Epikscan is a cluster aware, diagnostic script that runs basic health checks and gathers detailed, addressable system information from an RHEL, Scientific Linux, Oracle/OVM2, or CentOS 4, 5, or 6 system. A single archive is created for each host, containing the scan data along with linking information that can be merged with scans from other nodes to produce a cluster oriented report. HTML, text, XML, and SQLite3 database reports can be optionally generated to support both manual and automated fault analysis. The scan and merge process attempts to heuristically identify possible problems with the node or cluster configuration and highlights them in red to speed up the review and resolution process.
Nagios is a host, service, and network monitoring system that will watch your network and alert you to problems before your clients or end-users do. The system runs checks on hosts and services that you specify using plugins that return status information to Nagios. When problems are encountered, the system will send notifications to system administrators so that they can take action on the problem. The JumpBox for Nagios gives you a head start to using the system. It eliminates the complexity involved in getting the application installed, and allows you to focus on the configuration for your specific environment. Since Nagios is based on plugins, depending on what you want to do this will vary in complexity.
Diskus is a high-level hard drive diagnostic and limited repair tool. It checks the disk geometry by writing numbered IDs into the sectors of the hard drive. Later one can verify that these sector-IDs on the disk are still correct, thereby detecting data which was not correctly written. There is an option to "freshen" the data on your harddrive, which will read and rewrite the sectors. With modern drives this will re-map defective sectors.
Aranha is an application that uses an XML-RPC layer to retrieve information from one or more servers. The type of information gathered is implemented via plugins, and can be displayed or archived in several different ways. The data is gathered in Round Robin Databases (integrated with rrdtool) and can be accessed using a XUL interface available from the system. Plugins are very easy to write.
GResolver is a graphical DNS query tool. It allows system administrators to quickly and easily make the most common DNS queries without constructing lengthy dig commands. It supports all the main resource record types, including AAAA, AXFR, MX, and TXT, and the appropriate in-addr.arpa address is constructed from dotted-quad IP addresses when doing PTR queries. There are checkboxes for controlling the most commonly used options.