yum 更换源无效，报一下错误

base | 3.6 kB 00:00:00
docker-ce-stable | 3.5 kB 00:00:00
extras | 3.4 kB 00:00:00
http://jenkins.mono-project.com/repo/centos/repodata/repomd.xml: [Errno 14] HTTP Error 404 - Not Found
正在尝试其它镜像。
To address this issue please refer to the below wiki article

https://wiki.centos.org/yum-errors

If above article doesn't help to resolve this issue please use https://bugs.centos.org/.

One of the configured repositories failed (added from: http://jenkins.mono-project.com/repo/centos/),
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=jenkins.mono-project.com_repo_centos_ ...

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 jenkins.mono-project.com_repo_centos_
or
subscription-manager repos --disable=jenkins.mono-project.com_repo_centos_

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=jenkins.mono-project.com_repo_centos_.skip_if_unavailable=true

failure: repodata/repomd.xml from jenkins.mono-project.com_repo_centos_: [Errno 256] No more mirrors to try.
http://jenkins.mono-project.com/repo/centos/repodata/repomd.xml: [Errno 14] HTTP Error 404 - Not Found