merge with trunk

13 files changed, 172 insertions, 101 deletions

diff --git a/cloudinit/distros/__init__.py b/cloudinit/distros/__init__.py
index 5eab780b..418421b9 100644
--- a/cloudinit/distros/__init__.py
+++ b/cloudinit/distros/__init__.py
@@ -21,12 +21,13 @@
 #    You should have received a copy of the GNU General Public License
 #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from StringIO import StringIO
+import six
+from six import StringIO
 
 import abc
-import itertools
 import os
 import re
+import stat
 
 from cloudinit import importer
 from cloudinit import log as logging
@@ -36,6 +37,7 @@ from cloudinit import util
 
 from cloudinit.distros.parsers import hosts
 
+
 OSFAMILIES = {
     'debian': ['debian', 'ubuntu'],
     'redhat': ['fedora', 'rhel'],
@@ -73,6 +75,9 @@ class Distro(object):
         # to write this blob out in a distro format
         raise NotImplementedError()
 
+    def _write_network_config(self, settings):
+        raise NotImplementedError()
+
     def _find_tz_file(self, tz):
         tz_file = os.path.join(self.tz_zone_dir, str(tz))
         if not os.path.isfile(tz_file):
@@ -88,6 +93,13 @@ class Distro(object):
         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()
@@ -108,12 +120,11 @@ class Distro(object):
             arch = self.get_primary_arch()
         return _get_arch_package_mirror_info(mirror_info, arch)
 
-    def get_package_mirror_info(self, arch=None,
-                                availability_zone=None):
+    def get_package_mirror_info(self, arch=None, data_source=None):
         # This resolves the package_mirrors config option
         # down to a single dict of {mirror_name: mirror_url}
         arch_info = self._get_arch_package_mirror_info(arch)
-        return _get_package_mirror_info(availability_zone=availability_zone,
+        return _get_package_mirror_info(data_source=data_source,
                                         mirror_info=arch_info)
 
     def apply_network(self, settings, bring_up=True):
@@ -124,6 +135,14 @@ class Distro(object):
             return self._bring_up_interfaces(dev_names)
         return False
 
+    def apply_network_config(self, netconfig, bring_up=False):
+        # Write it out
+        dev_names = self._write_network_config(netconfig)
+        # Now try to bring them up
+        if bring_up:
+            return self._bring_up_interfaces(dev_names)
+        return False
+
     @abc.abstractmethod
     def apply_locale(self, locale, out_fn=None):
         raise NotImplementedError()
@@ -203,10 +222,19 @@ class Distro(object):
 
         # If the system hostname is different than the previous
         # one or the desired one lets update it as well
-        if (not sys_hostname) or (sys_hostname == prev_hostname
-                                  and sys_hostname != hostname):
+        if ((not sys_hostname) or (sys_hostname == prev_hostname 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
@@ -221,11 +249,6 @@ class Distro(object):
                 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:
@@ -272,12 +295,12 @@ class Distro(object):
             if header:
                 contents.write("%s\n" % (header))
             contents.write("%s\n" % (eh))
-            util.write_file(self.hosts_fn, contents.getvalue(), mode=0644)
+            util.write_file(self.hosts_fn, contents.getvalue(), mode=0o644)
 
     def _bring_up_interface(self, device_name):
         cmd = ['ifup', device_name]
         LOG.debug("Attempting to run bring up interface %s using command %s",
-                   device_name, cmd)
+                  device_name, cmd)
         try:
             (_out, err) = util.subp(cmd)
             if len(err):
@@ -307,6 +330,11 @@ class Distro(object):
             LOG.info("User %s already exists, skipping." % name)
             return
 
+        if 'create_groups' in kwargs:
+            create_groups = kwargs.pop('create_groups')
+        else:
+            create_groups = True
+
         adduser_cmd = ['useradd', name]
         log_adduser_cmd = ['useradd', name]
 
@@ -317,6 +345,7 @@ class Distro(object):
             "gecos": '--comment',
             "homedir": '--home',
             "primary_group": '--gid',
+            "uid": '--uid',
             "groups": '--groups',
             "passwd": '--password',
             "shell": '--shell',
@@ -333,8 +362,21 @@ class Distro(object):
 
         redact_opts = ['passwd']
 
