Poor man’s processes monitor (bash & awk script)
Recently a member of the Romanian Ubuntu Community asked for a script to monitor the running processes on his server . He didn’t requested for anything fancy, just a small utility that will be able to detect a hanging application (a process that is “eating” more than 80% of the CPU for a long period of time) and then log the results .
I am no sysadmin, but I am sure there are a lot of dedicated open-source solutions for monitoring a server .Still the functionality he asked for can be easily achieved by combining bash and awk .
One of the things I like Linux for is the power of the shell and the full-control over the your system . You can write a script for every repeating task that arise as bash is easy to learn but of course, hard to master . More as an exercise for myself I’ve proposed the following solution :
#!/bin/bash
#DATE: Nov 5, 2010
#AUTHOR: nomemory
#Maximum memory for a process (%)
declare -i MEM_LIMIT=1
#Maximum CPU for a process (%)
declare -i CPU_LIMIT=1
#Loop sleep interval
declare -i SEC_INT=30
while true; do
ps aux | awk -v MEM_LIMIT=${MEM_LIMIT}
-v CPU_LIMIT=${CPU_LIMIT}
-v CDATE="`date`" '{
if ($3 > CPU_LIMIT) {
printf "%s [ %10s %d %40s ] CPU LIMIT EXCEED: %2.2f (MAX: %2.2f) n",
CDATE, $1, $2, $11, $3, CPU_LIMIT
}
if ($4 > MEM_LIMIT) {
printf "%s [ %10s %d %40s ] MEM LIMIT EXCEED: %2.2f (MAX: %2.2f) n",
CDATE, $1, $2, $11, $4, MEM_LIMIT
}
}'
sleep ${SEC_INT}
done
If you run this script the output will probably look similar to this one :
Mon Nov 8 00:01:08 EET 2010 [ andrei 1718 /opt/google/chrome/google-chrome ] MEM LIMIT EXCEED: 2.20 (MAX: 1.00) Mon Nov 8 00:01:08 EET 2010 [ andrei 1726 pidgin ] MEM LIMIT EXCEED: 1.40 (MAX: 1.00) Mon Nov 8 00:01:08 EET 2010 [ andrei 1853 /opt/google/chrome/chrome ] CPU LIMIT EXCEED: 5.70 (MAX: 1.00) Mon Nov 8 00:01:08 EET 2010 [ andrei 1853 /opt/google/chrome/chrome ] MEM LIMIT EXCEED: 2.70 (MAX: 1.00) Mon Nov 8 00:01:08 EET 2010 [ andrei 2054 gnome-terminal ] CPU LIMIT EXCEED: 1.50 (MAX: 1.00) Mon Nov 8 00:01:08 EET 2010 [ andrei 2058 bash ] CPU LIMIT EXCEED: 1.70 (MAX: 1.00)