Information
https://docs.docker.com/articles/certificates/
2.http://docs.docker.com/articles/https/
Solution
chown root-root <path to Docker server certificate key file>
This would set the ownership and group-ownership for the Docker server certificate key
file to 'root'.Impact-None.Default Value-By default, the ownership and group-ownership for Docker server certificate key file is
correctly set to 'root'.