net: update net sequence, include wait on netdevs, opensuse netrules path

On systems with many interfaces, processing udev events may take a while.
Cloud-init expects devices included in a provided network-configuration
to be present when attempting to configure them.  This patch adds a step
in net configuration where it will check for devices provided in the
configuration and if not found, issue udevadm settle commands to wait
for them to appear.

Additionally, the default path for udev persistent network rules
70-persistent-net.rules may also be written to systems which include
the 75-net-generator.rules.  During boot, cloud-init and the
generator may race and interleave values causing issues.  OpenSUSE
will now use a newer file, 85-persistent-net-cloud-init.rules which
will take precedence over values created by 75-net-generator and
avoid collisions on the same file.

LP: #1817368

1 files changed, 21 insertions, 6 deletions

diff --git a/cloudinit/stages.py b/cloudinit/stages.py
index da7d349a..5f9d47b9 100644
--- a/cloudinit/stages.py
+++ b/cloudinit/stages.py
@@ -644,18 +644,21 @@ class Init(object):
                 return (ncfg, loc)
         return (self.distro.generate_fallback_config(), "fallback")
 
-    def apply_network_config(self, bring_up):
-        netcfg, src = self._find_networking_config()
-        if netcfg is None:
-            LOG.info("network config is disabled by %s", src)
-            return
-
+    def _apply_netcfg_names(self, netcfg):
         try:
             LOG.debug("applying net config names for %s", netcfg)
             self.distro.apply_network_config_names(netcfg)
         except Exception as e:
             LOG.warning("Failed to rename devices: %s", e)
 
+    def apply_network_config(self, bring_up):
+        # get a network config
+        netcfg, src = self._find_networking_config()
+        if netcfg is None:
+            LOG.info("network config is disabled by %s", src)
+            return
+
+        # request an update if needed/available
         if self.datasource is not NULL_DATA_SOURCE:
             if not self.is_new_instance():
                 if not self.datasource.update_metadata([EventType.BOOT]):
@@ -663,8 +666,20 @@ class Init(object):
                         "No network config applied. Neither a new instance"
                         " nor datasource network update on '%s' event",
                         EventType.BOOT)
+                    # nothing new, but ensure proper names
+                    self._apply_netcfg_names(netcfg)
                     return
+                else:
+                    # refresh netcfg after update
+                    netcfg, src = self._find_networking_config()
+
+        # ensure all physical devices in config are present
+        net.wait_for_physdevs(netcfg)
+
+        # apply renames from config
+        self._apply_netcfg_names(netcfg)
 
+        # rendering config
         LOG.info("Applying network configuration from %s bringup=%s: %s",
                  src, bring_up, netcfg)
         try: