Saturation-related Issues: Measure Memory Usage

Measure memory usage #

Measuring memory consumption is similar to CPU, and yet there are a few differences that we should take into account. But, before we get there, let’s go back to the Prometheus's graph screen and explore our first memory-related metric.

open "http://$PROM_ADDR/graph"

Just as with CPU, first we need to find out how much memory each of our nodes has.

Please type the expression that follows, press the Execute button, and switch to the Graph tab.

node_memory_MemTotal_bytes

Your result is likely to be different than mine. In my case, each node has around 4GB of RAM.

Knowing how much RAM each node has is of no use without knowing how much RAM is currently available. We can get that info through the node_memory_MemAvailable_bytes metric.

Please type the expression that follows, and press the Execute button.

node_memory_MemAvailable_bytes

We can see the available memory on each of the nodes of the cluster. In my case (screenshot below), each has around 3GB of available RAM.