Cent. OS Wikipedia. Cent. OS, from Community Enterprise Operating System is a Linux distribution that attempts to provide a free, enterprise class, community supported computing platform functionally compatible with its upstream source, Red Hat Enterprise Linux RHEL. In January 2. Cent. OS announced the official joining with Red Hat while staying independent from RHEL,7 under a new Cent. OS governing board. The first Cent. OS release in May 2. Cent. OS version 2, was forked from RHEL version 2. AS. 1 Since the release of version 7. Cent. OS officially supports only the x. IA 3. 2 with Physical Address Extension PAE. As of December 2. Alt. Arch releases of Cent. OS 7 are available for the IA 3. Power architecture, and for the ARMv. AArch. 64 variants of the ARM architecture. HistoryeditPrior to becoming known under its current name, Cent. OS originated as a build artifact of c. Aos Linux. 1. 2 At the time,when some of the c. Aos contributors were merely interested in this build artifact for their own use, citing difficulties in collaborating with other noteworthy Red Hat Enterprise Linux RHEL clones of the time. In June 2. David Parsley, the primary developer of Tao Linux another RHEL clone, announced the retirement of Tao Linux and its rolling into Cent. OS development. Taos users migrated to the Cent. Centos Kernel Source Rpm Download Package' title='Centos Kernel Source Rpm Download Package' />Download VirtualBox for Linux Hosts VirtualBox 5. Linux. Note The package architecture has to match the Linux kernel architecture, that is, if you are running. About The Author skytech. The author of this blog is a part time blogger who is very enthusiastic about computer technology and Linux open source and has more than 8. Although this article is titled and introduced to work with Red Hat Enterprise Linux 5. I will actually be using a Red Hat Linux clone named CentOS. I have a centos 5. Im working on that has a old version of openvmtools installed. How can I remove itYou only list the source repositories. Do you have the rhel repo set Also a different way is just to use the RHEL official DVD or set up centos repo if you can do. Red Hat Linux and SUSE Linux were the original major distributions that used the. HomePage Welcome to the ELRepo Project For the community, by the community. Welcome to ELRepo, an RPM repository for Enterprise Linux packages. News and feature lists of Linux and BSD distributions. Centos Kernel Source Rpm Download Package' title='Centos Kernel Source Rpm Download Package' />OS release via yum update. In July 2. 00. 9, it was reported in an open letter on the Cent. OS project web site that Cent. OSs founder, Lance Davis, had disappeared in 2. Davis had ceased contribution to the project, but continued to hold the registration for the Cent. OS domain and Pay. Pal account. In August 2. Cent. OS team reportedly made contact with Davis and obtained the centos. In July 2. 01. 0, Cent. Howto install gcc and development tools on Centos 7. RHEL, install gcc on Centos 7, install development tools on Centos 7, install gcc on RHEL 7. OS overtook Debian to become the most popular Linux distribution for web servers, with almost 3. Linux web servers using it. Debian retook the lead in January 2. In January 2. 01. Red Hat announced that it would sponsor the Cent. OS project, helping to establish a platform well suited to the needs of open source developers that integrate technologies in and around the operating system. As a result of these changes, ownership of Cent. OS trademarks was transferred to Red Hat,1. Cent. OS head developers however, they work as part of Red Hats Open Source and Standards team, which operates separately from the Red Hat Enterprise Linux team. A new Cent. OS governing board was also established. RHEL is available only through a paid subscription service that provides access to software updates and varying levels of technical support. The product