net/renderer/sysconfig: also use dns information from interface config

sysconfig renderer currently only uses global dns and search domain configuration in order to populate /etc/resolv.conf. This means it ignores interface specific dns configuration completely. This means, when global dns information is absent and only interface specific dns configuration is present, /etc/resolv.conf will not have complete dns information. Fix this so that per interface dns information is also taken into account along with global dns configuration in order to populate /etc/resolv.conf. Fixes: GH-5400 Signed-off-by: Ani Sinha <anisinha@redhat.com>
canonical · Jun 14, 2024 · 7987b85 · 7987b85
1 parent a01b8d3
commit 7987b85
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Showing 2 changed files with 229 additions and 6 deletions.
diff --git a/cloudinit/net/sysconfig.py b/cloudinit/net/sysconfig.py
@@ -824,11 +824,53 @@ def _render_vlan_interfaces(cls, network_state, iface_contents, flavor):
 
     @staticmethod
     def _render_dns(network_state, existing_dns_path=None):
-        # skip writing resolv.conf if network_state doesn't include any input.
+
+        found_nameservers = []
+        found_dns_search = []
+
+        for iface in network_state.iter_interfaces():
+            for subnet in iface["subnets"]:
+                # Add subnet-level DNS
+                if "dns_nameservers" in subnet:
+                    found_nameservers.extend(subnet["dns_nameservers"])
+                if "dns_search" in subnet:
+                    found_dns_search.extend(subnet["dns_search"])
+
+            # Add interface-level DNS
+            if "dns" in iface:
+                found_nameservers += [
+                    dns
+                    for dns in iface["dns"]["nameservers"]
+                    if dns not in found_nameservers
+                ]
+                found_dns_search += [
+                    search
+                    for search in iface["dns"]["search"]
+                    if search not in found_dns_search
+                ]
+
+        # When both global and interface specific entries are present,
+        # use them both to generate /etc/resolv.conf eliminating duplicate
+        # entries. Otherwise use global or interface specific entries whichever
+        # is provided.
+        if network_state.dns_nameservers:
+            found_nameservers += [
+                nameserver
+                for nameserver in network_state.dns_nameservers
+                if nameserver not in found_nameservers
+            ]
+        if network_state.dns_searchdomains:
+            found_dns_search += [
+                search
+                for search in network_state.dns_searchdomains
+                if search not in found_dns_search
+            ]
+
+        # skip writing resolv.conf if no dns information is provided in conf.
         if not any(
             [
-                len(network_state.dns_nameservers),
-                len(network_state.dns_searchdomains),
+                len(found_nameservers),
+                len(found_dns_search),
             ]
         ):
             return None
@@ -837,9 +879,9 @@ def _render_dns(network_state, existing_dns_path=None):
             content = resolv_conf.ResolvConf(
                 util.load_text_file(existing_dns_path)
             )
-        for nameserver in network_state.dns_nameservers:
+        for nameserver in found_nameservers:
             content.add_nameserver(nameserver)
-        for searchdomain in network_state.dns_searchdomains:
+        for searchdomain in found_dns_search:
             content.add_search_domain(searchdomain)
         header = _make_header(";")
         content_str = str(content)

