All contaniers forwards all its logs to stdout (best practice in container world). K8s will store the stdout as a local file per container on each k8s node - these files rotates and the logs are truncated after a while. To make the full logs accessable a fluentd containers monitors all changes in the stdout files and forwards the logs information to an ElasticSearch db for persistent storage. To view the log information in the ElasticSearch DB a Kibana client can be used. The receiving end can be an application that just writes the logs to a persistent storage as text files.