YumRepo Error: All mirror URLs are not using ftp, http[s] or file.

If you doing a yum update or yum install for CentOS 6. You might face the error:

Setting up Upgrade Process
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 retrieve repository metadata (repomd.xml) for repository: base. Please verify its path and try again

This is because YUM repository was removed from the main CentOS update servers. As a result, no security or feature upgrades are provided.

Where are these obsolete Yum Repository now? They are found in CentOS Vault Repository. To use the Vault repository, set up its repo configuration instead of the now defunct repositories configuration:

# curl https://www.getpagespeed.com/files/centos6-eol.repo --output /etc/yum.repos.d/CentOS-Base.repo

You may want to edit CentOS-Base.repo directly. My OS is CentOs 6.9

.....
.....
[base]
name=CentOS-$releasever - Base
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os&infra=$infra
#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/
baseurl=https://vault.centos.org/6.9/os/$basearch/
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

#released updates
[updates]
name=CentOS-$releasever - Updates
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates&infra=$infra
#baseurl=http://mirror.centos.org/centos/$releasever/updates/$basearch/
baseurl=https://vault.centos.org/6.9/updates/$basearch/
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras&infra=$infra
#baseurl=http://mirror.centos.org/centos/$releasever/extras/$basearch/
baseurl=https://vault.centos.org/6.9/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus&infra=$infra
#baseurl=http://mirror.centos.org/centos/$releasever/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib&infra=$infra
#baseurl=http://mirror.centos.org/centos/$releasever/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

For EPEL Repository

# curl https://www.getpagespeed.com/files/centos6-epel-eol.repo --output /etc/yum.repos.d/epel.repo

For SCLO repositories

# curl https://www.getpagespeed.com/files/centos6-scl-eol.repo --output /etc/yum.repos.d/CentOS-SCLo-scl.repo
# curl https://www.getpagespeed.com/files/centos6-scl-rh-eol.repo --output /etc/yum.repos.d/CentOS-SCLo-scl-rh.repo

References:

  1. How to fix yum after CentOS 6 went EOL

Yum History and Using Yum to Roll Back updates

Getting History of YUM actions

Point 1: List Yum actions list

(base) [root@hpc-node1 ~]# yum history list
Loaded plugins: fastestmirror, langpacks
ID | Login user | Date and time | Action(s) | Altered
-------------------------------------------------------------------------------
42 | root <root> | 2020-06-30 11:36 | I, U | 3
41 | 12345 | 2020-06-04 16:43 | Install | 2
40 | 12345 | 2020-06-04 16:26 | I, O, U | 878 E<
39 | 12345 | 2020-03-20 13:54 | Install | 1 >
38 | 12345 | 2020-03-20 13:46 | Install | 1
37 | 12345 | 2020-03-20 13:45 | Install | 2
36 | 12345 | 2020-03-20 13:44 | Install | 1
35 | 12345 | 2020-03-20 13:43 | Install | 28
34 | 12345 | 2020-03-20 12:52 | Update | 4
33 | 12345 | 2020-03-20 12:51 | Install | 1
32 | 12345 | 2020-03-20 12:43 | Update | 1
31 | 12345 | 2020-03-20 11:10 | Install | 1
30 | 12345 | 2020-03-20 10:53 | Install | 2
29 | 12345 | 2020-02-20 14:54 | Install | 1
28 | 12345 | 2020-01-23 16:10 | I, U | 2
27 | 12345 | 2020-01-15 15:03 | Update | 15
26 | 12345 | 2020-01-15 15:03 | I, U | 18
25 | 12345 | 2020-01-15 15:03 | Update | 3
24 | 12345 | 2019-11-07 11:00 | Install | 1 <
23 | 12345 | 2019-09-23 12:47 | Install | 1 >

Point 2: Undo the Yum action.

(base) [root@hpc-node1 boot]# yum history undo 42
Loaded plugins: fastestmirror, langpacks
Undoing transaction 42, from Tue Jun 30 11:36:18 2020
.....
.....
Running transaction
  Installing : ntpdate-4.2.6p5-29.el7.centos.x86_64                                                                                                                                             1/4
  Erasing    : ntp-4.2.6p5-29.el7.centos.2.x86_64                                                                                                                                                       2/4
  Erasing    : autogen-libopts-5.18-5.el7.x86_64                                                                                                                                                        3/4
  Cleanup    : ntpdate-4.2.6p5-29.el7.centos.2.x86_64                                                                                                                                                   4/4
  Verifying  : ntpdate-4.2.6p5-29.el7.centos.x86_64                                                                                                                                                     1/4
  Verifying  : ntp-4.2.6p5-29.el7.centos.2.x86_64                                                                                                                                                       2/4
  Verifying  : autogen-libopts-5.18-5.el7.x86_64                                                                                                                                                        3/4
  Verifying  : ntpdate-4.2.6p5-29.el7.centos.2.x86_64                                                                                                                                                   4/4

Removed:
  autogen-libopts.x86_64 0:5.18-5.el7                              ntp.x86_64 0:4.2.6p5-29.el7.centos.2                              ntpdate.x86_64 0:4.2.6p5-29.el7.centos.2

Installed:
  ntpdate.x86_64 0:4.2.6p5-29.el7.centos

Complete!

Point 3 – Check on the history of a particular package

yum history list ntpdate
Loaded plugins: fastestmirror, langpacks
ID     | Login user               | Date and time    | Action(s)      | Altered
-------------------------------------------------------------------------------
    43 | root               | 2020-07-06 11:31 | D, E           |    3
    42 | root               | 2020-06-30 11:36 | I, U           |    3
    40 | root               | 2020-06-04 16:26 | I, O, U        |  878 EE
     2 | root               | 2019-07-09 09:31 | I, U           | 1029 EE