From 7839668877e82e55b8306aa190cfc51d40b295ec Mon Sep 17 00:00:00 2001
From: Jeremy Edwards <jeremyedwards@google.com>
Date: Mon, 21 Jun 2021 16:02:17 +0000
Subject: [PATCH] GCE Windows: Set TCP/IP parameters to keep idle connections
 alive on GCE.

---
 cluster/gce/windows/configure.ps1       |  3 +++
 cluster/gce/windows/k8s-node-setup.psm1 | 19 +++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/cluster/gce/windows/configure.ps1 b/cluster/gce/windows/configure.ps1
index c8f8641cdc1..170602a9e80 100644
--- a/cluster/gce/windows/configure.ps1
+++ b/cluster/gce/windows/configure.ps1
@@ -129,6 +129,9 @@ try {
   $kube_env = Fetch-KubeEnv
   Set-EnvironmentVars
 
+  # Set the TCP/IP Parameters to keep idle connections alive.
+  Set-WindowsTCPParameters
+
   # Install Docker if the select CRI is not containerd and docker is not already
   # installed.
   if (${env:CONTAINER_RUNTIME} -ne "containerd") {
diff --git a/cluster/gce/windows/k8s-node-setup.psm1 b/cluster/gce/windows/k8s-node-setup.psm1
index bf78ef835a6..e317d1eecc3 100644
--- a/cluster/gce/windows/k8s-node-setup.psm1
+++ b/cluster/gce/windows/k8s-node-setup.psm1
@@ -1438,6 +1438,25 @@ function Configure_Dockerd {
  Restart-Service Docker
 }
 
+# Configures the TCP/IP parameters to be in sync with the GCP recommendation.
+# Not setting these values correctly can cause network issues for connections
+# that live longer than 10 minutes.
+# See: https://cloud.google.com/compute/docs/troubleshooting/general-tips#idle-connections
+function Set-WindowsTCPParameters {
+  Set-ItemProperty -Force -Confirm:$false -Path `
+    'HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters' `
+    -Name 'KeepAliveInterval' -Type Dword -Value 1000
+  Set-ItemProperty -Force -Confirm:$false `
+    -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters' `
+    -Name 'KeepAliveTime' -Type Dword -Value 60000
+  Set-ItemProperty -Force -Confirm:$false `
+    -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters' `
+    -Name 'TcpMaxDataRetransmissions' -Type Dword -Value 10
+
+  Log-Output 'TCP/IP Parameters'
+  Get-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters'
+}
+
 # Writes a CNI config file under $env:CNI_CONFIG_DIR for containerd.
 #
 # Prerequisites: