Files
dokku/plugins/scheduler-k3s/node_sysctls_test.go
Jose Diaz-Gonzalez 44cd566178 feat: manage node-level kernel sysctls on the k3s scheduler
Sysctls the kernel does not namespace, such as `vm.max_map_count`, cannot be set from a pod spec and previously had no answer beyond editing `/etc/sysctl.d` on each host by hand. `scheduler-k3s:node-sysctls:set` now applies them through a privileged daemonset, which reaches nodes joined later and reapplies after a reboot. Sysctls may be scoped to a node profile, with a profile scope inheriting the global values and overriding them on conflict so that every node is covered by exactly one daemonset. Clearing a sysctl stops dokku managing it but does not restore the previous value, which persists until the node reboots.
2026-08-07 09:10:00 -04:00

306 lines
9.8 KiB
Go

package scheduler_k3s
import (
"os"
"path/filepath"
"strings"
"testing"
"helm.sh/helm/v3/pkg/chart/loader"
"helm.sh/helm/v3/pkg/chartutil"
"helm.sh/helm/v3/pkg/engine"
)
func TestGetNodeSysctlsProperty(t *testing.T) {
if got := getNodeSysctlsProperty(""); got != "node-sysctls.global" {
t.Errorf("getNodeSysctlsProperty(\"\") = %q, want node-sysctls.global", got)
}
if got := getNodeSysctlsProperty("edge-workers"); got != "node-sysctls.profile.edge-workers" {
t.Errorf("getNodeSysctlsProperty(\"edge-workers\") = %q, want node-sysctls.profile.edge-workers", got)
}
}
// TestGetNodeSysctlsPropertyIsReserved asserts the property prefix is excluded from
// the annotations scan. Without this a property like node-sysctls.profile.pod would
// be mistaken for a pod annotation.
func TestGetNodeSysctlsPropertyIsReserved(t *testing.T) {
reserved := false
for _, prefix := range reservedAnnotationPrefixes {
if prefix == "node-sysctls." {
reserved = true
}
}
if !reserved {
t.Error("node-sysctls. is not in reservedAnnotationPrefixes")
}
}
func TestGetNodeSysctlsReleaseName(t *testing.T) {
if got := getNodeSysctlsReleaseName(""); got != "dokku-node-sysctls-global" {
t.Errorf("getNodeSysctlsReleaseName(\"\") = %q, want dokku-node-sysctls-global", got)
}
if got := getNodeSysctlsReleaseName("edge-workers"); got != "dokku-node-sysctls-profile-edge-workers" {
t.Errorf("getNodeSysctlsReleaseName(\"edge-workers\") = %q, want dokku-node-sysctls-profile-edge-workers", got)
}
}
func TestSortedSysctls(t *testing.T) {
got := sortedSysctls(map[string]string{
"vm.swappiness": "10",
"vm.max_map_count": "262144",
"fs.file-max": "100000",
})
want := []Sysctl{
{Name: "fs.file-max", Value: "100000"},
{Name: "vm.max_map_count", Value: "262144"},
{Name: "vm.swappiness", Value: "10"},
}
if len(got) != len(want) {
t.Fatalf("sortedSysctls() = %v, want %v", got, want)
}
for i := range got {
if got[i] != want[i] {
t.Errorf("sortedSysctls()[%d] = %v, want %v", i, got[i], want[i])
}
}
}
func TestSortedSysctlsEmpty(t *testing.T) {
if got := sortedSysctls(map[string]string{}); len(got) != 0 {
t.Errorf("sortedSysctls(empty) = %v, want empty", got)
}
}
func TestNodeSysctlsScopeLabel(t *testing.T) {
if got := nodeSysctlsScopeLabel(""); got != "unprofiled nodes" {
t.Errorf("nodeSysctlsScopeLabel(\"\") = %q, want 'unprofiled nodes'", got)
}
if got := nodeSysctlsScopeLabel("edge"); got != "node profile edge" {
t.Errorf("nodeSysctlsScopeLabel(\"edge\") = %q, want 'node profile edge'", got)
}
}
func renderNodeSysctlsTemplate(t *testing.T, values NodeSysctlsGlobalValues) string {
t.Helper()
chartDir := t.TempDir()
