Revert "Enable the Ray dashboard by default (#5976)" (#6068)

This reverts commit 6166ef3e09.

python/ray/services.py

@@ -12,10 +12,10 @@ import resource
 import socket
 import subprocess
 import sys
+import textwrap
 import time
 import redis
 
-import colorama
 import pyarrow
 # Ray modules
 import ray
@@ -1035,11 +1035,21 @@ def start_dashboard(host,
         ray_constants.PROCESS_TYPE_DASHBOARD,
         stdout_file=stdout_file,
         stderr_file=stderr_file)
-    dashboard_url = "{}:{}".format(
-        host if host != "0.0.0.0" else get_node_ip_address(), port)
-    logger.info("View the Ray dashboard at {}{}{}{}{}.".format(
-        colorama.Style.BRIGHT, colorama.Fore.GREEN, dashboard_url,
-        colorama.Fore.RESET, colorama.Style.NORMAL))
+    dashboard_url = "http://{}:{}".format(
+        host if host == "127.0.0.1" else get_node_ip_address(), port)
+    print("\n" + "=" * 70)
+    print("View the dashboard at {}.".format(dashboard_url))
+    if host == "127.0.0.1":
+        note = (
+            "Note: If Ray is running on a remote node, you will need to set "
+            "up an SSH tunnel with local port forwarding in order to access "
+            "the dashboard in your browser, e.g. by running "
+            "'ssh -L {}:{}:{} <username>@<host>'. Alternatively, you can set "
+            "webui_host=\"0.0.0.0\" in the call to ray.init() to allow direct "
+            "access from external machines.")
+        note = note.format(port, host, port)
+        print("\n".join(textwrap.wrap(note, width=70)))
+    print("=" * 70 + "\n")
     return dashboard_url, process_info