Skip to content

Admin cutover improve the pod label watch function #881

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
spai-p9 merged 5 commits into from
Sep 10, 2025
Merged

Admin cutover improve the pod label watch function #881

Changes from 3 commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
a345595
Add some debug logs
spai-p9 Sep 8, 2025
957c074
Add timeout for the client
spai-p9 Sep 8, 2025
980a003
increase timeout for watch and retry incase of error
spai-p9 Sep 8, 2025
9dbf3f8
remove logs inside the loop
spai-p9 Sep 10, 2025
e50709c
Merge branch 'main' into private/main/ghi-877
spai-p9 Sep 10, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
60 changes: 43 additions & 17 deletions v2v-helper/reporter/reporter.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@ import (
"math/rand"
"os"
"strings"
"time"

"github.com/platform9/vjailbreak/v2v-helper/pkg/utils"
corev1 "k8s.io/api/core/v1"
Expand Down Expand Up @@ -233,24 +234,49 @@ func (r *Reporter) GetCutoverLabel() (string, error) {

func (r *Reporter) WatchPodLabels(ctx context.Context, ch chan<- string) {
go func() {
watch, err := r.Clientset.CoreV1().Pods(r.PodNamespace).Watch(ctx, metav1.ListOptions{
FieldSelector: fmt.Sprintf("metadata.name=%s", r.PodName),
})
if err != nil {
fmt.Printf("Failed to watch pod labels: %v\n", err)
}
defer watch.Stop()
originalStartCutover := "no"
for event := range watch.ResultChan() {
pod, ok := event.Object.(*corev1.Pod)
if !ok {
continue
}
if cutover, ok := pod.Labels["startCutover"]; ok {
if cutover != originalStartCutover {
ch <- cutover
originalStartCutover = cutover
for {
select {
case <-ctx.Done():
fmt.Printf("Error: Context canceled for pod %s: %v\n", r.PodName, ctx.Err())
return
default:
fmt.Printf("Info: Starting watch for pod %s in namespace %s\n", r.PodName, r.PodNamespace)
timeoutSeconds := int64(172800)
watch, err := r.Clientset.CoreV1().Pods(r.PodNamespace).Watch(ctx, metav1.ListOptions{
FieldSelector: fmt.Sprintf("metadata.name=%s", r.PodName),
TimeoutSeconds: &timeoutSeconds,
})
if err != nil {
fmt.Printf("Error: Failed to start watch for pod %s: %v\n", r.PodName, err)
time.Sleep(5 * time.Second)
continue
}
Comment on lines +245 to +253
Copy link
Copy Markdown
Collaborator

@OmkarDeshpande7 OmkarDeshpande7 Sep 9, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

@spai-p9 Won't this create infinite watchers?

Copy link
Copy Markdown
Collaborator

@OmkarDeshpande7 OmkarDeshpande7 Sep 9, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

It will hog resources on the pod

Copy link
Copy Markdown
Collaborator Author

@spai-p9 spai-p9 Sep 10, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This only creates one watcher and the inner loop is a blocking for loop which does not exits until the channel gets closed, hence only one watch is present at a given particular time. the outer for loop is to ensure that if a channel gets closed due to some reason we create a new watch so we don't miss any update.

fmt.Printf("Info: Watch established for pod %s with timeout %d seconds\n", r.PodName, timeoutSeconds)
defer watch.Stop()
Comment thread
OmkarDeshpande7 marked this conversation as resolved.
originalStartCutover := "no"
fmt.Printf("Info: Entering event loop for pod %s\n", r.PodName)
for event := range watch.ResultChan() {
fmt.Printf("Info: Received event for pod %s: type=%v\n", r.PodName, event.Type)
pod, ok := event.Object.(*corev1.Pod)
if !ok {
fmt.Printf("Error: Received non-pod event for pod %s: %v\n", r.PodName, event.Object)
continue
}
if cutover, ok := pod.Labels["startCutover"]; ok {
if cutover != originalStartCutover {
fmt.Printf("Info: Label changed for pod %s: %s -> %s\n", r.PodName, originalStartCutover, cutover)
select {
case ch <- cutover:
fmt.Printf("Info: Sent label %s for pod %s to channel\n", cutover, r.PodName)
default:
fmt.Printf("Error: Channel blocked when sending label %s for pod %s\n", cutover, r.PodName)
}
originalStartCutover = cutover
}
}
}
fmt.Printf("Info: Watch channel closed for pod %s after ~%d seconds, retrying...\n", r.PodName, timeoutSeconds)
time.Sleep(5 * time.Second)
}
}
}()
Expand Down
Loading