alertmanager.url can not be an alias setup in /etc/hosts

[casertap]

Here is part of my docker-compose.yml

promalertmgr:
  build: promalertmgr/
  container_name: promalertmgr
  ports:
    - "9093:9093"
  expose:
    - "9093"
  command: "-config.file=/alertmanager.conf"
  env_file:
    - './.env'

prometheus:
  build: prometheus/
  container_name: prometheus
  links:
    - cadvisor
    - promalertmgr
    - streamapp
    - dashboardapp
    - analyzeapp
    - mongo
  ports:
    - "9090:9090"
  command: "-config.file=/etc/prometheus/prometheus.yml -alertmanager.url=http://192.168.99.100:9093"
  env_file:
    - './.env'

If I change this:

-alertmanager.url=http://192.168.99.100:9093

into this:

-alertmanager.url=promalertmgr:9093

It does not work anymore.

[casertap]

the alertmanager.url needs to be a public url. Meaning the url must be outside of the docker private network (it can not stay inside the private network of docker, using an alias will not work).
This can be a problem because the port 9093 is then open to anybody to see...

Someone interested in this issue?

[fabxc]

As in #164, there's nothing to be done on the Alertmanager side here.

[brancz]

@fuzzyami you need to include the protocol scheme in your url. alertmanager:9093 does not, you are likely looking for http://alertmanager:9093.

[fuzzyami]

@brancz - just figured it out. thanks though!
edit: for future readers - the error I encountered was
unsupported protocol scheme \"alertmanager\""

[AxelMonroyX]

I get the IP from docker inspect, replace it in a file and then run the prometheus container

docker run --name alert -p 9093 prom/alertmanager

ALERT_IP=$(docker inspect --format '{{ .NetworkSettings.IPAddress }}' alertmanagercontainer)
sed -i "s@ALERT_IP@${ALERT_IP}@g" prometheus.yml

docker run -v $PWD/prometheus.yml:/etc/prometheus/prometheus.yml -p 9090  --link alert:alert prom/prometheus

and my prometheus.yml looks like

alerting:
  alertmanagers:
  - static_configs:
    - targets:
       - ALERT_IP:9093