I am setting up kubernetes cluster using kubeadm on on-premise servers (Centos 7.6). I got the "Peer certificate error". I set sslverify=0 in kubernetes.conf and able to proceed. But want to know how to download the certificate and proceed without sslverify flase.

[root@k8s-master yum.repos.d]# yum install -y kubelet kubeadm kubectl --disableexcludes=kubernetes
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: centos.excellmedia.net
 * extras: centos.excellmedia.net
 * update: centos.excellmedia.net

https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64/repodata/repomd.xml: [Errno 14] curl#60 - "Peer's Certificate issuer is not recognized."
Trying other mirror.
It was impossible to connect to the CentOS servers.
This could mean a connectivity issue in your environment, such as the requirement to configure a proxy,
or a transparent proxy that tampers with TLS security, or an incorrect system clock.
You can try to solve this issue by using the instructions on 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 (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. Run the command with the repository temporarily disabled
        yum --disablerepo=kubernetes ...

 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 kubernetes
    or
        subscription-manager repos --disable=kubernetes

 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=kubernetes.skip_if_unavailable=true

failure: repodata/repomd.xml from kubernetes: [Errno 256] No more mirrors to try.
https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64/repodata/repomd.xml: [Errno 14] curl#60 - "Peer's Certificate issuer is not recognized."