So why should you care about hypervisors vs. containers? Bottomley explains that hypervisors, such as Hyper-V, KVM, and Xen, all have one thing in common: “They’re based on emulating virtual hardware.” That means they’re fat in terms of system requirements.
Bottomley also sees hypervisors as ungainly and not terribly efficient. He compares them to a Dalek from Dr. Who. Yes, they’re good at “EXTERMINATE,” but earlier models could be flummoxed by a simple set of stairs and include way too much extra gear.
Containers, on the other hand, are based on shared operating systems. They are much skinner and more efficient than hypervisors. Instead of virtualizing hardware, containers rest on top of a single Linux instance. This means you can “leave behind the useless 99.9% VM junk, leaving you with a small, neat capsule containing your application,” says Bottomley.
LXC 1.0: Your first Ubuntu container [1/10]
LXC 1.0: Your second container [2/10]
LXC 1.0: Advanced container usage [3/10]
LXC 1.0: Some more advanced container usage [4/10]
LXC 1.0: Container storage [5/10]
LXC 1.0: Security features [6/10]
LXC 1.0: Unprivileged containers [7/10]
LXC 1.0: Scripting with the API [8/10]
LXC 1.0: GUI in containers [9/10]
LXC 1.0: Troubleshooting and debugging [10/10]
Today's announced collaboration between Red Hat and dotCloud, the company behind Docker, is exciting for a lot of reasons. As the release notes: "Docker and OpenShift currently leverage the same building blocks to implement containers, such as Linux kernel namespaces and resource management with Control Groups (cGroups). Red Hat Enterprise Linux Gears in OpenShift use Security-Enhanced Linux (SELinux) access control policies to provide secure multi-tenancy and reduce the risk of malicious applications or kernel exploits."
If you're just starting out with Docker, it's super easy to follow the examples, get started and run a few things. However, moving to the next step, making your own Dockerfiles, can be a bit confusing. One of the more common points of confusion seems to be:
Where are my Docker images stored?
Table of Contents
- Linux Containers
1.1. Synopsis
1.2. This HOWTO - Kernel Setup
2.1. Configuration Options - Setup of the Controlling Host
3.1. Control group filesystem
3.2. Userspace tools - Container install
4.1. Bootstrap
4.2. Download existing
4.3. Using the lxc tools - Container definition setup
5.1. Configuration files
5.2. Container /dev - Container Creation and destruction
6.1. Creation
6.2. Destruction - Init setup
7.1. /etc/inittab
7.2. rc.sysinit replacement
7.3. /etc/inittab cleanup
7.4. other rc.d/runlevel cleanup
7.5. /etc/rc.d/runlevel cleanup can be skipped if you need a simple setup
7.6. rc.d script for starting/stopping containers - Notes
8.1. keychain behavior when running in a private pid namespace - Reference Documentation
- Useful Resources
- Related tools
Linux containers (LXC) is a lightweight virtualization technology built into Linux kernel. In my previous article, Debian Virtualization: LXC Application Containers, I have detailed the steps to configure and run a simple application container using LXC. LXC application containers are very lean and consume strictly the resources the application requires. This is in sharp contrast with other virtualization technologies which are running a full Linux distribution in VM.
Linux containers (LXC) is a lightweight virtualization technology built into Linux kernel. Unlike other similar technologies, the virtual machines (VM) are driven without any overhead by the kernel already running on the computer. In VM you run only the processes you need, most of the time without even going through the regular SysV or Linux init. This means that memory is used very conservatively. These lightweight containers are sometimes called application containers, as opposed to distribution containers where you run a full distro starting with SysV/Linux init.
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.
Exploitez les clones !
L'utilisation de machines virtuelles est devenu un impératif dans le cadre du développement agile de site Web.
Elle permet de monter des plateformes dédiées à un projet ou un test pour valider des choix technologiques, des orientations de design, faire du testing A/B, et ceux-ci rapidement, sans empiler des machines physiques et à coût quasi-nul.
Avec une bonne virtualisation, le cycle de vie du service est couvert de sa conception à son exploitation.
Si vous ne souhaitez ni supporter les mauvaises performances I/O des systèmes de virtualisations complets comme VMWare, Xen ou KVM, ni utiliser un noyau spécifique, LXC est la solution de virtualisation du moment.
Cet article vous présente comment créer une machine virtuelle LXC - LinuX Container - sur une plateforme Linux Ubuntu ou Debian like.
Interactive commandline tutorial
The best way to learn how Docker works is to use it!
This hands-on tutorial is 100% online, so you don't need to install a thing. In about 10-15 minutes you'll be familiar with the basic Docker commands.
(Très bien foutu)