Description

In case of unrequested Charon virtual machine stop, it is possible, using the systemd features, to restart Charon emulator automatically

Step-by-step guide

Additional considerations

To perform this procedure, you must have the necessary privileges to handle systemd service and execute systemctl commands
This documentation applies only to Linux distributions including the systemd feature. This does not apply to Red Hat Enterprise Linux 6

Setup your CHARON virtual machine as a service. To do so, refer to the corresponding documentation or install and use the Charon Linux Toolkit.
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Edit the service configuration file and add the following parameters:

Parameter	Type	Description
`Restart`	text	Configures whether the service shall be restarted when the service process exits, is killed, or a timeout is reached
`RestartSec`	numeric	Configures the time to sleep before restarting a service (as configured with `Restart=`). Takes a unit-less value in seconds, or a time span value such as "5min 20s". Defaults to 100ms.
`StartLimitInterval`	numeric	Configure service start rate limiting. By default, services which are started more than 5 times within 10 seconds are not permitted to start any more times until the 10 second interval ends. With these two options, this rate limiting may be modified. Use `StartLimitInterval=` to configure the checking interval (defaults to `DefaultStartLimitInterval=` in manager configuration file, set to 0 to disable any kind of rate limiting). Use `StartLimitBurst=` to configure how many starts per interval are allowed (defaults to `DefaultStartLimitBurst=` in manager configuration file).
`StartLimitBurst`	numeric

More parameters can be defined for auto-restart. Please refer to your Linux distribution documentation (see How to restart Charon-VAX/AXP on Linux automatically on failure#Links further)

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Example: The following service will restart in case of failure (Restart=on-failure) after 30 seconds (RestartSec=30) with a limit of 2 (StartLimitBurst=2) within 10 minutes (StartLimitInterval=600)

# vim /usr/lib/systemd/system/as4100.service

[Unit]Description=DEMO as4100After=atd.service postfix.service ncu.service aksusbd.serviceWants=aksusbd.service

[Service]Type=forkingWorkingDirectory=/charon/logExecStart=/opt/charon/bin/as4100 -d /my_services/as4100-service.cfgExecStop=/charon/scripts/mystopscript /my_services/as4100-service.cfgRestart=on-failureRestartSec=30StartLimitInterval=600StartLimitBurst=2

[Install]WantedBy=multi-user.target

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Reload systemd manager configuration:
# systemctl daemon-reload

Notes

Autoboot

Restarting Charon emulator does not mean booting the OpenVMS or Tru64 virtual system. You will need to setup the flags at SRM level for autoboot.

See the related documentation of your emulator

Charon-AXP

The default boot device and the action to be performed on boot have to be set

Example for Charon-AXP:

P00>>> set bootdef_dev dka0P00>>> set auto_action restart

Charon-VAX

CHARON-VAX can be configured to automatically boot an operating system at start up.

The MicroVAX 3100, VAX 6310 and VAX 4000 models boot automatically if the correct boot flags are set at the VAX console level:

>>>set halt reboot

Please check that the TOY, EEPROM and ROM containers (see above) are enabled so the console changes are saved upon reboots.

The ROM of certain VAX models (MicroVAX II, MicroVAX 3600, MicroVAX 3900, VAXserver 3600 and VAXserver 3900) does not allow the SRM console to accept the above command to enable auto booting. As a workaround, a specific setting can be defined in the configuration file:

set bdr boot=auto

The Charon-VAX 6000 models have a similar configuration setting:

set xmi boot=auto

Restart limit reached

In case the StartLimitBurst is reached during the interval, you will not be able to restart the service until you reset the failure counter.

Example:

# systemctl start charon_plutoJob for charon_pluto.service failed. See 'systemctl status charon_pluto.service' and 'journalctl -xn' for details.

# systemctl status charon_pluto

charon_pluto.service - DEMO as4100 pluto Loaded: loaded (/etc/systemd/system/charon_pluto.service; disabled) Active: failed (Result: start-limit) since Mon 2015-09-28 15:59:36 CEST; 3min 10s ago Process: 67122 ExecStop=/opt/charon/utils/charon_gstart stop /charon/pluto.cfg (code=exited, status=0/SUCCESS) Process: 62391 ExecStart=/opt/charon/utils/charon_gstart start /charon/pluto.cfg (code=exited, status=0/SUCCESS) Main PID: 62795 (code=killed, signal=KILL)

Sep 28 15:59:16 rhel71.localdomain systemd[1]: Unit charon_pluto.service entered failed state.Sep 28 15:59:36 rhel71.localdomain systemd[1]: charon_pluto.service holdoff time over, scheduling restart.Sep 28 15:59:36 rhel71.localdomain systemd[1]: Stopping DEMO as4100 pluto...Sep 28 15:59:36 rhel71.localdomain systemd[1]: Starting DEMO as4100 pluto...Sep 28 15:59:36 rhel71.localdomain systemd[1]: charon_pluto.service start request repeated too quickly, refusing to start.Sep 28 15:59:36 rhel71.localdomain systemd[1]: Failed to start DEMO as4100 pluto.Sep 28 15:59:36 rhel71.localdomain systemd[1]: Unit charon_pluto.service entered failed state.Sep 28 15:59:54 rhel71.localdomain systemd[1]: Starting DEMO as4100 pluto...Sep 28 15:59:54 rhel71.localdomain systemd[1]: charon_pluto.service start request repeated too quickly, refusing to start.Sep 28 15:59:54 rhel71.localdomain systemd[1]: Failed to start DEMO as4100 pluto.

# systemctl reset-failed charon_pluto

# systemctl start charon_pluto

# systemctl is-active charon_plutoactive

Charon Linux Toolkit integration

The Charon Linux Toolkit, starting version 41, is able to manage the auto-restart settings.

Starting with kit version 42, if auto-restart settings are defined they will be displayed in the virtual machines lists while navigating in the menu options and the failure counter will be reset on each start (from the menu)