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).
Optionally, the column can also report the number of buildable queue items that this node could take (not necessarily exclusively -- another suitable node might pick one up first), appended as e.g. 3/3/2 q:5 and reflected in the column name as "/queued". When colorizing is also enabled, this queue count is blue when empty, green while it does not exceed the configured executor count, uncolored while it does not exceed the configured executor count times a configurable factor N (an integer greater than 1, default 5), and red beyond that.
It never marks an agent offline.