[sc-20056] Low resource preset should take precedence over kernel 5.11 overrides

CHANGELOG.md

@@ -22,6 +22,8 @@ We use the following categories for changes:
 
 ### Fixed
 
+- Low resource preset should take precedence over kernel 5.11 overrides [#sc-20056]
+
 ### Removed
 
 ### Deprecated

cmd/deploy.go

@@ -6,7 +6,6 @@ import (
 	"strconv"
 	"time"
 
-	"github.com/blang/semver/v4"
 	"github.com/getsentry/sentry-go"
 	"github.com/imdario/mergo"
 	"github.com/pkg/errors"
@@ -46,7 +45,6 @@ const (
 	HELM_REPO_URL                     = "https://helm.groundcover.com"
 	CLUSTER_URL_FORMAT                = "%s/?clusterId=%s&viewType=Overview"
 	QUAY_REGISTRY_PRESET_PATH         = "presets/quay.yaml"
-	AGENT_KERNEL_5_11_PRESET_PATH     = "presets/agent/kernel-5-11.yaml"
 	CUSTOM_METRICS_PRESET_PATH        = "presets/backend/custom-metrics.yaml"
 	KUBE_STATE_METRICS_PRESET_PATH    = "presets/backend/kube-state-metrics.yaml"
 	STORAGE_CLASS_TEMPLATE_PATH       = "templates/backend/storage-class.yaml"
@@ -607,7 +605,7 @@ func generateChartValues(chartValues map[string]interface{}, apiKey, installatio
 			helm.BACKEND_LOW_RESOURCES_PATH,
 		}
 	} else {
-		agentPresetPath := helm.GetAgentResourcePresetPath(allocatableResources)
+		agentPresetPath := helm.GetAgentResourcePresetPath(allocatableResources, nodesReport.MaximalKernelVersion())
 		if agentPresetPath != helm.DEFAULT_PRESET {
 			overridePaths = append(overridePaths, agentPresetPath)
 		}
@@ -632,10 +630,6 @@ func generateChartValues(chartValues map[string]interface{}, apiKey, installatio
 		overridePaths = append(overridePaths, KUBE_STATE_METRICS_PRESET_PATH)
 	}
 
-	if semver.MustParseRange(">=5.11.0")(nodesReport.MaximalKernelVersion()) {
-		overridePaths = append(overridePaths, AGENT_KERNEL_5_11_PRESET_PATH)
-	}
-
 	if len(overridePaths) > 0 {
 		sentryHelmContext.ResourcesPresets = overridePaths
 		sentryHelmContext.SetOnCurrentScope()

pkg/helm/tune.go

@@ -3,6 +3,7 @@ package helm
 import (
 	"embed"
 
+	"github.com/blang/semver/v4"
 	"groundcover.com/pkg/k8s"
 	"k8s.io/apimachinery/pkg/api/resource"
 )
@@ -17,6 +18,13 @@ const (
 	AGENT_DEFAULT_MEMORY_THRESHOLD = "1024Mi"
 	AGENT_LOW_RESOURCES_PATH       = "presets/agent/low-resources.yaml"
 
+	// Starting from Linux kernel version 5.11, eBPF maps are accounted for in the memory cgroup
+	// of the process that created them. For this reason we need to increase the memory limit for
+	// the agent.
+	// https://github.com/cilium/ebpf/blob/v0.16.0/docs/ebpf/concepts/rlimit.md#resource-limits
+	AGENT_KERNEL_5_11_PRESET_PATH = "presets/agent/kernel-5-11.yaml"
+	KERNEL_5_11_SEMVER_EXPRESSION = ">=5.11.0"
+
 	EMPTYDIR_STORAGE_PATH = "presets/backend/emptydir-storage.yaml"
 
 	BACKEND_DEFAULT_TOTAL_CPU_THRESHOLD    = "12000m"
@@ -39,7 +47,7 @@ type AllocatableResources struct {
 	NodeCount   int
 }
 
