usage of multiple mysql db instances with openshift

[sneha]

hi,

i tried adding multiple db instance in .my.cnf file with mysql exporter version 0.15.0 but it only scrape DB instance only.

is there any sample to use mutliple DB instance for single exporter and how to distinguish scrape data is of which instance.

thanks,

sneha

[Brian Candler]

On Monday, 4 September 2023 at 10:15:06 UTC+1 sneha wrote:

i tried adding multiple db instance in .my.cnf file with mysql exporter version 0.15.0 but it only scrape DB instance only.

is there any sample to use mutliple DB instance for single exporter

Yes, there is an example Prometheus config at

https://github.com/prometheus/mysqld_exporter/#multi-target-support

(see under "On the prometheus side ... ")

It sets the `target` parameter for each scrape to the DB of interest, whilst setting __address__ to point to the exporter itself.

Before doing this, make sure you're able to scrape the exporter directly using curl, i.e.

curl 'http://localhost:9104/probe?target=server1:3306'

curl 'http://localhost:9104/probe?target=server2:3306'

should give you metrics for the two servers.

and how to distinguish scrape data is of which instance.

In a label.  The example config that I linked above copies "__param_target" to "instance", so the "instance" label tells you which DB target was being scraped.

[sneha]

Hi Brian,

thanks it worked , using curl i am able to scrape individual database.

any idea that is it possible in openshift to distinguish that metrics is of which instance.

Regards,

Sneha

[Brian Candler]

Prometheus adds "job" and "instance" labels to all scraped metrics.

Therefore, show some examples of your metrics once they have been stored in Prometheus: what is in the "instance" label? Does it not already distinguish them?

If not, then show your Prometheus scrape job configuration.

[sneha]

two instances are there but one of the instance get name from service in this case http, and other instance is without this name. unless i check with the target query i cant differentiate .

there are two parts one is service which looks like this 

apiVersion: v1

kind: Service

metadata:

    name: mysqld-exporter

    labels:

      app: mysqld-exporter

spec:

  type: ClusterIP

  ports:

   - port: 9104

     protocol: TCP

     name: http

  selector:

   app: mysqld-exporter

and other is service monitor which is like this 

apiVersion: monitoring.coreos.com/v1

kind: ServiceMonitor

metadata:

   name: mysqld-exporter

spec:

  endpoints:

    interval: 5s

    targetPort: 9104

namespaceSelector:

 matchNames:

  - default

selector:

  matchLabels:

   app: mysqld-exporter

[Brian Candler]

Please show what the metrics look like once scraped into Prometheus.

If you're only looking at "curl" output then you won't see these labels. They are added by Prometheus itself.

And if it still doesn't look right, show the actual Prometheus scrape job (i.e. from prometheus.yml; if that's built by some Kubernetes operator then show the file it builds)