is largely composed of software packages distributed under free software licenses and the source code for these packages is made public by Red Hat. Cent. OS developers use Red Hats source code to create a final product very similar to RHEL. Red Hats branding and logos are changed because Red Hat does not allow them to be redistributed. Cent. OS is available free of charge. Technical support is primarily provided by the community via official mailing lists, web forums, and chat rooms. The project is affiliated with Red Hat but aspires to be more public, open, and inclusive. While Red Hat employs most of the Cent. OS head developers, the Cent. OS project itself relies on donations from users and organizational sponsors. Versioning and releaseseditCent. OS releaseseditCent. OS version numbers for releases older than 7. Red Hat Enterprise Linux RHEL used to build a particular Cent. Best Publishing Software For Manuals Online. OS release. For example, Cent. OS 6. 5 is built from the source packages of RHEL 6 update 5 also known as RHEL version 6. RHEL 6. 2. 0Starting with version 7. Cent. OS version numbers also include a third part that indicates the monthstamp of the source code the release is based on. For example, version number 7. Cent. OS release to the zeroth update set of RHEL 7, while 1. June 2. 01. 4. Using the monthstamp allows installation images to be reissued for as of July 2. Since mid 2. 00. RHEL version 4. Red Hat Enterprise Linux 4. Red Hat has adopted a version naming convention identical to that used by Cent. OS for example, RHEL 4. RHEL 6. 5. 2. 2Cent. OS version. Architectures. RHEL base. Kernel. Cent. OS release date. RHEL release date. Delay days2. 1. IA 3. May 2. 00. 411. May 2. IA 3. 2, x. 86 6. IA 6. 4, s. 39. 0, s. March 2. 00. 42. October 2. IA 3. 2, x. 86 6. IA 6. 4, s. 39. 0, s. September 2. 00. 43 September 2. IA 3. 2, x. 86 6. IA 6. 4, s. 39. 0, s. January 2. 00. 51. December 2. 00. 44. IA 3. 23. 5. 2. 4. June 2. 00. 52. 51. May 2. 00. 52. 33. IA 3. 23. 6. 2. 4. November 2. 00. 52. September 2. 00. 53. IA 3. 2, x. 86 6. IA 6. 4, s. 39. 0, s. April 2. 00. 62. March 2. IA 3. 2, x. 86 6. August 2. 00. 62. July 2. 00. 63. 63. IA 3. 2, x. 86 6. IA 6. 4, s. 39. 0, s. July 2. 00. 72. 91. June 2. 00. 74. 14. IA 3. 2, x. 86 6. March 2. 00. 53. February 2. IA 3. 2, IA 6. 4, s. June 2. 00. 53. 28 June 2. IA 3. 2, x. 86 6. IA 6. 4, s. 39. 0, s. October 2. 00. 53. October 2. 00. 58. IA 3. 2, x. 86 6. IA 6. 4, s. 39. 0, s. March 2. 00. 63. March 2. IA 3. 2, x. 86 6. August 2. 00. 63. August 2. 00. 62. IA 3. 2, x. 86 6. IA 6. 44. 5. 2. 6. May 2. 00. 73. 61 May 2. IA 3. 2, x. 86 6. IA 6. 4, Alpha, s. Power. PC beta, SPARC beta4. December 2. 00. 73. November 2. 00. 73. IA 3. 2, x. 86 6. September 2. 00. 83. July 2. 00. 84. 05. IA 3. 2, x. 86 6. August 2. 00. 94. May 2. 00. 94. 29. IA 3. 2, x. 86 6. March 2. 01. 14. February 2. IA 3. 2, x. 86 6. April 2. 00. 74. March 2. IA 3. 2, x. 86 6. December 2. 00. 74. November 2. 00. 74. IA 3. 2, x. 86 6. June 2. 00. 84. 92. May 2. 00. 85. 03. IA 3. 2, x. 86 6. March 2. 00. 95. January 2. IA 3. 2, x. 86 6. October 2. 00. 95. September 2. 00. 95. IA 3. 2, x. 86 6. May 2. 01. 05. 53. March 2. 01. 05. IA 3. April 2. 01. 15. January 2. IA 3. 2, x. 86 6. September 2. 01. 15. July 2. 01. 16. 05. IA 3. 2, x. 86 6. March 2. 01. 26. February 2. IA 3. 2, x. 86 6. January 2. 01. 36. January 2. 01. 36. IA 3. 2, x. 86 6. October 2. 01. 36. September 2. 01. 36. IA 3. 2, x. 86 6. September 2. 01. 46. September 2. 01. 46. IA 3. 2, x. 86 6. July 2. 01. 16. 91. November 2. 01. 07. IA 3. 2, x. 86 6. December 2. 01. 17. May 2. 01. 17. 22. IA 3. 2, x. 86 6. December 2. 01. 17. December 2. 01. 17. IA 3. 2, x. 86 6. July 2. 01. 27. 52. June 2. 01. 27. 61. IA 3. 2, x. 86 6. March 2. 01. 37. February 2. IA 3. 2, x. 86 6. December 2. 01. 37. November 2. 01. 38. IA 3. 2, x. 86 6. October 2. 01. 48. October 2. 01. 48. IA 3. 2, x. 86 6. August 2. 