This monitor reports the number of executors "busy" with work, the "total" number of executors currently allowed to be live on the computer, and the number of executors "configured" on the node, e.g. 2/5/5.
The total and configured counts may temporarily differ, e.g. right after the configured executor count of a node is lowered while some of its executors are still busy.
Optionally, the counts can be colorized: blue when the node is fully idle, green when it has spare live executors, and red when more executors are busy than configured (an overcommitted node).
It never marks an agent offline.