Linux containers (LXCs) perform better and faster than virtual machines. We take a quick look at why this is so, compare Docker with a Linux container, and then explore the advantages of LXCs.
Containers behave like virtual machines. However, unlike virtual machines, which must replicate an entire operating system to function, containers only need to replicate the specific components they require to function. This lowers the application’s size and provides a noticeable performance boost. They also function far more quickly because, in contrast to traditional virtualisation, they essentially run on their host natively, albeit with an extra layer of security.
Linux containers started out as an open source project to offer an operating system-level virtualisation technique that makes use of the built-in capabilities of the Linux kernel. With major support from IBM, among others, the project began in the late 2000s and soon found its way into the mainline Linux kernel. Through this integration, LXCs were able to take advantage of native support and optimisations, which aided in their uptake and continued improvement.
Multiple isolated Linux systems, or containers, can be run on a single Linux host using Linux containers. LXCs enable containers to function as standalone systems with their own file system, process tree, and network interfaces while sharing the host kernel. They are frequently thought of as a more portable substitute for virtual machines and have paved the way for later advancements in containerisation, such as the creation of Docker.
Docker vs LXCs
In the Linux environment, containerisation technologies like Docker and LXC are similar, but they address different use cases and methods of deployment and isolation. Table 1 gives a quick comparison of Docker and LXC.
| Docker | LXC | |
| Level | Application | Operating system |
| Consists of | Microservices and the portability of applications across environments in mind. | Like a lightweight virtual machine, every LXC has its own file system, networking, users, and processes. |
| Aim | Creates a more user-friendly platform for container orchestration and deployment by abstracting LXC or other container runtimes under its engine. | Aims to create environments that closely mimic a fully functional Linux system. |
| Isolation | It isolates apps at the process level using container technology (cgroups, namespaces). Unlike other container operating systems that run multiple services or an entire Linux OS, Docker’s containers are more strictly sandboxed to run a single application or process. | Uses Linux namespaces (PID, NET, IPC, etc) to provide isolation for processes, filesystems, and networks. Within the container, it can run several services and complete Linux distributions. Although the degree of isolation is still shared with the host kernel, it is closer to traditional virtualisation. |
| Deployment | Docker is best suited for packaging, deploying, and operating single applications with all their dependencies in isolated environments because it was primarily created for application-level containerisation. Strong tools from Docker, such as Kubernetes, Docker Compose, and Docker Swarm, are available for managing numerous containers in intricate deployments. | When users need to run several programs and services (like a web server, database, etc) inside one container to simulate managing an entire system, LXC is better suited for system-level containerisation. |
| Setup | It provides a simpler command-line interface. | More complex than Docker. In LXC, system-level operations and configuration files require more manual configuration for networking, storage, and security management and configuration. |
| Image management |
Contains a sophisticated image management system. | Does not have a central image repository. |
| Orchestration | The most popular container runtime in Kubernetes, Docker offers native support for container orchestration via Docker Swarm. | There are no sophisticated orchestration features in LXC itself. Scripts can be used to manage and configure LXC containers, but no orchestration tools are included with the system. |
| Security | Compared to LXC, Docker’s default configuration is often more secure right out of the box because it includes tools like Notary for image signing, which makes sure containers only run trusted code. | Linux kernel features like namespaces and cgroups can be used to secure LXC, but further effort may be needed to properly isolate containers from the host. |
LXC components
Given below are the basic components of LXC we need to start with.
If we want to create a container, the following command is required:
lxc-create -n testcontainer -t Ubuntu
To start a container, we need the following code:
lxc-start -n testcontainer
To attach to a running container and execute commands inside it, type:
lxc-attach -n testcontainer
The command to stop the container is:
lxc-stop -n testcontainer
To destroy the containers and delete all the data, type:
lxc-destroy -n testcontainer
Advantages of LXC
Efficacy: Unlike virtual machines, which need a hypervisor and different OS instances, containers use the host OS’s kernel.
Performance: LXCs offer almost native speed due to the lack of overhead associated with executing different operating systems, such as virtual machines.
Resource isolation: You can restrict and assign resources like CPU, memory, and disk input/output to containers using cgroups.
Security: By using user namespaces and unprivileged containers, Linux containers can be isolated and secured with the right configuration.
Flexibility: Like traditional virtual machines, LXCs offer flexibility by allowing full-fledged Linux distributions to run within containers.
With Linux containers, you can run multiple isolated Linux environments on a single host and share a kernel thanks to a lightweight virtualisation technique. Using namespaces and control groups (cgroups), LXCs make sure that every container has its own filesystem, network interfaces, and process tree. Prominent features of LXCs are resource allocation, networking, and storage configuration files, as well as container management commands like lxc-create, lxc-start, and lxc-attach.
Linux containers are a great choice for system-level virtualisation because of their efficiency, flexibility, and near-native performance. This is especially useful when multiple services or full Linux distributions need to run in secure, isolated environments.
