prometheus health check

[lmzxqtom]

In the docker compose file, prometheus has a health check:

    healthcheck:
        test: ["CMD", "curl", "-f", "http://localhost:9090"]
        interval: 30s
        timeout: 10s
        retries: 5

Seems that this is run inside the docker contain, so prom/prometheus:v2.1.0 needs to have curl installed.