Network Load Balancer- Instances are always unhealthy

[Jatan Ajmera]

Hi , 

I have a network load balancer on Port 5050, which has an target pool with 3 instances and a health check associated with it on the same port. My instances are perfectly healthy and running but it is showing unhealthy for the load balancer, so i cannot actually use the load balancer. I have tried everything mentioned on stackoverflow and this group, but have had no luck figuring out the actual problem.

I also checked for the google-address-manager, but that doesnt seem to exist on my instances. I am using CentOS 7. 

Thanks,

Jatan

[Matt Hite]

Are you using a Google supplied CentOS image? 

AFAIK, if the google-address-manager doesn't exist on your system, you won't have the external address associated with the NLB automatically set up on the CentOS host and therefore will not be able to bind (or receive traffic destined to) the NLB address.

If you're going to supply your own image, you'll need to carefully follow these guidelines:

https://cloud.google.com/compute/docs/tutorials/building-images

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[Kamran (Google Cloud Support)]

Hello Jatan,

As described in this article:  

For a health check to be deemed successful, the instance must return a valid HTTP response with code 200 and close the connection normally within the timeoutSec period. If it does so, the health check service returns a status ofHEALTHY for that instance. 

So the first step for troubleshooting this issue is making sure that health check port is configured to send HTTP requests to the correct port which HTTP service on the servers is listening on and can respond with code 200. For example, if you are running multimedia conference tool on port 5050 and your health check is configured to send HTTP request on that port, the health check fails.

You can find more information on debugging health checks in load balancing on this GCP blog post.

Please let me know if you have further questions about HTTP health checks.

Sincerely,

[Jatan Ajmera]

Hi, 

I have already been able to successfully curl to the instances in my pool as follows:

curl -IL ip.add.ress.10:5050/health and i got the following status:

HTTP/1.1 200 OK

Date: Wed, 14 Sep 2016 23:02:55 GMT

Content-Length: 0

I have tried this from both the within the google private network/across instances and from outside the network, and both have returned 200 OK. I've also double checked my firewall rules to include the CIDR blocks for the health checks as well.

[Jatan Ajmera]

Hi,

I started a python server using the following command :

sudo python -m SimpleHTTPServer 80

aaand reconfigured the health check with port 80 and now it is showing up as healthy for all the instances.

So I am trying to figure out whether this is a bug or an issue of ACLS.

Thanks,

Jatan

[Kamran (Google Cloud Support)]

If you were not able to figure out the cause of issue, you can email me your project ID and the name of LB, and I'll take a look at your health check settings.

Sincerely,

[Костя Хомко]

Hello, 

please help me with this.

root@dev:~# curl -IL 35.***.**.***:8080/health

HTTP/1.1 404

Content-Type: text/html;charset=utf-8

Content-Language: en

Transfer-Encoding: chunked

Date: Sat, 13 Jan 2018 20:57:55 GMT

root@dev:~# curl -IL 35.***.**.***:80/health

HTTP/1.1 404 Not Found

Server: nginx/1.12.1 (Ubuntu)

Date: Sat, 13 Jan 2018 20:59:28 GMT

Content-Type: text/html

Content-Length: 178

Connection: keep-alive

Hot to pass the health check if i have nginx redirection rule enabled?

If to turn it off i simply get error code curl: (7) Failed to connect to 35.***.**.*** port 80: Connection refused