What's new in Fedora 17
by Thorsten Leemhuis
The GNOME Shell is now able to run without a 3D graphics driver. A major reorganisation of the filesystem structure, though much discussed, is not noticeable in everyday use. A new sandbox function allows applications to be easily isolated.
Three weeks later than original scheduled, the Fedora Project has released the seventeenth edition of its popular Linux distribution. The new version, code-named "Beefy Miracle", includes a controversial change which provoked lengthy debate within the Linux world during Fedora 17 development – the new Fedora does away with the /lib/, /lib64/, /bin/ and /sbin/ directories. In Fedora 17, all of the files which were previously located in these directories are now in similarly named sub-directories of /usr/. To ensure backwards compatibility, the deleted directories have been replaced with symbolic links that point to the new directories.
Because of this, users are unlikely to even notice that the change in filesystem structure, known as UsrMove, has taken place. When updating from a previous version, all files previously located in one of the deleted directories will be moved automatically. Users updating Fedora via Yum (which is officially not supported) will need to take a few extra steps to make the Initramfs move these files. This particular upgrade path is, however, of interest to those Fedora aficionados able to deal with any dependency problems or other difficulties.
One of the effects of the restructuring is that it's now easier to automatically snapshot a filesystem prior to installing updates. In the event of problems, users can then restore the previous state without losing changes made subsequently in /etc/ or /var/. It also becomes easier to mount /usr/ write-protected and for multiple systems to use a networked usr directory. Further reasons for the reorganisation are detailed on the UsrMove feature page on the Fedora wiki and in a post titled "The Case for the /usr Merge" on freedesktop.org. Developers at other distributions are also pondering following Fedora's lead, but none of the major distros have made an official announcement.
GNOME Shell without a 3D driver
Fedora now uses version 3.4.1 of GNOME as its default desktop; the point update includes a number of small improvements, bug fixes and translation updates for the major GNOME 3.4 release from March. The developers have improved the way this generation of GNOME interacts with the extensions.gnome.org web site, which currently offers more than one hundred extensions for Fedora 17 for modifying the behaviour of GNOME Shell to suit individual needs. GNOME 3.4 also includes major revisions to the browser and disk manager, as well as many minor enhancements, including space-saving scrollbars.
In Fedora 17, GNOME Shell, responsible for the user interface in GNOME 3.x, also works on systems with graphics drivers that do not support 3D acceleration. This is achieved with the help of the Mesa 3D driver llvmpipe, which performs 3D calculations using the main processor. Compared to modern 3D shooter games, the 3D performance required is modest, so that standard desktop processors deliver adequate performance to display the interface smoothly. Even in virtualisation environments, software rendering with llvmpipe often delivers enough performance required for smooth operation.
The KDE components in Fedora 17 are derived from KDE SC 4.8.3. For Fedora 16 users, this is nothing new, as it was recently updated to the latest version of KDE via the regular update channel. A plan to have llvmpipe calculate KDE SC desktop effects in the absence of a 3D driver has been deferred. When installing a widget using Plasma, to ensure that the widget is able to find everything it needs after installation, Plasma now requests all script and data packages required for the widget from the Fedora repository.
LibreOffice 188.8.131.52 also comes pre-installed; version 3.5.3 was released earlier this month. Fedora has also added GIMP 2.8, released in early May – major new features of which include a single-window mode and an improved text tool; it also has new functions for grouping layers and for transforming parts of images using a polygonal frame. The CUPS daemon, which is involved in controlling printing, can now, in conjunction with colord, use ICC colour profiles, resulting in improved colour fidelity.
Virtualisation and the cloud
Fedora 17 contains the libvirt sandbox, which was explained in some detail at this year's FOSDEM. With the help of virtualisation solution KVM (Kernel-based Virtual Machine) or container technology LXC (Linux Containers), it creates a sandbox to isolate applications. This does not require the installation of a virtualised operating system, as it uses the host's root filesystem, but is write-protected. The overhead is reported to be extremely small, but launching an application takes a little longer, as its takes a couple of seconds to set up a sandbox with KVM. With LXC, this should only require fractions of a second.
Virt-manager now supports USB pass-through. Fedora 17 also comes with multilayer virtual switch Open vSwitch, which has been specifically developed for use in virtualisation environments and is able to work on layers 2, 3 or 4. Kernel-side support was merged into Linux 3.3 at the start of this year.
Fedora now includes many of the components making up the oVirt project, which has developed much of the infrastructure and management software for virtualisation environments used in Red Hat Enterprise Virtualization (RHEV) 3.0 and elsewhere. Also new are components of the cloud computing platform OpenStack Essex, released in early April. Red Hat, which sponsors the Fedora Project, has started to contribute substantial code to OpenStack and is planning to use it in Red Hat products. Eucalyptus 3.1, OpenNebula, and the cloudstack from cloud.com were supposed to be being merged into Fedora 17 but were not ready in time.
As with Fedora 16, version 17 again saw plans for making Btrfs the default filesystem discarded. In Fedora 17, it is no longer even possible to format partitions with Btrfs from the installer. This function, which was available in Fedora 16 and its predecessors, appears to have fallen by the wayside in the course of work on the installer, but is set to return in Fedora 18. Btrfs can still be used on previously installed systems or when running from a LiveCD, and the improved, but still not officially released, tool for checking and repairing btrfs disks is also included in the distribution.
Ext4 should now support disks larger than 16 TB. From version 17, Fedora no longer mounts removable disks under /media/, but instead mounts them under /run/media/$USER/. The reason for the switch is a change in udisks.
Fedora contains everything required to be able to use LIO (linux-iscsi.org) to set up an NAS that can be addressed as a SCSI target via iSCSI or FCoE. The lead Fedora developer behind the change has posted a three-part screencast describing this feature in more detail. There have also been a range of enhancements to the cluster stack, useful in high availability and load balancing setups.