Chapter 10. Collecting Metrics and Monitoring the Cluster

Let us change our traditional attitude to the construction of programs. Instead of imagining that our main task is to instruct a computer what to do, let us concentrate rather on explaining to human beings what we want a computer to do.                                                                                                                –Donald Knuth

We managed to add centralized logging to our cluster. Logs from any container running inside any of the nodes are shipped to a central location. They are stored in Elasticsearch and available through Kibana. However, the fact that we have easy access to all the logs does not mean that we have all the information we would need to debug a problem or prevent it from happening in the first place. We need to complement our logs with the rest of the information about the system. We need much more than what logs alone can provide.