Search <book_title>...

Cluster Server 7.3.1 Bundled Agents Reference Guide - Linux

Last Published: 2019-06-14

Product(s): InfoScale & Storage Foundation (7.3.1)

Platform: Linux

Requirement for systemd support

In case of the RHEL 7, SLES 12, and later distributions, you can start applications in system.slice instead of user.slice. To do so, you must create a unit service file for your application under /etc/systemd/system/. The unit service file name must adhere to the system naming standard and must be unique.

Note:

You must reload the systemd daemon after you change the unit configuration as follows:

systemctl --system daemon-reload

A sample unit service file configuration for the Application agent follows:

Unit service file name:

/etc/systemd/system/vcs-app1.service

Unit service file contents option 1:

[Unit]
Description=Veritas Application service file
Before=vcs.service

[Service]
Type=forking
Restart=no 
KillMode=none
ExecStart=appStartCommand >/dev/null 2>&1 </dev/null
User=john

where, appStartCommand is the command to start the application.

Unit service file contents option 2:

[Unit]
Description=Veritas Application service file
Before=vcs.service

[Service]
Type=forking
Restart=no
KillMode=none
ExecStart=/Application/AppStartCustomScript.pl >/dev/null 2>&1 /null
User=john

where, AppStartCustomScript.pl is the script file that contains the command to start the application and its environment variables that are to be exported.

Sample contents of the AppStartCustomScript.pl file:

#!/usr/bin/perl

use warnings;
use strict;

system('appStartCommand&');

where, appStartCommand is the command to start the application.

The following table describes how the entries in the unit service file are interpreted.

Entry	Description
Before=vcs.service	This unit service is stopped before the `vcs` service.
Restart=no	This unit service is not started again after it fails.
KillMode=none	The kill signal is not delivered to the unit service file to stop the process. Instead, the VCS application agent handles this task using StopProgram or CleanProgram.
*ExecStart=appStartCommand* >/dev/null 2>&1 </dev/null or ExecStart=appStartScript >/dev/null 2>&1 </dev/null**	Either a direct command that is used to start the application or the path of the script file that contains the command.
User=john	The OS user who has privileges to start or stop the application. Note: The value of the User attribute of the application resource must be set to `root`. See Attributes for Application agent on Linux.
EnvironmentFile=/tmp/envfile	The environment variables file for the application.

Verifying that the application process has started

The following command and its sample output indicate that the application process has been started by the application user that was specified in the unit service file.

[root@localhost]# ps -ef | grep -i appStartCommand

A sample output is:

john 20845 1 0 15:29 ? 00:00:00 appStartCommand

Verifying the resource is online

When the resource is online, it appears as follows in the systemd context:

[root@localhost]# systemd-cgls
└─system.slice
  ├─sample_app.service
  │ └─20845 appStartCommand
  ├─vcs.service
  │ ├─20280 /opt/VRTSvcs/bin/had
  │ ├─20288 /opt/VRTSvcs/bin/hashadow
  │ ├─20307 /opt/VRTSvcs/bin/HostMonitor -type HostMonitor -agdir /
  │ └─20308 /opt/VRTSvcs/bin/Application/ApplicationAgent -type Application