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• The functions for terminating task processes by for the JobScheduler Master and Universal Agent have been extended to allow the use of both SIGTERM and SIGKILL signals  on on Unix servers. This allows :
  • SIGTERM is sent first and allows an orderly termination of task processes to take place
  over
  • within a limited period of time.
  • If the time allowed has been exceeded and the processes are still running then SIGKILL will be sent.
• The information contained in this article draws together detailed information contained in a range of issues and should primarily be of interest to persons in engineering and to a lesser extent persons in operating functions.

Feature History

This feature has been implemented stepwise between release 1.9.0 and 1.10.0 (see the table of issues below for more detailed information).

Related Issues

Support of this feature is subject to the following issues:features:

• Jira
  server SOS JIRA columns key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution serverId 6dc67751-9d67-34cd-985b-194a8cdc9602 key JS-1495

• Jira
  server SOS JIRA columns key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution serverId 6dc67751-9d67-34cd-985b-194a8cdc9602 key JS-1468

• Jira
  server SOS JIRA columns key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution

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• serverId 6dc67751-9d67-34cd-985b-194a8cdc9602 key JS-1463

• Jira
  server SOS JIRA columns key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution serverId 6dc67751-9d67-34cd-985b-194a8cdc9602 key JS-1421

• Jira
  server SOS JIRA columns key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution serverId 6dc67751-9d67-34cd-985b-194a8cdc9602 key JS-1420

• Jira
  server SOS JIRA columns key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution serverId 6dc67751-9d67-34cd-985b-194a8cdc9602 key JS-1382

• Jira
  server SOS JIRA columns key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution serverId 6dc67751-9d67-34cd-985b-194a8cdc9602 key JS-1307

• Jira
  server SOS JIRA columns key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution serverId 6dc67751-9d67-34cd-985b-194a8cdc9602 key JS-1163

• Jira
  server SOS JIRA columns key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution

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• serverId 6dc67751-9d67-34cd-985b-194a8cdc9602 key JOC-10

Use Case

Users who schedule programs and scripts that are aware of SIGTERM signals can implement clean-up procedures on receipt of the signal. Clean-up includes e.g. removal of temporary files, disconnect from a database and similar tasks.

• The use of both SIGTERM and SIGKILL signals on Unix servers has the following advantages:

  • The use of SIGTERM before SIGKILL means that there is a greater chance of data being saved after the signal has been issued.

  • The SIGTERM signal can - in contrast with SIGKILL - be monitored, i.e. a prepost-/postprocessing processing Script can be carried out. This means that the ending of a task by the JobScheduler can be reacted to and the user process itself can be ended.

  • The implementation of SIGTERM allows post-processing methods such as spooler_process_after() to complete within the timeout period.

• The time allowed between the SIGTERM and the SIGKILL signal signals can be specified in the command using the timeout attribute (the default is 15 sec): <kill_task … timeout=".."/>

• This feature can also be applied for:
  • remote processes, i.e. processes started by SSH and those started by an Agent,
  • child processes started by a process running on an agent (

    Jira
    server SOS JIRA columns key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution serverId 6dc67751-9d67-34cd-985b-194a8cdc9602 key JS-1468

    ).

Implementation

JobScheduler Master

The following operations can be carried out from the JobScheduler Operating Center interface (JOC) or by use of the command line:

1. Operation: kill immediately
   • JOC sends <kill_task immediately="yes"/>
   • The process is killed immediately using the SIGKILL signal.
2. Operation: terminate with timeout
   • JOC sends <kill_task immediately="yes" timeout="15"/>
   • The process receives a SIGTERM signal. Should that process not terminate within the specified timeout period then it will be killed with a SIGKILL signal.
3. Operation: terminate
   • JOC sends <kill_task immediately="yes" timeout="never"/>
   • The process receives a SIGTERM signal. Monitoring of the process termination as described in Operation 2 above is not carried out.

See also

• Jira
  server SOS JIRA columns key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution serverId 6dc67751-9d67-34cd-985b-194a8cdc9602 key JOC-10

JobScheduler Universal Agent (JUA)

The JobScheduler Universal Agent comes with two scripts - for Windows and for Unix systems - that allow uses a script to monitor and kill parent and child tasks on the Agent to be killed.

The scripts are:

• jobscheduler_agent_kill_task.cmd and

• jobscheduler_agent_kill_task.sh

They are script is to be found  the ./bin folder of the JUA installation.

