PackageKit can’t find file in /var/cache/PackageKit/

After installing RPM Fusion repos on Fedora 28 you might be getting an error shown by update manager every few minutes in GUI.
Error will say something like this: “Error when getting information for file “/var/cache/PackageKit/28/metadata/rpmfusion-nonfree-nvidia-driver/repodata/appstream.xml.gz”: No such file or directory

Error is described here https://bugzilla.redhat.com/show_bug.cgi?id=1580162 and seem to be caused by a repo that claims to support appdata but doesn’t actually provide it.

Error can be resolved by changing enabled_metadata=1 to enabled_metadata=0 in repo description file.
In case of above error change was made in /etc/yum.repos.d/rpmfusion-nonfree.repo and it now looks like this:

[rpmfusion-nonfree]
name=RPM Fusion for Fedora $releasever - Nonfree
#baseurl=http://download1.rpmfusion.org/nonfree/fedora/releases/$releasever/Everything/$basearch/os/
metalink=https://mirrors.rpmfusion.org/metalink?repo=nonfree-fedora-$releasever&arch=$basearch
enabled=1
enabled_metadata=0 #changed from 1 to 0
metadata_expire=14d
type=rpm-md
gpgcheck=1
repo_gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmfusion-nonfree-fedora-$releasever

[rpmfusion-nonfree-debuginfo]
name=RPM Fusion for Fedora $releasever - Nonfree - Debug
#baseurl=http://download1.rpmfusion.org/nonfree/fedora/releases/$releasever/Everything/$basearch/debug/
metalink=https://mirrors.rpmfusion.org/metalink?repo=nonfree-fedora-debug-$releasever&arch=$basearch
enabled=0
metadata_expire=7d
type=rpm-md
gpgcheck=1
repo_gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmfusion-nonfree-fedora-$releasever

[rpmfusion-nonfree-source]
name=RPM Fusion for Fedora $releasever - Nonfree - Source
#baseurl=http://download1.rpmfusion.org/nonfree/fedora/releases/$releasever/Everything/source/SRPMS/
metalink=https://mirrors.rpmfusion.org/metalink?repo=nonfree-fedora-source-$releasever&arch=$basearch
enabled=0
metadata_expire=7d
type=rpm-md
gpgcheck=1
repo_gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmfusion-nonfree-fedora-$releasever

After the change is made run pkcon repair and then pkcon update to check for any errors.

[[email protected] ~]# pkcon repair
                              [=========================]         
Finished                      [=========================]         
                              [=========================]         
Finished                      [=========================]         
[[email protected] ~]# pkcon update
Getting updates               [=========================]         
Finished                      [=========================]         
No packages require updating to newer versions.
[[email protected] ~]# 

How to enable h264 codec on Fedora 28

If you are running Fedora 28 you might have some issues with playing some type of videos in Firefox, Chromium and Vivaldi browsers.

You might be presented with a following type of error when trying to open video stream:
H.264 (High Profile) decoder is required to play the file, but is not installed

Also when visiting https://www.youtube.com/html5 you will see that browser does not support H.264 and MSE & H.264.

Here is how to enable H.264 for specific browsers.

Firefox

First you need to install and enable rpmfusion-free and rpmfusion-nonfree repositories.
Following command will install both RPM Fusion repositories.

sudo dnf install https://download1.rpmfusion.org/{free/fedora/rpmfusion-free,nonfree/fedora/rpmfusion-nonfree}-release-$(rpm -E %fedora).noarch.rpm

After that install compat-ffmpeg28 and ffmpeg-libs packages

sudo dnf install compat-ffmpeg28 ffmpeg-libs
Chromium

Chromium supports Vorbis, Theora, WebM and HTML5 audio and video standards, but does not include the non-free AAC, H.264, MP3 or Adobe Flash code that is found in Chrome.

To add H.264 you need to install chromium-libs-media-freeworld package from RPM Fusion.

Install RPM Fusion repositories.

sudo dnf install https://download1.rpmfusion.org/{free/fedora/rpmfusion-free,nonfree/fedora/rpmfusion-nonfree}-release-$(rpm -E %fedora).noarch.rpm

Install chromium-libs-media-freeworld package.

sudo dnf install chromium-libs-media-freeworld
Vivaldi

For Vivaldi you need to follow same steps as for Chromium, and add an extra step of copying a file to Vivaldi directory.

Install RPM Fusion repositories.

sudo dnf install https://download1.rpmfusion.org/{free/fedora/rpmfusion-free,nonfree/fedora/rpmfusion-nonfree}-release-$(rpm -E %fedora).noarch.rpm

Install chromium-libs-media-freeworld package.

sudo dnf install chromium-libs-media-freeworld

Copy /usr/lib64/chromium-browser/libffmpeg.so to /opt/vivaldi/lib/.

sudo cp -av /usr/lib64/chromium-browser/libffmpeg.so /opt/vivaldi/lib/
cp: overwrite '/opt/vivaldi/lib/libffmpeg.so'? y
removed '/opt/vivaldi/lib/libffmpeg.so'
'/usr/lib64/chromium-browser/libffmpeg.so' -> '/opt/vivaldi/lib/libffmpeg.so'

Last step will need to be repeated after every Vivaldi update.

Yum and curl returning “Illegal instruction (core dumped)” on Xen

When running yum or curl commands on a CentOS 6 XenServer Virtual Machine you might be getting an “Illegal instruction (core dumped)” error returned in your console output.

[email protected] [~]# yum update
Loaded plugins: fastestmirror, rhnplugin
Setting up Update Process
Loading mirror speeds from cached hostfile
 * base: mirror.us.leaseweb.net
 * cloudlinux-x86_64-server-6: xmlrpc.cln.cloudlinux.com
 * extras: mirror.teklinks.com
 * updates: mirror.teklinks.com
Illegal instruction (core dumped)

The issue is due to Python attempting to execute a CPU opcode advertised as available by the server’s host node virtualization system (XEN), but is not actually supported by the host node’s hardware.

Workaround

Issue can be resolved by running export NSS_DISABLE_HW_AES=1, and then running yum update, to update to newer packages, after which issue should not be happening anymore.

[email protected] [~]# export NSS_DISABLE_HW_AES=1
[email protected] [~]# yum -y update
References:

https://www.centos.org/forums/viewtopic.php?t=58002

https://forums.cpanel.net/threads/kvm-xen-hw_aes-detection-issues-yum-update-illegal-instruction.551681/