Onesis
Encyclopedia
oneSIS is an open-sourced software tool developed at Sandia National Laboratories
Sandia National Laboratories
The Sandia National Laboratories, managed and operated by the Sandia Corporation , are two major United States Department of Energy research and development national laboratories....

 aimed at easing systems administration in large-scale, Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

 cluster environments.

The official tag line for oneSIS is that it is a thin, role-based Single Image System for scalable cluster management. oneSIS is a simple and highly extensible method for deploying and managing one or more root images of supported Linux distribution
Linux distribution
A Linux distribution is a member of the family of Unix-like operating systems built on top of the Linux kernel. Such distributions are operating systems including a large collection of software applications such as word processors, spreadsheets, media players, and database applications...

s into a master image used as the root of diskless nodes. A single image can serve thousands of nodes.

Using oneSIS

oneSIS requires functional infrastructure, such as DHCP
Dynamic Host Configuration Protocol
The Dynamic Host Configuration Protocol is a network configuration protocol for hosts on Internet Protocol networks. Computers that are connected to IP networks must be configured before they can communicate with other hosts. The most essential information needed is an IP address, and a default...

, PXE
Preboot Execution Environment
The Preboot eXecution Environment is an environment to boot computers using a network interface independently of data storage devices or installed operating systems.PXE was introduced as part of the Wired for Management framework by Intel and is described in the specification The Preboot...

, and NFSroot; see HOWTO. Sysadmin has to determine which machine will serve as the source for the image that will eventually be deployed to the remaining machines in the cluster.

One of the easy-to-use conventions of oneSIS is that all configuration settings for all nodes within a cluster are controlled by a single file on the master node, /etc/sysimage. This file is used to list the machines in the cluster, define which machines belong to what class, and explains which classes boot which images from the NFSroot server and how their configuration settings differ. Changes applied to the master images appear instantly to the nodes using said images. Changing a node to boot into a different image only requires a quick modification to /etc/sysimage and a reboot of the target client. Since oneSIS was designed with the Linux-systems administrator in mind, users will not find proprietary-GUI
Graphical user interface
In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...

 frontends here; all the tools to image a box, copying root-images, converting diskless machines diskfull, etc are accessible exclusively through the command line interface (CLI). The goal is to let Linux systems administrators feel at home with the typical CLI tools they're already used to.

OneSIS benefits include:
  • Overall system complexity and administration overhead is reduced.
  • Potentially more stable and secure environment because sysadmins concentrate on hardening single images.
  • Images can be deployed in diskless and diskfull environments.
  • Uses standard tools and settings found in any Linux distribution and the open Linux kernel source.
  • Scalability.
  • Possibilities for load balancing and failover support.

External links

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