kubectl describe pod my-nginx-379829228-c5g9f

 for "POD" with ErrImagePull: "image pull failed for registry.access.redhat.com/rhel7/pod-infrastructure:latest, this may be because there are no credentials on this request.  details: (Get https://registry.access.redhat.com/v1/_ping: dial tcp: lookup registry.access.redhat.com on [::1]:53: read udp [::1]:34107->[::1]:53: read: connection refused)"

  8m    8m      1       {kubelet 127.0.0.1}             Warning FailedSync      Error syncing pod, skipping: failed to "StartContainer" for "POD" with ErrImagePull: "image pull failed for registry.access.redhat.com/rhel7/pod-infrastructure:latest, this may be because there are no credentials on this request.  details: (Get https://registry.access.redhat.com/v1/_ping: dial tcp: lookup registry.access.redhat.com on [::1]:53: read udp [::1]:54383->[::1]:53: read: connection refused)"

证书问题，处理方式如下：

yum install -y rhsm

wget http://mirror.centos.org/centos/7/os/x86_64/Packages/python-rhsm-certificates-1.19.10-1.el7_4.x86_64.rpm

rpm2cpio python-rhsm-certificates-1.19.10-1.el7_4.x86_64.rpm | cpio -iv --to-stdout ./etc/rhsm/ca/redhat-uep.pem | tee /etc/rhsm/ca/redhat-uep.pem