Centos : Update Centos 6

Issue : Error: Cannot find a valid baseurl for repo: base

Solutions : To fix this problem you edit /etc/yum.repos.d/CentOS-Base.repo and replace all mirrorlist

1. Go to /etc/yum.repos.d/ directory:

# cd /etc/yum.repos.d/

2. Make copy of original file:

# cp CentOS-Base.repo CentOS-Base.repo.old

3. Open and edit file with any text editor:

# vi CentOS-Base.repo

4. Replace mirrorlist‘s

Replace in sections:

[base]
name=CentOS-$releasever - Base
baseurl=https://vault.centos.org/6.10/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

# released updates
[updates]
name=CentOS-$releasever - Updates
baseurl=https://vault.centos.org/6.10/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

# additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
baseurl=https://vault.centos.org/6.10/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

5. Clean yum cache

# yum clean all

6. Run again yum update command:

# yum update

source : https://secure.subwayhost.com/knowledgebase/14/How-to-fix-YumRepo-Error-and-Cannot-find-valid-baseurl.html