diff --git a/tests/unittests/test_net.py b/tests/unittests/test_net.py
@@ -515,6 +515,8 @@
                         }
                     ],
                     "ip_address": "172.19.1.34",
+                    "dns_search": ["testweb.com"],
+                    "dns_nameservers": ["172.19.0.13"],
                     "id": "network0",
                 }
             ],
@@ -549,7 +551,9 @@
                 """
 ; Created by cloud-init automatically, do not edit.
 ;
+nameserver 172.19.0.13
 nameserver 172.19.0.12
+search testweb.com
 """.lstrip(),
             ),
             (
@@ -580,6 +584,8 @@
 BOOTPROTO=none
 DEFROUTE=yes
 DEVICE=eth0
+DNS1=172.19.0.13
+DOMAIN=testweb.com
 GATEWAY=172.19.3.254
 HWADDR=fa:16:3e:ed:9a:59
 IPADDR=172.19.1.34
@@ -594,7 +600,173 @@
                 """
 ; Created by cloud-init automatically, do not edit.
 ;
+nameserver 172.19.0.13
 nameserver 172.19.0.12
+search testweb.com
+""".lstrip(),
+            ),
+            (
+                "etc/NetworkManager/conf.d/99-cloud-init.conf",
+                """
+# Created by cloud-init automatically, do not edit.
+#
+[main]
+dns = none
+""".lstrip(),
+            ),
+            (
+                "etc/udev/rules.d/70-persistent-net.rules",
+                "".join(
+                    [
+                        'SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ',
+                        'ATTR{address}=="fa:16:3e:ed:9a:59", NAME="eth0"\n',
+                    ]
+                ),
+            ),
+        ],
+        "expected_network_manager": [
+            (
+                "".join(
+                    [
+                        "etc/NetworkManager/system-connections",
+                        "/cloud-init-eth0.nmconnection",
+                    ]
+                ),
+                """
+# Generated by cloud-init. Changes will be lost.
+
+[connection]
+id=cloud-init eth0
+uuid=1dd9a779-d327-56e1-8454-c65e2556c12c
+autoconnect-priority=120
+type=ethernet
+
+[user]
+org.freedesktop.NetworkManager.origin=cloud-init
+
+[ethernet]
+mac-address=FA:16:3E:ED:9A:59
+
+[ipv4]
+method=manual
+may-fail=false
+address1=172.19.1.34/22
+route1=0.0.0.0/0,172.19.3.254
+dns=172.19.0.13;
+dns-search=testweb.com;
+
+""".lstrip(),
+            ),
+        ],
+    },
+    {
+        "in_data": {
+            "services": [
+                {
+                    "type": "dns",
+                    "address": "172.19.0.12",
+                    "search": ["example1.com", "example2.com"],
+                }
+            ],
+            "networks": [
+                {
+                    "network_id": "dacd568d-5be6-4786-91fe-750c374b78b4",
+                    "type": "ipv4",
+                    "netmask": "255.255.252.0",
+                    "link": "eth0",
+                    "routes": [
+                        {
+                            "netmask": "0.0.0.0",
+                            "network": "0.0.0.0",
+                            "gateway": "172.19.3.254",
+                        }
+                    ],
+                    "ip_address": "172.19.1.34",
+                    "dns_search": ["example3.com"],
+                    "dns_nameservers": ["172.19.0.12"],
+                    "id": "network0",
+                }
+            ],
+            "links": [
+                {
+                    "ethernet_mac_address": "fa:16:3e:ed:9a:59",
+                    "mtu": None,
+                    "type": "physical",
+                    "id": "eth0",
+                },
+            ],
+        },
+        "in_macs": {
+            "fa:16:3e:ed:9a:59": "eth0",
+        },
+        "out_sysconfig_opensuse": [
+            (
+                "etc/sysconfig/network/ifcfg-eth0",
+                """
+# Created by cloud-init automatically, do not edit.
+#
+BOOTPROTO=static
+IPADDR=172.19.1.34
+LLADDR=fa:16:3e:ed:9a:59
+NETMASK=255.255.252.0
+STARTMODE=auto
+""".lstrip(),
+            ),
+            (
+                "etc/resolv.conf",
+                """
+; Created by cloud-init automatically, do not edit.
+;
+nameserver 172.19.0.12
+search example3.com example1.com example2.com
+""".lstrip(),
+            ),
+            (
+                "etc/NetworkManager/conf.d/99-cloud-init.conf",
+                """
+# Created by cloud-init automatically, do not edit.
+#
+[main]
+dns = none
+""".lstrip(),
+            ),
+            (
+                "etc/udev/rules.d/85-persistent-net-cloud-init.rules",
+                "".join(
+                    [
+                        'SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ',
+                        'ATTR{address}=="fa:16:3e:ed:9a:59", NAME="eth0"\n',
+                    ]
+                ),
+            ),
+        ],
+        "out_sysconfig_rhel": [
+            (
+                "etc/sysconfig/network-scripts/ifcfg-eth0",
+                """
+# Created by cloud-init automatically, do not edit.
+#
+BOOTPROTO=none
+DEFROUTE=yes
+DEVICE=eth0
+DNS1=172.19.0.12
+DOMAIN=example3.com
+GATEWAY=172.19.3.254
+HWADDR=fa:16:3e:ed:9a:59
+IPADDR=172.19.1.34
+NETMASK=255.255.252.0
+ONBOOT=yes
+TYPE=Ethernet
+USERCTL=no
+""".lstrip(),
+            ),
+            (
+                "etc/resolv.conf",
+                """
+; Created by cloud-init automatically, do not edit.
+;
+nameserver 172.19.0.12
+search example3.com example1.com example2.com
 """.lstrip(),
             ),
             (
@@ -645,14 +817,21 @@
 address1=172.19.1.34/22
 route1=0.0.0.0/0,172.19.3.254
 dns=172.19.0.12;
+dns-search=example3.com;
 
 """.lstrip(),
             ),
         ],
     },
     {
         "in_data": {
-            "services": [{"type": "dns", "address": "172.19.0.12"}],
+            "services": [
+                {
+                    "type": "dns",
+                    "address": "172.19.0.12",
+                    "search": "example.com",
+                }
+            ],
             "networks": [
                 {
                     "network_id": "public-ipv4",
@@ -713,6 +892,7 @@
 ; Created by cloud-init automatically, do not edit.
 ;
 nameserver 172.19.0.12
+search example.com
 """.lstrip(),
             ),
             (
@@ -760,6 +940,7 @@
 ; Created by cloud-init automatically, do not edit.
 ;
 nameserver 172.19.0.12
+search example.com
 """.lstrip(),
             ),
             (