Importer log messages are absent on Kibana

Problem

Importer log entries are absent in Kibana

Some of our importers produce log messages during failure handling that are sent to the importer.log file. One example is the GitHub Importer

Prior to GitLab.com switching to Kubernetes, the Omnibus log file at /var/log/gitlab/gitlab-rails/importer.log used to be available for search in the indexed data on Kibana. This appears to have regressed after we moved to using Kubernetes.

The logs are required for the GitLab Support team (and other teams) to diagnose unexpected issues with the use of our various importers.

Desired outcome

Importer log entries are searchable in Kibana

Acceptance criteria

Entries such as the code line here should be searchable on Kibana's GPRD indexes (Rails/Sidekiq)