+        groups = kwargs.get('groups')
+        if groups:
+            if isinstance(groups, (list, tuple)):
+                kwargs['groups'] = ",".join(groups)
+            else:
+                groups = groups.split(",")
+
+        if create_groups:
+            for group in kwargs.get('groups').split(","):
+                if not util.is_group(group):
+                    self.create_group(group)
+                    LOG.debug("created group %s for user %s", name, group)
+
         # Check the values and create the command
-        for key, val in kwargs.iteritems():
+        for key, val in kwargs.items():
 
             if key in adduser_opts and val and isinstance(val, str):
                 adduser_cmd.extend([adduser_opts[key], val])
@@ -380,6 +422,10 @@ class Distro(object):
         if 'plain_text_passwd' in kwargs and kwargs['plain_text_passwd']:
             self.set_passwd(name, kwargs['plain_text_passwd'])
 
+        # Set password if hashed password is provided and non-empty
+        if 'hashed_passwd' in kwargs and kwargs['hashed_passwd']:
+            self.set_passwd(name, kwargs['hashed_passwd'], hashed=True)
+
         # Default locking down the account.  'lock_passwd' defaults to True.
         # lock account unless lock_password is False.
         if kwargs.get('lock_passwd', True):
@@ -393,7 +439,7 @@ class Distro(object):
         if 'ssh_authorized_keys' in kwargs:
             # Try to handle this in a smart manner.
             keys = kwargs['ssh_authorized_keys']
-            if isinstance(keys, (basestring, str)):
+            if isinstance(keys, six.string_types):
                 keys = [keys]
             if isinstance(keys, dict):
                 keys = list(keys.values())
@@ -468,7 +514,7 @@ class Distro(object):
                              util.make_header(base="added"),
                              "#includedir %s" % (path), '']
                     sudoers_contents = "\n".join(lines)
-                    util.write_file(sudo_base, sudoers_contents, 0440)
+                    util.write_file(sudo_base, sudoers_contents, 0o440)
                 else:
                     lines = ['', util.make_header(base="added"),
                              "#includedir %s" % (path), '']
@@ -478,7 +524,7 @@ class Distro(object):
             except IOError as e:
                 util.logexc(LOG, "Failed to write %s", sudo_base)
                 raise e
-        util.ensure_dir(path, 0750)
+        util.ensure_dir(path, 0o750)
 
     def write_sudo_rules(self, user, rules, sudo_file=None):
         if not sudo_file:
@@ -491,7 +537,7 @@ class Distro(object):
         if isinstance(rules, (list, tuple)):
             for rule in rules:
                 lines.append("%s %s" % (user, rule))
-        elif isinstance(rules, (basestring, str)):
+        elif isinstance(rules, six.string_types):
             lines.append("%s %s" % (user, rules))
         else:
             msg = "Can not create sudoers rule addition with type %r"
@@ -506,7 +552,7 @@ class Distro(object):
                 content,
             ]
             try:
-                util.write_file(sudo_file, "\n".join(contents), 0440)
+                util.write_file(sudo_file, "\n".join(contents), 0o440)
             except IOError as e:
                 util.logexc(LOG, "Failed to write sudoers file %s", sudo_file)
                 raise e
@@ -517,8 +563,10 @@ class Distro(object):
                 util.logexc(LOG, "Failed to append sudoers file %s", sudo_file)
                 raise e
 
-    def create_group(self, name, members):
+    def create_group(self, name, members=None):
         group_add_cmd = ['groupadd', name]
+        if not members:
+            members = []
 
         # Check if group exists, and then add it doesn't
         if util.is_group(name):
@@ -528,21 +576,21 @@ class Distro(object):
                 util.subp(group_add_cmd)
                 LOG.info("Created new group %s" % name)
             except Exception:
-                util.logexc("Failed to create group %s", name)
+                util.logexc(LOG, "Failed to create group %s", name)
 
         # Add members to the group, if so defined
         if len(members) > 0:
             for member in members:
                 if not util.is_user(member):
                     LOG.warn("Unable to add group member '%s' to group '%s'"
-                            "; user does not exist.", member, name)
+                             "; user does not exist.", member, name)
                     continue
 
                 util.subp(['usermod', '-a', '-G', name, member])
                 LOG.info("Added user '%s' to group '%s'" % (member, name))
 
