Introduction-

What are the different Container technology?

Container technology has started after 2013. There is a high potential of getting confused about available container types like Docker , LXC/LXD and CoreOS rocket.

What’s LXC?
LXC (Linux Containers) is an operating-system-level virtualization method for running multiple isolated Linux systems (containers) on a control host using a single Linux kernel.
LXC is a userspace interface for the Linux kernel containment features. Through a powerful API and simple tools, it lets Linux users easily create and manage system or application containers.

Benefits of Linux Containers:
1 – Lightweight built-in virtualization
2 – Application/server isolation
3 – Easy deployment and management
4 – No additional licensing

Weaknesses of Linux Containers:
1 – Locked into the host kernel
2 – Supported only on Linux

Current LXC uses the following kernel features to contain processes:
– Kernel namespaces (ipc, uts, mount, pid, network and user)
– Apparmor and SELinux profiles
AppArmor is a Linux kernel security module that allows the system administrator to restrict programs’ capabilities with per-program profiles.
Security-Enhanced Linux is a Linux kernel security module that provides a mechanism for supporting access control security policies.
– Seccomp policies
– Chroots (using pivot_root)
– Kernel capabilities
– CGroups (control groups)

LXC is currently made of a few separate components:
– The liblxc library
– A set of standard tools to control the containers
– Distribution container templates
– Several language bindings for the API:
– python3
– Go
– ruby
– Haskell

The Linux kernel provides the cgroups functionality that allows limitation and prioritization of resources (CPU, memory, block I/O, network, etc.) without the need for starting any virtual machines, and also namespace isolation functionality that allows complete isolation of an applications’ view of the operating environment, including process trees, networking, user IDs and mounted file systems.

LXC containers are often considered as something in the middle between a chroot and a full fledged virtual machine. The goal of LXC is to create an environment as close as possible to a standard Linux installation but without the need for a separate kernel.
LXC combines the kernel’s cgroups and support for isolated namespaces to provide an isolated environment for applications. Docker can also use LXC as one of its execution drivers, enabling image management and providing deployment services.

What’s LXD?
LXD is a next generation system container manager. It offers a user experience similar to virtual machines but using Linux containers instead. LXD isn’t a rewrite of LXC, in fact it’s building on top of LXC to provide a new, better user experience. Under the hood, LXD uses LXC through liblxc and its Go binding to create and manage the containers.

What is difference between LXD vs Docker?
– Docker focuses on application delivery from development to production, while LXD’s focus is system containers.
– LXC in market since 2008 as compare to Docker 2013.
– Earlier Docker was based on LXC. Later Docker replaced it with libcontainer.
– Docker specializes in deploying apps
– LXD specializes in deploying (Linux) Virtual Machines

Application build using LXC?
Anbox – Android in a Box
Anbox is a container-based approach to boot a full Android system on a regular GNU/Linux system like Ubuntu. In other words: Anbox will let you run Android on your Linux system without the slowness of virtualization.

Reference –
WebSite: https://linuxcontainers.org
Version: LXC 2.1.x
https://linuxcontainers.org/lxd/getting-started-cli
http://www.tothenew.com/blog/lxc-linux-containers

Thank you,
Arun Bagul