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Collect logs from Docker and Docker Compose containers with the OpenTelemetry Collector, reading the files written by Docker’s default json-file logging driver. The same Collector can also forward traces and metrics from your apps — see Connect OpenTelemetry Collector to Bronto.

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Prerequisites

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Run the Collector

Add the Collector to your docker-compose.yml and give it read access to Docker’s container log directory:
docker-compose.yml
services:
  otel-collector:
    image: otel/opentelemetry-collector-contrib:latest
    command: ["--config=/etc/otel/config.yaml"]
    volumes:
      - ./otel-config.yaml:/etc/otel/config.yaml:ro
      - /var/lib/docker/containers:/var/lib/docker/containers:ro
The Collector tails the container logs, unwraps Docker’s JSON envelope, and ships to Bronto:
otel-config.yaml
receivers:
  filelog/docker:
    include:
      - /var/lib/docker/containers/*/*-json.log
    operators:
      - type: json_parser
    resource:
      service.name: <YOUR_DATASET_NAME>
      service.namespace: <YOUR_COLLECTION_NAME>

processors:
  batch:

exporters:
  otlphttp/brontologs:
    logs_endpoint: "https://ingestion.<REGION>.bronto.io/v1/logs"
    compression: gzip
    headers:
      x-bronto-api-key: <YOUR_API_KEY>

service:
  pipelines:
    logs:
      receivers: [filelog/docker]
      processors: [batch]
      exporters: [otlphttp/brontologs]
Set <REGION> to eu or us.

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What you will see in Bronto

Open Search and filter by service.name. Docker’s json-file driver wraps each line as {"log": "...", "stream": "stdout|stderr", "time": "..."}; the json_parser operator promotes those into fields, so you get the container’s message, the stream, and a timestamp. Bronto’s Custom Parser extracts further structure from the message body.

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Troubleshooting

  • No logs? Confirm the driver is json-file (docker inspect -f '{{.HostConfig.LogConfig.Type}}' <container>) and that the Collector mounts /var/lib/docker/containers read-only.
  • Per-service datasets? Run one Collector centrally with a service.name per environment, or route by container labels with an attributes processor.
  • For general issues, see OTel Collector troubleshooting.

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Alternative: Fluent Bit

If you already run Fluent Bit, tail the container log files and forward them over HTTP. The docker multiline parser reassembles partial lines from the json-file driver:
fluent-bit.conf
[INPUT]
    name              tail
    path              /var/lib/docker/containers/*/*-json.log
    multiline.parser  docker
    tag               docker

[OUTPUT]
    name        http
    match       docker
    host        ingestion.<REGION>.bronto.io
    port        443
    tls         on
    format      json_lines
    compress    gzip
    header      x-bronto-api-key    <YOUR_API_KEY>
    header      x-bronto-dataset    <YOUR_DATASET_NAME>
    header      x-bronto-collection <YOUR_COLLECTION_NAME>
Set Format to json_lines, not json. You can also point Docker’s native fluentd logging driver at Fluent Bit. See Connect Fluent Bit to Bronto for installation.