Asterisk is a hybrid TDM and packet voice PBX (Private Branch eXchange) and IVR platform with ACD functionality. It acts as middleware between the Internet (IAX, SIP, MGCP, Skinny, H.323), telephony channels (like Zaptel, T1, PRI, E1, FXO, FXS, VoIP, VoFR, ISDN, modems, Internet Phone Jack, etc.), and applications (like voice-mail, conferencing, directories, MP3 players, intercoms, etc.). It has many advanced features such as a codec translation API. The base distribution includes several channel backends, as well as applications. However, the beauty of Asterisk is its ability to be extended using its APIs, dynamic module loader, and AGI scripting interface. End users can even write their own applications that run on the system in C or any scripting language of their choice.
ClusterNFS is a set of patches for the "Universal NFS Daemon" (UNFSD) to allow multiple clients to nfs mount the same root filesystem by providing "tagged" filenames. When a client requests the file "/path/filename", the ClusterNFS server checks for the existence of files of the form "/path/filename$$TAG=value$$". If such a file exists and the client has a matching value for KEY, this file is returned. If the client does not have a matching value or no such file exists, the file request proceeds as normal. Currently supported keys include HOST (hostname), IP (IP number), CLIENT (matches any nfs client) and CREATE (for "tagged" creation of files).
Condor is a high throughput system, scheduling and providing large amounts of computational power over a long period of time. It provides the efficient use of a large variety of systems, from idle desktop workstations and dedicated clusters to grid systems all over the world, while its incredibly flexible configuration implements and maintains the machine owner's desired policy for the machine's availability.
fCluster is a multi-threaded client/server redundancy application for your Linux firewall solution. fCluster is designed for the production environment with features that include: dynamic firewall synchronization, support for both ipchains and netfilter, user definable polling intervals and fail-over sequence, and email notification of a system failure. It also includes a Perl administration utility that allows you to configure both the server and the client from one machine, and view the status of the local and remote machines.
The Linux Virtual Server Project is a project to cluster many real servers together into a highly available, high-performance virtual server. The LVS load balancer handles connections from clients and passes them on the the real servers (so-called Layer 4 switching) and can virtualize almost any TCP or UDP service, like HTTP, HTTPS, NNTP, FTP, DNS, ssh, POP3, IMAP4, SMTP, etc. It is fully transparent to the client accessing the virtual service.
Heartbeat is a full-function high-availability system for Linux and other POSIX-like OSes. It monitors services and restarts them on errors. When managing a cluster (more than 1 machine), it will also monitor the members of the cluster and begin recovery of lost services in less than a second. It runs over serial ports and UDP broadcast/multicast, as well as OpenAIS multicast. It is easily adapted to different interconnect media and protocols. When used in a cluster, it can operate using shared disks, data replication, or no data sharing. Versions starting with 2.0 are comparable to any commercial HA package, providing resource monitoring, larger clusters, and detailed dependency information.
mod_backhand is a load balancing module for Apache. It provides per-request HTTP redirection within a heterogeneous Apache server cluster. Each request is processed and run through a set of "candidacy functions" to determine which server is best suited to respond. The request is then proxied to that server. Facilities are in place to allow you to write your own dynamically loadable decision making algorithms. Everything about the request and the current availability of resources can be used in the decision-making process.
The OpenLDAP Project is a collaborative effort to provide a robust, commercial-grade, fully featured, open source LDAP software suite. The project is managed by a worldwide community of volunteers that use the Internet to communicate, plan, and develop OpenLDAP Software and its related documentation. OpenLDAP Software provides a complete LDAP implementation including server, clients, C SDK, and associated tools.
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.