Merge lp:~harlowja/cloud-init/cloud-init-dns-sysconfig into lp:~cloud-init-dev/cloud-init/trunk

[Joshua Harlow]

It appears that 'dns_nameservers' and 'dns_search' can be a per subnet/iface specification and the eni renderer actually handles this so make an attempt to in the sysconfig renderer as well.

[lp:~harlowja/cloud-init/cloud-init-dns-sysconfig]

1244. By Joshua Harlow on 2016-06-18

Ensure dns indexes are shared among subinterfaces

[Ryan Harper (raharper)]

This is fairly forward looking. Depending on the OS support for this sort of thing, it's certainly desirable for users to want to say things like "send queries to this server out this interface" however, I don't know of an OS that does this without more configuration elsewhere on the system.

For example, on Debian/Ubuntu, resolvconf and glibc certainly aren't doing this by default. One can imagine a more sophisticated bind or dnsmasq configuration but we're not doing that at this time.

[Joshua Harlow (harlowja)]

Ya, I had a hard time finding out how to make it so that each interface could have its own dns server and such configuration; it really seems like not many systems allow for doing this very well...

[Server Team CI bot (server-team-bot)]

PASSED: Continuous integration, rev:1244
https://server-team-jenkins.canonical.com/job/cloud-init-ci/41/
Executed test runs:
    None: https://server-team-jenkins.canonical.com/job/lp-vote-on-merge/15/console

Click here to trigger a rebuild:
https://server-team-jenkins.canonical.com/job/cloud-init-ci/41/rebuild

review: Approve (continuous-integration)

[Scott Moser (smoser)]

Hello,
Thank you for taking the time to contribute to cloud-init. Cloud-init has moved its revision control system to git. As a result, we are marking all bzr merge proposals as 'rejected'. If you would like to re-submit this proposal for review, please do so by following the current HACKING documentation at http://cloudinit.readthedocs.io/en/latest/topics/hacking.html .

Unmerged revisions

1244. By Joshua Harlow on 2016-06-18

Ensure dns indexes are shared among subinterfaces

1243. By Joshua Harlow on 2016-06-18

Add sysconfig 'dns_nameservers' and 'dns_search' per interface/subnet handling

=== modified file 'cloudinit/net/sysconfig.py'
--- cloudinit/net/sysconfig.py	2016-06-15 23:15:28 +0000
+++ cloudinit/net/sysconfig.py	2016-06-18 01:07:35 +0000
@@ -116,6 +116,11 @@
                                      'name': self._route_name})
 
 
+class _SharedInt(object):
+    def __init__(self):
+        self.value = 0
+
+
 class NetInterface(ConfigMap):
     """Represents a sysconfig/networking-script (and its config + children)."""
 
@@ -131,6 +136,7 @@
         super(NetInterface, self).__init__()
         self.children = []
         self.routes = Route(iface_name, base_sysconf_dir)
+        self.last_dns_idx = _SharedInt()
         self._kind = kind
         self._iface_name = iface_name
         self._conf['DEVICE'] = iface_name
@@ -160,9 +166,12 @@
         return self.iface_fn_tpl % ({'base': self._base_sysconf_dir,
                                      'name': self.name})
 
-    def copy(self, copy_children=False, copy_routes=False):
+    def copy(self, copy_children=False, copy_routes=False,
+             share_dns_idx=True):
         c = NetInterface(self.name, self._base_sysconf_dir, kind=self._kind)
         c._conf = self._conf.copy()
+        if share_dns_idx:
+            c.last_dns_idx = self.last_dns_idx
         if copy_children:
             c.children = list(self.children)
         if copy_routes:
@@ -238,6 +247,13 @@
                                                       iface_cfg.name))
         if 'netmask' in subnet:
             iface_cfg['NETMASK'] = subnet['netmask']
+        if 'dns_nameservers' in subnet:
+            for nameserver in subnet['dns_nameservers']:
+                ns_key = "DNS%s" % iface_cfg.last_dns_idx.value
+                iface_cfg.last_dns_idx.value += 1
+                iface_cfg[ns_key] = nameserver
+        if 'dns_search' in subnet:
+            iface_cfg['SEARCH'] = " ".join(subnet['dns_search'])
         for route in subnet.get('routes', []):
             if _is_default_route(route):
                 if route_cfg.has_set_default:
@@ -332,13 +348,18 @@
     @staticmethod
     def _render_dns(network_state, existing_dns_path=None):
         content = resolv_conf.ResolvConf("")
+        is_existing = False
         if existing_dns_path and os.path.isfile(existing_dns_path):
             content = resolv_conf.ResolvConf(util.load_file(existing_dns_path))
+            is_existing = True
         for nameserver in network_state.dns_nameservers:
             content.add_nameserver(nameserver)
         for searchdomain in network_state.dns_searchdomains:
             content.add_search_domain(searchdomain)
-        return "\n".join([_make_header(';'), str(content)])
+        if is_existing:
+            return str(content)
+        else:
+            return "\n".join([_make_header(';'), str(content)])
 
     @classmethod
     def _render_bridge_interfaces(cls, network_state, iface_contents):