- ZeroVM is an open-source virtualization platform that allows you to create and host virtual machines.
- Hashicorp is a open-source software solution assists enterprises in creating and managing portable software deployment environments such as VirtualBox.
- Rancher is an open-source project that provides a platform for managing and running containers.
Docker is an open-source platform that allows you to define and run various containers for your code. And it has taken the enterprise software industry by storm.
This is mainly thanks to its ability to automate and simplify application deployment. But though Docker has become the standard in containerization, there are some great Docker alternatives available on the market today.
It’s undeniable how incredibly powerful, reliable, and easy to use Docker is. It makes it easy to develop multi-platform software. It also lets you quickly test your application without installing it on every server. What’s more, it allows you to scale up your application without the need for more hardware.
However, as we’ve mentioned, Docker isn’t the only container platform out there. So, if you need to swap in an alternative for one reason or another, read on.
This is an open-source virtualization platform that allows you to create and host virtual machines. It has a robust set of features but is still quite lightweight. Thanks to it, users can build a safe and isolated environment for embedding apps.
ZeroVM virtualizes at the application level. It does so by embedding a program in an isolated environment, providing the advantage of speedier deployment.
Running ZeroVM is safe for applications that run unverified code in virtual environments. That’s because it stops attackers from accessing application data. ZeroVM also differs from container technologies because it can isolate individual processes at the application level. It also has the quickest startup time—less than 6 milliseconds.
Since ZeroVM doesn’t function at the operating system level, it can be deployed for application processes. Thus, it provides developers with a highly secure, isolated virtual environment.
This Hashicorp open-source software solution assists enterprises in creating and managing portable software deployment environments; like VirtualBox, for example. Vagrant’s simple workflow and automation allow developers to create portable development environments easily.
While Docker can run software on a containerized system on Windows, Linux, and macOS at a low cost, it does not support all operating systems, including BSD. So, when delivering apps to BSD systems, vagrant production parity outperforms Docker.
Lack of Complete Capability
However, Vagrant does not support full containerization. Since it lacks complete capability when used in microservices-heavy settings, Vagrant is especially beneficial when you need consistent and accessible development procedures; or when BDS deployments are required.
You can use Vagrant to create virtual machine images and share them with your teams across many platforms to build virtual environments that use the same compilers and libraries. This is in contrast to Docker, which frequently reverts to the previous image when restarted.
Overall, Vagrant is used for creating unique workflow environments on virtual machines, providing users with the benefits of automation, decreased setup time, and increased productivity.
Rancher is an open-source project that provides a platform for managing and running containers. It has a dashboard, orchestration, and networking features. Rancher also uses automation to simplify maintaining a complex environment. This comes in handy when an administrator needs to cancel a user’s access rights across several clusters in an organization.
Rancher is a large-scale virtualization solution that, in contrast to other top Docker alternatives, excels at managing groups of orchestration engines, such as Kubernetes and Docker Swarm.
Namely, it enables customers to automate and control any cluster process built with them. And, as a result of their diverse functions, Rancher, Docker Swarm, and Docker can all be employed at different levels.
Businesses that use Rander enjoy a production-ready Kubernetes infrastructure – whether on-premises or as a service – decreased overhead management, an application catalog, automated deployment, and more.
When you want to run your app in production, you need a consistent and reliable environment. This means you don’t want to rely on the vagaries of the cloud provider or the whims of your infrastructure.
Containerd is designed specifically for production applications, providing a high-quality, low-latency experience across your containers. It also lets you use them with zero downtime, so if something goes wrong, it won’t interrupt any services running in your cluster.
Since Containerd runs independently by using runC as a low-level container runtime, users can install it without running Docker. Depending on your requirements, you can use a high-level runtime like kata-runtime.
When you install Docker, Containerd is also automatically installed, and it uses its CRI plugin to run the Kubernetes Container Runtime Interface (CRI).
#6: Microsoft Azure Container Registry
Microsoft Azure Container Registry is a public, cloud-based Docker registry and service. Azure Container Registry makes it easy to build, ship, and run container-based applications in the cloud. What’s more, ACR is a fully managed service that stores your containers in Microsoft’s highly available and secure infrastructure.
You can also use ACR to collaborate with partners, customers, or other groups by managing the permissions of those who can access your containers. You can import existing images from any registry that supports the Open Container Initiative (OCI) specification, such as Docker Hub.
In addition, Microsoft Azure makes it simple for developers to transition from a monolithic architecture to a containerized environment. It also simplifies container administration without requiring specialized knowledge.
In fact, Microsoft Azure is now a more comprehensive choice for managing container clusters, since developers can operate and scale programs using Kubernetes, Docker Swarm, and other container orchestrators.
