We did see that Knox gateway servers failing to return Load balancer url after submitting a WebHDFS commands.
It could be seen that the logs in the server as below,
2017-02-15 20:15:51,050 DEBUG hadoop.gateway (UrlRewriteProcessor.java:rewrite(157)) - Rewrote URL: http://<Gateway-server-hostname>:50075/webhdfs/v1/user/<username>/test2?op=CREATE&user.name=<usernam..., direction: OUT via explicit rule: WEBHDFS/webhdfs/outbound/namenode/headers/location to URL: https://<Gateway-server-hostname>:8443/gateway/production/webhdfs/data/v1/webhdfs/v1/user/<username>...
It is seen that corrupted deployment director (/var/lib/knox/data/deployment) can lead to this issue.
1. Take a backup of the deployment directory
2. Delete the directory contents
3. Restart Knox server (recreates the contents).