Issue: Enabling --enable-feature=auto-reload-config and --web.enable-remote-write-receiver for Prometheus 3.0

[msavdert]

Hello,

I am trying to use the latest features introduced in Prometheus 3.0. Specifically, I want to enable the --enable-feature=auto-reload-config feature and the --web.enable-remote-write-receiver parameter for accept remote write from Grafana Alloy agent. However, I am encountering difficulties in properly configuring these parameters in playbooks.

My Alloy agent error is below.

err="server returned HTTP status 404 Not Found: remote write receiver needs to be enabled with --web.enable-remote-write-receiver"

Thanks.

[M4jx]

I'm currently facing the same issue. It is not possible to set web.enable-remote-write-receiver via prometheus_config_flags_extra

Here is a snippet from my ansible playbook

  roles:
    - role: prometheus.prometheus.prometheus
      prometheus_version: "3.0.0"
      prometheus_web_listen_address: "0.0.0.0:9090"
      prometheus_config_flags_extra:
        { alertmanager.timeout: 4410s, web.enable-remote-write-receiver: true }

Executing sudo systemctl status prometheus.service yields the following.

 prometheus.service - Prometheus
     Loaded: loaded (/etc/systemd/system/prometheus.service; enabled; vendor preset: enabled)
     Active: active (running) since Mon 2024-11-25 16:09:17 UTC; 14min ago
   Main PID: 4517 (prometheus)
      Tasks: 8 (limit: 9478)
     Memory: 26.3M
        CPU: 1.672s
     CGroup: /system.slice/prometheus.service
             └─4517 /usr/local/bin/prometheus --storage.tsdb.path=/var/lib/prometheus --storage.tsdb.retention.time=30d --storage.tsdb.retention.size=0 --web.config.file=/etc/prometheus/web_config.yml --web.console.libraries=/etc/prometheus/console_libraries --web.console.templates=/etc/prometheus/consoles --web.listen-address=0.0.0.0:9090 --web.external-url= --alertmanager.timeout=4410s  --config.file=/etc/prometheus/prometheus.yml

As you can see alertmanager.timeout was set succcessfully, but not web.enable-remote-write-receiver.

Tested on:
v3.0.0 and v2.54.1

[ollie-nye]

We managed to get this to behave by setting the value to an empty string in the config:

roles:
    - role: prometheus.prometheus.prometheus
      prometheus_version: "3.0.0"
      prometheus_web_listen_address: "0.0.0.0:9090"
      prometheus_config_flags_extra:
        alertmanager.timeout: 4410s
        web.enable-remote-write-receiver: ""

Then it seemed to behave!