Help scripting to start, check, and restart processes
Here it goes from my unexperienced point of view. I am using CentOS 5.6. I have a Java based server that needs to be running 24/7/365. To begin from the machine the server is on rebooting; I SSH in to a shell, cd to the server dir, screen -S server1, and execute ./exec (listed below) in the screen. This runs the Java server and restarts the it's process if/when stopped.
exec
I would like to automate this starting process with a script using a crontab job. This script(s) would need to do what I do manually to start the server, perform checks to make sure the 3 processes are always running (screen, exec, java) and be able to restart them in their appropriate environment (command line or screen).
I have tried the psybnc psybncchk script with some adjustments to try and do some of this, but my knowledge of scripting is very minimal.
cbchk
When I kill all of the processes, then run the above script, the shell screen gets spammed with arrows and the server's starting info displays inside the never ending arrows. When I attach to the screen, Java is continually stating errors nonstop. I've also tried adding " & echo $! > cb.pid" after the ./exec to automate getting the PID, but that makes the screen unusable for some reason.
While exec is running, it's keeping the Java server running, but when all of the processes are killed, I'm not sure how to script the starting sequence and have it make sure everything stays running. Any and all help will be greatly appreciated. Thank you.
hi all
How can I make a program start up automatically after the computer restart/startup in fedora?
something like:
... Establish a shell then run some of command code.
Thanks for Help!! (1 Reply)
I need a shell script to kill apache and restart it, in case the number of processes keeps growing. The logic is like the below, but I don't know how to get the number and neither the syntax. Could somebody kindly help?
if no_of_processes (ps ax ¦ grep httpd) > 200
then
killall httpd... (14 Replies)
I'm wondering how I should make a script that can start, stop, and restart another script.
What I need to be able to do, is start and stop a perl script from the command line. The easiest way of doing this seems to be to have another script, starting and stopping the other script. I have BASH,... (7 Replies)
Hi All,
is there a way or script that i can check my AIX 5.3 OS will restart before i made restart? is there a script that can check all the startup files are ok before restarting. it is because i was stuck last time when i restart my PC because some startup files were missing:o. (2 Replies)
Please anyone tell me
In my last interview the HR asks me how to monitor, start,stop & kill the various processes and subprocesses.
Please anyone explain me clearly. It's my personal request (3 Replies)
Is there any functional difference between:
issuing separate stop/start commands like this;
super (handler) (instance) stop
super (handler) (instance) start
versus issuing a single recycle command like this;
super (handler) (instance) restart (3 Replies)
Hi all
I have networker running on a RHEL 5.7 and over time it hangs. So the solution backup team proposed is to check if the process is hung, to stop and start it.
Unfortunately for me, the rc script only allows three commands, start, stop and status (no restart option) so I managed to set... (15 Replies)
Hello,
I'l like to create a script that restart a service (/etc/init.d/httpd restart) and also check if after restart the service is actually running. Sometimes it happen that at the first try the service fails to restart.
Thanks (2 Replies)
Discussion started by: bazzola
2 Replies
LEARN ABOUT SUNOS
wait
wait(1) User Commands wait(1)NAME
wait - await process completion
SYNOPSIS
/bin/sh
wait [pid...]
/bin/jsh /bin/ksh /usr/xpg4/bin/sh
wait [pid...]
wait [ % jobid...]
/bin/csh
wait
DESCRIPTION
The shell itself executes wait, without creating a new process. If you get the error message cannot fork,too many processes, try using the
wait command to clean up your background processes. If this doesn't help, the system process table is probably full or you have too many
active foreground processes. There is a limit to the number of process IDs associated with your login, and to the number the system can
keep track of.
Not all the processes of a pipeline with three or more stages are children of the shell, and thus cannot be waited for.
/bin/sh, /bin/jsh
Wait for your background process whose process ID is pid and report its termination status. If pid is omitted, all your shell's currently
active background processes are waited for and the return code will be 0. The wait utility accepts a job identifier, when Job Control is
enabled (jsh), and the argument, jobid, is preceded by a percent sign (%).
If pid is not an active process ID, the wait utility will return immediately and the return code will be 0.
csh
Wait for your background processes.
ksh
When an asynchronous list is started by the shell, the process ID of the last command in each element of the asynchronous list becomes
known in the current shell execution environment.
If the wait utility is invoked with no operands, it will wait until all process IDs known to the invoking shell have terminated and exit
with an exit status of 0.
If one or more pid or jobid operands are specified that represent known process IDs (or jobids), the wait utility will wait until all of
them have terminated. If one or more pid or jobid operands are specified that represent unknown process IDs (or jobids), wait will treat
them as if they were known process IDs (or jobids) that exited with exit status 127. The exit status returned by the wait utility will be
the exit status of the process requested by the last pid or jobid operand.
The known process IDs are applicable only for invocations of wait in the current shell execution environment.
OPERANDS
The following operands are supported:
One of the following:
pid The unsigned decimal integer process ID of a command, for which the utility is to wait for the termination.
jobid A job control job ID that identifies a background process group to be waited for. The job control job ID notation is applicable
only for invocations of wait in the current shell execution environment, and only on systems supporting the job control option.
USAGE
On most implementations, wait is a shell built-in. If it is called in a subshell or separate utility execution environment, such as one of
the following,
(wait)
nohup wait ...
find . -exec wait ... ;
it will return immediately because there will be no known process IDs to wait for in those environments.
EXAMPLES
Example 1: Using A Script To Identify The Termination Signal
Although the exact value used when a process is terminated by a signal is unspecified, if it is known that a signal terminated a process, a
script can still reliably figure out which signal is using kill, as shown by the following (/bin/ksh and /usr/xpg4/bin/sh):
sleep 1000&
pid=$!
kill -kill $pid
wait $pid
echo $pid was terminated by a SIG$(kill -l $(($?-128))) signal.
Example 2: Returning The Exit Status Of A Process
If the following sequence of commands is run in less than 31 seconds (/bin/ksh and /usr/xpg4/bin/sh):
sleep 257 | sleep 31 &
jobs -l %%
then either of the following commands will return the exit status of the second sleep in the pipeline:
wait <pid of sleep 31>
wait %%
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment variables that affect the execution of wait: LANG, LC_ALL, LC_CTYPE, LC_MES-
SAGES, and NLSPATH.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
SEE ALSO csh(1), jobs(1), ksh(1), sh(1), attributes(5), environ(5), standards(5)SunOS 5.10 12 Dec 1997 wait(1)