Great question! The issue with your initial symlink approach is likely that InfluxDB isn't actually writing logs to /var/log/influx.log or /var/log/error.log by default—its default logging behavior sends output to stdout/stderr (which is why you can see logs via docker logs), so those symlinks weren't being used at all. Let's walk through a few reliable ways to get InfluxDB logs into /var/log/file.log on your host.

1. Configure InfluxDB to write logs directly to a mounted file (Recommended) #

This method leverages InfluxDB's native logging configuration, ensuring all logs (including those that might not go to stdout/stderr) are captured in your target file.

• Create/modify an InfluxDB config file
  First, grab the default config from the container:

  docker run --rm influxdb:latest cat /etc/influxdb/influxdb.conf > ./influxdb.conf
  

  Then edit the [logging] section to specify a log file path inside the container:

  [logging]
    level = "info"  # Adjust log level as needed: debug, info, warn, error, fatal
    file.path = "/var/log/influxdb/file.log"  # Path inside the container
    format = "auto"  # Keep default or set to "json" for structured logs
  

• Prepare the host log file and set permissions
  InfluxDB runs as the influxdb user (UID 1000 by default) inside the container, so ensure the host file has the right permissions:

  touch /var/log/file.log
  chown 1000:1000 /var/log/file.log
  

• Run the container with mounted volumes
  Mount your custom config and the host log file to the container path you specified:

  docker run -d \
    --name influxdb \
    -v ./influxdb.conf:/etc/influxdb/influxdb.conf \
    -v /var/log/file.log:/var/log/influxdb/file.log \
    influxdb:latest -config /etc/influxdb/influxdb.conf
  

  Now all InfluxDB logs will be written directly to /var/log/file.log on your host.

2. Redirect container stdout/stderr to the host file #

If you don't want to modify InfluxDB's config, you can directly redirect the container's stdout and stderr streams to your host file when starting the container.

Use this command to append logs (instead of overwriting) to /var/log/file.log:

docker run -d \
  --name influxdb \
  influxdb:latest >> /var/log/file.log 2>&1

⚠️ Note: This method only captures logs that InfluxDB sends to stdout/stderr. Some internal logs might not be included, and if you restart the container, you'll need to reapply the redirection (or use a process manager like systemd to handle this persistently).

3. Use Docker's logging driver with log rotation #

If you want to keep using docker logs but also have logs saved to a file with automatic rotation, configure Docker's local logging driver.

• Create or edit /etc/docker/daemon.json:

  {
    "log-driver": "local",
    "log-opts": {
      "max-size": "10m",
      "max-file": "5",
      "path": "/var/log/docker"
    }
  }
  

• Restart Docker to apply the changes:

  systemctl restart docker
  

  Now all container logs (including InfluxDB) will be stored in /var/log/docker with rotation. You can still use docker logs influxdb to view logs, or directly access the log files in the specified directory.

Why your initial symlink method didn't work #

InfluxDB doesn't write logs to /var/log/influx.log or /var/log/error.log out of the box. By default, it sends all logs to stdout and stderr, which Docker captures and stores in its own log system (hence why docker logs works). Your symlinks were pointing to /dev/stdout and /dev/stderr, but since InfluxDB wasn't using those files, the symlinks had no effect.

内容的提问来源于stack exchange，提问作者Prasoon