Thanks for your reply @eldeberde.
Ok, solved the issue. I 've tried to spot all issues I encountered and it was a conglomerate : )
1)Error in the directory name containing the certifiate: no need to escape “:”
2)After each change in the certrificate, I didn’t restart docker daemon.
3)Errors in the variables passed to registry container: REGISTRY_AUTH_HTPASSWD_PATH need to refer to container path not docker node path ( /auth/htpasswd NOT /home/ajn/auth/htpasswd)
[ajn@dockerstd1 ~]$ docker login myregistry.ajnouri.com:5000/my-busybox
Username: test
Password:
Login Succeeded