01. 58. July 2. 01. 58. 41. IA 3. 2, x. 86 6. May 2. 01. 68. 51. May 2. 01. 68. 61. IA 3. 2, x. 86 6. April 2. 01. 78. March 2. July 2. 01. 42. 11. June 2. 01. 49. 12. March 2. 01. 59. March 2. December 2. 01. 59. November 2. 01. 59. December 2. 01. 69. November 2. 01. 69. September 2. 01. 71. July 2. 01. 71. 011. Alt. Arch releaseseditAlt. Arch releases are released by the Alternative Architecture Special Interest Group Alt. Arch SIG to support architectures that are not supported by the base Cent. OS releases. Cent. OS version. Architectures. RHEL base. Cent. OS release date. AArch. 64. 7. 1. 4 August 2. IA 3. 21. 2 October 2. IA 3. 27. 2. 19 December 2. ARMv. 7hl. 19 December 2. Power. PC6. 4 Tech. Preview1. 9 December 2. Power. PC8 LE Tech. Linux System Administration and Configuration. Related Yo. Linux Configuration and Admin Tutorials. The Linux boot process. Quotas Assign disk resource limits to users or groups. Managing groups and user security Linux Networking tutorial. DHCP Server tutorial. NIS Server Client configuration tutorial. Configuring an internet web server. Apache, DNS, FTP. Internet Server Security. System optimization System re configuration Commands used to re configure video, keyboard, mouse, datetime, sound card, NIC, Printer. Installing a new kernel RPMYo. Linux Tutorials Index. Monitoring the system Basic command line pstree Processes and parent child relationshipstop Show top processesmpstat Report processors related statistics. Example mpstat AUbuntu install apt get install sysstatdstat generate system resource statistics report. Examples dstat a, dstat fUbuntu install apt get install dstatiostat Report CPU statistics and inputoutput statistics for devices and partitions. Report virtual memory statisticsstat display file or file system status. Example stat f devsda. NFS statisticsUbuntu install apt get install nfs common. Display Linux kernel version in use. Display Red Hat Linux Release. Tell how long the system has been running. Also number of users and systems load average. Show who is logged on and what they are doing. List all currently loaded kernel modules. Same as cat procmodulessbinrunlevel. Displays the systems current runlevel. Displayschanges the systems node name. Must also manually change hostname setting in etcsysconfignetwork. Command will change entry in etchostsservice. Red HatFedora command to display status of system services. Example service status all. Help service help. Also see ntpstat. GUIGraphical gnome system monitor. Operating system monitor and usage graphing. Graphical system monitor. Additional RPM package gkrellmps. D load meter. Very cool 3 D graphics. Operating system monitor load, memory, swap, net, disk,. List of tools. Process Management. Processes execute within their own process environment, they have their own memory, current working directory, priority, process ID, parent process ID and the file access privileges of the user ID under which they execute. The basic Linux monitoring commands such as pstree and ps auxw. Sometimes a process must be terminated. To terminate a process. Identify the process. OR. ps auxw. OR. Kill the process. This will perform an orderly shutdown of the process. If it hangs give a stronger signal with. This method is not as sanitary and thus less preferred. A signal may be given to the process. The program must be programmed to handle the given signal. See usrincludebitssignum. For example, to restart a process after updating its configuration file. HUP lt process id number. In the previous example, the HUP signal was sent to the process. The software was written to trap for the signal so that it could respond. If the software command is not written to respond to a particular. Identify all known signals fuser l. Process Monitoring and Management GUI Tools xosview Oldie but goodie. Su. SE. QPS See below. Also see the GUI tool QPS. Handles MOSIX cluster. This tool is outstanding for monitoring, adjusting nice values priorities. RPM available from this site. It is so simple to use, no instructions are necessary. It can monitor a program to make sure it isnt doing something bad. It is also reverse engineer what applications are doing and the environments. I love this tool Note The RPM provided was compiled for Red. Hat 7. x. For Red. Hat 8. 