CentOS
From WebHostingBuzz Wiki
CentOS stands for Community ENTerprise Operating System and is an operating system created from the source code of Red Hat Enterprise Linux. It is available for free. CentOS aims to be 100% binary compatible with its upstream vendors redistribution policy. Its developers also try their best to keep this software up to date which results in a secure and reliable operating system, for running on Dedicated Hosting Servers.
Since Red Hat Enterprise Linux is largely made up of free and open source code, CentOS developers could also use the same architecture to build a freely available clone of RHEL. WebHostingBuzz strongly supports all open source projects and this is the major reason we run CentOS on nearly all our web hosting servers.
What was the need of developing CentOS?
CentOS provides a free server operating software platform to everyone. CentOS is built from publicly available open source code. It complies with RHEL's redistribution policies and aims to be 100% binary compatible with it. Its made for folks who need a quality operating system without worrying its cost or support issues.
How long does it take for CentOS to publish a fix?
CentOS always tries to make the RPM packages available on the mirrors within 3 days of their release however its usually available within 24 hours.
How can user get Updates?
CentOS is managed through an application called yum which is a recommended tool for performing updates and package installation. A version of up2date is also provided and connects to the CentOS Network (CN) for updates on CentOS 3. Users need to first verify the RPM-GPG-KEY and then install it. This stops people from modifying software. In CentOS 4, yum imports the key, but only after the user sees the key and can verify it is authentic.
Why are names such as redhat, rhel, or rh are still contained in many RPMs?
CentOS is an open sourced software and is a collection of the contributions made by many software makers such as RedHat, Gnome.org, X.org, KDE.org, OpenOffice.org etc. Proper trademark credits have to be given to their respective owners as this is how GPL works.
Are upstream Source RPMs changed by CentOS ?
No this is not done by CentOS as per their policy.
Can users contribute to CentOS?
Yes. You can contribute to the CentOS Project.
How is CentOS related to RHEL?
CentOS is not related or affiliated with RHEL as it is built from freely available open source SRPMS.
Where can I get my CentOS RPM package?
We have a list of CentOS and other repositories which you can search to download the needed package.
What architectures does CentOS Support?
- CentOS 2 works with x86 only.
- CentOS 3 works with x86, x86_64 (AMD64 and Intel EM64T), s390, s390x, ia64 (Intel Itanium2).
- CentOS 4 works with x86, x86_64, s390, s390x and ia64. ppc (PowerPC), alpha (DEC Alpha) and sparc are released in beta for CentOS 4.
- CentOS 5 works with x86 and x86_64. ia64, ppc (PowerPC) and sparc are being developed.
Which flavor does CentOS provide compared to RHEL?
CentOS is built out of AS Enterprise Sources.
How can I easily compare CentOS with its other versions?
You can compare CentOS on DistroWatch.com.
What are all the CentOS repositories (directories)?
- addons - Contains packages required to build the main Distribution.
- apt - (CentOS-4 only) Contains all the apt RPMS for the CentOS site.
- centosplus - Packages contributed by CentOS Developers and the Users.
- contrib - Packages contributed by the CentOS Users, who do not overlap with any of the core Distribution packages.
- docs - Contains manuals and release notes for CentOS
- extras - Packages built and maintained by the CentOS developers for added functionality.
- isos - Contains the ISOs.
- os - Contains the base OS tree that is on the Main ISO files.
- updates - Contains updates released for the CentOS.
How do I download CentOS ISOs?
You can download CentOS ISOs from the official website.
How do I install X?
Use the `yum groupinstall` feature. You should be able to see all the yum groups available with the command: yum grouplist To install X and Gnome or KDE use this : yum groupinstall "X Window System" "GNOME Desktop Environment" or yum groupinstall "X Window System" "KDE (K Desktop Environment)" You may want to add few other groups like `"Graphical Internet" or "Office/Productivity". For running CentOS 5, yum groupinstall "GNOME Desktop Environment" may complain about a missing libgaim.so.0. This is a known bug.
Why does yum groupinstall "GNOME Desktop Environment" complains about a missing libgaim.so.0?
The work around with yum is --exclude=nautilus-sendto groupinstall "GNOME Desktop Environment". This bug would be fixed in CentOS 5.3.
Specifications associated with the different CentOS versions?
Check out CentOS Product Page for more information.
Does CentOS support multimedia formats such as MP3?
No it does not however you can use third party repository, namely rpmforge for example if you want mp3 support for xmms, then install xmms-mp3 from that repository.
Can I install CentOS 5 with just one CD?
You can only do a minimal install with one CD.
What kernels are available with CentOS?
CentOS 5 works with
- kernel: Normal kernel that supports both UP and SMP machines.
- kernel-PAE: Only x86 CPUs that work with Physical Address Extensions can run this kernel.
- kernel-xen: Linux kernel compiled with PAE support works on the Xen hypervisor, for both privileged (dom0) and unprivileged (domU) domains.
Is Bind is broken in CentOS 5?
It only looks broken but it is not. Bind-9.3.3 does not install config files in CentOS however you can just copy the example files from /usr/share/doc/bind-9.x.x/sample/etc/ and /usr/share/doc/bind-9.x.x/sample/var/ to start your own configuration or you can use system-config-bind to set things up.
How do I change my web server's hostname?
Running as root:
- hostname server1.webhostingbuzz.com (where server1.webhostingbuzz.com is the host name)
- /etc/sysconfig/network should complete the task.
How should I disable IPv6?
- Edit /etc/sysconfig/network and set "NETWORKING_IPV6" to "no"
- Add the following to /etc/modprobe.conf :
alias ipv6 off alias net-pf-10 off
- Run chkconfig ip6tables off to disable the IPv6 firewall
- Reboot the system
Is there a root password for CentOS 5 Live CD?
There is no root password for CentOS 5.
Will CentOS support other architectures?
Yes the planned architectures are ia64 (Itanium), ppc (PowerPC, POWER), sparc. The support for these should be released soon.
Does CentOS 5 support PHP 5.2.5?
At this time it does not support PHP 5.2.5. Current supported version is PHP 5.1.6.
Where can I find a more detailed manual for CentOS?
What is the location of the current mirrors for CentOS?
Prior Releases of CentOS
The information below was taken from CentOS Official website.
| CentOS Release | Architectures | RHEL base | |
|---|---|---|---|
| 2 | i386 | 2.1 | |
| 3.1 | i386, x86_64, ia64, s390, s390x | 3 | |
| 3.4 - Server CD | i386, x86_64, ia64, s390, s390x | 3.4 | - |
| 3.7 | i386, x86_64, ia64, s390, s390x | 3.7 | - |
| 3.8 | i386, x86_64 | 3.8 | - |
| 4.3 - Server CD | i386 | 4.3 | - |
| 4.6 | i386, x86_64, ia64, alpha, s390, s390x, ppc (beta), sparc (beta) | 4.6 | |
| 4.7 | i386, x86_64 | 4.7 | |
| 5 | i386, x86_64 | 5 | |
| 5.1 | i386, x86_64 | 5.1 | |
| 5.1 - LiveCD | i386 | 5.1 | - |
| 5.2 | i386, x86_64 | 5.2 | |
| 5.2 - LiveCD | i386 | 5.2 | - |
References:
www.centos.org/modules/tinycontent/index.php?id=2 www.centos.org/modules/tinycontent/index.php?id=13 www.centos.org/docs/5/ www.centos.org/product.html www.gnu.org/copyleft/gpl.html www.distrowatch.com/table.php?distribution=centos
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