kubernetes: curl command from kubectl for "exec" does not work

Running this command: kubectl --v=99 exec nginx-app-2883164633-2u2nf "ls":

Outputs the sample curl command: http://paste.openstack.org/show/495175/

Trying the curl command does not work: http://paste.openstack.org/show/495176/

{ “kind”: “Status”, “apiVersion”: “v1”, “metadata”: {}, “status”: “Failure”, “message”: “Upgrade request required”, “reason”: “BadRequest”, “code”: 400

• Connection #0 to host 127.0.0.1 left intact }