Graphite cURL error 52: Empty reply from server

Icinga Web Modules Visualization, Metrics & Reporting
1

Hello, I have the following problem in Icinga2.
When I click on graphite-host, the message comes up:graphite cURL error 52: Empty reply from server.

In the graphite-backand module I set http://localhost:8080 and enabled insecure connection.

When I enter https://localhost:8080 I get the message: cURL error 35: OpenSSL SSL_connect: SSL_ERROR_SYSCALL in connection to localhost:8080

The web server runs under nginx.

Unfortunately, I’m not a big Linux expert either. Therefore I would be happy about any help.

Best regards
Ernst

2

Hi @EHeine,
Is grahite-web or graphite-api listening on that port ( ss -tlpen | grep 8080 )?

3

Hi,

here is the result. It doesn´t look like that.

ss -tlpen | grep 8080
LISTEN 0 100 127.0.0.1:8080 0.0.0.0:* users:((“uwsgi”,pid=133231,fd=5),(“uwsgi”,pid=133230,fd=5),(“uwsgi”,pid=133228,fd=5)) ino:887330 sk:5 cgroup:/system.slice/uwsgi.service ↔
root@icinga:/etc#

4

That is actually looking good, that should be the python uwsgi http server.
So, something is listening there. The interesting question is now,
why it does not respond with anything useful.

Could you search through the logs a bit if maybe the graphite part throws
any errors or warnings?
I don’t know anything about your setup, so maybe start looking in /var/log for something looking like “graphite”, “uwsgi”, “djagno” or something like that.

5

in icinga2.log this message repeats:

[2024-05-06 00:00:11 +0200] critical/GraphiteWriter: Exception during Graphite operation: Verify that your backend is operational!
[2024-05-06 00:00:18 +0200] information/IdoMysqlConnection: Pending queries: 0 (Input: 2/s; Output: 3/s)
[2024-05-06 00:00:18 +0200] information/WorkQueue: #11 (GraphiteWriter, graphite) items: 1, rate: 0.516667/s (31/min 153/5min 460/15min); empty in 9 seconds
[2024-05-06 00:00:18 +0200] information/GraphiteWriter: Finished reconnecting to Graphite in 0.000640869 second(s).
[2024-05-06 00:00:33 +0200] critical/GraphiteWriter: Cannot write to TCP socket on host ‘localhost’ port ‘8080’.
Context:
(0) Processing check result for ‘icinga.xyz.de’

All other logs are empty.

6

weird, can you try something like curl http://localhost:8080 there?

7

Hi,

heine@icinga:~$ curl http://localhost:8080
curl: (52) Empty reply from server

Which port did you enter under Module-graphite-Backend?

If I enter port 2003 as it says in the instructions, then I get the error:

cURL error 28: Operation timed out after 10001 milliseconds with 0 bytes received

Best regard

Ernst

8

Port 2003 should be the data writer by default, which is not (necessarily) the same process which will render your pictures.
I think something is wrong with your graphite-web