 
-def _get_package_mirror_info(mirror_info, availability_zone=None,
+def _get_package_mirror_info(mirror_info, data_source=None,
                              mirror_filter=util.search_for_mirror):
     # given a arch specific 'mirror_info' entry (from package_mirrors)
     # search through the 'search' entries, and fallback appropriately
@@ -550,21 +598,28 @@ def _get_package_mirror_info(mirror_info, availability_zone=None,
     if not mirror_info:
         mirror_info = {}
 
-    ec2_az_re = ("^[a-z][a-z]-(%s)-[1-9][0-9]*[a-z]$" %
-        "north|northeast|east|southeast|south|southwest|west|northwest")
+    # ec2 availability zones are named cc-direction-[0-9][a-d] (us-east-1b)
+    # the region is us-east-1. so region = az[0:-1]
+    directions_re = '|'.join([
+        'central', 'east', 'north', 'northeast', 'northwest',
+        'south', 'southeast', 'southwest', 'west'])
+    ec2_az_re = ("^[a-z][a-z]-(%s)-[1-9][0-9]*[a-z]$" % directions_re)
 
     subst = {}
-    if availability_zone:
-        subst['availability_zone'] = availability_zone
+    if data_source and data_source.availability_zone:
+        subst['availability_zone'] = data_source.availability_zone
+
+        if re.match(ec2_az_re, data_source.availability_zone):
+            subst['ec2_region'] = "%s" % data_source.availability_zone[0:-1]
 
-    if availability_zone and re.match(ec2_az_re, availability_zone):
-        subst['ec2_region'] = "%s" % availability_zone[0:-1]
+    if data_source and data_source.region:
+        subst['region'] = data_source.region
 
     results = {}
-    for (name, mirror) in mirror_info.get('failsafe', {}).iteritems():
+    for (name, mirror) in mirror_info.get('failsafe', {}).items():
         results[name] = mirror
 
-    for (name, searchlist) in mirror_info.get('search', {}).iteritems():
+    for (name, searchlist) in mirror_info.get('search', {}).items():
         mirrors = []
         for tmpl in searchlist:
             try:
@@ -604,30 +659,30 @@ def _get_arch_package_mirror_info(package_mirrors, arch):
 # is the standard form used in the rest
 # of cloud-init
 def _normalize_groups(grp_cfg):
-    if isinstance(grp_cfg, (str, basestring)):
+    if isinstance(grp_cfg, six.string_types):
         grp_cfg = grp_cfg.strip().split(",")
-    if isinstance(grp_cfg, (list)):
+    if isinstance(grp_cfg, list):
         c_grp_cfg = {}
         for i in grp_cfg:
-            if isinstance(i, (dict)):
+            if isinstance(i, dict):
                 for k, v in i.items():
                     if k not in c_grp_cfg:
-                        if isinstance(v, (list)):
+                        if isinstance(v, list):
                             c_grp_cfg[k] = list(v)
-                        elif isinstance(v, (basestring, str)):
+                        elif isinstance(v, six.string_types):
                             c_grp_cfg[k] = [v]
                         else:
                             raise TypeError("Bad group member type %s" %
                                             type_utils.obj_name(v))
                     else:
-                        if isinstance(v, (list)):
+                        if isinstance(v, list):
                             c_grp_cfg[k].extend(v)
-                        elif isinstance(v, (basestring, str)):
+                        elif isinstance(v, six.string_types):
                             c_grp_cfg[k].append(v)
                         else:
                             raise TypeError("Bad group member type %s" %
                                             type_utils.obj_name(v))
-            elif isinstance(i, (str, basestring)):
+            elif isinstance(i, six.string_types):
                 if i not in c_grp_cfg:
                     c_grp_cfg[i] = []
             else:
@@ -635,7 +690,7 @@ def _normalize_groups(grp_cfg):
                                 type_utils.obj_name(i))
         grp_cfg = c_grp_cfg
     groups = {}
-    if isinstance(grp_cfg, (dict)):
+    if isinstance(grp_cfg, dict):
         for (grp_name, grp_members) in grp_cfg.items():
             groups[grp_name] = util.uniq_merge_sorted(grp_members)
     else:
@@ -661,29 +716,29 @@ def _normalize_groups(grp_cfg):
 # entry 'default' which will be marked as true
 # all other users will be marked as false.
 def _normalize_users(u_cfg, def_user_cfg=None):
-    if isinstance(u_cfg, (dict)):
+    if isinstance(u_cfg, dict):
         ad_ucfg = []
         for (k, v) in u_cfg.items():
-            if isinstance(v, (bool, int, basestring, str, float)):
+            if isinstance(v, (bool, int, float) + six.string_types):
                 if util.is_true(v):
                     ad_ucfg.append(str(k))
-            elif isinstance(v, (dict)):
+            elif isinstance(v, dict):
                 v['name'] = k
                 ad_ucfg.append(v)
             else:
                 raise TypeError(("Unmappable user value type %s"
                                  " for key %s") % (type_utils.obj_name(v), k))
         u_cfg = ad_ucfg
-    elif isinstance(u_cfg, (str, basestring)):
+    elif isinstance(u_cfg, six.string_types):
         u_cfg = util.uniq_merge_sorted(u_cfg)
 
