Generate memory dumps for docker container processes

dump_docker_memory.sh

#!/usr/bin/env bash
#
# Generate core dumps of docker container processes
#
# Usage:
#  ./dump_docker_memory.sh [containerid]
#
# Output directory will be created in /tmp
#

set -eo pipefail

containerid=$1
if [[ "$containerid" = "" ]]; then
	echo "Usage: $0 [containerid]"
	exit 1
fi

dir="/tmp/${containerid}"
mkdir -p "${dir}"
rm -f $dir/core.*
pushd $dir

echo
echo "Finding process ID for ${containerid}..."
pid=$(docker inspect "${containerid}" | grep '"Pid"' | head -n1 | awk -F':' '{print $2}' | sed 's/[^0-9]//g')

if [[ "$pid" = "0" ]]; then
	echo "Container ${containerid} is not running."
	exit 1
fi

echo
echo "Looking for child processes..."
children=$(pstree -p $pid | awk -F'}' '{print $2}' | sed 's/[^0-9]*//g')

for child in $children; do
	echo
	echo "Dumping for pid ${child}..."
	gcore $child
done

echo
echo "Dumps are available in ${dir}:"
ls -la ${dir}/core.*
echo