We explored several products that can be used to centralize logging. As you saw, all are very similar, and we can assume that most of the other solutions follow the same principles. We need to collect logs across the cluster. We used Fluentd for that, which is the most widely accepted solution that you will likely use no matter which database receives those logs (Azure being an exception).
Log entries collected with Fluentd are shipped to a database which, in our case, is Papertrail, Elasticsearch, or one of the solutions provided by hosting vendors. Finally, all solutions offer a UI that allows us to explore the logs.
I usually provide a single solution for a problem but, in this case, there are quite a few candidates for your need for centralized logging. Which one should you choose? Will it be Papertrail, Elasticsearch-Fluentd...