman, matching its name is tailor-made to create pods. Pods are a way to organize and group multiple containers under one entity name, unlike Podman docker doesn’t support pods.
- Support For Docker Swarm
Many developers/organizations who rely on the docker swarm as a tool may not fall back to Podman as it does not support Docker Swarm. Though Podman has recently extended its support for docker-compose to make it also compliant with a dokcer swarm, docker being a natural fir may pose a tough challenge.
To further digest the differences, let me compile the same in the form of a table:
Now that you know some basic factors which differentiate Podman from docker, let me help you with this burning question which one to choose?
Podman Vs Docker: Which One To Choose?
You can choose Docker if:
- You need a robust and well-documented container orchestration ecosystem. Docker is a go-to tool and with a large community, you can expect all the support available if you feel stuck somewhere while implementing it
- You are looking to implement container orchestration without any hassle and with quick support. Docker swarm support makes docker stand compared to Podman as it has to rely on alternatives that are not as feature-rich as Docker Swarm or Kubernetes.
You can choose Podman if:
- You need a highly secure and reliable system. Podman’s architecture is inherently designed to be more secure than Docker’s due to the rootless and deamon-less architecture.
- You are looking to move to Kubernetes for your container orchestration needs later on. Podman is tailor made to support the concept of Pod which is a key object used by kubernetes. Want to get a practcial and deep understanding about kubernetes , do try Best course for docker and Kubernetes.
Can Podman be a replacement for docker?It depends. If you are starting up with containerization tech from scratch in your company you can definitely get started with Podman, but if your company is already invested heavily in the docker ecosystem, switching can be a costly affair, so analyzing the tech debt has to be considered here.
Can docker and Podman Co-exist as an Idea? Why not? As both of them are OCI compliant there is quite a possibility for both to co-exist, one can leverage docker’s potential to build an app for the dev environment and to make their prod environment more secure they can leverage Podman’s capabilities.
Docker is well suited for the businesses looking to adopt robust containerization system that is designed to be reliable , scalable and has a larger tech commun ity ti support developers. Podman should not be seen as a competition to docker but a good to have tool for kickstarting the containerization journey if you are just getting started as an organization.
Frequently Asked Questions (FAQs)
- Is Docker better than Podman?
It’s contextual, as we discussed above, which one to choose section if you are looking to implement more reliable and secure production-ready containerization systems Podman can be a better choice but if you are looking for a more robust and well-tested ecosystem that has a well-established use cases and community support Docker is a better tool.
Docker can be good for someone based on the use case but for someone, Podman can do the better job.
- Is Podman safer than Docker?
Podman is touted and designed to be more secure than Docker as it does not require root access. Podman images are created according to OCI standards so that they can be easily pushed to other container management tools and registries. You can run Podman without having root access and privileges.
- Can I use Podman rather than Docker?
It is totally upon your use case and if that use case requires you to go for Podman you can definitely do that. Podman has all that is required to get started with Container orchestration needs, especially if you want to look for a more secure, customizable platform that nurtures the concept of Pods.