How to use QEMU

QEMU is a generic and open source processor emulator which achieves a good emulation speed by using dynamic translation.

QEMU has two operating modes:

QEMU is available on Fedora repository. It can be installed by using DNF:

To discover the qemu commands that are installed perform the following:

In the following examples where "qemu" is, substitute your command for executing qemu. E.g.

or

Of course, this does not apply to "qemu-img".

Create the virtual image for the system:

Of course you are not obliged to take 5GB.

Note: Even if you take 10GB this does NOT mean that the image does really HAVE the size of 10GB. It just means that your new system is limited up to 10GB - if the new system takes only 1,2 GB also the image will only be at 1,2GB.

Now let’s install the OS. Put in the install CD and type into your konsole (all in one line without break):

"-user -net" is important to have internet access within your new system. "-m 196" is the Set virtual RAM size (megabytes), default is 128 MB, I chose 196.

The install may take some time. After the install, qemu will try to boot the new OS itself. Maybe this may fail (was the case for me) - but don’t worry. If that happens: just close the qemu window and type the following command into your konsole to launch your new OS:

Type, in the proper directory

To get kernel output dumped to a file outside the virtual system, add e.g. "-serial file:/tmp/qemu-output.log" to the qemu command line. When booting the virtual system, add "console=ttyS0" to the kernel boot parameters.

This output is particularly helpful if you are having trouble booting the system, in which case you may also wish to remove "rhgb" and "quiet" from the kernel boot parameters.