From 5e5dd95320f2f51b68e1870a59a33b5eb273fafc Mon Sep 17 00:00:00 2001
From: ojmhetar <ojmhetar@gmail.com>
Date: Thu, 4 Oct 2018 00:52:50 -0700
Subject: [PATCH] Add eviction-hard and feature-gates flag (#64)

---
 apis/defaults.go       | 23 ++++++++++++++++++++---
 constants/constants.go |  5 ++++-
 utils/install.go       |  5 +++++
 3 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/apis/defaults.go b/apis/defaults.go
index 7d092d5..62baad0 100644
--- a/apis/defaults.go
+++ b/apis/defaults.go
@@ -19,9 +19,10 @@ func SetInitDefaults(config *InitConfiguration) {
 	config.MasterConfiguration.APIVersion = "kubeadm.k8s.io/v1alpha1"
 	config.MasterConfiguration.KubernetesVersion = constants.KubernetesVersion
 	config.MasterConfiguration.NoTaintMaster = true
-	config.MasterConfiguration.APIServerExtraArgs = map[string]string{
-		"service-node-port-range": constants.ServiceNodePortRange,
-	}
+
+	addOrAppend(&config.MasterConfiguration.APIServerExtraArgs, "feature-gates", constants.FeatureGates)
+	addOrAppend(&config.MasterConfiguration.ControllerManagerExtraArgs, "feature-gates", constants.FeatureGates)
+	addOrAppend(&config.MasterConfiguration.SchedulerExtraArgs, "feature-gates", constants.FeatureGates)
 
 }
 
@@ -63,3 +64,19 @@ func SetMasterConfigurationNetworkingDefaultsWithNetworking(config *InitConfigur
 		config.MasterConfiguration.Networking.DNSDomain = config.Networking.DNSDomain
 	}
 }
+
+func addOrAppend(extraArgs *map[string]string, key string, value string) {
+	// Create a new map if it doesn't exist.
+	if *extraArgs == nil {
+		*extraArgs = make(map[string]string)
+	}
+	// Add the key with the value if it doesn't exist. Otherwise, append the value
+	// to the pre-existing values.
+	prevFeatureGates := (*extraArgs)[key]
+	if prevFeatureGates == "" {
+		(*extraArgs)[key] = value
+	} else {
+		featureGates := prevFeatureGates + "," + value
+		(*extraArgs)[key] = featureGates
+	}
+}
diff --git a/constants/constants.go b/constants/constants.go
index d72c1cc..9857a8e 100644
--- a/constants/constants.go
+++ b/constants/constants.go
@@ -29,6 +29,8 @@ const (
 	Execute              = 0744
 	Read                 = 0644
 	ServiceNodePortRange = "80-32767"
+	// TODO: Add PodPriority when introduced in kubeadm
+	FeatureGates = "ExperimentalCriticalPodAnnotation=true"
 )
 
 const (
@@ -63,11 +65,12 @@ const (
 	KubeletMaxPods      = 500
 	KubeletKubeAPIQPS   = 20
 	KubeletKubeAPIBurst = 40
+	KubeletEvictionHard = "memory.available<600Mi,nodefs.available<10%"
 
 	NodeadmKubeletSystemdDropinFilename = "20-nodeadm.conf"
 	NodeadmKubeletSystemdDropinTemplate = `[Service]
 Environment="KUBELET_DNS_ARGS=--cluster-dns={{ .ClusterDNS }} --cluster-domain={{ .ClusterDomain }}"
-Environment="KUBELET_EXTRA_ARGS=--max-pods={{ .MaxPods }} --fail-swap-on={{ .FailSwapOn }} --hostname-override={{ .HostnameOverride }} --kube-api-qps={{ .KubeAPIQPS }} --kube-api-burst={{ .KubeAPIBurst }}"
+Environment="KUBELET_EXTRA_ARGS=--max-pods={{ .MaxPods }} --fail-swap-on={{ .FailSwapOn }} --hostname-override={{ .HostnameOverride }} --kube-api-qps={{ .KubeAPIQPS }} --kube-api-burst={{ .KubeAPIBurst }} --feature-gates={{ .FeatureGates}} --eviction-hard={{ .EvictionHard }}"
 `
 )
 
diff --git a/utils/install.go b/utils/install.go
index fefb24e..4aee33e 100644
--- a/utils/install.go
+++ b/utils/install.go
@@ -120,6 +120,8 @@ func placeAndModifyNodeadmKubeletSystemdDropin(netConfig apis.Networking) {
 		HostnameOverride string
 		KubeAPIQPS       int
 		KubeAPIBurst     int
+		EvictionHard     string
+		FeatureGates     string
 	}{
 		FailSwapOn:       constants.KubeletFailSwapOn,
 		MaxPods:          constants.KubeletMaxPods,
@@ -128,6 +130,8 @@ func placeAndModifyNodeadmKubeletSystemdDropin(netConfig apis.Networking) {
 		HostnameOverride: hostnameOverride,
 		KubeAPIQPS:       constants.KubeletKubeAPIQPS,
 		KubeAPIBurst:     constants.KubeletKubeAPIBurst,
+		EvictionHard:     constants.KubeletEvictionHard,
+		FeatureGates:     constants.FeatureGates,
 	}
 
 	writeTemplateIntoFile(constants.NodeadmKubeletSystemdDropinTemplate, "nodeadm-kubelet-systemd-dropin", confFile, data)
@@ -259,6 +263,7 @@ ExecStartPre=-/usr/bin/docker kill vip
 ExecStartPre=-/usr/bin/docker rm vip
 ExecStop=/usr/bin/docker stop vip
 Restart=on-failure
+MemoryLow=10M
 [Install]
 WantedBy=multi-user.target
 	`