From the official CentOS wiki page, CentOS 5 end-of-life (EOL) date is March 31st, 2017. It has stopped receiving full updates since the 1st quarter of 2014. After its EOL in 2017, CentOS will no longer be officially maintained by the CentOS group, i.e. no more maintenance updates.
For CentOS 6, it will stop receiving full updates in the 2nd quarter of 2017, and maintenance updates will stop on November 30th, 2020.
What does this mean for those who are running various legacy applications on CentOS 5 (or RedHat Enterprise Linux 5)?
Well, for one, CentOS 5 and your applications will continue to work as usual. What it means is that if there are security bugs found, the chances of you getting a patch update/fixes will be quite slim. And the vendor(s) of your application(s) may/may not continue to support them on CentOS 5.
So, the practical course of action is to plan ahead – and start thinking of how you will migrate your enterprise applications over to the CentOS 6 or CentOS 7.
Unfortunately, there are no easy way to upgrade from CentOS 5 to CentOS 6 – it has to be done manually.
The recommended way is setup a similar (or higher) spec machine, install CentOS 6 and all the required libraries and associated applications and then migrate the data from the old CentOS 5 server to the new CentOS 6. It is a manual and tedious process, but it is the safest. And it would definitely require a lot of planning and time to execute it. Here are 2 references from CentOS and RedHat:
Upgrade from CentOS 6 to CentOS 7 is possible via an ‘upgrade tool’ – but it is still in “experimental” (imho) mode as of this writing – see this article:
Note: If you’re a Web-Host and using Cpanel/WHM on CentOS 5 – you may want to take note of the following EOL dates for Cpanel/WHM.
Cpanel / WHM End of Life Dates:
|CentOS 5.x, Red Hat® Enterprise Linux 5.x, CloudLinux™ 5.x||August 31, 2017|
|CentOS 6.x, Red Hat Enterprise Linux 6.x, CloudLinux 6.x||May 30, 2021|
|CentOS 7.x, Red Hat Enterprise Linux 7.x, CloudLinux 7.x||December 31, 2024|
It would be wise to start planning now and not wait until the last minute 🙂