The support time for CentOS 3 ended on 2010-10-30; for CentOS 4 on 2012-02-29. This is called an EOL -- End of Life -- for support of a version.
The upstream publishes formal product Life cycle information.
What options do you have as a person running CentOS?
Why
No patches anymore
As of 2010/10/01, there is no scheduled public release of the sources used to build the 3 level updates by the upstream of the src.rpm composing their Extended Life Support product offering; a similar notice also exists as to the sources used to build the 4 level product updates. As such, there will no more updates from the CentOS project for CentOS 3 or CentOS 4.
Migration
- Move back to Red Hat ELS
1. Virtualize
- CAVEAT: That will only take care of the hardware side of the story, not the software part...
- CentOS virtualisation products
- xen
- kvm
- Commercial products (non endorsed by CentOS)
- VMWare's ESXi/Workstation/Players
Oracle's VirtualBox
Citrix's XenServer
2. Upgrade
2.1. migrate to CentOS 5
- 7 years primary support life; later extended to ten years
- Mar 31, 2017 EOL
- i386 x86_64 support
- prerequisites
- services changes (match to upstream)
2.2. migrate to CentOS 6
- 7 years primary support life; later extended to ten years
- November 30, 2020 EOL
- i386 x86_64 support