From c7e084eec058d9e8b8e9cadf1a864ea33ded7f77 Mon Sep 17 00:00:00 2001
From: Jordan Liggitt <liggitt@google.com>
Date: Wed, 10 Feb 2021 11:24:57 -0500
Subject: [PATCH] Switch add-on manager to use lease for leader election

---
 cluster/addons/addon-manager/CHANGELOG.md   |  4 +++
 cluster/addons/addon-manager/Makefile       |  4 +--
 cluster/addons/addon-manager/kube-addons.sh | 29 +++++++++++++--------
 3 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/cluster/addons/addon-manager/CHANGELOG.md b/cluster/addons/addon-manager/CHANGELOG.md
index 635e99660be..5547246a29a 100644
--- a/cluster/addons/addon-manager/CHANGELOG.md
+++ b/cluster/addons/addon-manager/CHANGELOG.md
@@ -1,3 +1,7 @@
+### Version 9.1.4 (Wed February 10 2021 Jordan Liggitt <liggitt@google.com>)
+ - Update kubectl to v1.20.2.
+ - Fix a bug in leader election (https://github.com/kubernetes/kubernetes/issues/98966)
+
 ### Version 9.1.3 (Mon November 30 2020 Spencer Peterson <spencerjp@google.com>)
  - Update kubectl to v1.19.3.
 
diff --git a/cluster/addons/addon-manager/Makefile b/cluster/addons/addon-manager/Makefile
index c23831ed8f6..3f1abe00605 100644
--- a/cluster/addons/addon-manager/Makefile
+++ b/cluster/addons/addon-manager/Makefile
@@ -15,8 +15,8 @@
 IMAGE=gcr.io/k8s-staging-addon-manager/kube-addon-manager
 ARCH?=amd64
 TEMP_DIR:=$(shell mktemp -d)
-VERSION=v9.1.3
-KUBECTL_VERSION?=v1.19.3
+VERSION=v9.1.4
+KUBECTL_VERSION?=v1.20.2
 
 BASEIMAGE=k8s.gcr.io/debian-base-$(ARCH):v1.0.0
 
diff --git a/cluster/addons/addon-manager/kube-addons.sh b/cluster/addons/addon-manager/kube-addons.sh
index b09575ad65f..859ce8759b1 100755
--- a/cluster/addons/addon-manager/kube-addons.sh
+++ b/cluster/addons/addon-manager/kube-addons.sh
@@ -273,15 +273,22 @@ function is_leader() {
   fi
   # shellcheck disable=SC2086
   # Disabling because "${KUBECTL_OPTS}" needs to allow for expansion here
-  KUBE_CONTROLLER_MANAGER_LEADER=$(${KUBECTL} ${KUBECTL_OPTS} -n kube-system get ep kube-controller-manager \
-    -o go-template=$'{{index .metadata.annotations "control-plane.alpha.kubernetes.io/leader"}}' \
-    | sed 's/^.*"holderIdentity":"\([^"]*\)".*/\1/')
-  # If there was any problem with getting the leader election results, var will
-  # be empty. Since it's better to have multiple addon managers than no addon
-  # managers at all, we're going to assume that we're the leader in such case.
-  log INFO "Leader is $KUBE_CONTROLLER_MANAGER_LEADER"
-  # KUBE_CONTROLLER_MANAGER_LEADER value is in the form "${HOSTNAME}_*"
-  # Here we verify that the value is either empty or is in the expected form for the leader
-  KUBE_CONTROLLER_MANAGER_LEADER="${KUBE_CONTROLLER_MANAGER_LEADER##${HOSTNAME}_*}"
-  [[ "$KUBE_CONTROLLER_MANAGER_LEADER" == "" ]]
+  KUBE_CONTROLLER_MANAGER_LEADER=$(${KUBECTL} ${KUBECTL_OPTS} -n kube-system get leases.v1.coordination.k8s.io kube-controller-manager -o "jsonpath={.spec.holderIdentity}")
+
+  case "${KUBE_CONTROLLER_MANAGER_LEADER}" in
+  "")
+    log ERR "No leader election info found."
+    return 1
+    ;;
+
+  "${HOSTNAME}"_*)
+    log INFO "Leader is $KUBE_CONTROLLER_MANAGER_LEADER"
+    return 0
+    ;;
+
+  *)
+    log INFO "Leader is $KUBE_CONTROLLER_MANAGER_LEADER, not ${HOSTNAME}_*"
+    return 1
+    ;;
+  esac
 }