Prometheus scrape /metric with custom header
I have an application that will be monitored by Prometheus, but the application need the custom header key like :
x-auth-token: <customrandomtoken>
What should I do with prometheus.yml?
Solution 1:
Prometheus itself does not have a way to define custom headers in order to reach an exporter. The idea of adding the feature was discussed in this GitHub issue. Tl;dr: if you need a custom header, inject it with a forward or a reverse proxy.
The prometheus-blackbox-exporter
tag suggest that the question is about the exporter that makes probes, which is a separate thing and it does have a way to set headers. Only, it does not scrape metrics, it makes them.
Blackbox exporter has it's own configuration file and it consists of modules. A module is a set of parameters, defining how to do the probe and what result to expect. Here is an example of a module that looks for 200-299 response code and uses X-Auth-Token
header:
modules:
http_2xx_with_header:
prober: http
http:
headers:
X-Auth-Token: skdjfh98732hjf22exampletoken
More examples can be found here and the list of configuration options - here.
When you made the blackbox exporter to load the new configuration, you need to adjust Prometheus configuration as well:
scrape_configs:
- job_name: 'blackbox'
metrics_path: /probe
params:
module: [http_2xx_with_header] # <- Here goes the name of the new module
static_configs:
- targets:
- http://prometheus.io
relabel_configs:
- source_labels: [__address__]
target_label: __param_target
- source_labels: [__param_target]
target_label: instance
- target_label: __address__
replacement: 127.0.0.1:9115