I don’t know what causes it, but since it would not happen in case of a new installation, you can try to remove the docker-ce repo from your cache and add it again following the official documentation:
@rimelek , Thanks I already tried it. Let me share the screen output for your verification. The server has the external communication.
[root@centos7-sanka yum.repos.d]# yum-config-manager \
> --add-repo \
> https://download.docker.com/linux/centos/docker-ce.repo
Loaded plugins: langpacks, product-id
adding repo from: https://download.docker.com/linux/centos/docker-ce.repo
Traceback (most recent call last):
File "/bin/yum-config-manager", line 203, in <module>
grabber = yb.repos.listEnabled()[0].grabfunc
IndexError: list index out of range
The yum command putput.
# yum install docker-ce
Loaded plugins: langpacks, product-id, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
https://download.docker.com/linux/centos/docker-ce.repo/repodata/repomd.xml: [Errno 14] HTTPS Error 404 - Not Found
Trying other mirror.
One of the configured repositories failed (download.docker.com),
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. Disable the repository, 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 download_docker_package
4. 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=download_docker_package.skip_if_unavailable=true
failure: repodata/repomd.xml from download_docker_package: [Errno 256] No more mirrors to try.
https://download.docker.com/linux/centos/docker-ce.repo/repodata/repomd.xml: [Errno 14] HTTPS Error 404 - Not Found