diff -Nru netplan.io-0.99/debian/changelog netplan.io-0.99/debian/changelog
--- netplan.io-0.99/debian/changelog	2020-05-28 21:09:51.000000000 +0000
+++ netplan.io-0.99/debian/changelog	2021-01-15 07:38:20.000000000 +0000
@@ -1,3 +1,10 @@
+netplan.io (0.99-0ubuntu3~18.04.4) bionic; urgency=medium
+
+  * d/p/0001-Don-t-fail-if-same-primary-slave-was-set-before-LP-1.patch
+    - Fix primary slave on the bond not getting set (LP: #1817651)
+
+ -- Seyeong Kim <seyeong.kim@canonical.com>  Fri, 15 Jan 2021 07:38:20 +0000
+
 netplan.io (0.99-0ubuntu3~18.04.3) bionic; urgency=medium
 
   * d/p/0004-Fix-process_link_changes-handling-up-interfaces.patch:
diff -Nru netplan.io-0.99/debian/patches/0001-Don-t-fail-if-same-primary-slave-was-set-before-LP-1.patch netplan.io-0.99/debian/patches/0001-Don-t-fail-if-same-primary-slave-was-set-before-LP-1.patch
--- netplan.io-0.99/debian/patches/0001-Don-t-fail-if-same-primary-slave-was-set-before-LP-1.patch	1970-01-01 00:00:00.000000000 +0000
+++ netplan.io-0.99/debian/patches/0001-Don-t-fail-if-same-primary-slave-was-set-before-LP-1.patch	2021-01-15 07:38:20.000000000 +0000
@@ -0,0 +1,83 @@
+From 35548a4f4fe99932122272f7bb2ef1bf4eb38bb9 Mon Sep 17 00:00:00 2001
+From: Lukas Maerdian <lukas.maerdian@canonical.com>
+Date: Fri, 15 May 2020 08:24:59 +0200
+Subject: [PATCH] Don't fail if same primary slave was set before (LP:
+ #1817651) (#136)
+
+The netplan parser might run multiple passes, if unknown interfaces/netdefs are detected during a prior pass. In that case it would fail to set a bond's primary slave, because it was set before (to the same interface).
+
+Fixes: https://bugs.launchpad.net/ubuntu/+source/netplan.io/+bug/1817651
+---
+ src/parse.c                   |  5 ++++-
+ tests/generator/test_bonds.py | 42 +++++++++++++++++++++++++++++++++++
+ 2 files changed, 46 insertions(+), 1 deletion(-)
+
+Index: netplan.io-0.99/src/parse.c
+===================================================================
+--- netplan.io-0.99.orig/src/parse.c
++++ netplan.io-0.99/src/parse.c
+@@ -1482,7 +1482,10 @@ handle_bond_primary_slave(yaml_document_
+     if (!component) {
+         add_missing_node(node);
+     } else {
+-        if (cur_netdef->bond_params.primary_slave)
++        /* If this is not the primary pass, the primary slave might already be equally set. */
++        if (!g_strcmp0(cur_netdef->bond_params.primary_slave, scalar(node))) {
++            return TRUE;
++        } else if (cur_netdef->bond_params.primary_slave)
+             return yaml_error(node, error, "%s: bond already has a primary slave: %s",
+                               cur_netdef->id, cur_netdef->bond_params.primary_slave);
+
+Index: netplan.io-0.99/tests/generator/test_bonds.py
+===================================================================
+--- netplan.io-0.99.orig/tests/generator/test_bonds.py
++++ netplan.io-0.99/tests/generator/test_bonds.py
+@@ -299,6 +299,48 @@ UseMTU=true
+                               'switchports.network': '[Match]\nDriver=yayroute\n\n'
+                                                      '[Network]\nLinkLocalAddressing=no\nBond=bn0\n'})
+
++    def test_bond_primary_slave_duplicate(self):
++        self.generate('''network:
++  version: 2
++  renderer: networkd
++  ethernets:
++    eno1: {}
++    enp65s0: {}
++    dummy2: {}
++  bonds:
++    bond0:
++      interfaces: [eno1, enp65s0]
++      parameters:
++        primary: enp65s0
++        mode: balance-tlb
++  vlans:
++    vbr-v10:
++      id: 10
++      link: vbr
++  bridges:
++    vbr:
++      interfaces: [dummy2]''', expect_fail=False)
++
++        self.assert_networkd({'eno1.network': '[Match]\nName=eno1\n\n[Network]\nLinkLocalAddressing=no\nBond=bond0\n',
++                              'enp65s0.network': '''[Match]
++Name=enp65s0
++
++[Network]
++LinkLocalAddressing=no
++Bond=bond0
++PrimarySlave=true
++''',
++                              'dummy2.network': '[Match]\nName=dummy2\n\n[Network]\nLinkLocalAddressing=no\nBridge=vbr\n',
++                              'bond0.network': '[Match]\nName=bond0\n\n'
++                                                '[Network]\nLinkLocalAddressing=ipv6\nConfigureWithoutCarrier=yes\n',
++                              'bond0.netdev': '[NetDev]\nName=bond0\nKind=bond\n\n[Bond]\nMode=balance-tlb\n',
++                              'vbr-v10.network': '[Match]\nName=vbr-v10\n\n'
++                                                 '[Network]\nLinkLocalAddressing=ipv6\nConfigureWithoutCarrier=yes\n',
++                              'vbr-v10.netdev': '[NetDev]\nName=vbr-v10\nKind=vlan\n\n[VLAN]\nId=10\n',
++                              'vbr.network': '[Match]\nName=vbr\n\n'
++                                             '[Network]\nLinkLocalAddressing=ipv6\nConfigureWithoutCarrier=yes\nVLAN=vbr-v10\n',
++                              'vbr.netdev': '[NetDev]\nName=vbr\nKind=bridge\n'})
++
+     def test_bond_with_gratuitous_spelling(self):
+         """Validate that the correct spelling of gratuitous also works"""
+         self.generate('''network:
diff -Nru netplan.io-0.99/debian/patches/series netplan.io-0.99/debian/patches/series
--- netplan.io-0.99/debian/patches/series	2020-05-28 21:09:51.000000000 +0000
+++ netplan.io-0.99/debian/patches/series	2021-01-15 07:38:20.000000000 +0000
@@ -2,3 +2,4 @@
 disable-networkd-tunnels-ipip-gre.patch
 Fix-invalid-bond-mode-SRU-regression-LP-1877643.patch
 0004-Fix-process_link_changes-handling-up-interfaces.patch
+0001-Don-t-fail-if-same-primary-slave-was-set-before-LP-1.patch