add /health_check for load balancers

[cailiang9]

No description provided.

[takluyver]

I'm not quite sure what this means - is it related to tmpnb or jupyterhub, perhaps?

[cailiang9]

Thanks! we have our own docker spawner which is hard to integrate with tmpnb. So I run notebook directly and need a /health_check.

[takluyver]

I'm still not sure what you're after. What information would be in the response of /health_check? What are you trying to load balance? Sorry if this is obvious relative to tmpnb or something - I don't know much about that part of the project.

[ellisonbg]

Are you interest in a /health_check REST endpoint that a load balancer can hit to get the status of the notebook server?

[danielfrg]

I +1 a /health endpoint. This is useful in also for some schedulers for example for a liveliness check for Kubernetes (https://lukemarsden.github.io/docs/user-guide/liveness/).

I personally like what Elasticsearch does: https://www.elastic.co/guide/en/elasticsearch/reference/current/cluster-health.html - but in general a return code of 200 would be good enough in most cases.

[gsemet]

would be really useful

[afaq404alam]

Do we have any updates on this? It would be really useful to have a /health endpoint which just simply returns status 200.

[skully]

Any update regarding this issue?

[mgax]

For a quick-and-dirty solution, the /static/favicons/favicon.ico URL always returns a 200 response.

[FlorinAndrei]

For a quick-and-dirty solution, the /static/favicons/favicon.ico URL always returns a 200 response.

I've tried that with the latest version and I get 404.

Having a plain, dumb URL that always returns code 200 would be really useful.

[afshin]

You can hit /api and it will return a JSON response that contains the version of the notebook package and it does not require authentication.

cf.

notebook/notebook/base/handlers.py

Lines 851 to 855 in 6fe9755

	class APIVersionHandler(APIHandler):
	def get(self):
	# not authenticated, so give as few info as possible
	self.finish(json.dumps({"version":notebook.__version__}))

[FlorinAndrei]

You can hit /api and it will return a JSON response that contains the version of the notebook package and it does not require authentication.

cf.

notebook/notebook/base/handlers.py

Lines 851 to 855 in 6fe9755

	class APIVersionHandler(APIHandler):
	def get(self):
	# not authenticated, so give as few info as possible
	self.finish(json.dumps({"version":notebook.__version__}))

That does it. Folks, we have a solution. A good endpoint to check the health of a Jupyter Notebook instance is simply /api - it returns 200 OK and not much else.

# curl -v http://localhost:8888/api
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8888 (#0)
> GET /api HTTP/1.1
> Host: localhost:8888
> User-Agent: curl/7.58.0
> Accept: */*
> 
< HTTP/1.1 200 OK
< Server: TornadoServer/6.1
< Content-Type: application/json
< Date: Fri, 25 Jun 2021 18:50:32 GMT
< X-Content-Type-Options: nosniff
< Content-Security-Policy: frame-ancestors 'self'; report-uri /api/security/csp-report; default-src 'none'
< Etag: "846b4f8f33764576d6b3026face5fa7e4d0bd57b"
< Content-Length: 20

[kevin-bates]

Thanks for the tip @afshin - closing.