cloud-init-dev team mailing list archive

[Brian Rak <brak@xxxxxxxxx>]

Brian Rak has proposed merging lp:~brak/cloud-init/dont-overwrite-hostname into lp:cloud-init.

Requested reviews:
  cloud init development team (cloud-init-dev)

For more details, see:
https://code.launchpad.net/~brak/cloud-init/dont-overwrite-hostname/+merge/256348

Based on what I understand, the 'update_hostname' task is only supposed to be setting the hostname once per instance.  If something else modifies the hostname after update_hostname sets it, update_hostname should not overwrite those changes.  (To overwrite, it seems you'd use 'set_hostname' instead).

The update_hostname function actually detects this case already, but all it does is emit a debug log entry about it.

This patch detects the case when the hostname has been changed by something else after cloud-init has set it, and will not overwrite the hostname again.
-- 
Your team cloud init development team is requested to review the proposed merge of lp:~brak/cloud-init/dont-overwrite-hostname into lp:cloud-init.

=== modified file 'cloudinit/distros/__init__.py'
--- cloudinit/distros/__init__.py	2015-01-26 16:14:06 +0000
+++ cloudinit/distros/__init__.py	2015-04-15 15:35:56 +0000
@@ -208,6 +208,15 @@
                                   and sys_hostname != hostname):
             update_files.append(sys_fn)
 
+        # If something else has changed the hostname after we set it
+        # initially, we should not overwrite those changes (we should
+        # only be setting the hostname once per instance)
+        if (sys_hostname and prev_hostname and
+                sys_hostname != prev_hostname):
+            LOG.info("%s differs from %s, assuming user maintained hostname.",
+                       prev_hostname_fn, sys_fn)
+            return
+
         # Remove duplicates (incase the previous config filename)
         # is the same as the system config filename, don't bother
         # doing it twice
@@ -222,11 +231,6 @@
                 util.logexc(LOG, "Failed to write hostname %s to %s", hostname,
                             fn)
 
-        if (sys_hostname and prev_hostname and
-                sys_hostname != prev_hostname):
-            LOG.debug("%s differs from %s, assuming user maintained hostname.",
-                       prev_hostname_fn, sys_fn)
-
         # If the system hostname file name was provided set the
         # non-fqdn as the transient hostname.
         if sys_fn in update_files: