more doc cleanups

ucloud/docs/source/troubleshooting.rst

@@ -0,0 +1,24 @@
+Installation Troubleshooting
+============================
+
+etcd doesn't start
+------------------
+
+.. code-block:: sh
+
+    [root@archlinux ~]# systemctl start etcd
+    Job for etcd.service failed because the control process exited with error code.
+    See "systemctl status etcd.service" and "journalctl -xe" for details
+
+possible solution
+~~~~~~~~~~~~~~~~~
+Try :code:`cat /etc/hosts` if its output contain the following
+
+.. code-block:: sh
+
+    127.0.0.1    localhost.localdomain localhost
+    ::1        localhost localhost.localdomain
+
+
+then unfortunately, we can't help you. But, if it doesn't contain the
+above you can put the above in :file:`/etc/hosts` to fix the issue.