Installing Java for External KVM Access

Installing Java on Ubuntu

Add the repository

sudo add-apt-repository ppa:webupd8team/java

Update package data

sudo apt-get update

Load the Java installer

sudo apt-get install oracle-java8-installer

Installing Java in Linux

The KVM console requires your system have the Java Runtime Environment and Java Web Plugin installed on your browser. We recommend using Oracle JRE as Open JRE may not work. The required software is usually installed automatically, but if you encounter any problems, these instructions will guide you through the installation process.

You can also install Java packages manually by downloading them from the official site and following our instructions.

The following installation guide is for Ubuntu.

Unpack the archive ("*" is the version of Java you downloaded packages for):

tar -xvpf jre-*.tar.gz

Move the extracted files to the system folder:

sudo mv ./jre* /usr/lib/jvm/jre*

Add the packages for the Java version that we are going to use:

sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/jre*/bin/java [number]

[number] assigns a priority to the installation and can be any number. (Use any number other than zero if there are other Java alternatives that can be deleted if necessary.) Launch the added packages by entering the priority you assigned this installation (in the [number] field) and press Enter:

sudo update-alternatives --config java

Check the version to make sure the packages are active:

java -version

Make a symbolic link for the browser using the folder for our system architecture and deleting previously installed files and packages:

mkdir ~/.mozilla/plugins
ln -s /usr/lib/jvm/jre*/lib/amd64/ ~/.mozilla/plugins/

Check that everything is working. More detailed instructions can be found at the following link:

If necessary, these packages can be similarly installed for any other Linux distro, provided you modify the tree to match the relevant architecture.

Potential KVM Console Errors and How to Resolve Them

In MacOS X, if the “security & privacy” setting “allow applications downloaded from” is set to “mac app store and identified developers”, then the KVM applet will not launch (the Allow button will be inactive). You will have to change the value of “allow applications downloaded” to “anywhere”.

If the Java applet launches, but you receive a connection error message, then you will have to make sure the outgoing port hasn’t been closed by the firewall. For more details, contact tech support.

Enabling Java 6 in MacOS X

According to the official documentation, you just have to execute several commands in the terminal (requires administrator privileges):

sudo mkdir -p /Library/Internet\ Plug-Ins/disabled
sudo mv /Library/Internet\ Plug-Ins/JavaAppletPlugin.plugin /Library/Internet\ Plug-Ins/disabled
sudo ln -sf /System/Library/Java/Support/Deploy.bundle/Contents/Resources/JavaPlugin2_NPAPI.plugin /Library/Internet\ Plug-Ins/JavaAppletPlugin.plugin
sudo ln -sf /System/Library/Frameworks/JavaVM.framework/Commands/javaws /usr/bin/javaws


Since Java 6 distributions have been deleted from the Internet and unsigned applications have been blocked in the latest version of Java 7, we’ve added 100% working versions here.

You can also try version 8.