Soon with the application lifetime feature (https://issues.apache.org/jira/browse/YARN-3813) you wouldn't have to write such scripts. You would simply set lifetime of the app to 20 mins during creation and it would kill itself on the 20th min mark.
Until then, something like this script might help (assuming you have access to yarn command line). This script can be easily enhanced to run as a cronjob if required, where say it will trigger every 1 min and look for specific apps which has crossed certain lifetime and kill them.
Hope this helps -
#!/bin/bash
if [ "$#" -lt 2 ]; then
echo "Usage: $0 <app_id> <max_life_in_mins>"
exit 1
fi
finish_time=`yarn application -status $1 2>/dev/null | grep "Finish-Time" | awk '{print $NF}'`
if [ $finish_time -ne 0 ]; then
echo "App $1 is not running"
exit 1
fi
time_diff=`date +%s`-`yarn application -status $1 2>/dev/null | grep "Start-Time" | awk '{print $NF}' | sed 's!$!/1000!'`
time_diff_in_mins=`echo "("$time_diff")/60" | bc`
echo "App $1 is running for $time_diff_in_mins min(s)"
if [ $time_diff_in_mins -gt $2 ]; then
echo "Killing app $1"
echo yarn application -kill $1
else
echo "App $1 should continue to run"
fi
