How to use fluentd+elasticsearch+grafana to display the first 12 characters of the container ID?
Try something like this at the end of containers.input.conf:
<filter kubernetes.**> @type record_transformer enable_ruby <record> docker.container_id ${record["docker.container_id"][0,12]} </record></filter>
If it is okay to only store 12-character IDs, you can add a fluent filter parser (tested with Fluent Bit only):
parsers.conf
[PARSER] Name dockerid_parser Format regex Regex ^(?<container_id>.{12})fluent-docker.conf
[SERVICE] ... Parsers_File /full/path/to/parsers.conf...[FILTER] Name parser Match * Key_Name container_id Parser dockerid_parser Reserve_Data On...