From f9aa2867dfb5e6e511f77810e0353fe98e2bbfa3 Mon Sep 17 00:00:00 2001
From: Jiri Olsa <jolsa@kernel.org>
Date: Sat, 22 Jun 2024 20:26:27 +0000
Subject: [PATCH] tetragon: Add keep-sensors-on-exit option

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 cmd/tetragon/main.go          | 12 ++++++++++--
 docs/data/tetragon_flags.yaml |  3 +++
 pkg/option/config.go          |  2 ++
 pkg/option/flags.go           |  6 ++++++
 4 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/cmd/tetragon/main.go b/cmd/tetragon/main.go
index b2103212cd0..b5aabc19fb4 100644
--- a/cmd/tetragon/main.go
+++ b/cmd/tetragon/main.go
@@ -223,6 +223,10 @@ func tetragonExecute() error {
 		log.Info("Force loading smallprograms")
 	}
 
+	if option.Config.KeepSensorsOnExit {
+		log.Info("Not unloading sensors on exit")
+	}
+
 	if viper.IsSet(option.KeyNetnsDir) {
 		defaults.NetnsDir = viper.GetString(option.KeyNetnsDir)
 	}
@@ -456,7 +460,9 @@ func tetragonExecute() error {
 		return err
 	}
 	defer func() {
-		initialSensor.Unload()
+		if !option.Config.KeepSensorsOnExit {
+			initialSensor.Unload()
+		}
 	}()
 
 	cgrouprate.NewCgroupRate(ctx, pm, base.CgroupRateMap, &option.Config.CgroupRate)
@@ -467,7 +473,9 @@ func tetragonExecute() error {
 	sensorMgWait = nil
 	observer.GetSensorManager().LogSensorsAndProbes(ctx)
 	defer func() {
-		observer.RemoveSensors(ctx)
+		if !option.Config.KeepSensorsOnExit {
+			observer.RemoveSensors(ctx)
+		}
 	}()
 
 	err = loadTpFromDir(ctx, option.Config.TracingPolicyDir)
diff --git a/docs/data/tetragon_flags.yaml b/docs/data/tetragon_flags.yaml
index 648c9739947..81820d0f993 100644
--- a/docs/data/tetragon_flags.yaml
+++ b/docs/data/tetragon_flags.yaml
@@ -134,6 +134,9 @@ options:
       usage: help for tetragon
     - name: k8s-kubeconfig-path
       usage: Absolute path of the kubernetes kubeconfig file
+    - name: keep-sensors-on-exit
+      default_value: "false"
+      usage: Do not unload sensors on exit
     - name: kernel
       usage: Kernel version
     - name: kmods
diff --git a/pkg/option/config.go b/pkg/option/config.go
index b07091afd55..c083d17e765 100644
--- a/pkg/option/config.go
+++ b/pkg/option/config.go
@@ -95,6 +95,8 @@ type config struct {
 	HealthServerInterval int
 
 	Base string
+
+	KeepSensorsOnExit bool
 }
 
 var (
diff --git a/pkg/option/flags.go b/pkg/option/flags.go
index ea0bc6f95f9..641957a54b6 100644
--- a/pkg/option/flags.go
+++ b/pkg/option/flags.go
@@ -105,6 +105,8 @@ const (
 	KeyHealthTimeInterval  = "health-server-interval"
 
 	KeyBase = "base"
+
+	KeyKeepSensorsOnExit = "keep-sensors-on-exit"
 )
 
 type UsernameMetadaCode int
@@ -220,6 +222,8 @@ func ReadAndSetFlags() error {
 	Config.HealthServerInterval = viper.GetInt(KeyHealthTimeInterval)
 
 	Config.Base = viper.GetString(KeyBase)
+
+	Config.KeepSensorsOnExit = viper.GetBool(KeyKeepSensorsOnExit)
 	return nil
 }
 
@@ -376,4 +380,6 @@ func AddFlags(flags *pflag.FlagSet) {
 	flags.Int(KeyHealthTimeInterval, 10, "Health server interval in seconds")
 
 	flags.String(KeyBase, defaults.DefaultMapPrefix, "base")
+
+	flags.Bool(KeyKeepSensorsOnExit, false, "Do not unload sensors on exit")
 }