I have QEMU installed but as I don't really use it and it's recently had lots of security vulnerabilities discovered in it so I would like to fully remove it. I installed it with sudo apt-get install qemu as far as I know. When I run sudo apt-get purge qemu it only says that it removes qemu but when it had its most recent update I saw that it had many dependencies and other packages called qemu something which it didn't remove along with the qemu package.
So how can I fully remove it so that all of its config files and packages installed by it are removed? Obviously if dependencies are used by other programs that it uses then I don't want to remove them too, but only things it installed and that are not needed by other programs. I tried running sudo apt-get autoremove which is the equivalent to what the answers here say so that didn't help (it didn't remove anything).
I am running Ubuntu GNOME 15.10 with GNOME 3.18.
Information Update:
I upgraded my machine to Ubuntu GNOME 16.04 with GNOME 3.20, I don't remember whether I reinstalled qemu before or after the upgrade, but I did along with qemu-kvm and the virt-manager package. But now even after purging all three of them and seemingly removing all of the dependencies they installed, I still have a problem. It doesn't seem to have actually removed all the changes they made to my system.
For instance this was the output from systemctl status qemu-kvm.service:
● qemu-kvm.service - LSB: QEMU KVM module loading script
Loaded: loaded (/etc/init.d/qemu-kvm; bad; vendor preset: enabled)
Active: failed (Result: exit-code) since Sun 2016-08-14 13:19:28 BST; 33min ago
Docs: man:systemd-sysv-generator(8)
Process: 2099 ExecStart=/etc/init.d/qemu-kvm start (code=exited, status=5)
Aug 14 13:19:28 <Computer-Name> systemd[1]: Starting LSB: QEMU KVM module loading script...
Aug 14 13:19:28 <Computer-Name> systemd[1]: qemu-kvm.service: Control process exited, code=exited status=5
Aug 14 13:19:28 <Computer-Name> systemd[1]: Failed to start LSB: QEMU KVM module loading script.
Aug 14 13:19:28 <Computer-Name> systemd[1]: qemu-kvm.service: Unit entered failed state.
Aug 14 13:19:28 <Computer-Name> systemd[1]: qemu-kvm.service: Failed with result 'exit-code'.
And this was the output from journalctl | grep qemu:
Aug 14 13:19:23 <Computer-Name> ureadahead[866]: ureadahead:/lib/udev/rules.d/60-qemu-system-common.rules: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-alpha: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/lib/x86_64-linux-gnu/qemu/block-curl.so: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-arm: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/lib/x86_64-linux-gnu/qemu/block-iscsi.so: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/lib/x86_64-linux-gnu/qemu/block-dmg.so: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/lib/x86_64-linux-gnu/qemu/block-rbd.so: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-aarch64: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-cris: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-i386: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-lm32: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-m68k: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-microblaze: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-microblazeel: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-x86_64: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-ppc64: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-ppcemb: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-sh4: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-sh4eb: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-sparc: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-sparc64: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-unicore32: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-xtensaeb: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-mips: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-mips64el: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-mipsel: No such file or directory
Aug 14 13:19:24 >Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-or32: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-ppc: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-xtensa: No such file or directory
Aug 14 13:19:24 <Computer-Name> ureadahead[866]: ureadahead:/usr/bin/qemu-system-mips64: No such file or directory
Aug 14 13:19:25 <Computer-Name> systemd[1]: qemu-kvm.service: Control process exited, code=exited status=5
Aug 14 13:19:25 <Computer-Name> systemd[1]: qemu-kvm.service: Unit entered failed state.
Aug 14 13:19:25 <Computer-Name> systemd[1]: qemu-kvm.service: Failed with result 'exit-code'.
Aug 14 13:19:25 <Computer-Name> ureadahead[866]: ureadahead:/usr/share/qemu/init/qemu-kvm-init: No such file or directory
Aug 14 13:19:27 <Computer-Name> systemd[1]: qemu-kvm.service: Control process exited, code=exited status=5
Aug 14 13:19:27 <Computer-Name> systemd[1]: qemu-kvm.service: Unit entered failed state.
Aug 14 13:19:27 <Computer-Name> systemd[1]: qemu-kvm.service: Failed with result 'exit-code'.
Aug 14 13:19:28 <Computer-Name> systemd[1]: qemu-kvm.service: Control process exited, code=exited status=5
Aug 14 13:19:28 <Computer-Name> systemd[1]: qemu-kvm.service: Unit entered failed state.
Aug 14 13:19:28 <Computer-Name> systemd[1]: qemu-kvm.service: Failed with result 'exit-code'.
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-arm: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-armeb: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-cris: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-m68k: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-mips: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-mips64: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-mipsel: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-mips64el: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-ppc: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-ppc64: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-ppc64abi32: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-ppc64le: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-s390x: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-sh4: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-sh4eb: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-sparc: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-microblaze: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-sparc32plus: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-aarch64: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-alpha: No such file or directory
Aug 14 13:19:31 <Computer-Name> ureadahead[866]: ureadahead:/var/lib/binfmts/qemu-sparc64: No such file or directory
Aug 14 13:19:32 <Computer-Name> ureadahead[866]: ureadahead:/etc/libvirt/qemu/Ubuntu_GNOME_16-04_GNOME_3-18.xml: No such file or directory
Aug 14 13:19:32 <Computer-Name> ureadahead[866]: ureadahead:/etc/libvirt/qemu/Ubuntu_GNOME_16-10_GNOME_3-21.xml: No such file or directory
Aug 14 13:19:32 <Computer-Name> ureadahead[866]: ureadahead:/etc/libvirt/qemu/Ubuntu_Unity_16-04.xml: No such file or directory
Aug 14 13:19:32 <Computer-Name> ureadahead[866]: ureadahead:/etc/libvirt/qemu/Ubuntu_GNOME_16-04_GNOME_3-20.xml: No such file or directory
Aug 14 13:20:42 <Computer-Name> /usr/lib/gdm3/gdm-x-session[3320]: dbus-update-activation-environment: setting LIBVIRT_DEFAULT_URI=qemu:///system
So clearly QEMU isn't completely gone. But I want it to be so how do I completely remove it and all the changes it made?
When I run service --status-all | grep qemu this is the output:
[ - ] qemu-kvm
So it appears that it is there even though it may not be active as it does not seem to currently be running and I think that the - sign probably indicates its current status as many of the other services have + signs. So would it be safe then to just remove this service? And if so, how can this be done?
Best Answer
First some clarification :
qemuis a metapackage, depending on all other qemu-related packages.As I use the
synapticpackage management tool which has the possibility to save the complete installation history of all time, I am able to tell you which packages are installed alongsideqemu.To remove all the
qemurelated packages - open a terminal and execute the following command :Note : This is from Ubuntu 16.04 - in case that a single package (example : libboost-random1.58.0) has a different name in Ubuntu 15.10 you can check this with
dpkg --get-selections. But most packages should have the same name ... now you have completely removed every trace ofqemu.I have checked the packages for
wilyon packages.ubuntu.com and I found one package with a different name :libxen-4.6which inwilyislibxen-4.5- so you have to replace this in thepurgecommand. You also may consider to keep thelibpackages, just to be on the safe side.Update addressing your comment that you still have a not running qemu-kvm service listed :
This is a startup service which is running when you additionally installed the
qemu-kvmpackage.You have two options, you can disable the service with
systemctl disable qemu-kvmor you can remove the service withsudo rm /etc/init.d/qemu-kvm. To also remove the configuration file, executesudo rm /etc/init/qemu-kvm.conf. Now reboot the system - the service will be gone.