     users = {}
     for user_config in u_cfg:
-        if isinstance(user_config, (str, basestring, list)):
+        if isinstance(user_config, (list,) + six.string_types):
             for u in util.uniq_merge(user_config):
                 if u and u not in users:
                     users[u] = {}
-        elif isinstance(user_config, (dict)):
+        elif isinstance(user_config, dict):
             if 'name' in user_config:
                 n = user_config.pop('name')
                 prev_config = users.get(n) or {}
@@ -784,11 +839,11 @@ def normalize_users_groups(cfg, distro):
         old_user = cfg['user']
         # Translate it into the format that is more useful
         # going forward
-        if isinstance(old_user, (basestring, str)):
+        if isinstance(old_user, six.string_types):
             old_user = {
                 'name': old_user,
             }
-        if not isinstance(old_user, (dict)):
+        if not isinstance(old_user, dict):
             LOG.warn(("Format for 'user' key must be a string or "
                       "dictionary and not %s"), type_utils.obj_name(old_user))
             old_user = {}
@@ -813,7 +868,7 @@ def normalize_users_groups(cfg, distro):
     default_user_config = util.mergemanydict([old_user, distro_user_config])
 
     base_users = cfg.get('users', [])
-    if not isinstance(base_users, (list, dict, str, basestring)):
+    if not isinstance(base_users, (list, dict) + six.string_types):
         LOG.warn(("Format for 'users' key must be a comma separated string"
                   " or a dictionary or a list and not %s"),
                  type_utils.obj_name(base_users))
@@ -822,12 +877,12 @@ def normalize_users_groups(cfg, distro):
     if old_user:
         # Ensure that when user: is provided that this user
         # always gets added (as the default user)
-        if isinstance(base_users, (list)):
+        if isinstance(base_users, list):
             # Just add it on at the end...
             base_users.append({'name': 'default'})
-        elif isinstance(base_users, (dict)):
+        elif isinstance(base_users, dict):
             base_users['default'] = dict(base_users).get('default', True)
-        elif isinstance(base_users, (str, basestring)):
+        elif isinstance(base_users, six.string_types):
             # Just append it on to be re-parsed later
             base_users += ",default"
 
@@ -852,11 +907,11 @@ def extract_default(users, default_name=None, default_config=None):
             return config['default']
 
