The platform is all about app containers and containerization. If you’re new to , it is a way of packing a software application and all its dependencies into a single image. Containers allow users to separate an application from its infrastructure, so the app works in a predefined way regardless of the environment. Docker containerization While other types of containerizing software exist, Docker’s products and services are expected to change drastically by the end of 2022. How, you might ask? Not so long ago, was a free open source platform preferred by developers. But starting , the new Docker Desktop subscription policy requires licensing for the . So what’s the confusion? Docker from 31 January 2022 commercial user Should we panic about this licensing update and start choosing an alternative to Docker Desktop? Let’s find out. and the Ecosystem Docker Container According to , a container is a separate unit of software that stores an application’s code, its libraries, and dependencies. IBM There is a widespread misconception that Docker is all about containers only. Well, that’s not true and Docker is only part of the container ecosystem that consists of large, different projects. What unites the two is the requirement to meet the Open Container Initiative (OCI) and Kubernetes Container Runtime Interface (CRI) standards. What are Containers Used For? Containers are mostly used in the following scenarios: In the multi-cloud environments: when using from different vendors multiple cloud services when an application works with different public clouds In the cloud migration process for legacy software modernization. In the . When applications are split into smaller and independent services, containers are essential in deploying and maintaining the provider’s services. microservice architecture When used in the ways mentioned above, containers solve the following problems: Setting up an environment for new software development. Building and compiling software applications. Running and testing an application in different environments. Deploying the application in a cloud platform such as Kubernetes or AWS. Running third-party software. What is ? Docker is a simplified platform for development, shipping, and running containerized applications. The platform provides an open-source engine that automates the deployment of any application in a lightweight, self-contained space for on-premises and cloud use. Docker Docker architecture overview Docker was the first company to ever package the advanced Linux kernel features. This made development and deployment faster. Instead of building an entire server from scratch to run a service application, you could run a Docker container image on the host and start the application, using a few host resources in multiple environments. An is a read-only, organized collection of filesystem changes that form the basis of a container. A is a runnable instance of an image. Each container has its own filesystem, memory, and network interface. Also, containers are much lighter than . image container virtual machine (VM) images Docker Tools Containerization is a relatively new concept in software development, and we’ll show you how it works in the case of Docker. Docker Engine At the heart of the Docker ecosystem is the which is a . A container runtime is a software tool for loading container images, monitoring, isolating system resources, and managing the container lifecycle. It allows you to create and run containers on any development machine and then store or upload container images through a container registry such as or . Docker Engine container runtime Docker Hub Azure Container Registry Docker Hub is a service provided by Docker for finding and sharing container images. Docker Hub As applications grow and start to include containers deployed on different servers, they get harder to work with. Everything from coordinating to planning the use of vast numbers of containers, organizing how these containers interact with each other, as well as scaling multiple container instances become harder than they should be. Kubernetes in Docker Docker provides the tool for defining and running multi-container applications. enables the deployment and configuration of multiple containers simultaneously. A better solution for large systems would be using Docker for containerization and image creation. For container management, use more specialized software tools called . Docker Compose Docker Compose orchestrators , also known as . It was developed by Google to manage, automate, and scale containerized applications. Essentially, in projects. Docker simplifies the process of creating containers, while Kubernetes takes over the management of the containers. That’s considered the main Kubernetes vs Docker difference. Kubernetes K8s Docker and Kubernetes are often used together and Possible Docker Issues Solutions Docker products are on a whole new level. Portability, isolation, scalability, consistency, repeatability, and automation are just a few features you can expect from Docker tools. Their widespread use and the existence of a powerful community speak for the company. However, there is still a downside to using Docker tools. Below are some of the most common reasons why developers would look for Docker container alternatives: Security Issues Containers have a weak point in the when it comes to routing, security, or detection. There is limited security in the Docker architecture itself. A user with access to the Docker daemon has root advantage over the host system. Additionally, there is no division of containers between different users on the same system. Everyone can see all the containers running on the host system. connection between services Use next-generation alternatives, which are initially aimed at better safety and ease of use. A good example is , a great Docker open-source container alternative with no daemon at all. Solution: Podman Orchestration issues Docker can’t manage the container launch order. Though it has an orchestration tool called , its functionality is limited compared to powerful orchestrators like Kubernetes. Besides, Docker Swarm works only with Docker containers. Docker Swarm Use Docker alternatives like Kubernetes for container orchestration. Kubernetes supports multiple container types: Docker, containers, CRI-O, and any solution that corresponds to the CRI standard. Solution: Isolation issues Docker does not provide 100% isolation of resources between containers. And, there could be a mess in the images repository as all the users have the power to change something. Use next-generation alternatives aiming at better safety and ease of use. Unlike Docker, stores images and containers in different directories. The Podman repository is in the user’s home directory. Each user has his own, separate set of containers so that several users can work on the host simultaneously. Solution: Podman Reliability Issues The Docker daemon service is responsible for all the work with registries, images, containers, and the kernel. But, a single service means an increased risk of failure. When a daemon process fails, all the running containers are left on their own. Use containerization tools that have no daemon – for example, . Solution: Podman Firewall Issues Docker interferes with the system firewall by adding its own firewall rules to the system. There is no reliable