if err := os.MkdirAll(filepath.Join(chartDir, "templates"), 0o755); err != nil {
t.Fatalf("mkdir: %v", err)
}
chartYAML := []byte("apiVersion: v2\nname: test\nversion: 0.0.1\n")
if err := os.WriteFile(filepath.Join(chartDir, "Chart.yaml"), chartYAML, 0o644); err != nil {
t.Fatalf("write Chart.yaml: %v", err)
}
tpl, err := templates.ReadFile("templates/node-sysctls-chart/templates/daemonset.yaml")
if err != nil {
t.Fatalf("read daemonset template: %v", err)
}
if err := os.WriteFile(filepath.Join(chartDir, "templates", "daemonset.yaml"), tpl, 0o644); err != nil {
t.Fatalf("write daemonset template: %v", err)
}
loaded, err := loader.Load(chartDir)
if err != nil {
t.Fatalf("load chart: %v", err)
}
sysctls := []interface{}{}
for _, sysctl := range values.Sysctls {
sysctls = append(sysctls, map[string]interface{}{"name": sysctl.Name, "value": sysctl.Value})
}
renderValues, err := chartutil.ToRenderValues(loaded, map[string]interface{}{
"global": map[string]interface{}{
"image": values.Image,
"pause_image": values.PauseImage,
"profile_name": values.ProfileName,
"release_name": values.ReleaseName,
"sysctls": sysctls,
},
}, chartutil.ReleaseOptions{Name: "test", Namespace: "kube-system"}, nil)
if err != nil {
t.Fatalf("ToRenderValues: %v", err)
}
rendered, err := engine.Render(loaded, renderValues)
if err != nil {
t.Fatalf("render: %v", err)
}
for name, content := range rendered {
if filepath.Base(name) == "daemonset.yaml" {
return content
}
}
t.Fatalf("daemonset.yaml not rendered; got: %v", rendered)
return ""
}
// TestNodeSysctlsDaemonSetRendering asserts each scope targets a disjoint set of
// nodes. If both the global and a profile DaemonSet landed on the same node they
// would race writing the same /proc/sys file, making the result depend on pod
// scheduling order.
func TestNodeSysctlsDaemonSetRendering(t *testing.T) {
base := NodeSysctlsGlobalValues{
Image: DefaultNodeSysctlsImage,
PauseImage: DefaultNodeSysctlsPauseImage,
Sysctls: []Sysctl{{Name: "vm.max_map_count", Value: "262144"}},
}
t.Run("global scope excludes profiled nodes", func(t *testing.T) {
values := base
values.ReleaseName = "dokku-node-sysctls-global"
manifest := renderNodeSysctlsTemplate(t, values)
if !strings.Contains(manifest, "operator: DoesNotExist") {
t.Errorf("global daemonset missing DoesNotExist affinity:\n%s", manifest)
}
if !strings.Contains(manifest, "key: dokku.com/node-profile") {
t.Errorf("global daemonset missing node profile affinity key:\n%s", manifest)
}
if strings.Contains(manifest, "nodeSelector:") {
t.Errorf("global daemonset should not use a nodeSelector:\n%s", manifest)
}
})
t.Run("profile scope targets only its own nodes", func(t *testing.T) {
values := base
values.ProfileName = "edge-workers"
values.ReleaseName = "dokku-node-sysctls-profile-edge-workers"
manifest := renderNodeSysctlsTemplate(t, values)
if !strings.Contains(manifest, "dokku.com/node-profile: \"edge-workers\"") {
t.Errorf("profile daemonset missing nodeSelector:\n%s", manifest)
}
if strings.Contains(manifest, "DoesNotExist") {
t.Errorf("profile daemonset should not carry the global affinity:\n%s", manifest)
}
})
t.Run("tolerates every taint", func(t *testing.T) {
values := base
values.ReleaseName = "dokku-node-sysctls-global"
manifest := renderNodeSysctlsTemplate(t, values)
if !strings.Contains(manifest, "- operator: Exists") {
t.Errorf("daemonset does not tolerate all taints:\n%s", manifest)
}
})
t.Run("applies each sysctl privileged", func(t *testing.T) {
values := base
