Gauge
In plain terms
A metric representing a value that can go up or down.
Going deeper
A gauge measures a current value that fluctuates, like memory usage or temperature, capturing a snapshot in time. It can rise and fall.
Under the hood
Unlike a counter, it isn't monotonic; reflects instantaneous state.
Examples
Memory usage, active connections, temperature, queue depth, Prometheus.
Think of it like...
Like a fuel gauge showing the current level, rising and falling as you go.