0 one must. QT library RPMs to satisfy dependencies. Xt 2. 3. 1 8. i. Then install qps rpm ivh qps 1. Note Fedora Core 3 rpm ivh qt. These older RH 8. AMD6. 4 Fedora Core 3 x. OS system. Configuring QPS to run applications against a process Select Command Edit Commands. Add. Description GDB. Command Line xterm T GDB C e gdb d directory where source code is located pidp. Description gdb. Command Line xterm T gdb c p e gdb procpexe p As issued in RPM. Description strace. Command Line xterm T strace c p e sh c strace f pp sleep 1. Try it with the process qps itself. Show output written by process. T strace c p e sh c strace f q e tracewrite pp sleep 1. Description truss Solaris command. Command Line xterm T truss C p e sh c truss f p p sleep 1. Process Priority Control. Multi tasking operating systems executes processes in a time slice fashion sharing the processing resources base on their current privilege. Privileges are not constant and elevate if they have not received an execution allocation in the processor after a given time. This is to ensure that all processes get executed regardless of priority although a process can get squeezed out of the time allocation alltogether if the system is overloaded. Higher priority processes may get more time allocated on the processor than a lower priority process but it is likely that the lower process will get some processor allocation. Many system process which manage the system environment execute at an elevated priority in order to guarentee that they get executed. User processes can have their priority elevated using the nice command. Nice values have a range from 2. Beware that if the priority is elevated higer than a system process, the behavior of the system may be compromised. Modify process scheduling priority. Lower scheduling priority runs slower and less likely to slow you down. Default for nice n is 1. Show default for any process nice executable. Shows nice value to be used if run. IPCs Semaphores, Shared Memory and Queues. Note that some processes may use Linux Inter. Process Communication or IPC. Identify the semaphores ipcsipcs q List share queues. Shared memory. ipcs s List Semaphores. Remove the semaphores ipcrm s lt ipcs id. Example If you are running Apache, you may see the following. DIR ipcs m Shared Memory Segments key shmid owner perms bytes nattch status 0x. Processes attached to open files or open network ports. The command lsof. List processes attached to a given file lsof filename. DIR lsof varlogmailmanqrunner. REG 3,5 6. 57 4. REG 3,5 6. REG 3,5 6. 57 4. REG 3,5 6. REG 3,5 6. 57 4. REG 3,5 6. REG 3,5 6. 57 4. REG 3,5 6. The process attached to an open file can be killed using the command. List all open files on system lsofLong list. List all files opened by user lsof u user id. The commands netstat punta and socklist will list open network connections. Example netstat anp. Use the command lsof i TCP port number to see the processes attached to the port. Example. rootnode DIR lsof i TCP 3. COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME. IPv. 4 7. 56. 00. TCP ldap LISTEN. IPv. TCP ldap LISTEN. IPv. TCP ldap LISTEN. IPv. TCP ldap LISTEN. IPv. TCP ldap LISTEN. This shows that the command slapd running under user id ldap. Restricting user resources ulimit bash shell command. Shell and process resources may be controlled and reported using the. Display the limits of a shell using the bash command. Limits can be set for the number of open files and. View file size limits ulimit f. See limits assigned in etcsecurity discussed below.