-func GetAgentResourcePresetPath(allocatableResources *AllocatableResources) string {
+func GetAgentResourcePresetPath(allocatableResources *AllocatableResources, maxKernelVersion semver.Version) string {
 	defaultCpuThreshold := resource.MustParse(AGENT_DEFAULT_CPU_THRESHOLD)
 	defaultMemoryThreshold := resource.MustParse(AGENT_DEFAULT_MEMORY_THRESHOLD)
 
@@ -50,6 +58,10 @@ func GetAgentResourcePresetPath(allocatableResources *AllocatableResources) stri
 		return AGENT_LOW_RESOURCES_PATH
 	}
 
+	if semver.MustParseRange(KERNEL_5_11_SEMVER_EXPRESSION)(maxKernelVersion) {
+		return AGENT_KERNEL_5_11_PRESET_PATH
+	}
+
 	return DEFAULT_PRESET
 }
 

pkg/helm/tune_test.go

@@ -3,13 +3,19 @@ package helm_test
 import (
 	"testing"
 
+	"github.com/blang/semver/v4"
 	"github.com/stretchr/testify/assert"
 	"groundcover.com/pkg/helm"
 	"groundcover.com/pkg/k8s"
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
 )
 
+var (
+	Kernel510Semver = semver.MustParse("5.10.0")
+	Kernel511Semver = semver.MustParse("5.11.0")
+)
+
 func TestTuneResourcesValuesAgentLow(t *testing.T) {
 	// arrange
 	agentLowCpu := resource.MustParse(helm.AGENT_DEFAULT_CPU_THRESHOLD)
@@ -28,7 +34,7 @@ func TestTuneResourcesValuesAgentLow(t *testing.T) {
 	resources := helm.CalcAllocatableResources(lowNodeReport)
 
 	// act
-	cpu := helm.GetAgentResourcePresetPath(resources)
+	cpu := helm.GetAgentResourcePresetPath(resources, Kernel510Semver)
 
 	// assert
 	assert.Equal(t, helm.AGENT_LOW_RESOURCES_PATH, cpu)
@@ -52,12 +58,36 @@ func TestTuneResourcesValuesAgentDefault(t *testing.T) {
 	resources := helm.CalcAllocatableResources(defaultNodeReport)
 
 	// act
-	cpu := helm.GetAgentResourcePresetPath(resources)
+	cpu := helm.GetAgentResourcePresetPath(resources, Kernel510Semver)
 
 	// assert
 	assert.Equal(t, helm.DEFAULT_PRESET, cpu)
 }
 
+func TestTuneResourcesValuesAgentNewKernel(t *testing.T) {
+	// arrange
+	agentDefaultCpu := resource.MustParse(helm.AGENT_DEFAULT_CPU_THRESHOLD)
+	agentDefaultCpu.Add(*resource.NewMilliQuantity(1, resource.DecimalSI))
+
+	agentDefaultMemory := resource.MustParse(helm.AGENT_DEFAULT_MEMORY_THRESHOLD)
+	agentDefaultMemory.Add(*resource.NewQuantity(1, resource.BinarySI))
+
+	defaultNodeReport := []*k8s.NodeSummary{
+		{
+			CPU:    &agentDefaultCpu,
+			Memory: &agentDefaultMemory,
+		},
+	}
+
+	resources := helm.CalcAllocatableResources(defaultNodeReport)
+
+	// act
+	cpu := helm.GetAgentResourcePresetPath(resources, Kernel511Semver)
+
+	// assert
+	assert.Equal(t, helm.AGENT_KERNEL_5_11_PRESET_PATH, cpu)
+}
+
 func TestTuneResourcesValuesBackendLow(t *testing.T) {
 	// arrange
 	backendLowCpu := resource.MustParse(helm.BACKEND_DEFAULT_TOTAL_CPU_THRESHOLD)