The appropriate script is called with the parameter -kill-agent-task-id=...  and

• finds the process containing that id
• kills the process including all children

The JUA start script starts the Agent with the new -kill-script parameter

• by default the -kill-script is parameterized with the path to the respective kill script for Windows/Unix.
• the environment variable SCHEDULER_KILL_SCRIPT can be used to set a different kill script.

script option can be  used to specify a different kill script if necessary. See the Command Line Options section in JobScheduler Universal Agent - Installation & Operation for more information.

See also

• Jira
  server SOS JIRA columns key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution serverId 6dc67751-9d67-34cd-985b-194a8cdc9602 key JS-1468

• Jira
  server SOS JIRA columns key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution serverId 6dc67751-9d67-34cd-985b-194a8cdc9602 key JS-1495

for more detailed information about the implementationSee  JS-1468 & JS-1495 for more detailed information.

Delimitation

• This feature is intended for Unix platforms that implement the SIGTERM and SIGKILL signals. It is not intended for Windows platforms for which exclusively the Kill kill Immediately command applies.
• When using traps then please consider that the process created by the <shell> the <script ... language="shell"/> element receives the signal. Subsequent scripts that are called within the <shell> <script ... language="shell"/> element will not receive the signal. You could therefore:
  • configure traps directly within the <shell> <script ... language="shell"/> element. The shell process will then receive and handle the signal.
  • configure traps in a shell script that is added by an <include> element instead of being stated within the <shell> the <script ... language="shell"/> element. The included shell script will receive and handle the signal.
  • forward signals to subsequent shell scripts that are called within a <shell> <script ... language="shell"/> element.

• This feature has been fully implemented on for the Universal Agent and It has been implemented for classic for the Classic JobScheduler Agents (JS-1420).

Workarounds

• Should job scripts not be able to catch signals by traps then you can use a monitor script, i.e. a post-processing script, that would be called by JobScheduler on receipt of a SIGTERM signal (JS-1463). For example:

  Code Block
  language xml title Workaround for shell jobs with a timeout
  <job name="shell_with_javascript_monitor"> <script language="shell"> <![CDATA[ echo hello world! sleep 45 ]]> </script> <monitor name="process0" ordering="0"> <script language="java:javascript"> <![CDATA[ function spooler_process_before(){ return true; } ]]> </script> </monitor> <run_time /> </job>

Examples

• Jira
  server SOS JIRA columns key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution serverId 6dc67751-9d67-34cd-985b-194a8cdc9602 key JS-1420

  ).

Implementation Summary

The implementation of the different termination operations available for the JobScheduler Master and Universal Agent is summarized in the table below.

The links lead to the issues relevant to the implementation of the feature.

The termination operations available are:

• Terminate: <kill_task immediately="true" timeout="...">
• Kill: <kill_task immediately="true">
• Timeout: a job with the timeout attribute.

	Windows Standalone	Linux Standalone	Windows Classic Agent	Linux Classic Agent	Windows Universal Agent	Linux Universal Agent
Shell job
Terminate	not supported		not supported	JS-1420	not supported
Kill				JS-1421	JS-1468	JS-1468
Timeout	JS-1463	JS-1463				JS-1468
Shell job with monitor
Terminate	not supported		not supported		not supported	JS-1468
Kill					JS-1382	JS-1468
Timeout						JS-1382
API job
Terminate	not supported		not supported		not supported
Kill
Timeout

Task Termination in JOC

The following screenshot shows how a task can be terminated using the Task menu in JOC's Task pane. This pane is shown in the Jobs tab when the task is running and the task can be terminated either with timeout or immediately.

Image Added

Examples

Using a SIGTERM trap to show the difference between the kill and terminate commands

Download the Example

job_trap_sigterm.job.xml.zip

Description

This example contains a job that uses a sigterm SIGTERM trap to show the difference between the <kill_task> and <terminate_task> commands provided by JOC.

...

<?xml version="1.0" encoding="ISO-8859-1"?>
<job  title="test test">
    <script  language="shell">
        <![CDATA[
trap 'echo sigterm will be ignored' 15
for i in 1 2 3 4 5 6 7 8 9 0
do
date
sleep 10
done
sleep 60
        ]]>
    </script>

    <run_time />
</job>

Change Management References

References

• JobScheduler Reference Documentation:
  • the <kill_task> XML command

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