Users can utilize Microsoft Azure Container Registry to deploy containerized apps from the Azure platform to other virtual platforms using third-party technologies such as Docker Enterprise Edition and OpenShift.
Users can also take advantage of strong visual studio tools for debugging and deploying containerized apps.
#5: LXC (Linux Containers)
LXC is a technology that allows you to create and manage Linux containers, since LXC provides OS-level virtualization. It also allows running multiple isolated Linux systems (containers) on a single control host using the same kernel and storage, but with individual user spaces and ids.
Although Linux’s LXC is an older containerization technology that was abandoned in favor of Docker, it made a powerful comeback by capitalizing on Docker’s flaws, such as inadequate volume management and sharing host resources (IP address, system files, hostname, and so on).
It supports namespaces and control groups for resource control, has full support for seccomp filtering, can run multiple kernels simultaneously (each with its own memory space), and provides all the standard APIs for controlling processes.
Both Docker and LXC are popular containerization engines because they’re lightweight and easy to deploy. But LXC can also be used as a replacement for hypervisors and is highly favored for various data-intensive applications and activities.
#4: Kubernetes (K8)
Kubernetes is a platform for managing containerized applications. It is the de facto standard for orchestrating containerized workloads in production environments with built-in monitoring, logging, and alerting features. It’s important to note that Kubernetes supports multiple platforms, including Windows, Linux, and Mac OS.
Kubernetes has been around for years and has evolved into a mature platform used by startups and corporations alike. It’s a great tool for any company looking to gain more control over its infrastructure through automation and orchestration. If you want to run many containerized applications on different platforms, you’ll likely need Kubernetes.
Although Docker has a comparable orchestration function, it can only manage a node (a cluster of containers), and it lacks an automatic node rescheduling feature for inactive ones. Still, one advantage of Kubernetes is its ability to scale either up or down, depending on demand.
This can help you handle unexpected spikes in traffic or allow you to use fewer servers when you don’t need them. Kubernetes also has built-in redundancy with its automated failover system.
VirtualBox, which was first released in 2007, is comparable to Docker in that they are both virtual platforms used for designing and running applications. Unlike Docker, developers can use VirtualBox to create many virtual machines that run on various operating systems.
VirtualBox also has robust security protections, since virtual machines produced on it don’t share the host’s Operating System kernel. This is in contrast to Docker containers, which pose higher security risks by sharing this kernel.
So, while VirtualBox may be less portable than other Docker alternatives, it provides users with the advantage of running any OS type on a single system. This includes operating Graphics-based programs smoothly, easy file and folder sharing, cross-platform support, and a more secure virtual environment without the need for hardware virtualization.
OpenVZ (Open Virtuozzo), offered by the Virtuozzo company, is a virtualization platform for Linux. It’s designed to create lightweight virtual machines that can run your operating system and applications on the same physical server.
OpenVZ is more secure than other options because it uses a private network inside each container. This means that even if someone manages to get into one container, they won’t have access to others on the same node.
Users can use OpenVZ to create several isolated Linux containers on a single Linux server. As a result, these containers are used to build isolated environments to host virtual servers. Each container functions as a separate server in this situation, with its own root access, memory, IP address, system libraries, applications, and files.
This keeps programs running in VZ containers from clashing, and allows each application to be launched independently.
The Network File System (NFS) of OpenVZ is also a significant component. This functionality allows users to access network disk files from OpenVZ-hosted virtual servers.
RedHat’s Podman is a daemon-free, open-source, Linux-native container engine used to generate, execute, and manage Linux OCI containers and container images. Podman has a command-line interface similar to Docker, but it runs slightly differently.
One notable distinction between Docker and Podman is that the former uses a persistent, self-contained runtime called “dockerd” to handle its objects. Podman, on the other hand, does not rely on a daemon to function. Instead, it launches containers as child processes. It also uses a runtime process to connect directly with the registry and the Linux kernel. This is why Podman is referred to as daemon-less container technology.
The lack of a daemon enhances Podman’s flexibility as a container engine because it removes the reliance on a single process that could operate as a point of failure. Podman is also distinct from Docker in that it does not require root access. This feature adds an extra security buffer by restricting potentially harmful processes from changing critical system settings and exposing the container.
Podman may also operate pods (groups of one or more containers controlled as a single entity, sharing a pool of resources). Podman users can now migrate their workloads to Kubernetes due to this new capability.
Best Docker Alternatives: Bottom Line
Docker container technology enables organizations of all sizes to deliver software faster and easier by isolating the precise details of each application from its dependencies. It is one of the most popular open-source tools in the containerization industry today.
However, switching to Docker may not be necessary if your company already uses another container management system, such as Kubernetes or Mesosphere DC/OS. There are several alternatives available that offer more functionality than Docker while still maintaining its ease of use and portability.
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