[RESOLVED] Unable to save&test a prometheus datasource

  • What Grafana version and what operating system are you using?
    Grafana 8.8.3 on Ubuntu 20.04

  • What are you trying to achieve?
    add prometheus datasource of a LAN Linux VM

  • How are you trying to achieve it?
    On grafana web interface I try to fullfil the settings of a new datasource

  • What happened?
    When selectin “save and test” the test fail

  • What did you expect to happen?
    test Ok

  • Did you receive any errors in the Grafana UI or in related logs? If so, please tell us exactly what they were.
    The error message with port 9100 is :

Error reading Prometheus: bad_response: readObjectStart: expect { or n, but found <, error found in #1 byte of …| <|…, bigger context …| Node Exporter|…

The error message with port 9090 is :

Error reading Prometheus: client_error: client error: 404

When I try a

curl http://“local.ip.of.vm”:9100/metrics

i get a “normal answer with a lot of exporter”

When I try a

curl http://“local.ip.of.vm”:9090/metrics

i get :

Error 404 Not Found

HTTP ERROR 404 Not Found

URI: /metrics
MESSAGE: Not Found
SERVLET: org.eclipse.jetty.servlet.ServletHandler$Default404Servlet-3ee39da0

Powered by Jetty:// 9.4.44.v20210927

PS : the localhost:9090 datasource works … (but not the localhost:9100)

Thanks for help

Error found…
In fact I miss using Prometheus.
I was trying to create 3 Prometheus database for 3 host in stead of telling Prometheus to watch and save in his unique database the 3 hosts…

By the way I had to re-create the dashboard. I did not succeed to change in grafana the database link to dashboard.
is there a way to change it and not re-creat the dashboard?

were you able to resolve this?