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, 67 insertions, 21 deletions

diff --git a/cloudinit/net/__init__.py b/cloudinit/net/__init__.py
index 624c9b42..f3cec794 100644
--- a/cloudinit/net/__init__.py
+++ b/cloudinit/net/__init__.py
@@ -9,6 +9,7 @@ import errno
 import logging
 import os
 import re
+from functools import partial
 
 from cloudinit.net.network_state import mask_to_net_prefix
 from cloudinit import util
@@ -292,18 +293,10 @@ def generate_fallback_config(blacklist_drivers=None, config_driver=None):
         return None
 
 
-def apply_network_config_names(netcfg, strict_present=True, strict_busy=True):
-    """read the network config and rename devices accordingly.
-    if strict_present is false, then do not raise exception if no devices
-    match.  if strict_busy is false, then do not raise exception if the
-    device cannot be renamed because it is currently configured.
-
-    renames are only attempted for interfaces of type 'physical'.  It is
-    expected that the network system will create other devices with the
-    correct name in place."""
+def extract_physdevs(netcfg):
 
     def _version_1(netcfg):
-        renames = []
+        physdevs = []
         for ent in netcfg.get('config', {}):
             if ent.get('type') != 'physical':
                 continue
@@ -317,11 +310,11 @@ def apply_network_config_names(netcfg, strict_present=True, strict_busy=True):
                 driver = device_driver(name)
             if not device_id:
                 device_id = device_devid(name)
-            renames.append([mac, name, driver, device_id])
-        return renames
+            physdevs.append([mac, name, driver, device_id])
+        return physdevs
 
     def _version_2(netcfg):
-        renames = []
+        physdevs = []
         for ent in netcfg.get('ethernets', {}).values():
             # only rename if configured to do so
             name = ent.get('set-name')
@@ -337,16 +330,69 @@ def apply_network_config_names(netcfg, strict_present=True, strict_busy=True):
                 driver = device_driver(name)
             if not device_id:
                 device_id = device_devid(name)
-            renames.append([mac, name, driver, device_id])
-        return renames
+            physdevs.append([mac, name, driver, device_id])
+        return physdevs
+
+    version = netcfg.get('version')
+    if version == 1:
+        return _version_1(netcfg)
+    elif version == 2:
+        return _version_2(netcfg)
+
+    raise RuntimeError('Unknown network config version: %s' % version)
+
 
-    if netcfg.get('version') == 1:
-        return _rename_interfaces(_version_1(netcfg))
-    elif netcfg.get('version') == 2:
-        return _rename_interfaces(_version_2(netcfg))
+def wait_for_physdevs(netcfg, strict=True):
+    physdevs = extract_physdevs(netcfg)
+
+    # set of expected iface names and mac addrs
+    expected_ifaces = dict([(iface[0], iface[1]) for iface in physdevs])
+    expected_macs = set(expected_ifaces.keys())
+
+    # set of current macs
+    present_macs = get_interfaces_by_mac().keys()
+
+    # compare the set of expected mac address values to
+    # the current macs present; we only check MAC as cloud-init
+    # has not yet renamed interfaces and the netcfg may include
+    # such renames.
+    for _ in range(0, 5):
+        if expected_macs.issubset(present_macs):
+            LOG.debug('net: all expected physical devices present')
+            return
 
-    raise RuntimeError('Failed to apply network config names. Found bad'
-                       ' network config version: %s' % netcfg.get('version'))
+        missing = expected_macs.difference(present_macs)
+        LOG.debug('net: waiting for expected net devices: %s', missing)
+        for mac in missing:
+            # trigger a settle, unless this interface exists
+            syspath = sys_dev_path(expected_ifaces[mac])
+            settle = partial(util.udevadm_settle, exists=syspath)
+            msg = 'Waiting for udev events to settle or %s exists' % syspath
+            util.log_time(LOG.debug, msg, func=settle)
+
+        # update present_macs after settles
+        present_macs = get_interfaces_by_mac().keys()
+
+    msg = 'Not all expected physical devices present: %s' % missing
+    LOG.warning(msg)
+    if strict:
+        raise RuntimeError(msg)
+
+
+def apply_network_config_names(netcfg, strict_present=True, strict_busy=True):
+    """read the network config and rename devices accordingly.
+    if strict_present is false, then do not raise exception if no devices
+    match.  if strict_busy is false, then do not raise exception if the
+    device cannot be renamed because it is currently configured.
+
+    renames are only attempted for interfaces of type 'physical'.  It is
+    expected that the network system will create other devices with the
+    correct name in place."""
+
+    try:
+        _rename_interfaces(extract_physdevs(netcfg))
+    except RuntimeError as e:
+        raise RuntimeError('Failed to apply network config names: %s' % e)
 
 
 def interface_has_own_mac(ifname, strict=False):