GNU parallel is a shell tool for executing jobs in parallel locally or using remote computers. A job is typically a single command or a small script that has to be run for each of the lines in the input. The typical input is a list of files, a list of hosts, a list of users, a list of URLs, or a list of tables. If you use xargs today you will find GNU parallel very easy to use, as GNU parallel is written to have the same options as xargs. If you write loops in shell, you will find GNU parallel may be able to replace most of the loops and make them run faster by running several jobs in parallel. GNU parallel makes sure output from the commands is the same output as you would get had you run the commands sequentially. This makes it possible to use output from GNU parallel as input for other programs.
The Linux Replicated High Availability Manager (Linuxha.net) allows the creation of clusters for application high availability through data replication. Currently, clusters are limited to two nodes, but multiple applications can be hosted and failed-over between the nodes. The software uses DRBD to provide the data replication facillity.
The Spread Toolkit provides tools for developing reliable and robust distributed applications ranging from collaboration tools to fault-tolerant database servers to replicated Web servers. It consists of a daemon which provides multicast messaging, reliability, ordering, and membership services, and a library which applications link with. Spread provides a simple API for writing group applications and is designed to provide high performance for local and wide area networking applications.
Crossroads is a daemon running in user space, and features extensive configurability, polling of back ends using wake up calls, status reporting, many algorithms to select the "right" back end for a request (and user-defined algorithms for very special cases), and much more. Crossroads is service-independent: it is usable for any TCP service, such as HTTP(S), SSH, SMTP, RDP, and database connections. In the case of HTTP balancing, Crossroads can provide session stickiness for back end processes that need sessions, but aren't session-aware of other back ends. Crossroads can be run as a stand-alone daemon or via inetd, and features a management Web interface for monitoring and for modification of parameters.
Collax V-Cube+ is a HA cluster management suite based on a 64bit Linux system and KVM to provide server virtualization. It offers solutions for single virtualization hosts, as well as high availability management on two or more nodes, allowing embedded HA storage using DRBD and iSCSI. By using live snapshots, automatic live migration, and incremental backups, the availability of virtual machines is increased tremendously in case of hardware and software maintenance or even hardware failures. Virtual network switches and the protocols GVRP, LLDP, and RSTP help to set up a virtual DMZ.
Ganglia is a scalable distributed monitoring system for high-performance computing systems such as clusters and grids. It is based on a hierarchical design targeted at federations of clusters. Ganglia is currently in use on over 500 clusters around the world and has scaled to handle clusters with 2000 nodes.
FAI (fully automatic installation) is a non-interactive system to install a Debian GNU/Linux operating system on a group of PCs or a Linux cluster. After installation, the systems are fully configured and ready to run. It is a scalable method for performing unattended installation and updating. Changes to the configuration files of the operating system are made by cfengine, shell, and Perl scripts.