From 3ccf736bd176dd7b1cbe1cbeb9b868bb91079d24 Mon Sep 17 00:00:00 2001
From: Peter Hunt <pehunt@redhat.com>
Date: Thu, 27 May 2021 15:09:10 -0400
Subject: [PATCH] sysctl tutorial: drop net.ipv4.route.min_pmtu

The tutorial is busted, and likely always has been busted. the net.* sysctls are applied to containers when they're in a private network namespace.
However, net.ipv4.route.min_pmtu is not one of the sysctls that are added to a new network namespace.

This commit replaces uses with "net.core.somaxconn", an unsafe sysctl that is able to be applied to a namespace

Signed-off-by: Peter Hunt <pehunt@redhat.com>
---
 modules/nodes-containers-sysctls-setting.adoc | 6 +++---
 modules/nodes-containers-sysctls-unsafe.adoc  | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/modules/nodes-containers-sysctls-setting.adoc b/modules/nodes-containers-sysctls-setting.adoc
index 771b531dc8..dd2f7b0bf9 100644
--- a/modules/nodes-containers-sysctls-setting.adoc
+++ b/modules/nodes-containers-sysctls-setting.adoc
@@ -14,7 +14,7 @@ that node. As with node-level sysctls, use the taints and toleration feature
 or labels on nodes to schedule those pods onto the right nodes.
 
 The following example uses the pod `securityContext` to set a safe sysctl
-`kernel.shm_rmid_forced` and two unsafe sysctls, `net.ipv4.route.min_pmtu` and
+`kernel.shm_rmid_forced` and two unsafe sysctls, `net.core.somaxconn` and
 `kernel.msgmax`. There is no distinction between _safe_ and _unsafe_ sysctls in
 the specification.
 
@@ -42,8 +42,8 @@ spec:
     sysctls:
     - name: kernel.shm_rmid_forced
       value: "0"
-    - name: net.ipv4.route.min_pmtu
-      value: "552"
+    - name: net.core.somaxconn
+      value: "1024"
     - name: kernel.msgmax
       value: "65536"
   ...
diff --git a/modules/nodes-containers-sysctls-unsafe.adoc b/modules/nodes-containers-sysctls-unsafe.adoc
index 1a649ac636..cee30b7c35 100644
--- a/modules/nodes-containers-sysctls-unsafe.adoc
+++ b/modules/nodes-containers-sysctls-unsafe.adoc
@@ -60,7 +60,7 @@ spec:
   kubeletConfig:
     allowedUnsafeSysctls: <2>
       - "kernel.msg*"
-      - "net.ipv4.route.min_pmtu"
+      - "net.core.somaxconn"
 ----
 <1> Specify the label from the machine config pool.
 <2> List the unsafe sysctls you want to allow.