If you see error:
[root@tutorialspots /]# yum install bmon -y Loaded plugins: fastestmirror base | 3.6 kB 00:00 epel/x86_64/metalink | 17 kB 00:00 epel | 4.7 kB 00:00 extras | 3.4 kB 00:00 mariadb | 2.9 kB 00:00 nodesource | 2.5 kB 00:00 remi-safe | 2.9 kB 00:00 updates | 3.4 kB 00:00 vz-base | 951 B 00:00 vz-updates | 951 B 00:00 Loading mirror speeds from cached hostfile * base: mirror.sale-dedic.com * epel: mirrors.colocall.net * extras: centos.mirror.far.fi * remi-safe: mirror.reconn.ru * updates: mirror.sale-dedic.com One of the configured repositories failed (Unknown), and yum doesn't have enough cached data to continue. At this point the only safe thing yum can do is fail. There are a few ways to work "fix" this: 1. Contact the upstream for the repository and get them to fix the problem. 2. Reconfigure the baseurl/etc. for the repository, to point to a working upstream. This is most often useful if you are using a newer distribution release than is supported by the repository (and the packages for the previous distribution release still work). 3. Run the command with the repository temporarily disabled yum --disablerepo=<repoid> ... 4. Disable the repository permanently, so yum won't use it by default. Yum will then just ignore the repository until you permanently enable it again or use --enablerepo for temporary usage: yum-config-manager --disable <repoid> or subscription-manager repos --disable=<repoid> 5. Configure the failing repository to be skipped, if it is unavailable. Note that yum will try to contact the repo. when it runs most commands, so will have to try and fail each time (and thus. yum will be be much slower). If it is a very temporary problem though, this is often a nice compromise: yum-config-manager --save --setopt=<repoid>.skip_if_unavailable=true file is encrypted or is not a database
How to fix it?
Open file /etc/yum.conf then add the line:
Example file /etc/yum.conf
[root@tutorialspots /]# cat /etc/yum.conf [main] cachedir=/var/cache/yum/$basearch/$releasever keepcache=0 debuglevel=2 logfile=/var/log/yum.log exactarch=1 obsoletes=1 gpgcheck=1 plugins=1 installonly_limit=5 bugtracker_url=http://bugs.centos.org/set_project.php?project_id=23&ref=http://b ugs.centos.org/bug_report_page.php?category=yum distroverpkg=centos-release ip_resolve=4 # This is the default, if you make this bigger yum won't see if the metadata # is newer on the remote and so you'll "gain" the bandwidth of not having to # download the new metadata and "pay" for it by yum not having correct # information. # It is esp. important, to have correct metadata, for distributions like # Fedora which don't keep old packages around. If you don't like this checking # interupting your command line usage, it's much better to have something # manually check the metadata once an hour (yum-updatesd will do this). # metadata_expire=90m # PUT YOUR REPOS HERE OR IN separate files named file.repo # in /etc/yum.repos.d