58 Zeilen
2,3 KiB
Markdown
58 Zeilen
2,3 KiB
Markdown
Logging in mailcow: dockerized consists of multiple stages, but is, after all, much more flexible and easier to integrate into a logging daemon than before.
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In Docker the containerized application (PID 1) writes its output to stdout. For real one-application containers this works just fine.
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Some containers log or stream to multiple destinations.
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No container will keep persistent logs in it. Containers are transient items!
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In the end, every line of logs will reach the Docker daemon - unfiltered.
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The **default logging driver is "json"**.
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### Filtered logs
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Some logs are filtered and written to Redis keys but also streamed to a Redis channel.
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The Redis channel is used to stream logs with failed authentication attempts to be read by fail2ban-mailcow.
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The Redis keys are persistent and will keep 10000 lines of logs for the web UI.
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This mechanism makes it possible to use whatever Docker logging driver you want to, without losing
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the ability to read logs from the UI or ban suspicious clients with fail2ban-mailcow.
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Redis keys will only hold logs from applications and filter out system messages (think of cron etc.).
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### Logging drivers
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Here is the good news: Since Docker has some great logging drivers, you can integrate mailcow: dockerized into your existing logging environment with ease.
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Docker logging drivers can now be implemented as plugins, next to Dockers integrated drivers.
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Logging driver plugins are available in Docker 17.05 and higher.
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Edit `docker-compose.yml` and append, for example, this block to use the "gelf" logging plugin:
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```
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logging:
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log_driver: "gelf"
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options:
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gelf-address: "udp://graylog:12201"
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gelf-tag: "mailcow-logs"
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```
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Linux users can also add or edit the Docker daemons configuration file `/etc/docker/daemon.json` to affect the global logging behavior. Windows users please have a look at the [docker documentation](https://docs.docker.com/engine/reference/commandline/dockerd//#windows-configuration-file):
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```
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{
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...
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"log-driver": "gelf",
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"log-opts": {
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"gelf-address": "udp://graylog:12201",
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"gelf-tag": "mailcow-logs"
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}
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...
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}
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```
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Restart the Docker daemon and run `docker-compose down && docker-compose up -d` to recreate the containers with the new logging driver.
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