I can use ‘–storage.local.memory-chunks’ to limit the memory usage when prometheus 1.X.
Prometheus 2.0 uses the OS page cache for data. It will only use as much memory as it needs to operate. The good news is the memory use is far efficient than 1.x. The amount needed to collect more data is minimal.
There is some extra memory needed if you do a large amount of queries, or queries that require a large amount of data.
You will want to monitor the memory use of the Prometheus process (process_resident_memory_bytes) and how much page cache the node has left (node_exporter, node_memory_Cached).