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feat: cull notebooks based on terminal activity (as well as kernel activity) #740

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a02268b
Allow kernel idleness check to also account for terminal activity
krishanbhasin-px Nov 11, 2025
7baf9df
fixup! Allow kernel idleness check to also account for terminal activity
krishanbhasin-px Nov 11, 2025
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176 changes: 148 additions & 28 deletions components/notebook-controller/controllers/culling_controller.go
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Original file line number Diff line number Diff line change
Expand Up @@ -32,12 +32,14 @@ const DEFAULT_IDLENESS_CHECK_PERIOD = "1"
const DEFAULT_ENABLE_CULLING = "false"
const DEFAULT_CLUSTER_DOMAIN = "cluster.local"
const DEFAULT_DEV = "false"
const DEFAULT_TRACK_TERMINAL_ACTIVITY = "false"

var CULL_IDLE_TIME = 0
var ENABLE_CULLING = false
var IDLENESS_CHECK_PERIOD = 0
var CLUSTER_DOMAIN = ""
var DEV = false
var TRACK_TERMINAL_ACTIVITY = false

// When a Resource should be stopped/culled, then the controller should add this
// annotation in the Resource's Metadata. Then, inside the reconcile loop,
Expand Down Expand Up @@ -67,6 +69,13 @@ type KernelStatus struct {
Connections int `json:"connections"`
}

// Each terminal of the Notebook Server has a status.
// TerminalStatus struct:
type TerminalStatus struct {
Name string `json:"name"`
LastActivity string `json:"last_activity"`
}

// CullingReconciler : Type of a reconciler that will be culling idle notebooks
type CullingReconciler struct {
client.Client
Expand Down Expand Up @@ -240,6 +249,48 @@ func getNotebookApiKernels(nm, ns string, log logr.Logger) []KernelStatus {
return kernels
}

func getNotebookApiTerminals(nm, ns string, log logr.Logger) []TerminalStatus {
// Get the Terminals' status from the Server's `/api/terminals` endpoint
client := &http.Client{
Timeout: time.Second * 10,
}

domain := GetEnvDefault("CLUSTER_DOMAIN", DEFAULT_CLUSTER_DOMAIN)
url := fmt.Sprintf(
"http://%s.%s.svc.%s/notebook/%s/%s/api/terminals",
nm, ns, domain, ns, nm)
if GetEnvDefault("DEV", DEFAULT_DEV) != "false" {
url = fmt.Sprintf(
"http://localhost:8001/api/v1/namespaces/%s/services/%s:http-%s/proxy/notebook/%s/%s/api/terminals",
ns, nm, nm, ns, nm)
}

resp, err := client.Get(url)
if err != nil {
log.Info(fmt.Sprintf("Could not GET terminals from %s: %v", url, err))
return nil
}

// Decode the body
defer resp.Body.Close()
if resp.StatusCode != 200 {
log.Info(fmt.Sprintf(
"Warning: GET to %s: %d (terminals endpoint may not be available for this notebook type)",
url, resp.StatusCode))
return nil
}

var terminals []TerminalStatus

err = json.NewDecoder(resp.Body).Decode(&terminals)
if err != nil {
log.Error(err, "Error parsing JSON response for Notebook API Terminals.")
return nil
}

return terminals
}

func allKernelsAreIdle(kernels []KernelStatus, log logr.Logger) bool {
// Iterate on the list of kernels' status.
// If all kernels are on execution_state=idle then this function returns true.
Expand All @@ -254,57 +305,118 @@ func allKernelsAreIdle(kernels []KernelStatus, log logr.Logger) bool {
return true
}

func getMostRecentKernelActivity(kernels []KernelStatus, log logr.Logger) (time.Time, error) {
// Get the most recent last_activity timestamp from all kernels
var recentTime time.Time

if len(kernels) == 0 {
return recentTime, nil
}

// Parse the first kernel's timestamp
kernelTime, err := time.Parse(time.RFC3339, kernels[0].LastActivity)
if err != nil {
log.Error(err, "Error parsing the last-activity from the /api/kernels")
return recentTime, err
}
recentTime = kernelTime

// Check remaining kernels for more recent activity
for i := 1; i < len(kernels); i++ {
kernelLastActivity, err := time.Parse(time.RFC3339, kernels[i].LastActivity)
if err != nil {
log.Error(err, "Error parsing the last-activity from the /api/kernels")
continue
}
if kernelLastActivity.After(recentTime) {
recentTime = kernelLastActivity
}
}

return recentTime, nil
}

func getMostRecentTerminalActivity(terminals []TerminalStatus, log logr.Logger) (time.Time, error) {
// Get the most recent last_activity timestamp from all terminals
var recentTime time.Time

if len(terminals) == 0 {
return recentTime, nil
}

// Check all terminals for most recent activity
for i := 0; i < len(terminals); i++ {
terminalLastActivity, err := time.Parse(time.RFC3339, terminals[i].LastActivity)
if err != nil {
log.Error(err, "Error parsing the last-activity from the /api/terminals")
continue
}
if recentTime.IsZero() || terminalLastActivity.After(recentTime) {
recentTime = terminalLastActivity
}
}

return recentTime, nil
}

// Update LAST_ACTIVITY_ANNOTATION
func updateNotebookLastActivityAnnotation(meta *metav1.ObjectMeta, log logr.Logger) {

log.Info("Updating the last-activity annotation. Checking /api/kernels")
nm, ns := meta.GetName(), meta.GetNamespace()
kernels := getNotebookApiKernels(nm, ns, log)
if kernels == nil {
log.Info("Could not GET the kernels status. Will not update last-activity.")

