kubernetes: [Installation Failure] Mirror unavailable when yum install

OS: redhat 7.2 I followed the tutorials in kubernetes.io, but failed when yum install.

# cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=http://yum.kubernetes.io/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg
       https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF
# setenforce 0
# yum install -y docker kubelet kubeadm kubectl kubernetes-cni
# systemctl enable docker && systemctl start docker
# systemctl enable kubelet && systemctl start kubelet

After create kubernetes.repo, I get the info as below when I try yum update :

Loaded plugins: fastestmirror, product-id, search-disabled-repos, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
base                                                                        | 3.6 kB  00:00:00     
docker-main-repo                                                            | 2.9 kB  00:00:00     
dockerrepo                                                                  | 2.9 kB  00:00:00     
extras                                                                      | 3.4 kB  00:00:00     
http://yum.kubernetes.io/repos/kubernetes-el7-x86_64/repodata/repomd.xml: [Errno 14] HTTPS Error 302 - Found
Trying other mirror.


 One of the configured repositories failed (Kubernetes),
 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 kubernetes

     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=kubernetes.skip_if_unavailable=true

failure: repodata/repomd.xml from kubernetes: [Errno 256] No more mirrors to try.
http://yum.kubernetes.io/repos/kubernetes-el7-x86_64/repodata/repomd.xml: [Errno 14] HTTPS Error 302 - Found

I’m not sure whether the mirrors are missing, could you give me some suggestions?