Docker is a platform that allows developers to easily create, deploy, and run applications in containers. Containers are lightweight, portable, and self-sufficient environments that include all the necessary dependencies and libraries for an application to run.
Docker uses a technology called containerization, which allows applications to run in isolated environments on a single machine or across multiple machines in a cluster. This makes it easy to manage and scale applications, as well as to ensure consistency across different development, testing, and production environments.
Docker provides a command-line interface (CLI) and a RESTful API for interacting with the Docker daemon, which is responsible for managing the containers. The Docker CLI allows developers to build, run, and manage containers, while the RESTful API allows other tools and systems to interact with the Docker daemon.
Docker images are the building blocks of the Docker platform. They are snapshots of an application and its dependencies, and they can be used to create new containers. Developers can create their own images or use images from the Docker Hub, which is a public repository of Docker images.
Installing Docker on Ubuntu is simple, you can use the following command:
sudo apt-get update
sudo apt-get install docker.io
After installing Docker, you can start using it by running the docker command in the terminal.
Alternatives to Docker:
- rkt (Rocket): is an application container engine developed by CoreOS. It is designed to be more secure and configurable than Docker. It uses a more secure approach to containerization by isolating the application and its dependencies in a separate namespace and enforcing privilege separation. It uses the App Container (appc) image format, which is a specification for packaging and distributing containerized applications.
To install rkt on Ubuntu:
sudo apt-add-repository -y ppa:projectatomic/ppa
sudo apt-get update
sudo apt-get install -y rktTo install LXC on Ubuntu:
sudo apt install lxc
- LXD: is a container hypervisor developed by Canonical, which is built on top of LXC and provides a user-friendly interface for managing containers. It supports multiple container runtimes, including Docker and rkt, and provides advanced features such as live migration and network management.
To install LXD on Ubuntu:
sudo apt-add-repository -y ppa:ubuntu-lxc/lxd-stable
sudo apt-get update
sudo apt-get install -y lxd
- ContainerD: is an open-source container runtime developed by Docker, it is a lightweight alternative to Docker daemon, it’s more focused on the runtime of containers. It’s focused on providing a stable and reliable runtime for containers, it can be integrated with other orchestration tools like Kubernetes.
To install ContainerD on Ubuntu:
sudo apt-get update sudo apt-get install containerd
- Kubernetes: is an open-source container orchestration system that allows you to manage and deploy containers at scale. It works with multiple container runtimes, including Docker, and provides advanced features such as automatic scaling and self-healing.
There are different ways to install Kubernetes on Ubuntu, but one of the most common ways is to use the Kubernetes package manager, kubeadm. To install kubeadm, you need to add the Kubernetes apt repository to your system:
sudo apt-get update && sudo apt-get install -y apt-transport-https curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add - echo "deb https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee -a /etc/apt/sources.list.d/kubernetes.list sudo apt-get update sudo apt-get install -y kubeadm
After installing kubeadm, you can use it to set up a Kubernetes cluster, you can use the command kubeadm init to initialize the master node, and then use kubeadm join to add worker nodes to the cluster.
Please note that installing Kubernetes using kubeadm is just one of the many ways to install it, there are other ways like using kops, kubicorn, and more.
- OpenShift: It’s a container application platform, developed by Red Hat, it’s based on Kubernetes and provides additional features such as a built-in registry, routing, and security.
To install OpenShift on Ubuntu, you can use the OpenShift installer, it’s a command-line tool that automates the installation of OpenShift. You can download the installer from the OpenShift website and then use it to set up a cluster.
Please note that installing OpenShift on a single machine is not recommended for production use, OpenShift is designed to run on clusters of machines.
Additionally, there are several Docker substitutes available, including:
- A tool for creating and managing virtual machine environments is called Vagrant. It can be used to build secure test environments and development environments.
- You can use VirtualBox, a virtualization program, to run different operating systems on a single computer.
- VMware is a commercial virtualization program that offers enterprise-level capabilities like high availability and disaster recovery. It enables you to run different operating systems on a single computer.
- Microsoft created the virtualization program Hyper-V, which is integrated into the Windows operating system and lets you run different operating systems on the same machine.
Why do we need an alternative to Docker?
Security: Using an alternative that offers more security features might be preferred by some users. One such alternative is rkt (Rocket), which offers a more secure method of containerization by isolating the application and its dependencies in a different namespace and enforcing privilege separation.
Feature set: Some individuals may want a substitute that offers a different set of characteristics that better meet their requirements. For managing and deploying containers at scale, Kubernetes is an open-source container orchestration system that offers cutting-edge features like autonomous scaling and self-healing.
Support: Some individuals may prefer a substitute that is created and supported by their company or a specific vendor, such as Red Hat’s OpenShift.
Also,
- Performance: Some people might prefer an alternative that provides better performance for their use case. for example, if you have a high-performance application, you might prefer to use an alternative that provides lower overhead and more direct access to the host system’s resources.
- Integration: Some people might prefer an alternative that integrates better with other tools and systems that they are already using, for example, if you are already using Kubernetes, you might prefer to use an alternative that can easily integrate with Kubernetes such as ContainerD.
It’s important to evaluate and understand the features of each alternative and choose the one that best suits your needs.
