Fluentd Docker Metrics Input Plugin

This is a Fluentd plugin to collect Docker metrics periodically.

It's assumed to run on the host server. It periodically runs Docker Remote API calls to fetch container IDs and looks at /sys/fs/cgroups/<metric_type>/docker/<container_id>/ for relevant stats. You can say this is an implementation of the metric collection strategy outlined in this blog post.

to be uploaded on Rubygems

<source>
  type docker_metrics
  stats_interval 1m
</source>

• stats_interval: how often to poll Docker containers for stats. The default is every minute.
• cgroup_path: The path to cgroups pseudofiles. The default is sys/fs/cgroup.
• tag_prefix: The tag prefix. The default value is "docker"

2014-11-22 17:48:26 +0000 docker.blkio.io_queued: {"key":"blkio_io_queued_total","value":0,"type":"counter","hostname":"precise64","id":"24f5fb3bfc429e88aa3dbacd704667899dc496067cedcfa58dd84da42e7cb3cf","name":"/world"}
2014-11-22 17:48:26 +0000 docker.blkio.sectors: {"key":"blkio_sectors","value":136,"type":"counter","hostname":"precise64","id":"24f5fb3bfc429e88aa3dbacd704667899dc496067cedcfa58dd84da42e7cb3cf","name":"/world"}

In particular, each event is a key-value pair of individual metrics. Also, it has

• hostname is the hostname of the Docker host
• id is the ID of the container
• name is the descriptive name of the container (a la docker inspect --format '{{ .Names }}')