I am wondering if we can stop a Single JVM within specific time limit. If it is not stopping within that time limit then kill the process from shell script.
If we are executing ./stopServer.sh JVM_Name - It will run till the jvm will not get stopped or till any error and exit.
What I am trying to do is :./stopServer.sh JVM_Name - If this do not stopped within 2 min(suppose), then kill the process (But How to figure out it is not stopped within 2 mins through shell script before the process go for killing). I can write the condition to kill . But not sure how to do checks if the JVM stopped within 2 mins or not so that we can go ahead to kill process.
Can anyone please suggest shell script code to identify if the jvm is stopped within specific time limit or not?
A JVM is a process and as such can be stopped with the kill command - kill $processid or more brutal kill -9 $processid
If you start the JVM from a script using something like java ... then I suggest putting a & at the end of that line and in the following line
processid=$!
which saves the id of the background process.
Then
sleep 120
will wait for 2 min.
Now you have two options - either just kill
kill $processid /dev/null 2>&1
or first check if the processid might (very unlikely) be reused by another process (or use some other way to check if your JVM has finished, maybe a file that indicates this from your java program) and then if it matches use the kill.
ps -ef|grep -w $processid |grep -w java > /dev/null
If it has returncode zero then continue with the kill
test $? -eq 0 && kill $processid
I usually would trust that the processid is either my JVM or not used at all
Related
I've turned a program I wrote into a service, and I have a bash script that runs to start up the actual program, since there are things that have to be started in a particular order. The contents of the startup script (called with start-stop-daemon from the init.d script look like :
./rfid_reader &
sleep 2
java ReaderClass &
This works fine, but how do I go about killing them when it comes time to stop the process?
I've seen pidfiles used, do I just get the PIDs of the two programs, write them to a file, and then kill them when it comes time to shut them down, or do I have to ps -ef | grep program to get their PIDs?
I don't think killall is a good idea to do this. You'd better to record the PID of the program started in background in some file(e.g. PID_FILE) and then kill $(<$PID_FILE) to stop it.
Please refer to this thread for how to get the PID the previous started background program.
Assuming you know the name of your program, you can kill them as below :
killall -KILL program_name
I'm trying to write a script that runs a java program "Loop", and then after 5 seconds, terminates that java program, however, it's not terminating the program when I use the "pkill" option, I'm sorry for asking such a basic question, and I have looked around the internet, but I can't find a solution. Here is my code:
#!/bin/bash
javac Loop.java
java Loop
sleep 5
pkill -n java
When I run the command pkill -n java from the terminal, as opposed to in a script, it does as I expected, why is this?
Your bash script is waiting for java to complete so you'll need to run it as a background process which will start your Loop code and then return immediately, allowing the rest of your script to run:
java Loop &
More information: http://tldp.org/LDP/abs/html/x9644.html
Since you run java Loop in foreground, the next line sleep 5 doesn't get executed until your JVM exits (which is probably never, if Loop is actually an infinite loop).
So you need to start that in background:
java Loop &
Also, for killing that specific background job (rather than killing the newest JVM), you can do:
kill $!
I have written a script to initiate multi-processing
for i in `seq 1 $1`
do
/usr/bin/php index.php name&
done
wait
A cron run every min - myscript.sh 3 now three background process get initiated and after some time I see list of process via ps command. I see all the processes are together in "Sleep" or "Running" mode...Now I wanted to achieve that when one goes to sleep other processes must process..how can I achieve it?. Or this is normal.
This is normal. A program that can run will be given time by the operating system... when possible. If all three are sleeping, then the system is most likely busy and time is being given to other processes.
On a linux box, I have at most 3 java jars files running. How do I quickly kill all 3 with one command?
Usually I would:
ps ex - get the processes running
then find the process ids then do:
kill -9 #### #### ####
Any way to shorten this process? My eyes hurts from squinting to find the process ids.
My script does the following:
nohup ./start-gossip &
nohup ./start &
nohup ./start-admin &
Is there a way to get the process ids of each without looking it up?
Short answer:
pkill java
This looks up a process (or processes) to kill by name. This will find any other java processes too, so be careful. It also accepts -9, but you should avoid using -9 unless something is really broken.
EDIT:
Based on updates, you may be able to specify the script names to pkill as well (I'm not positive). But, the more traditional way to handle this issue is to leave pid files around. After you start a new process and background it, its pid is available in $!. If you write that pid to a file, then it's easy to check if the process is still running and kill just the processes you mean to. There is some chance that the pid will be reused, however.
You can save the PIDs when you start the processes so you can use them later:
nohup ./start-gossip &
START_GOSSIP_PID=$!
nohup ./start &
START_PID=$!
nohup ./start-admin &
START_ADMIN_PID=$!
...
kill -9 $START_GOSSIP_PID
kill -9 $START_PID
kill -9 $START_ADMIN_PID
This has the advantage (over pkill) of not killing off any other processes that coincidentally have similar names. If you don't want to perform the kill operation from the script itself, but just want to have the PIDs handy, write them to a file (from the script):
echo $START_GOSSIP_PID > /some/path/start_gossip.pid
Or even just do this when you launch the process, rather than saving the PID to a variable:
nohup ./start-gossip &
echo $! > /some/path/start_gossip.pid
To get the process id of that java process run
netstat -tuplen
Process ID (PID) of that process whom you want to kill and run
kill -9 PID
I know I can start the process with cron, but how would I go about stopping it? I thought about starting a new process1 everyday at 00:00, then at 23:59 I'd start a process2 doing ps -aux | grep process1, getting the pid from the line and then killing it, but I was wondering if there's be a better way to do it.
I could use Python or Java too if it's easier with either language.
Record its PID:
nohup my_service &
echo $! > /var/run/my_service.pid
and then kill by that PID.
You might want to check both PID and process name to make sure that during the day the process did not crash and some other process did not get that PID. (And even better idea would be to set up supervisor.) But if you are sure that there are no other process with that name you can simply use pkill or killall.