Enable TUN/TAP With OpenVZ Or Virtuozzo Containers For OpenVPN

On the masternode, perform the following:

lsmod | grep tun

If that yields no results, you have to load it into the kernel:

modprobe tun

Next, you'll want to ensure this module is loaded across system reboots so you can do either of the following:

echo 'modprobe tun' >> /etc/rc.local

--- OR ---

echo 'modprobe tun' >> /etc/rc.modules

...whichever you are accustom to.

Next we have to allow the container access to the TUN/TAP device:
(use your container ID in place of CT_ID)

vzctl set CT_ID --devices c:10:200:rw --save
vzctl set CT_ID --capability net_admin:on --save

Lastly, we have to create the device and assign the proper permissions to it:
(use your container ID in place of CT_ID)

vzctl stop CT_ID
vzctl exec CT_ID mkdir -p /dev/net
vzctl exec CT_ID mknod /dev/net/tun c 10 200
vzctl exec CT_ID chmod 600 /dev/net/tun
vzctl start CT_ID

Your container should now be able to install OpenVPN or other VPN software.

Repairing Unable To RDP To A Parallels Virtuozzo Container

Virtuozzo containers uses it's masternode's operating system files in part to run. Because of this, Windows Updates or other changes can cause it to not function properly.

One common issue is RDP suddenly not working. Luckily it's rather trivial to repair.

First step is to RDP to your Virtuozzo master node.

Second step is to open a cmd window and then enter each of these commands one line at a time (substitute the actual container ID in place of CT_ID):

vzfsctl lnkctl CT_ID --link c:\vz\private\CT_ID\root\windows\system32\drivers\rdpwd.sys --dst \windows\system32\drivers\rdpwd.sys --system

vzfsctl lnkctl CT_ID --link c:\vz\private\CT_ID\root\windows\system32\drivers\RdpDD.sys --dst \windows\system32\drivers\RdpDD.sys --system

vzfsctl lnkctl CT_ID --link c:\vz\private\CT_ID\root\windows\system32\drivers\termdd.sys --dst \windows\system32\drivers\termdd.sys --system

vzfsctl lnkctl CT_ID --link c:\vz\private\CT_ID\root\windows\system32\termsrv.dll --dst \windows\system32\termsrv.dll --system

If the file linking was your problem you should immediately be able to RDP to the container once again.