     tmp_users = users.items()
-    tmp_users = dict(itertools.ifilter(safe_find, tmp_users))
+    tmp_users = dict(filter(safe_find, tmp_users))
     if not tmp_users:
         return (default_name, default_config)
     else:
-        name = tmp_users.keys()[0]
+        name = list(tmp_users)[0]
         config = tmp_users[name]
         config.pop('default', None)
         return (name, config)
@@ -866,7 +921,7 @@ def fetch(name):
     locs, looked_locs = importer.find_module(name, ['', __name__], ['Distro'])
     if not locs:
         raise ImportError("No distribution found for distro %s (searched %s)"
-                           % (name, looked_locs))
+                          % (name, looked_locs))
     mod = importer.import_module(locs[0])
     cls = getattr(mod, 'Distro')
     return cls
@@ -877,5 +932,9 @@ def set_etc_timezone(tz, tz_file=None, tz_conf="/etc/timezone",
     util.write_file(tz_conf, str(tz).rstrip() + "\n")
     # This ensures that the correct tz will be used for the system
     if tz_local and tz_file:
-        util.copy(tz_file, tz_local)
+        # use a symlink if there exists a symlink or tz_local is not present
+        if os.path.islink(tz_local) or not os.path.exists(tz_local):
+            os.symlink(tz_file, tz_local)
+        else:
+            util.copy(tz_file, tz_local)
     return
diff --git a/cloudinit/distros/arch.py b/cloudinit/distros/arch.py
index 68bf1aab..93a2e008 100644
--- a/cloudinit/distros/arch.py
+++ b/cloudinit/distros/arch.py
@@ -66,7 +66,7 @@ class Distro(distros.Distro):
                   settings, entries)
         dev_names = entries.keys()
         # Format for netctl
-        for (dev, info) in entries.iteritems():
+        for (dev, info) in entries.items():
             nameservers = []
             net_fn = self.network_conf_dir + dev
             net_cfg = {
@@ -74,7 +74,7 @@ class Distro(distros.Distro):
                 'Interface': dev,
                 'IP': info.get('bootproto'),
                 'Address': "('%s/%s')" % (info.get('address'),
-                        info.get('netmask')),
+                                          info.get('netmask')),
                 'Gateway': info.get('gateway'),
                 'DNS': str(tuple(info.get('dns-nameservers'))).replace(',', '')
             }
@@ -86,7 +86,7 @@ class Distro(distros.Distro):
 
         if nameservers:
             util.write_file(self.resolve_conf_fn,
-                    convert_resolv_conf(nameservers))
+                            convert_resolv_conf(nameservers))
 
         return dev_names
 
@@ -102,7 +102,7 @@ class Distro(distros.Distro):
     def _bring_up_interface(self, device_name):
         cmd = ['netctl', 'restart', device_name]
         LOG.debug("Attempting to run bring up interface %s using command %s",
-                   device_name, cmd)
+                  device_name, cmd)
         try:
             (_out, err) = util.subp(cmd)
             if len(err):
@@ -129,7 +129,7 @@ class Distro(distros.Distro):
         if not conf:
             conf = HostnameConf('')
         conf.set_hostname(your_hostname)
-        util.write_file(out_fn, str(conf), 0644)
+        util.write_file(out_fn, conf, 0o644)
 
     def _read_system_hostname(self):
         sys_hostname = self._read_hostname(self.hostname_conf_fn)
diff --git a/cloudinit/distros/debian.py b/cloudinit/distros/debian.py
index b09eb094..5d7e6cfc 100644
--- a/cloudinit/distros/debian.py
+++ b/cloudinit/distros/debian.py
@@ -26,6 +26,7 @@ from cloudinit import distros
 from cloudinit import helpers
 from cloudinit import log as logging
 from cloudinit import util
+from cloudinit import net
 
 from cloudinit.distros.parsers.hostname import HostnameConf
 
@@ -45,7 +46,8 @@ APT_GET_WRAPPER = {
 class Distro(distros.Distro):
     hostname_conf_fn = "/etc/hostname"
     locale_conf_fn = "/etc/default/locale"
-    network_conf_fn = "/etc/network/interfaces"
+    network_conf_fn = "/etc/network/interfaces.d/50-cloud-init.cfg"
+    links_prefix = "/etc/systemd/network/50-cloud-init-"
 
     def __init__(self, name, cfg, paths):
         distros.Distro.__init__(self, name, cfg, paths)
@@ -76,6 +78,15 @@ class Distro(distros.Distro):
         util.write_file(self.network_conf_fn, settings)
         return ['all']
 
