There are many network monitoring tools which your network team can utilize in order to monitor your organization’s network and server.
GroundWork Monitor Community Edition provides a essential IT monitoring solution that enables you to maintain network visibility and control. This is a single server deployment that leverages the strengths of 15 other open source projects such as Nagios, rrdtool and nmap. It combines the results of these projects in to a system that evaluates the status, events and performance of monitored devices and presents these results in an easy to understand web application.
The Community Edition has the following key features:
Availability monitoring - alerts if devices are up or not.
Ability to monitor servers, devices and applications which gives you the flexibility to monitor all of the integral components within your network.
Performance monitoring - gives insight on latency before a server is offline
Basic auto-discovery and configuration tools to help identify additional devices on the network which is a great time-saving function if your network is constantly changing.
ZABBIX is an enterprise-class open source distributed monitoring solution.
ZABBIX is software for monitoring of your applications, network and servers. ZABBIX supports both polling and trapping techniques to collect data from monitored hosts. A flexible notification mechanism allows easy and quickly configure different types of notifications for pre-defined events.
Some key ZABBIX features includes:
Distributed monitoring
Auto-discovery
Scalable and flexible
Web Monitoring
Dashboard capabilities
Escalations and notifications
Nagios is the leader in system, network, and application monitoring. It’s the industry standard for good reason.It allows you to gain insight into your network and fix problems before customers know they even exist. It’s stable, scalable, supported, and extensible.
Nagios provide comprehensive network monitoring to monitor windows, linux, routers, switches, firewalls, printers, services and applications.
When there is a problem the relevant person can be notified via email, pager and cellphone. With Nagios, you can be assured that all Service Level Agreements are met.
Zenoss Core is an award-winning open source IT monitoring product that effectively manages the configuration, health and performance of networks, servers and applications through a single, integrated software package.
The most popular IT Management project on SourceForge.Net, Zenoss software has been downloaded over 750,000 times and deployed in over 18,000 organizations in over 175 countries.
The key capabilities within Zenoss Core are:
Auto-Discovery - Scans the entire IT infrastruture nad provides a comprehensive view of the inter relationships throughout the envirenment.
Availability Management - Suite of active availibility monitors to test key resources accross the infrastructure.
Performance Monitoring - Graphing of real time threshold analysis.
Event & Log Management - Ability to aggregate log and event information from various sources mentioned above.
Splunk you can troubleshoot application outages, investigate security incidents very quickly as it ias all integrated. Unlike traditional approaches to managing IT, Splunk is software that lets you search and analyze all your IT infrastructure data from a single location in real time.
Splunk’s integrated approach keeps infrastructure available, secure and compliant. From an operations point of view, service levels can be improved as you can recover from problems faster.
Splunk is compliant with E-Discovery, FFIEC, FISMA, HIPAA, PCI, SOX.
openQRM is a very comprehensive and flexible Open Source Infrastracture Management Solution. Its fully pluggable architecture focuses on automatic, rapid- and appliance-based deployment, monitoring, high-availability, cloud computing and especially on supporting and conforming multiple virtualization technologies.
openQRM is a single-management console for the complete IT-Infrastructure and provides a well defined API which can be used to integrate third-party tools as additional plugins. This provides companies with a highly scalable system that supports small companies as well as global businesses who have large server base, multi-os & high-availability requirements.
Key features includes:
Support for different virtualization technologies
High-availability : “N to 1″ fail-over
Ready-made-server-images via the image-shelf plugin
Integrated storage management
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. It leverages widely used technologies such as XML for data representation, XDR for compact, portable data transport, and RRDtool for data storage and visualization. It uses carefully engineered data structures and algorithms to achieve very low per-node overheads and high concurrency. The implementation is robust, has been ported to an extensive set of operating systems and processor architectures, and is currently in use on thousands of clusters around the world. It has been used to link clusters across university campuses and around the world and can scale to handle clusters with 2000 nodes.
Monitorix is a free, open source, lightweight system monitoring tool designed to monitorize as many services as it can. At this time it monitors from the CPU load and temperatures to the users using the system. Network devices activity, network services demand and even the devices’ interrupt activity are also monitored. The current status of any corporate Linux server with Monitorix installed can be accessed via a web browser.
It has been designed to be used under production UNIX/Linux servers, but you can use it to monitor embedded devices, or in your laptop or even in your Linux box at home as well.
Initially all its development was created for monitoring Red Hat, Fedora and CentOS Linux, so this project was made keeping in mind these distributions. Since 0.8.0 though, is easier to port it to other Linux distributions and even to other UNIX systems like FreeBSD.
OpenNMS is an enterprise grade network management platform developed under the open source model. It consists of a community supported open-source project as well as a commercial services, training, and support organization. Some of OpenNMS’s key features includes auto-discovery, service level polling, snmp data collection, events and notifications in case of outages, dashboards.
Serio IT Service View is a free, no device limitation tool which allows you to monitor server, alert you of any problems, automatically take corrective action like rebooting, starting and stopping services within a monitored server. Works well with other standard plugins such as:
Web Page and Web Application Monitoring Plugin
Generic Ping Test Plugin
Oracle Login & SQL Exec Plugin
Serio IT Service View also has a MIB compiler and scripting language to assist you in writing your own plugins.
Tuesday, June 23, 2009
Monday, April 27, 2009
Friday, November 23, 2007
PC Boot Init Process in Linux
1. BIOS: The Basic Input/Output System is the lowest level interface between the computer and peripherals. The BIOS performs integrity checks on memory and seeks instructions on the Master Boor Record (MBR) on the floppy drive or hard drive.
2. The MBR points to the boot loader (GRUB or LILO: Linux boot loader).
3. Boot loader (GRUB or LILO) will then ask for the OS label which will identify which kernel to run and where it is located (hard drive and partition specified). The installation process requires to creation/identification of partitions and where to install the OS. GRUB/LILO is also configured during this process. The boot loader then loads the Linux operating system.
4. The first thing the kernel does is to execute init program. Init is the root/parent of all processes executing on Linux.
5. The first processes that init starts is a script /etc/rc.d/rc.sysinit
6. Based on the appropriate run-level, scripts are executed to start various processes to run the system and make it functional.
The Linux Init Processes:
The init process is the last step in the boot procedure and identified by process id "1". Init is responsible for starting system processes as defined in the /etc/inittab file. Init typically will start multiple instances of "getty" which waits for console logins which spawn one's user shell process. Upon shutdown, init controls the sequence and processes for shutdown. The init process is never shut down. It is a user process and not a kernel system process although it does run as root.
System Processes:
Process ID 0 is the Scheduler
Process ID 1 is the init process
Process ID 2 is the kflushd
Process ID 3 is the kupdate
Process ID 4 is the kpiod
Process ID 5 is the kswapd
Process ID 6 is the mdrecoveryd
Run /sbin/initlog
Run devfs to generate/manage system devices
Run network scripts: /etc/sysconfig/network
Start graphical boot (If so configured): rhgb
Start console terminals, load keymap, system fonts and print console greeting: mingetty, setsysfonts The various virtual console sessions can be viewed with the key-stroke: ctrl-alt-F1 through F6. F7 is reserved for the GUI screen invoked in run level 5.
Mount /proc and start device controllers.
Done with boot configuration for root drive. (initrd) Unmount root drive.
Re-mount root file system as read/write
Direct kernel to load kernel parameters and modules: sysctl, depmod, modprobe
Set up clock: /etc/sysconfig/clock
Perform disk operations based on fsck configuration
Check/mount/check/enable quotas non-root file systems: fsck, mount, quotacheck, quotaon
Initialize logical volume management: vgscan, /etc/lvmtab
Activate syslog, write to log files: dmesg
Configure sound: sndconfig
Activate PAM
Activate swapping: swapon
Run Levels:
LINUX has six states of operation of which "0" is the shutdown state and "3" and above are fully operational with all essential processes running for user interaction. Upon system boot the LINUX system /sbin/init program starts other processes by performing the following:
Init will bring up the machine by starting processes as defined in the /etc/inittab file.
The computer will be booted to the runlevel as defined by the initdefault directive in the /etc/inittab file.
Runlevel "5" will boot the system into GUI mode using XDM and X-Windows. Booting to runlevel "3" (often called console mode) is often used by servers which do not need a graphical user interface. If booted to init level "3" one can promote the run level with the command
[root prompt]#
· The inittab file will allow you to capture key sequences (ctrl-alt-del), start dial in internet connections etc.
One of these process started by init is /sbin/rc. This script runs a series of scripts in the directories /etc/rc.d/rc0.d/, /etc/rc.d/rc1.d/, /etc/rc.d/rc2.d/, etc
Scripts in these directories are executed for each boot state of operation until it becomes fully operational. Scripts beginning with S denote startup scripts while scripts beginning with K denote shutdown (kill) scripts. Numbers follow these letters to denote the order of execution. (lowest to highest)
One may switch init levels by issuing the init command with the appropriate runlevel. Use the command "init #" where # is one of s,S,0,1,3,5,6. The command telinit does the same.
The scripts for a given run level are run during boot and shutdown. The scripts are found in the directory /etc/rc.d/rc#.d/ where the symbol # represents the run level. i.e. the run level "3" will run all the scripts in the directory /etc/rc.d/rc3.d/ which start with the letter "S" during system boot. This starts the background processes required by the system. During shutdown all scripts in the directory which begin with the letter "K" will be executed. This system provides an orderly way to bring the system to different states for production and maintenance modes.
List state and run level of all services which can be started by init: chkconfig --list or service --status-all grep running
Run Level Commands
Shutdown:
init 0
shutdown -h now
-a: Use file /etc/shutdown.allow
-c: Cancel scheduled shutdown.
halt -p
-p: Turn power off after shutdown.
poweroff
Reboot: init 6
shutdown -r now
reboot
Enter single user mode: init 1
2. The MBR points to the boot loader (GRUB or LILO: Linux boot loader).
3. Boot loader (GRUB or LILO) will then ask for the OS label which will identify which kernel to run and where it is located (hard drive and partition specified). The installation process requires to creation/identification of partitions and where to install the OS. GRUB/LILO is also configured during this process. The boot loader then loads the Linux operating system.
4. The first thing the kernel does is to execute init program. Init is the root/parent of all processes executing on Linux.
5. The first processes that init starts is a script /etc/rc.d/rc.sysinit
6. Based on the appropriate run-level, scripts are executed to start various processes to run the system and make it functional.
The Linux Init Processes:
The init process is the last step in the boot procedure and identified by process id "1". Init is responsible for starting system processes as defined in the /etc/inittab file. Init typically will start multiple instances of "getty" which waits for console logins which spawn one's user shell process. Upon shutdown, init controls the sequence and processes for shutdown. The init process is never shut down. It is a user process and not a kernel system process although it does run as root.
System Processes:
Process ID 0 is the Scheduler
Process ID 1 is the init process
Process ID 2 is the kflushd
Process ID 3 is the kupdate
Process ID 4 is the kpiod
Process ID 5 is the kswapd
Process ID 6 is the mdrecoveryd
Run /sbin/initlog
Run devfs to generate/manage system devices
Run network scripts: /etc/sysconfig/network
Start graphical boot (If so configured): rhgb
Start console terminals, load keymap, system fonts and print console greeting: mingetty, setsysfonts The various virtual console sessions can be viewed with the key-stroke: ctrl-alt-F1 through F6. F7 is reserved for the GUI screen invoked in run level 5.
Mount /proc and start device controllers.
Done with boot configuration for root drive. (initrd) Unmount root drive.
Re-mount root file system as read/write
Direct kernel to load kernel parameters and modules: sysctl, depmod, modprobe
Set up clock: /etc/sysconfig/clock
Perform disk operations based on fsck configuration
Check/mount/check/enable quotas non-root file systems: fsck, mount, quotacheck, quotaon
Initialize logical volume management: vgscan, /etc/lvmtab
Activate syslog, write to log files: dmesg
Configure sound: sndconfig
Activate PAM
Activate swapping: swapon
Run Levels:
LINUX has six states of operation of which "0" is the shutdown state and "3" and above are fully operational with all essential processes running for user interaction. Upon system boot the LINUX system /sbin/init program starts other processes by performing the following:
Init will bring up the machine by starting processes as defined in the /etc/inittab file.
The computer will be booted to the runlevel as defined by the initdefault directive in the /etc/inittab file.
Runlevel "5" will boot the system into GUI mode using XDM and X-Windows. Booting to runlevel "3" (often called console mode) is often used by servers which do not need a graphical user interface. If booted to init level "3" one can promote the run level with the command
[root prompt]#
· The inittab file will allow you to capture key sequences (ctrl-alt-del), start dial in internet connections etc.
One of these process started by init is /sbin/rc. This script runs a series of scripts in the directories /etc/rc.d/rc0.d/, /etc/rc.d/rc1.d/, /etc/rc.d/rc2.d/, etc
Scripts in these directories are executed for each boot state of operation until it becomes fully operational. Scripts beginning with S denote startup scripts while scripts beginning with K denote shutdown (kill) scripts. Numbers follow these letters to denote the order of execution. (lowest to highest)
One may switch init levels by issuing the init command with the appropriate runlevel. Use the command "init #" where # is one of s,S,0,1,3,5,6. The command telinit does the same.
The scripts for a given run level are run during boot and shutdown. The scripts are found in the directory /etc/rc.d/rc#.d/ where the symbol # represents the run level. i.e. the run level "3" will run all the scripts in the directory /etc/rc.d/rc3.d/ which start with the letter "S" during system boot. This starts the background processes required by the system. During shutdown all scripts in the directory which begin with the letter "K" will be executed. This system provides an orderly way to bring the system to different states for production and maintenance modes.
List state and run level of all services which can be started by init: chkconfig --list or service --status-all grep running
Run Level Commands
Shutdown:
init 0
shutdown -h now
-a: Use file /etc/shutdown.allow
-c: Cancel scheduled shutdown.
halt -p
-p: Turn power off after shutdown.
poweroff
Reboot: init 6
shutdown -r now
reboot
Enter single user mode: init 1
Sunday, May 6, 2007
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