641c79c902
Adds "helm-toolkit.utils.merge" which is a replacement for the upstream sprig "merge" function which didn't quite do what we wanted, specifically it didn't merge slices, it just overrode one with the other. This PS also updates existing callsites of the sprig merge with "helm-toolkit.utils.merge". Change-Id: I456349558d4cf941d1bcb07fc76d0688b0a10782
Fluentd-logging
OpenStack-Helm defines a centralized logging mechanism to provide insight into the the state of the OpenStack services and infrastructure components as well as underlying kubernetes platform. Among the requirements for a logging platform, where log data can come from and where log data need to be delivered are very variable. To support various logging scenarios, OpenStack-Helm should provide a flexible mechanism to meet with certain operation needs. This chart proposes fast and lightweight log forwarder and full featured log aggregator complementing each other providing a flexible and reliable solution. Especially, Fluent-bit is proposed as a log forwarder and Fluentd is proposed as a main log aggregator and processor.
Mechanism
Fluent-bit, Fluentd meet OpenStack-Helm's logging requirements for gathering, aggregating, and delivering of logged events. Flunt-bit runs as a daemonset on each node and mounts the /var/lib/docker/containers directory. The Docker container runtime engine directs events posted to stdout and stderr to this directory on the host. Fluent-bit then forward the contents of that directory to Fluentd. Fluentd runs as deployment at the designated nodes and expose service for Fluent-bit to foward logs. Fluentd should then apply the Logstash format to the logs. Fluentd can also write kubernetes and OpenStack metadata to the logs. Fluentd will then forward the results to Elasticsearch and to optionally kafka. Elasticsearch indexes the logs in a logstash-* index by default. kafka stores the logs in a 'logs' topic by default. Any external tool can then consume the 'logs' topic.