cloud-init-dev team mailing list archive

[Lars Kellogg-Stedman <lars@xxxxxxxxxx>]

Lars Kellogg-Stedman has proposed merging lp:~larsks/cloud-init/fix-systemd-detection into lp:cloud-init.

Requested reviews:
  cloud init development team (cloud-init-dev)
Related bugs:
  Bug #1461201 in cloud-init: "Check for systemd (in distros/rhel.py) is fragile"
  https://bugs.launchpad.net/cloud-init/+bug/1461201

For more details, see:
https://code.launchpad.net/~larsks/cloud-init/fix-systemd-detection/+merge/260885

check for systemd using sd_booted() semantics

The existing cloud-init code determines if systemd is in use by looking at the
distribution name and version. This is prone to error because:

- RHEL derivatives other than CentOS (e.g., Scientific Linux) will fail this test, and
- Distributions that are not derived from RHEL also use systemd

This patch makes cloud-init use the same logic that is used in systemd's
sd_booted() method
(http://www.freedesktop.org/software/systemd/man/sd_booted.html)

-- 
Your team cloud init development team is requested to review the proposed merge of lp:~larsks/cloud-init/fix-systemd-detection into lp:cloud-init.

=== modified file 'cloudinit/distros/__init__.py'
--- cloudinit/distros/__init__.py	2015-05-19 15:21:34 +0000
+++ cloudinit/distros/__init__.py	2015-06-02 20:30:42 +0000
@@ -27,6 +27,7 @@
 import abc
 import os
 import re
+import stat
 
 from cloudinit import importer
 from cloudinit import log as logging
@@ -89,6 +90,13 @@
         self._write_hostname(writeable_hostname, self.hostname_conf_fn)
         self._apply_hostname(writeable_hostname)
 
+    def uses_systemd(self):
+        try:
+            res = os.lstat('/run/systemd/system')
+            return stat.S_ISDIR(res.st_mode)
+        except:
+            return False
+
     @abc.abstractmethod
     def package_command(self, cmd, args=None, pkgs=None):
         raise NotImplementedError()

=== modified file 'cloudinit/distros/rhel.py'
--- cloudinit/distros/rhel.py	2015-05-15 20:28:24 +0000
+++ cloudinit/distros/rhel.py	2015-06-02 20:30:42 +0000
@@ -111,14 +111,6 @@
             rhel_util.update_sysconfig_file(self.network_conf_fn, net_cfg)
         return dev_names
 
-    def uses_systemd(self):
-        # Fedora 18 and RHEL 7 were the first adopters in their series
-        (dist, vers) = util.system_info()['dist'][:2]
-        major = (int)(vers.split('.')[0])
-        return ((dist.startswith('Red Hat Enterprise Linux') and major >= 7)
-                or (dist.startswith('CentOS Linux') and major >= 7)
-                or (dist.startswith('Fedora') and major >= 18))
-
     def apply_locale(self, locale, out_fn=None):
         if self.uses_systemd():
             if not out_fn: