Outputting Graphics via Xvfb Virtual Display

1. Install Xvfb:

sudo apt-get install xvfb

2. Save the listing contents to the file Foresight-xvfb below before Xvfb startup setup as a service on the display No. 987 (it is important that the dpi value is set to 96):

#!/bin/bash

### BEGIN INIT INFO

# Provides:          foresight-xvfb

# Required-Start:    $local_fs $remote_fs $network $syslog $named

# Required-Stop:     $local_fs $remote_fs $network $syslog $named

# Default-Start:     2 3 4 5

# Default-Stop:      0 1 6

# X-Interactive:     true

# Short-Description: Start/stop xvfb server for Foresight Analytics Platform

### END INIT INFO

#VER=1

PIDFILE=/var/run/foresight-xvfb.pid

XVFB=/usr/bin/Xvfb

XVFBARGS=":987 -screen 0 1152x864x24 -ac -dpi 96 +extension GLX +render -noreset"

case "$1" in

  start)

    echo -n "Starting virtual X frame buffer: Xvfb"

    start-stop-daemon --start --quiet --pidfile $PIDFILE --make-pidfile --background --exec $XVFB -- $XVFBARGS

    echo "."

    ;;

  stop)

    echo -n "Stopping virtual X frame buffer: Xvfb"

    start-stop-daemon --stop --quiet --pidfile $PIDFILE

    echo "."

    ;;

  restart)

    $0 stop

    $0 start

    ;;

  *)

    echo "Usage: /etc/init.d/Foresight-xvfb {start|stop|restart}"

    exit 1

esac

exit 0

3. Copy the foresight-xvfb file to the /etc/init.d/ directory, make it executable:

sudo chmod +x /etc/init.d/Foresight-xvfb

4. Add the service to autorun on the system startup:

sudo update-rc.d Foresight-xvfb defaults

5. Specify the following in the settings file for Apache HTTP Server environment variables:

export DISPLAY=:987

6. Start the Foresight-xvfb service:

sudo service Foresight-xvfb start

Restart BI server for the settings to be applied.

1. Install the xorg-x11-server-Xvfb package:

sudo yum install xorg-x11-server-Xvfb

2. Add the init script at /etc/init.d/Foresight-xvfb with the contents (it is important that the dpi value is set to 96):

#!/bin/bash

#

# /etc/rc.d/init.d/Foresight-xvfb

#

# chkconfig: 345 85 28

# description: Start/stop xvfb server for Foresight Analytics Platform

# processname: Xvfb

# pidfile: /var/run/Foresight-xvfb.pid

#

. /etc/rc.d/init.d/functions

#VER=1

LOCKFILE=/var/lock/subsys/Foresight-xvfb

PIDFILE=/var/run/Foresight-xvfb.pid

XVFB=/usr/bin/Xvfb

XVFBARGS=":987 -screen 0 1152x864x24 -ac -dpi 96 +extension GLX +render -noreset"

case "$1" in

  start)

    [ -x $XVFB ] || exit 5

    echo -n "Starting virtual X frame buffer: Xvfb"

    PID=`pidofproc -p $PIDFILE foresight-xvfb`

    if [[ (-z $PID) || ($PID -eq 0) ]]; then

    $XVFB $XVFBARGS & echo $! > $PIDFILE

    fi

    RETVAL=$?

    echo "."

    [ $RETVAL -eq 0 ] && touch $LOCKFILE

    ;;

  stop)

    echo -n "Stopping virtual X frame buffer: Xvfb"

    killproc -p $PIDFILE $XVFB

    RETVAL=$?

    echo "."

    [ $RETVAL -eq 0 ] && rm -f $LOCKFILE

    ;;

  restart)

    $0 stop

    $0 start

    ;;

    status)

    status -p $PIDFILE $XVFB

    ;;

  *)

    echo "Usage: /etc/init.d/Foresight-xvfb {start|stop|restart|status}"

  exit 1

esac

exit $?

The loading priority for Foresight-xvfb must be higher than that of httpd (the number is less). To do this, compare the second number in the # chkconfig script comments: 345 85 28 and the httpd script.

3. Make the init script /etc/init.d/Foresight-xvfb executable:

sudo chmod +x /etc/init.d/Foresight-xvfb

4. Export the DISPLAY variable into "/etc/sysconfig/httpd" with the display number that is specified in the script in the XVFBARGS variable:

export DISPLAY=:987

5. Add the Foresight-xvfb service to autorun:

sudo chkconfig --add Foresight-xvfb

sudo chkconfig Foresight-xvfb on

6. Start the Foresight-xvfb service:

sudo service Foresight-xvfb start

Restart BI server for the settings to be applied.

1. Create a task file /etc/init/foresight-xvfb.conf with the contents:

# xvfb - X Virtual Frame Buffer
 
description "X Virtual Frame Buffer"
 
start on runlevel [2345]
script
Xvfb :987 -screen 0 1152x864x24 -ac -dpi 96 +extension GLX +render -noreset
end script

2. Start the task by executing the command:

sudo start foresight-xvfb

1. Create a service file /etc/systemd/system/foresight-xvfb.service with the contents:

[Unit]
Description=X Virtual Frame Buffer
Before=httpd.target
 
[Service]
ExecStart=/usr/bin/Xvfb :987 -screen 0 1152x864x24 -ac -dpi 96 +extension GLX +render -noreset
Type=simple
PIDFile=/var/run/foresight-xvfb.pid
 
[Install]
WantedBy=multi-user.target

2. Add foresight-xvfb to autorun and start the service:

sudo systemctl daemon-reload
sudo systemctl enable foresight-xvfb
sudo systemctl start foresight-xvfb