way to manage network access to the container through the firewall. Additionally, there is an issue when combining Docker with other services that try to manage the firewall, for example, with a VPN client-server. Deny the Docker daemon service the permission to make changes in the system’s firewall. Instead, create all the necessary rules manually. Solution: Docker Hub Issues registry contains both official and non-official images. Most of the non-official images are poorly built and have vulnerabilities. The authors of such images usually don’t provide any quality guarantees or support either. Docker Hub Whenever possible, build any image used in the project yourself and put it in your own registry for Docker images. Never run randomly selected images on your system. Solution: Installation Issues There are multiple ways to install Docker. But some features may stop working or may work unexpectedly when doing the custom installations. Always install Docker tools according to the instructions from the . Solution: official Docker site With all these unresolved issues, it’s no wonder companies and development teams are always in search of other alternatives to Docker containers. Besides, these problems were exacerbated by the latest announcement from the Docker team – Docker Desktop – when it announced that part of the Docker ecosystem, is no longer free for everyone. and What Has Docker Desktop Changed has recently caught the attention of the container community after the new changes in its subscription policy. Docker Desktop (DD) is an all-in-one application for Mac or Windows environments that enables building and sharing containerized applications and microservices. Docker Desktop includes Docker Engine, Docker CLI (Command Line Interface) client, Docker Compose, Kubernetes, just to mention a few. Docker Desktop on Mac and Windows is a way to run Linux (create a Linux VM) so that can work. Docker Desktop Docker Engine What has changed in the Docker licensing policy? The Docker company recently announced that it would be making changes in its Docker Desktop subscription terms. Docker Desktop is the only Docker solution without a complete alternative yet. The new were announced on August 31, 2021, with a grace period up to January 31, 2022. During this period, Docker Desktop users need to decide on a subscription plan if they want to continue using the Docker Desktop license. Otherwise, they will have to switch to other Docker Desktop alternatives. changes The officials expressed that these changes are vital to the improvement of their product and scaling their business. With Docker Desktop now , the company is one big step closer to its goals. reaching have 3.3 million installations The New Subscription Policy Back to our topic, only the subscription plan is free – it is available for . If a company has more than 250 employees or its revenue is greater than $10 million, it will have to use one of the paid subscriptions: , , or . Simply put, large business users must go for a Docker Desktop enterprise license to get additional features – secure software supply chain management, centralized policy visibility, and controls. Smaller businesses will enjoy Docker Desktop for free. Personal small businesses, individual use, and non-commercial open-source projects Pro Team Business If you don’t need , then nothing has changed for your business. Note: Docker Desktop If you don’t need Docker Desktop, then nothing has changed for your business – you can still choose any tool (Docker, Podman, CRI-O, etc.) for container creation and orchestration. Most of the extra features provided by the involve using the images registry. For example, the ability to scan images from the for vulnerabilities. But normally, companies use registries provided by Cloud vendors. Docker Desktop paid plans Docker Hub Docker Hub When do you really need Docker Desktop? is for people who crave a simplified installation process but don’t want to use the command line. Docker Desktop facilitates easy Docker setup and integration with (Windows Subsystem for Linux). Docker Desktop WSL Speaking of Linux, may still not be fully available for Linux users. The thing is DD is supported on Mac and Windows only. But to use Docker in non-Linux operating systems, developers need a Virtual Machine and that’s what does. Everything else (Docker CLI, Docker Engine, and other Docker tools) remains free and open source under the . Docker Desktop Docker Desktop Apache v.2 license Alternatives Docker Desktop When using you’ll probably find the mentioned above. Some of these issues were partially solved in the paid subscriptions. For example, the provides centralized management, enhanced security, and SAML SSO in the near future. But others (together with the new tariffication) of the DD, may force you to search for alternative solutions. Docker Desktop Docker issues Business plan per-user-per-month Docker Desktop and Kubernetes Most of the DD alternatives are focused on building and pushing images and having environments. In similar cases, you would only use Docker to build and push container images in local environments. This can be done with Docker Desktop, through Kube API, and using Minikube as a Linux VM. local Kubernetes In other cases that don’t require Kubernetes (for example, running containers directly, using ), there is no other alternative to Docker Compose Docker Desktop. You can replace Docker Desktop with one of the following alternatives: 1. Run a VM and manage it yourself. and the are still free. Install a Linux VM on the Windows host (for example, via Hyper-V or VirtualBox) and then install the Docker CLI inside WSL and connect over SSH. For development purposes, (building and running images), use . Docker CLI Docker Engine Podman 2. Use to install and manage a VM and also get a Kubernetes cluster up and running from Windows. But note that Minikube doesn’t have a GUI (Graphical User Interface) and doesn’t work with M1 chips, so may not work on new MacBooks. Minikube 3. Use RancherDesktop, a free open-source application for Mac, Windows, and Linux. It simplifies building, pushing, pulling, running container images, and also includes Kubernetes. It’s simple to use and has a built-in GUI. But since this tool is relatively new, you risk missing out on CLI, and multiple features. It may also have bugs. Final Thoughts In the container ecosystem, there are no “Docker containers”, there are just “containers”, and there are no “Docker images”, just “container images.” You are free to use any alternative containers to Docker, as long as it follows the industry standards around container formats and runtimes. Please remember that Docker is a tool. Sometimes, the best option is to use lightweight virtual machines. In other cases, using more specialized tools may help. It all boils down to the purpose, project goals, and the application features. The only Docker product that has no fully equipped alternative is Docker Desktop for Mac and Windows. But, it’s only a matter of time, before other companies launch products that can substitute DD. For now, try analyzing if provides any additional value for your business or not. If you don’t use any Docker Desktop features beyond what Docker itself is offering, it’s worth considering other options. But if there is significant additional value, it’s worth paying for the out-of-the-box functionality. Docker Desktop