When using the commands "yum install/update" on Centos 6 you will get an error:
Loaded plugins: fastestmirror, replace
Setting up Update Process
Determining fastest mirrors
YumRepo Error: All mirror URLs are not using ftp, http[s] or file.
Eg. Invalid release/repo/arch combination/
removing mirrorlist with no valid mirrors: /var/cache/yum/x86_64/6/base/mirrorlist.txt
Error: Cannot find a valid baseurl for repo: base (base/updates/contrib)
Reason: Centos 6 is out of date and is no longer officially supported.
Solution: Manual change CentOS-Base.repo
Step 1:
Open the following files one by one:
/var/cache/yum/x86_64/6/base/mirrorlist.txt
/var/cache/yum/x86_64/6/extras/mirrorlist.txt
/var/cache/yum/x86_64/6/updates/mirrorlist.txt
Add the following line at the end of the files:
https://vault.centos.org/6.10/
Step 2:
Open file "CentOS-Base.repo" and modify all blocks according to the form below
vi /etc/yum.repos.d/Centos-Base.repo
[base]
name=CentOS-$releasever - Base
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os&infra=$infra
baseurl=http://vault.centos.org/6.10/centosplus/$basearch/
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
gpgcheck=1
#released updates
[updates]
name=CentOS-$releasever - Base
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os&infra=$infra
baseurl=http://vault.centos.org/6.10/centosplus/$basearch/
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
gpgcheck=1
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Base
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os&infra=$infra
baseurl=http://vault.centos.org/6.10/centosplus/$basearch/
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
gpgcheck=1
#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Base
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os&infra=$infra
baseurl=http://vault.centos.org/6.10/centosplus/$basearch/
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
gpgcheck=1
Step 3: Done ! Solved !
Now on you can continue to use yum normally