+    def _write_network_config(self, netconfig):
+        ns = net.parse_net_config_data(netconfig)
+        net.render_network_state(target="/", network_state=ns,
+                                 eni=self.network_conf_fn,
+                                 links_prefix=self.links_prefix,
+                                 netrules=None)
+        util.del_file("/etc/network/interfaces.d/eth0.cfg")
+        return []
+
     def _bring_up_interfaces(self, device_names):
         use_all = False
         for d in device_names:
@@ -97,7 +108,7 @@ class Distro(distros.Distro):
         if not conf:
             conf = HostnameConf('')
         conf.set_hostname(your_hostname)
-        util.write_file(out_fn, str(conf), 0644)
+        util.write_file(out_fn, str(conf), 0o644)
 
     def _read_system_hostname(self):
         sys_hostname = self._read_hostname(self.hostname_conf_fn)
@@ -159,8 +170,9 @@ class Distro(distros.Distro):
 
         # Allow the output of this to flow outwards (ie not be captured)
         util.log_time(logfunc=LOG.debug,
-            msg="apt-%s [%s]" % (command, ' '.join(cmd)), func=util.subp,
-            args=(cmd,), kwargs={'env': e, 'capture': False})
+                      msg="apt-%s [%s]" % (command, ' '.join(cmd)),
+                      func=util.subp,
+                      args=(cmd,), kwargs={'env': e, 'capture': False})
 
     def update_package_sources(self):
         self._runner.run("update-sources", self.package_command,
diff --git a/cloudinit/distros/freebsd.py b/cloudinit/distros/freebsd.py
index c59a074b..91bf4a4e 100644
--- a/cloudinit/distros/freebsd.py
+++ b/cloudinit/distros/freebsd.py
@@ -17,8 +17,8 @@
 #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import os
-
-from StringIO import StringIO
+import six
+from six import StringIO
 
 import re
 
@@ -207,8 +207,9 @@ class Distro(distros.Distro):
 
         redact_opts = ['passwd']
 
-        for key, val in kwargs.iteritems():
-            if key in adduser_opts and val and isinstance(val, basestring):
+        for key, val in kwargs.items():
+            if (key in adduser_opts and val and
+               isinstance(val, six.string_types)):
                 adduser_cmd.extend([adduser_opts[key], val])
 
                 # Redact certain fields from the logs
@@ -287,7 +288,7 @@ class Distro(distros.Distro):
         nameservers = []
         searchdomains = []
         dev_names = entries.keys()
-        for (device, info) in entries.iteritems():
+        for (device, info) in entries.items():
             # Skip the loopback interface.
             if device.startswith('lo'):
                 continue
@@ -339,7 +340,7 @@ class Distro(distros.Distro):
                 resolvconf.add_search_domain(domain)
             except ValueError:
                 util.logexc(LOG, "Failed to add search domain %s", domain)
-        util.write_file(self.resolv_conf_fn, str(resolvconf), 0644)
+        util.write_file(self.resolv_conf_fn, str(resolvconf), 0o644)
 
         return dev_names
 
diff --git a/cloudinit/distros/gentoo.py b/cloudinit/distros/gentoo.py
index 09dd0d73..6267dd6e 100644
--- a/cloudinit/distros/gentoo.py
+++ b/cloudinit/distros/gentoo.py
@@ -66,7 +66,7 @@ class Distro(distros.Distro):
     def _bring_up_interface(self, device_name):
         cmd = ['/etc/init.d/net.%s' % device_name, 'restart']
         LOG.debug("Attempting to run bring up interface %s using command %s",
-                   device_name, cmd)
+                  device_name, cmd)
         try:
             (_out, err) = util.subp(cmd)
             if len(err):
@@ -88,7 +88,7 @@ class Distro(distros.Distro):
                 (_out, err) = util.subp(cmd)
                 if len(err):
                     LOG.warn("Running %s resulted in stderr output: %s", cmd,
-                            err)
+                             err)
             except util.ProcessExecutionError:
                 util.logexc(LOG, "Running interface command %s failed", cmd)
                 return False
@@ -108,7 +108,7 @@ class Distro(distros.Distro):
         if not conf:
             conf = HostnameConf('')
         conf.set_hostname(your_hostname)
-        util.write_file(out_fn, str(conf), 0644)
+        util.write_file(out_fn, conf, 0o644)
 
