URL

https://docs.redhat.com/en/documentation/red_hat_openshift_logging/6.2/html/installing_logging/installing-logging

https://docs.redhat.com/en/documentation/red_hat_openshift_logging/6.2/html/upgrading_logging/index 

ISSUE

The Logging stack has different component: Log Collector, Log Store and Visualization. The 3 components are not mandatory to have them installed as:

1. An admin could desire to have only deployed the Red Hat Log Collector to log forward logs to a destination managed not being the Red Logging Log Store
2.  An admin could desire to collect the logs with the Red Hat Log Collector and store the data in the Red Hat Log Store, but not having the visualization provided by Red Hat and deploy their own log visualization
3. An admin could desire to have deployed the full Red Hat Logging stack that include: Log collector, Log store and Visualization 

As it's now documented, it seems that all the components are required/mandatory and this leads to:
1. Install the full Red Hat Logging stack when it's only forwarded the logs to a end-user application and not to the Red Hat Logging Store using a lot of not needed resources
2. Frequent questions through the different channels: support cases, etc about if it's really needed to have the full stack.

Then, it's required to have an installation and upgrade guide where it makes clear that not required all the components and depending on the different use case, you can deploy only the components required for that specific use case.