values.ReleaseName = "dokku-node-sysctls-global"
values.Sysctls = []Sysctl{
{Name: "vm.max_map_count", Value: "262144"},
{Name: "vm.swappiness", Value: "10"},
}
manifest := renderNodeSysctlsTemplate(t, values)
if !strings.Contains(manifest, "privileged: true") {
t.Errorf("daemonset init container is not privileged:\n%s", manifest)
}
if !strings.Contains(manifest, `sysctl -w "vm.max_map_count=262144"`) {
t.Errorf("daemonset missing max_map_count write:\n%s", manifest)
}
if !strings.Contains(manifest, `sysctl -w "vm.swappiness=10"`) {
t.Errorf("daemonset missing swappiness write:\n%s", manifest)
}
})
t.Run("image overrides reach both containers", func(t *testing.T) {
values := base
values.ReleaseName = "dokku-node-sysctls-global"
values.Image = "registry.internal/busybox:1.36"
values.PauseImage = "registry.internal/pause:3.9"
manifest := renderNodeSysctlsTemplate(t, values)
if !strings.Contains(manifest, `image: "registry.internal/busybox:1.36"`) {
t.Errorf("daemonset did not use the sysctl image override:\n%s", manifest)
}
if !strings.Contains(manifest, `image: "registry.internal/pause:3.9"`) {
t.Errorf("daemonset did not use the pause image override:\n%s", manifest)
}
})
}
// TestMergeNodeSysctls asserts a profile scope inherits the global sysctls and
// overrides them on conflict. Profiled nodes are excluded from the global
// DaemonSet, so a global value omitted here would never reach them.
func TestMergeNodeSysctls(t *testing.T) {
cases := []struct {
name string
global map[string]string
profile map[string]string
want []Sysctl
}{
{
name: "no sysctls at all",
global: map[string]string{},
profile: map[string]string{},
want: []Sysctl{},
},
{
name: "profile inherits global values",
global: map[string]string{"vm.max_map_count": "262144"},
profile: map[string]string{},
want: []Sysctl{{Name: "vm.max_map_count", Value: "262144"}},
},
{
name: "profile wins on conflict",
global: map[string]string{"vm.max_map_count": "262144"},
profile: map[string]string{"vm.max_map_count": "524288"},
want: []Sysctl{{Name: "vm.max_map_count", Value: "524288"}},
},
{
name: "profile adds to global",
global: map[string]string{"vm.max_map_count": "262144"},
profile: map[string]string{"vm.swappiness": "10"},
want: []Sysctl{
{Name: "vm.max_map_count", Value: "262144"},
{Name: "vm.swappiness", Value: "10"},
},
},
{
name: "profile only",
global: map[string]string{},
profile: map[string]string{"vm.swappiness": "10"},
want: []Sysctl{{Name: "vm.swappiness", Value: "10"}},
},
}
for _, tc := range cases {
t.Run(tc.name, func(t *testing.T) {
got := mergeNodeSysctls(tc.global, tc.profile)
if len(got) != len(tc.want) {
t.Fatalf("mergeNodeSysctls() = %v, want %v", got, tc.want)
}
for i := range got {
if got[i] != tc.want[i] {
t.Errorf("mergeNodeSysctls()[%d] = %v, want %v", i, got[i], tc.want[i])
}
}
})
}
}
// TestMergeNodeSysctlsDoesNotMutateInputs asserts the merge leaves the caller's maps
// alone, since resolveNodeSysctlScopes reuses the global map across every profile.
func TestMergeNodeSysctlsDoesNotMutateInputs(t *testing.T) {
global := map[string]string{"vm.max_map_count": "262144"}
profile := map[string]string{"vm.max_map_count": "524288", "vm.swappiness": "10"}
mergeNodeSysctls(global, profile)
if len(global) != 1 || global["vm.max_map_count"] != "262144" {
t.Errorf("mergeNodeSysctls() mutated the global map: %v", global)
}
if len(profile) != 2 {
t.Errorf("mergeNodeSysctls() mutated the profile map: %v", profile)
}
}