     def _read_system_hostname(self):
         sys_hostname = self._read_hostname(self.hostname_conf_fn)
diff --git a/cloudinit/distros/net_util.py b/cloudinit/distros/net_util.py
index 8b28e2d1..cadfa6b6 100644
--- a/cloudinit/distros/net_util.py
+++ b/cloudinit/distros/net_util.py
@@ -103,7 +103,7 @@ def translate_network(settings):
             consume[cmd] = args
     # Check if anything left over to consume
     absorb = False
-    for (cmd, args) in consume.iteritems():
+    for (cmd, args) in consume.items():
         if cmd == 'iface':
             absorb = True
     if absorb:
diff --git a/cloudinit/distros/parsers/hostname.py b/cloudinit/distros/parsers/hostname.py
index 617b3c36..efb185d4 100644
--- a/cloudinit/distros/parsers/hostname.py
+++ b/cloudinit/distros/parsers/hostname.py
@@ -16,7 +16,7 @@
 #    You should have received a copy of the GNU General Public License
 #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from StringIO import StringIO
+from six import StringIO
 
 from cloudinit.distros.parsers import chop_comment
 
@@ -84,5 +84,5 @@ class HostnameConf(object):
             hostnames_found.add(head)
         if len(hostnames_found) > 1:
             raise IOError("Multiple hostnames (%s) found!"
-                           % (hostnames_found))
+                          % (hostnames_found))
         return entries
diff --git a/cloudinit/distros/parsers/hosts.py b/cloudinit/distros/parsers/hosts.py
index 94c97051..3c5498ee 100644
--- a/cloudinit/distros/parsers/hosts.py
+++ b/cloudinit/distros/parsers/hosts.py
@@ -16,7 +16,7 @@
 #    You should have received a copy of the GNU General Public License
 #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from StringIO import StringIO
+from six import StringIO
 
 from cloudinit.distros.parsers import chop_comment
 
diff --git a/cloudinit/distros/parsers/resolv_conf.py b/cloudinit/distros/parsers/resolv_conf.py
index 5733c25a..2ed13d9c 100644
--- a/cloudinit/distros/parsers/resolv_conf.py
+++ b/cloudinit/distros/parsers/resolv_conf.py
@@ -16,7 +16,7 @@
 #    You should have received a copy of the GNU General Public License
 #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from StringIO import StringIO
+from six import StringIO
 
 from cloudinit import util
 
@@ -132,7 +132,7 @@ class ResolvConf(object):
             # Some hard limit on 256 chars total
             raise ValueError(("Adding %r would go beyond the "
                               "256 maximum search list character limit")
-                              % (search_domain))
+                             % (search_domain))
         self._remove_option('search')
         self._contents.append(('option', ['search', s_list, '']))
         return flat_sds
diff --git a/cloudinit/distros/parsers/sys_conf.py b/cloudinit/distros/parsers/sys_conf.py
index 20ca1871..6157cf32 100644
--- a/cloudinit/distros/parsers/sys_conf.py
+++ b/cloudinit/distros/parsers/sys_conf.py
@@ -16,7 +16,8 @@
 #    You should have received a copy of the GNU General Public License
 #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from StringIO import StringIO
+import six
+from six import StringIO
 
 import pipes
 import re
@@ -69,15 +70,14 @@ class SysConf(configobj.ConfigObj):
         return out_contents.getvalue()
 
