How do I check if a package is installed on my server?

Are you looking to know about all dpkg commands with options? Have a read from the below link.

15 dpkg commands to Manage Debian based Linux Servers

To List all Installed Packages

Here less is a simple text reader used to scroll through the list of packages in a new buffer that opens in the existing terminal window. The list will not be mixed with other terminal commands and output. Hit q to return to the terminal prompt. See man less for more info.

dpkg -l | less

To check whether a package is installed or not:

dpkg -l {package_name}
dpkg -l vlc

To check if the package is installed or not (for example, vlc). If installed, launch the package:

dpkg -l | grep vlc

Show the location where the package is installed. The -S (capital S) stands for "search"

sudo dpkg -S {package_name}
sudo dpkg -S skype

To use Grep to search:

dpkg -l | grep {keywords}
dpkg -l | grep pdf

apt -qq list PACKAGE can also be used for checking whether the PACKAGE is installed.

If installed it'll print something like (with [installed] at the end of the line):

$ apt -qq list awscli
awscli/stable,now 1.4.2-1 all [installed]

If not installed the output will be:

$ apt -qq list awscli
awscli/stable 1.4.2-1 all

Use dpkg

This command is the Debian package manager.

You can list all the installed packages with

dpkg -l

You can see details for a specific package with

dpkg -p packagename

And to learn if it is installed, use

dpkg -s packagename | grep Status

You can learn which package contains the software you want with

apt-cache search name*  

In your case you should use this command to search the package name you want

apt-cache search virtual machine host