Log docker container instance with promtail

Grafana Loki
1

Hi,

I want to log my caddy instance with promtail.

I was able to log all containers with this approach:
scrape_configs:

  - job_name: docker
    docker_sd_configs:
      - host: unix:///var/run/docker.sock
        refresh_interval: 5s
    relabel_configs:
      - source_labels: [__meta_docker_container_name]
        regex: '\/?(.*)'
        target_label: instance
    pipeline_stages:
      - docker: {}

But I was not able to scrape only one specific docker container with the instance name “caddy_caddy_1” in my case.

Where and how should I do this?

2

Do you see any log from the container when you do docker logs?

3

Yes, I can see the logs of all container with my approach.

So what I want to do is, only to focus on one container with the name caddy_caddy_1 instead of logging all instances

4

I see. You can use drop (drop | Grafana Loki documentation), and drop all logs that don’t match the container name.

5

This is not really working for me because we change our setup from time to time.

Why is the opposite way not possible? I would like to filter just for the containers which I am interested in?

6

Is my approach maybe completely wrong?

I guess this is a common task to obsorve logs from docker container nowadays.