how to find MAX memory from docker stats?

Question

With docker stats you can see the memory usage of a container over time.

Is there a way to find what the highest value of memory usage was while running

Answer 1

I took a sampling script from here and aggregated data by @pl_rock. But be careful - the sort command only compares string values - so the results are usually wrong (but ok for me). Also mind that docker is sometimes reporting wrong numbers (ie. more allocated mem than physical RAM).

Here is the script:

#!/bin/bash

"$@" & # Run the given command line in the background.
pid=$!

echo "" > stats

while true; do
  sleep 1
  sample="$(ps -o rss= $pid 2> /dev/null)" || break

  docker stats --no-stream --format "{{.MemUsage}} {{.Name}} {{.Container}}" | awk '{ print strftime("%Y-%m-%d %H:%M:%S"), $0 }' >> stats
done

for containerid in `awk '/.+/ { print $7 }' stats | sort | uniq`
do
    grep "$containerid" stats | sort -r -k3 | tail -n 1
    # maybe: | sort -r -k3 -h | head -n 1
    # see comment below (didnt tested)
done