     def _quote(self, value, multiline=False):
-        if not isinstance(value, (str, basestring)):
+        if not isinstance(value, six.string_types):
             raise ValueError('Value "%s" is not a string' % (value))
         if len(value) == 0:
             return ''
         quot_func = None
         if value[0] in ['"', "'"] and value[-1] in ['"', "'"]:
             if len(value) == 1:
-                quot_func = (lambda x:
-                                self._get_single_quote(x) % x)
+                quot_func = (lambda x: self._get_single_quote(x) % x)
         else:
             # Quote whitespace if it isn't the start + end of a shell command
             if value.strip().startswith("$(") and value.strip().endswith(")"):
@@ -90,10 +90,10 @@ class SysConf(configobj.ConfigObj):
                         # to use single quotes which won't get expanded...
                         if re.search(r"[\n\"']", value):
                             quot_func = (lambda x:
-                                            self._get_triple_quote(x) % x)
+                                         self._get_triple_quote(x) % x)
                         else:
                             quot_func = (lambda x:
-                                            self._get_single_quote(x) % x)
+                                         self._get_single_quote(x) % x)
                     else:
                         quot_func = pipes.quote
         if not quot_func:
diff --git a/cloudinit/distros/rhel.py b/cloudinit/distros/rhel.py
index d9588632..812e7002 100644
--- a/cloudinit/distros/rhel.py
+++ b/cloudinit/distros/rhel.py
@@ -73,7 +73,7 @@ class Distro(distros.Distro):
         searchservers = []
         dev_names = entries.keys()
         use_ipv6 = False
-        for (dev, info) in entries.iteritems():
+        for (dev, info) in entries.items():
             net_fn = self.network_script_tpl % (dev)
             net_cfg = {
                 'DEVICE': dev,
@@ -111,13 +111,6 @@ class Distro(distros.Distro):
             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('Fedora') and major >= 18))
-
     def apply_locale(self, locale, out_fn=None):
         if self.uses_systemd():
             if not out_fn:
@@ -132,7 +125,11 @@ class Distro(distros.Distro):
         rhel_util.update_sysconfig_file(out_fn, locale_cfg)
 
     def _write_hostname(self, hostname, out_fn):
-        if self.uses_systemd():
+        # systemd will never update previous-hostname for us, so
+        # we need to do it ourselves
+        if self.uses_systemd() and out_fn.endswith('/previous-hostname'):
+            util.write_file(out_fn, hostname)
+        elif self.uses_systemd():
             util.subp(['hostnamectl', 'set-hostname', str(hostname)])
         else:
             host_cfg = {
@@ -155,7 +152,9 @@ class Distro(distros.Distro):
         return (host_fn, self._read_hostname(host_fn))
 
     def _read_hostname(self, filename, default=None):
-        if self.uses_systemd():
+        if self.uses_systemd() and filename.endswith('/previous-hostname'):
+            return util.load_file(filename).strip()
+        elif self.uses_systemd():
             (out, _err) = util.subp(['hostname'])
             if len(out):
                 return out
diff --git a/cloudinit/distros/rhel_util.py b/cloudinit/distros/rhel_util.py
index 063d536e..84aad623 100644
--- a/cloudinit/distros/rhel_util.py
+++ b/cloudinit/distros/rhel_util.py
@@ -50,7 +50,7 @@ def update_sysconfig_file(fn, adjustments, allow_empty=False):
         ]
         if not exists:
             lines.insert(0, util.make_header())
-        util.write_file(fn, "\n".join(lines) + "\n", 0644)
+        util.write_file(fn, "\n".join(lines) + "\n", 0o644)
 
 
 # Helper function to read a RHEL/SUSE /etc/sysconfig/* file
@@ -86,4 +86,4 @@ def update_resolve_conf_file(fn, dns_servers, search_servers):
                 r_conf.add_search_domain(s)
             except ValueError:
                 util.logexc(LOG, "Failed at adding search domain %s", s)
-    util.write_file(fn, str(r_conf), 0644)
+    util.write_file(fn, r_conf, 0o644)
diff --git a/cloudinit/distros/sles.py b/cloudinit/distros/sles.py
index 43682a12..620c974c 100644
--- a/cloudinit/distros/sles.py
+++ b/cloudinit/distros/sles.py
@@ -62,7 +62,7 @@ class Distro(distros.Distro):
         nameservers = []
         searchservers = []
         dev_names = entries.keys()
-        for (dev, info) in entries.iteritems():
+        for (dev, info) in entries.items():
             net_fn = self.network_script_tpl % (dev)
             mode = info.get('auto')
             if mode and mode.lower() == 'true':
@@ -113,7 +113,7 @@ class Distro(distros.Distro):
         if not conf:
             conf = HostnameConf('')
         conf.set_hostname(hostname)
-        util.write_file(out_fn, str(conf), 0644)
+        util.write_file(out_fn, str(conf), 0o644)
 
     def _read_system_hostname(self):
         host_fn = self.hostname_conf_fn