A wise approach before jumping into any software is to study alternatives. What is the most popular platform for developing, delivering, and running containerized applications? Probably, the first name that will be recalled is Docker. But are there any worthy alternatives to containerization and Docker’s services? For the last few years, docker competitors have become more mature and ready to propose more features to their users than Docker. So you might want to consider it before taking any IT decision for your product or even a whole company. Yes! Being in DevOps for more than seven years, I have tested plenty of Docker substitutions, and here is my list of decent alternatives that might fit your needs. 1. as a Substitute to Docker Podman Podman is considered the most powerful competitor to Docker. Moreover, it can substitute the latter due to the ability to manage Docker’s container images. It also differs from Docker in some approaches to run containers. While Docker uses a daemon, Podman refuses it. This gives Podman some advantages in case of some unexpected troubles with the central daemon. In Docker’s case, such distress will lead to a catastrophe for containers. 2. The Technology of Virtualization LXC This technology was a predecessor to Docker, but it was shaded by the latter. It has some similarities and differences with Docker. a general approach to containerization as an alternative to running a central daemon or program. Similarities: Docker assumes running just one process for every container. LXC allows you to manage more processes in every container. Still, Docker’s containers are to a greater extent portable than LXC’s ones due to Docker's abstracting capabilities. Differences: 3. Extended Command Set Buildah Since this container management instrument was also devised by RedHat as Podman, it has some similarities to it. For example, it is based on a fork-exec technique that allows running containers without the necessity of a central daemon or root connection. In contrast to Docker, Buildah allows you to undertake many changes at one level. Moreover, it gives the possibility to construct an empty container image for keeping metadata. However, its end result is inferior compared to Docker’s. 4. The Constructor of Containers Kaniko If you need to create images of containers inside other containers, you can resort to Kaniko. Following Podman and Buildah, it doesn’t need a daemon and can create images out of Docker’s files. However, since Kaniko is more oriented to the Kubernetes platform, it is hardly suitable and rather inconvenient for local development. 5. Daemon Containerd Currently, Containerd is a separate project for free use by customers. However, before starting its autonomous functioning, it was an element of the Docker system. Its advantage is compatibility with Windows and Linux, as well as portability. And its mission is the simplification of running container life cycles. 6. Alternative Decision of CRI-O CRI-O is a platform project-oriented to dealing with the Kubernetes. It was developed for running and restarting containers but in a more slight version. CRI-O can draw data from any container registry, set them on a disk, and start a low-level runtime. 7. Security-oriented rkt It is one of the most important alternatives to Docker due to its versatility and orientation to the issue of safety. Like some other alternatives, it doesn’t have a daemon and can manage Docker containers. It is provided for free and can compete with docker. Thus, in the situation of moving Docker to proprietary ways of functioning, users have some alternatives to experiment with. If your company didn’t use Docker’s services before, it is worthwhile to start with some other options. They fully cope with all functions fulfilled by Docker and can be a decent substitution to it.