// Also check terminals if terminal tracking is enabled
var terminals []TerminalStatus
if TRACK_TERMINAL_ACTIVITY {
log.Info("Terminal tracking enabled. Checking /api/terminals")
terminals = getNotebookApiTerminals(nm, ns, log)
}

// If we can't get any activity data, don't update
if kernels == nil && terminals == nil {
log.Info("Could not GET kernels or terminals status. Will not update last-activity.")
return
} else if len(kernels) == 0 {
log.Info("Notebook has no kernels. Will not update last-activity")
}

// If both are empty (no kernels and no terminals), don't update
if len(kernels) == 0 && len(terminals) == 0 {
log.Info("Notebook has no kernels or terminals. Will not update last-activity")
return
}

updateTimestampFromKernelsActivity(meta, kernels, log)
updateTimestampFromActivity(meta, kernels, terminals, log)
}

func updateTimestampFromKernelsActivity(meta *metav1.ObjectMeta, kernels []KernelStatus, log logr.Logger) {
func updateTimestampFromActivity(meta *metav1.ObjectMeta, kernels []KernelStatus, terminals []TerminalStatus, log logr.Logger) {

if !allKernelsAreIdle(kernels, log) {
// At least on kernel is "busy" so the last-activity annotation should
// should be the current time.
// If any kernel is busy, update to current time
if len(kernels) > 0 && !allKernelsAreIdle(kernels, log) {
// At least one kernel is "busy" so the last-activity annotation should
// be the current time.
t := createTimestamp()
log.Info(fmt.Sprintf("Found a busy kernel. Updating the last-activity to %s", t))

meta.Annotations[LAST_ACTIVITY_ANNOTATION] = t
return
}

// Checking for the most recent kernel last_activity. The LAST_ACTIVITY_ANNOTATION
// should be the most recent kernel last-activity among the kernels.
recentTime, err := time.Parse(time.RFC3339, kernels[0].LastActivity)
if err != nil {
log.Error(err, "Error parsing the last-activity from the /api/kernels")
return
}
// Get the most recent activity from kernels and terminals using helper functions
kernelTime, _ := getMostRecentKernelActivity(kernels, log)
terminalTime, _ := getMostRecentTerminalActivity(terminals, log)

for i := 1; i < len(kernels); i++ {
kernelLastActivity, err := time.Parse(time.RFC3339, kernels[i].LastActivity)
if err != nil {
log.Error(err, "Error parsing the last-activity from the /api/kernels")
return
}
if kernelLastActivity.After(recentTime) {
recentTime = kernelLastActivity
}
// Use whichever timestamp is most recent
recentTime := kernelTime
if terminalTime.After(kernelTime) {
recentTime = terminalTime
}
t := recentTime.Format(time.RFC3339)

meta.Annotations[LAST_ACTIVITY_ANNOTATION] = t
log.Info(fmt.Sprintf("Successfully updated last-activity from latest kernel action, %s", t))
// Update the annotation with the most recent activity
if !recentTime.IsZero() {
t := recentTime.Format(time.RFC3339)
meta.Annotations[LAST_ACTIVITY_ANNOTATION] = t
log.Info(fmt.Sprintf("Successfully updated last-activity from latest kernel/terminal action, %s", t))
}
}

func updateLastCullingCheckTimestampAnnotation(meta *metav1.ObjectMeta, log logr.Logger) {
Expand Down Expand Up @@ -425,6 +537,14 @@ func initGlobalVars() error {
ENABLE_CULLING = true
}

trackTerminalActivity := GetEnvDefault("TRACK_TERMINAL_ACTIVITY", DEFAULT_TRACK_TERMINAL_ACTIVITY)
if trackTerminalActivity == "true" {
TRACK_TERMINAL_ACTIVITY = true
log.Info("Terminal activity tracking is ENABLED")
} else {
log.Info("Terminal activity tracking is DISABLED (only kernel activity will be tracked)")
}

CLUSTER_DOMAIN = GetEnvDefault("CLUSTER_DOMAIN", DEFAULT_CLUSTER_DOMAIN)

cullPeriod := GetEnvDefault("IDLENESS_CHECK_PERIOD", DEFAULT_IDLENESS_CHECK_PERIOD)
Expand Down
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