Filebeat container does not send logs to Elastic - docker

Question

On my local machine running Ubuntu 18.04 via "Windows Subsystem Linux 2" on Windows 10, I am running Elastic 7.3, Kibana 7.3 and Elastic 7.3 docker containers.
Set-up is successful and Filebeat seems to monitor containers correctly. However, Kibana does not show any logs.
Setup
To set-up Elastic and Kibana I use the following commands
docker pull docker.elastic.co/elasticsearch/elasticsearch:7.3.1
docker run --network=lognetwork --name=elasticsearch -p 9200:9200 -p 9300:9300 -e "discovery.type=single-node" docker.elastic.co/elasticsearch/elasticsearch:7.3.1
docker pull docker.elastic.co/kibana/kibana:7.3.1
docker run --name=kibana --network=lognetwork -e ELASTICSEARCH_HOSTS=http://elasticsearch:9200 -p 5601:5601 docker.elastic.co/kibana/kibana:7.3.1
After these two commands, the logs from Kibana container show it successfully connects to Elastic:
{"type":"log","#timestamp":"2019-09-01T13:22:18Z","tags":["status","plugin:spaces#7.3.1","info"],"pid":6,"state":"green","message":"Status changed from yellow to green - Ready","prevState":"yellow","prevMsg":"Waiting for Elasticsearch"}
I can also go to Kibana dashboard on http://localhost:5601 as well as Elastic on http://localhost:9200 both function properly
I then set up filebeat:
docker run --network=lognetwork docker.elastic.co/beats/filebeat:7.3.1 setup -E setup.kibana.host=kibana:5601 -E output.elasticsearch.hosts=["elasticsearch:9200"]
I can see both Elastic and Kibana container logs and returning 200. The logs on the Filebeat container show:
Index setup finished.
Loading dashboards (Kibana must be running and reachable)
Loaded dashboards
Loaded machine learning job configurations
Loaded Ingest pipelines
Finally, I pull the default config from Elastic site, launch Filebeat and attach to the container
curl -L -O https://raw.githubusercontent.com/elastic/beats/7.3/deploy/docker/filebeat.docker.yml
docker run -d --network=lognetwork --name=filebeat --user=root --volume="$(pwd)/filebeat.docker.yml:/usr/share/filebeat/filebeat.yml:ro" --volume="/var/lib/docker/containers:/var/lib/docker/containers:ro" --volume="/var/run/docker.sock:/var/run/docker.sock:ro" docker.elastic.co/beats/filebeat:7.3.1 filebeat -e -strict.perms=false -E output.elasticsearch.hosts=["elasticsearch:9200"]
docker attach filebeat
I can see Filebeat sending monitoring pulse but when it does, elastic logs do not show anything new.
To test, I launch Docker "hello-world" which generates several lines of logs
docker run hello-world
Filebeat shows the following log
2019-09-01T13:30:40.624Z INFO log/input.go:148 Configured paths: [/var/lib/docker/containers/460cc8c215ff69ecf28685c9cf89c0e56d0b3e4f680b8bf29beb5b570ebb7a14/*-json.log]
2019-09-01T13:30:40.624Z INFO input/input.go:114 Starting input of type: container; ID: 16402101064670842079
I then go to http://localhost:5601
Results:
Kibana shows no logs. Clicking for "check for new data" does not show anything either.
The folder /var/lib/docker/containers is also empty. The path returned by filebeat log (/var/lib/docker/containers/460cc8c215ff69ecf28685c9cf89c0e56d0b3e4f680b8bf29beb5b570ebb7a14/) does not seem to exist.
Expected:
- Kibana to show the "hello world" docker container logs
- To see a log file under /var/lib/docker/containers
What am I missing?
Thank you,
Olivier

Answer 1

Well, it took me many hours before asking on SO, and of course, 30mn after asking I found the answer.
The trick was to check where the logs were created as running Docker-Desktop on WSL2 is slightly different than running Docker on Linux.
docker inspect filebeat | grep LogPath
returns:
"LogPath": "/var/data/docker-desktop/default/daemon-data/containers/fd56c5e43c9206baaadd33d3a711e523107622450d0deafb498e7940d809f779/fd56c5e43c9206baaadd33d3a711e523107622450d0deafb498e7940d809f779-json.log
Then changing the volume map accordingly volume="/var/data/docker-desktop/default/daemon-data/containers:/var/lib/docker/containers:ro" when launching filebeat did the job:
docker run -d
--network=lognetwork
--name=filebeat
--user=root
--volume="$(pwd)/filebeat.docker.yml:/usr/share/filebeat/filebeat.yml:ro"
--volume="/var/data/docker-desktop/default/daemon-data/containers:/var/lib/docker/containers:ro"
--volume="/var/run/docker.sock:/var/run/docker.sock:ro"
docker.elastic.co/beats/filebeat:7.3.1 filebeat -e -strict.perms=false -E output.elasticsearch.hosts=["elasticsearch:9200"]
The logs are now properly shown on kibana

Answer 2

In my case :
Docker desktop installed in Windows 10 + WSL2 enabled in docker.
I was trying to use file beat to collect logs of all docker containers.
ELK + Filebeat were also running as docker containers.
The pipeline: Filebeat -> logstash -> elastic search -> kibana
Problem: Filebeat was not finding logs from docker. But from a local mounted folder it was sending logs to ELK and was showing up in kibana.
Solution: I was running docker-compose up from wsl bash shell. Instead I ran the same from windows powershell, or cmd and the logs from docker containers started to appear in kibana.
In docker-compose file:
filebeat:
volumes:
- /var/run/docker.sock:/var/run/docker.sock
- /var/lib/docker:/var/lib/docker
- ./MYLOG_TEST:/usr/share/filebeat/mylog
- ./MY_filebeat.yml:/usr/share/filebeat/filebeat.yml
and in MY_filebeat.yml:
filebeat.inputs:
#for docker logs
- type: container # for older filestream version use docker as type
enabled: true
paths:
- /var/lib/docker/containers/**/*.log
#for my test log files
- type: log # for filebeat latest versions8.1+, use filestream as type
enabled: true
paths:
- /usr/share/filebeat/mylog/*.log