One possibility: /etc/rc.local

The content says it:

# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits. 
#
# By default this script does nothing

The execution bits are set to 755 on my system already. (chmod 755 /etc/rc.local)

You can put any command in there, which will be executed as root.

This is ok for your purpose as long as you do not change runlevels, I guess. (If you do not know what runlevels are, nevermind).

If you're using TigerVNC then it installs /etc/init.d/vncserver which starts all vncservers configured in /etc/sysconfig/vncservers E.g. following would start 2 instances on display 1 & 2 at start up.

# <display>:<user>
VNCSERVERS="1:root"
VNCSERVERARGS[1]="-geometry 1920x1080"

VNCSERVERS="2:guest"
VNCSERVERARGS[2]="-geometry 800x600 -SecurityTypes None"

this seems to be an old post but the topic might be still interesting for some users. To have vnc to start at boot up, you will need to

1. install a vnc server software (here we will be using x11vnc)
2. configure a startup script (used to start the vnc service)

Step 1 - install x11vnc server

from a command line, type

 sudo apt-get install x11vnc

To add security, you should set a pwd

sudo x11vnc -storepasswd

Step 2 - Configure your startup script

• if your ubuntu version is lower 15.04,

you create the config file under /etc/init.d/x11vnc.conf and populate it with the correct commands to be executed

start on login-session-start  
script  
/usr/bin/x11vnc -xkb -auth
/var/run/lightdm/root/:0
-noxrecord -noxfixes -noxdamage 
-rfbauth /etc/x11vnc.pass 
-forever -bg -rfbport 5900 -o /var/log/x11vnc.log  
end script

• if your ubuntu version is 15.04 or later,

these systems are using systemd and you will need to create your service unit file under /lib/systemd/system/x11vnc.service and populate it with the correct commands to be executed

[Unit] Description=Start x11vnc at startup. After=multi-user.target

[Service] Type=simple ExecStart=/usr/bin/x11vnc -auth guess -forever
-loop -noxdamage -repeat -rfbauth /home/USERNAME/.vnc/passwd -rfbport 5900 -shared

[Install] WantedBy=multi-user.target

Reload the service

sudo systemctl daemon-reload

sudo systemctl enable x11vnc.service

You can find detailed information on Help Ubuntu Community wiki page (see here) or you can try to use this quick to use recipice

• For Ubuntu version lower than 15.04, check this post
• For Ubuntu version 15.04 or later, check this post

Hope this is helpful

Add the below line to crontab file. This means the command after the keyword @reboot gets executed during very reboot.

@reboot /usr/bin/vncserver :1

To open crontab file, need to use the command crontab -e

You can have cron start stuff for you at boot time. Just use the string "@reboot" in place of the numbers that you normally use to specify when the thing should run.

For example, here's how I start Dropbox on a machine on which it doesn't otherwise start automatically:

# m h  dom mon dow   command
@reboot         /usr/bin/dropbox start

'sudo update-rc.d vncserver defaults' reported that there was missing; "Required-Stop:" (even empty). So I added it like below. And no more warning.

    #!/bin/sh -e
    ### BEGIN INIT INFO
    # Provides:          vncserver
    # Required-Start:    networking
    # Required-Stop:     
    # Default-Start:     3 4 5
    # Default-Stop:      0 6
    ### END INIT INFO