As you know CentOS 5 е EOL (End-Of-Life) from March 31st 2017. Which leads to the following very interesting problem:

# yum update
Loaded plugins: fastestmirror, security
Loading mirror speeds from cached hostfile
YumRepo Error: All mirror URLs are not using ftp, http[s] or file.
 Eg. Invalid release/
YumRepo Error: All mirror URLs are not using ftp, http[s] or file.
 Eg. Invalid release/
removing mirrorlist with no valid mirrors: /var/cache/yum/extras/mirrorlist.txt
Error: Cannot find a valid baseurl for repo: extras

The problem is short, that lists the CentOS mirrors 5 they are already lost and when we try to take content directly we get the following refusal:

# curl 'http://mirrorlist.centos.org/?release=5&arch=i386&repo=os'
Invalid release

In general, the most sensible idea is to reinstall the tin with a normal distribution., which supports a working distribution upgrade. Unfortunately, this is not the case with me, and this is not an option on the table at all. So we had to play a bit of a gypsy scheme – we start using Vault mirror. In a moment of perfectly clear creature and common sense I know, that I will not receive, any updates that are not the purpose of the exercise, а искаме просто да има работещ yum с, който да инсталирам пакет, който ми е необходим. За целта за коментираме всички mirrorlist променливи и добавяме baseurl в /etc/yum.repos.d/CentOS-Base.repo. Накрая получаваме yum repo от вида на

[base]
name=CentOS-$releasever - Base
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
baseurl=http://vault.centos.org/5.11/os/i386/
#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5

#released updates
[updates]
name=CentOS-$releasever - Updates
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
baseurl=http://vault.centos.org/5.11/updates/i386/
#baseurl=http://mirror.centos.org/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5

#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
baseurl=http://vault.centos.org/5.11/extras/i386/
#baseurl=http://mirror.centos.org/centos/$releasever/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5

Finally we play a yum clean all && yum update. If everything ends without getting an error, then we have successfully completed the scheme and we can safely install the obsolete packages.