Network plugin does not set DNS server when using Proxmox

[regner]

When using Proxmox the config that is generated for cloud-init has the DNS server key as "dns_nameserver" but the network plugin expects it to be "dns-nameserver".

I don't know cloudinit like, at all really, so I don't know if the standard allows both or what. I know the cloudinit config works for our Ubuntu images which makes me lean towards the standard, or at least the normal implementation of it, works with either.

I believe this is the responsible regex causing the issue: https://github.com/cloudbase/cloudbase-init/blob/master/cloudbaseinit/utils/debiface.py#L56

[ader1990]

Hello,

Can you share the cloud config drive format (aka what metadata type is loaded by cloudbase-init)? Is it NoCloud? I will use this information to see how cloud-init implements it so that we can have a mirrored implementation.

Also, if you could share the metadata files from the metadata ISO attached by proxmox, that would be great.

Thank you.

[ader1990]

It is probable that cloud-init does not use the debiface network config, but a more advanced one from the metadata (I need the metadata files from the config drive ISO to confirm this). If that is the case, the cloudbase-init logs would be required too, to check why the advanced version was not used.

[regner]

For metadata we are using: cloudbaseinit.metadata.services.configdrive.ConfigDriveService

Here is the contents of OPENSTAT/LATEST/META_DATA.JSON:

{
     "uuid": "eed9becb0af80e83116020a37066cf04dd212e05",
     "network_config": { "content_path": "/content/0000" }
}

Here are the contents of OPENSTACK/LATEST/USER_DATA:

#cloud-config
hostname: something
manage_etc_hosts: true
chpasswd:
  expire: False
users:
  - default
package_upgrade: true

[ader1990]

For metadata we are using: cloudbaseinit.metadata.services.configdrive.ConfigDriveService

Here is the contents of OPENSTAT/LATEST/META_DATA.JSON:

{
     "uuid": "eed9becb0af80e83116020a37066cf04dd212e05",
     "network_config": { "content_path": "/content/0000" }
}

Here are the contents of OPENSTACK/LATEST/USER_DATA:

#cloud-config
hostname: something
manage_etc_hosts: true
chpasswd:
  expire: False
users:
  - default
package_upgrade: true

Hello,

Can you share the openstack/latest/content/0000? A quick fix would be to add an OR to the regexp here, https://github.com/cloudbase/cloudbase-init/blob/master/cloudbaseinit/utils/debiface.py#L56.

r"(dns-nameservers\s+)|(dns_nameservers\s+)|(dns-nameserver\s+)|(dns_nameserver\s+)(?P<dnsnameservers>.+)"

Can you try the regexp above?

EDIT: the above regexp works only for dns_nameserver case.

Thank you, Adrian Vladu

[ader1990]

Correct regexp:

r"(dns-nameservers|dns_nameservers|dns-nameserver|dns_nameserver)\s+(?P<dnsnameservers>.+)"

[gee456]

Any update on this?

[alexanderek]

same issue :(

[izmmisha]

Same problem with Proxmox 6.4-4 Here is content of OPENSTACK/CONTENT/0000

auto lo
iface lo inet loopback

        dns_nameservers 192.168.0.2
        dns_search local
auto eth0
iface eth0 inet static
        address 192.168.66.71
        netmask 255.255.255.0
        gateway 192.168.66.254

It generated by configdrive2_network

After applying proposed changes I get this in logs:

2021-12-06 16:12:26.591 4208 INFO cloudbaseinit.utils.debiface [-] Parsing Debian config...
auto lo
iface lo inet loopback

        dns_nameservers 192.168.0.2
        dns_search local
auto eth0
iface eth0 inet static
        address 192.168.66.71
        netmask 255.255.255.0
        gateway 192.168.66.254

2021-12-06 16:12:26.591 4208 DEBUG cloudbaseinit.utils.debiface [-] Found new interface: {'name': None, 'mac': None, 'address': None, 'address6': None, 'netmask': None, 'netmask6': None, 'broadcast': None, 'gateway': None, 'gateway6': None, 'dnsnameservers': ['192.168.0.2']} _add_nic C:\Program Files\Cloudbase Solutions\Cloudbase-Init\Python\lib\site-packages\cloudbaseinit\utils\debiface.py:104
2021-12-06 16:12:26.591 4208 DEBUG cloudbaseinit.utils.debiface [-] Found new interface: {'name': 'eth0', 'mac': None, 'address': '192.168.66.71', 'address6': None, 'netmask': '255.255.255.0', 'netmask6': None, 'broadcast': None, 'gateway': '192.168.66.254', 'gateway6': None, 'dnsnameservers': None} _add_nic C:\Program Files\Cloudbase Solutions\Cloudbase-Init\Python\lib\site-packages\cloudbaseinit\utils\debiface.py:104

No dns nameservers configured.

Switching to 'nocloud' is also not possible, as proxmox generating ISO without joliet-long extension, and file meta-data has name META_DATA instead.

[izmmisha]

For someone who want to make it work with proxmox:

diff --git a/cloudbaseinit/plugins/common/networkconfig.py b/cloudbaseinit/plugins/common/networkconfig.py
index 8704721..9aa995c 100644
--- a/cloudbaseinit/plugins/common/networkconfig.py
+++ b/cloudbaseinit/plugins/common/networkconfig.py
@@ -57,6 +57,15 @@ def _preprocess_nics(network_details, network_adapters):
     if not network_adapters:
         raise exception.CloudbaseInitException(
             "no network adapters available")
+
+    #Proxmox compatibility, "dnsnameservers" is present only in lo interface details
+    default_nameservers = None
+    for nic in network_details:
+        if None == getattr(nic, "name", None):
+            default_nameservers = getattr(nic, "dnsnameservers", None)
+            if default_nameservers:
+                break
+
     # Sort VM adapters by name (assuming that those
     # from the context are in correct order).
     # Do this for a better matching by order
@@ -115,7 +124,7 @@ def _preprocess_nics(network_details, network_adapters):
                 nic.broadcast,
                 nic.gateway,
                 nic.gateway6,
-                nic.dnsnameservers
+                nic.dnsnameservers or default_nameservers
             )
         refined_network_details.append(nic)
     return refined_network_details
diff --git a/cloudbaseinit/utils/debiface.py b/cloudbaseinit/utils/debiface.py
index 4c4c26a..37d4c34 100644
--- a/cloudbaseinit/utils/debiface.py
+++ b/cloudbaseinit/utils/debiface.py
@@ -53,7 +53,7 @@ FIELDS = {
                         r"(?P<{}>\S+)".format(GATEWAY)),
     GATEWAY6: re.compile(r"post-up ip -6 route add default via "
                          r"(?P<{}>.+) dev".format(GATEWAY6)),
-    DNSNS: re.compile(r"dns-nameservers\s+(?P<{}>.+)".format(DNSNS))
+    DNSNS: re.compile(r"(dns-nameservers|dns_nameservers|dns-nameserver|dns_nameserver)\s+(?P<{}>.+)".format(DNSNS))
 }
 IFACE_TEMPLATE = dict.fromkeys(FIELDS.keys())
 # Map IPv6 availability by value index under `NetworkDetails`.

Not sure that it will be applied to cloudbase-init, probably it should be fixed in proxmox with moving to nocloud.