Lightweight virtualization is a hot topic these days. Also called “operating system-level virtualization,” it allows you to run multiple applications or systems on one host without a hypervisor. The advantages are obvious: not having a hypervisor, the layer between the host hardware and the operating system and its applications, is eliminated, allowing a much more efficient use of resources. That, in turn, reduces the virtualization overhead while still allowing for separation and isolation of multiple tasks on one host. As a result, lightweight virtualization is very appealing in environments where resource use is critical, like server hosting or outsourcing business.
One specific example of operating system-level virtualization is Linux Containers, also sometimes called “LXC” for short. We already introduced Linux Containers to SUSE customers and users in February 2012 as a part of SUSE Linux Enterprise Server 11 SP2. Linux Containers employ techniques like Control Groups (cgroups) to perform resource isolation to control CPU, memory, network, block I/O and namespaces to isolate the process view of the operating system, including users, processes or file systems. That provides advantages similar to those of “regular” virtualization technologies – such as KVM or Xen –, but with much smaller I/O overhead, storage savings and the ability to apply dynamic parameter changes without the need to reboot the system. The Linux Containers infrastructure is supported in SUSE Linux Enterprise 11 and will remain supported in SUSE Linux Enterprise 12.
Now, we are taking a next step to further enhance our virtualization strategy and introduce you to Docker. Docker is built on top of Linux Containers with the aim of providing an easy way to deploy and manage applications. It packages the application including its dependencies in a container, which then runs like a virtual machine. Such packaging allows for application portability between various hosts, not only across one data center, but also to the cloud. And starting with SUSE Linux Enterprise Server 12 we plan to make Docker available to our customers so they can start using it to build and run their containers. This is the another step in enhancing the SUSE virtualization story, building on top of what we have already done with Linux Containers. Leveraging the SUSE ecosystem, Docker and Linux Containers are not only a great way to build, deploy and manage applications; the idea nicely plugs into tools like Open Build Service and Kiwi for easy and powerful image building or SUSE Studio, which offers a similar concept already for virtual machines. Docker easily supports rapid prototyping and a fast deployment process; thus when combined with Open Build Service, it’s a great tool for developers aiming to support various platforms with a unified tool chain. This is critical for the future because those platforms easily apply also to clouds, public, private and hybrid. Combining Linux Containers, Docker, SUSE’s development and deployment infrastructures and SUSE Cloud, our OpenStack-based cloud infrastructure offering, brings flexibility in application deployment to a completely new level.
Introducing Docker follows the SUSE philosophy by offering choice in the virtualization space, allowing for flexibility, performance and simplicity for Linux in data centers and the cloud.