Kubernetes delete deployment signal

Question

I have the following python code:

import time
import os
import signal
from abc import abstractmethod

class Stopper:
    stop = False
    
    @staticmethod
    def safe_stop(*args):
        Stopper.stop = true


signal.signal(signal.SIGINT, Stopper.safe_stop)
signal.signal(signal.SIGTERM, Stopper.safe_stop)

while not Stopper.stop:
    print("Running...")
    time.sleep(1)

os.system("touch /mnt/pod/sig")
print("Done")

And I create a deployment that contains an image with the above Python code.

When I delete the deployment using kubectl delete -f sig.yaml my Python code does not create the sig file indication and it's not printing the "Done" message.

At this link: https://cloud.google.com/blog/products/containers-kubernetes/kubernetes-best-practices-terminating-with-grace I see that k8s send SIGINT, SIGTERM signals but nothing happens in my application.

How can I make k8s send the signal to my application? What am I doing wrong?

If you run this outside Kubernetes (either stopping the program with `^C` or kill(1)) does it work? The `@abstractmethod` doesn't seem right, and I suspect you're correctly receiving the signal but the function call is failing. — David Maze, Mar 09 '21 at 13:52
@DavidMaze Yes, If I run it and stop the progam ^C it's wokring for me — Mar Teen, Mar 10 '21 at 10:58

score 0 · Answer 1 · answered Mar 09 '21 at 13:50

The problem is in your Python code. You need to adjust the class arguments and use Stopper.stop = True (with capitalized T).

The following code worked with Python 3:

import time
import os
import signal
from abc import abstractmethod

class Stopper:
    stop = False
    
    @abstractmethod
    def safe_stop(self, args):
        Stopper.stop = True


signal.signal(signal.SIGINT, Stopper.safe_stop)
signal.signal(signal.SIGTERM, Stopper.safe_stop)

while not Stopper.stop:
    print("Running...")
    time.sleep(1)

os.system("touch /mnt/pod/sig")
print("Done")

Hi, I fix the typo but it still not working – Mar Teen Mar 10 '21 at 08:29 — Mar Teen, Mar 10 '21 at 08:29

Kubernetes delete deployment signal

1 Answers1