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Revision as of 13:21, 26 June 2016 by Alsadi (talk | contribs) (good idea to take a look at dnf.conf even if you have not edited it manually)

What is DNF system upgrade?

dnf-plugin-system-upgrade is a plugin for the dnf package manager which handles system upgrades. It is the recommended upgrade method for Fedora 21 and later.

What does DNF system upgrade do?

DNF system upgrade can upgrade your system to a newer release of Fedora, using a mechanism similar to that used for offline package updates. The updated packages are downloaded while the system is running normally, then the system reboots to a special environment (implemented as a systemd target) to install them. Once installation of the updated packages is complete, the system reboots again to the new Fedora release.

How do I use it?

  1. Back up your important data. Every system change is potentially risky, be prepared. In case you update your workstation, it is also wise to download a Workstation Live image and make sure your hardware (graphics card, wifi, etc) works well with the latest kernel and drivers.
  2. Update your system using the standard updater for your desktop or dnf:
    $ sudo dnf update --refresh

    It is recommended to reboot the computer, especially if you've just installed a new kernel.

    • Please note that there is an issue if you use a non-default plymouth boot theme. If you do, please follow the issue description to make sure your upgrade will not be affected.
    • Double check your DNF configuration in /etc/dnf/dnf.conf, if you have done any custom configuration (either manually or via third-party tool), it's recommended to revert it to default before updating and upgrading your system.
  3. Install Package-x-generic-16.pngdnf-plugin-system-upgrade package:
    $ sudo dnf install dnf-plugin-system-upgrade
  4. Download the updated packages:
    $ sudo dnf system-upgrade download --refresh --releasever=36

    Change the --releasever= number if you want to upgrade to a different system release. Most people will want to upgrade to the latest stable release, which is 36, but if you're running Fedora 34, you might want to upgrade just to Fedora 35. You can also use 37 for upgrading to Branched or rawhide for upgrading to Rawhide (warning: those are not stable releases).

    • If some of your packages have unsatisfied dependencies, the upgrade will refuse to continue until you run it again with an extra --allowerasing option. This often happens with packages installed from third-party repositories for which an updated repositories hasn't been yet published. Please study very careful the output and examine which packages are going to be removed. None of them should be essential for system functionality, but some of them might be important for your productivity.
    • In case of unsatisfied dependencies, you can sometimes see more details if you add --best option to the command line.
  5. Trigger the upgrade process:
     $ sudo dnf system-upgrade reboot

    This will reboot your machine immediately. The system should boot again into Fedora using the same kernel, but this time, the upgrade process appears on the boot screen.

  6. Wait for the upgrade process to complete.

Frequently Asked Questions

How do I report issues that I find with upgrades?

First see Common F36 bugs or Common F37 bugs to check if the problem is a very prominent issue we already know of. If it is not there, search for an existing bug report. If you do not see a report that matches your symptoms, you can file a new report from the search page. Please follow the bug reporting instructions mentioned in this README and in man dnf.plugin.system-upgrade.

If you hit issues after upgrade with a specific package, file a bug against the package with which you are having issues.

Does DNF system upgrade verify the software it runs or installs during upgrade?

Yes. The package signing keys for newer Fedora releases are sent to older Fedora releases in order to allow DNF to verify the integrity of the packages it downloads. You can disable this function with the --nogpgcheck parameter if you need to do so for any reason (not recommended, you're then opened to attacks from malicious software).

Will packages in third party repositories be upgraded?

Yes, if they are set up like regular DNF repositories and do not hard code the repository path. Commonly-used third party repositories usually work fine, but if you attempt to upgrade prior to or soon after an official Fedora release, they may not have updated their repository paths yet, and DNF may be unable to find their packages. This will usually not prevent the upgrade running successfully, though, and you can update the packages from the third-party repository later.

Can I use DNF system upgrade to upgrade to a pre-release (e.g. a Beta)?

Yes. It should always be possible to attempt such an upgrade. Of course, this function is as subject to temporary breakage as is any other aspect of a pre-release, and generally speaking, the earlier the release in question, the less likely it is to work without problems.

Optional post-upgrade tasks

These are tasks you can do after a successful upgrade. They are mostly intended for power users. If you are a general user who doesn't use terminal daily, you don't need to worry about this.

Update system configuration files

Most configuration files are stored in /etc. If there are any updates to them and you touched some of those files before, RPM creates new files with either .rpmnew suffix (the new default config file), or .rpmsave suffix (your old config file backed up). You can search for these files, go through the changes and make sure your custom changes are still included and the new defaults are applied as well. A tool that tried to simplify this is rpmconf. Install the package, and then use it as:

$ sudo rpmconf -a

See more information in its manual page.

Clean up old packages

You can see list of packages with broken dependencies like this:

$ sudo dnf repoquery --unsatisfied

Ideally there should be none. If there are some, consider removing them, because they are not likely to work properly anyway.

You can see duplicated packages (packages with multiple versions installed) like this:

$ sudo dnf repoquery --duplicated

For ordinary packages, just the latest version should be installed. But there can be exceptions to the rule, only remove what you are sure you no longer need.

Some packages might stay on your system while they have been removed from the repositories. See them using:

$ sudo dnf list extras

If you don't use these, you can consider removing them. Please note that this list is only valid if you have a fully updated system. Otherwise you'll see all installed packages which are no longer in the repositories, because there is a newer update available. So before acting on these, make sure you have run sudo dnf update and generate the list of extra packages again. Also, this list might contain packages installed from third-party repositories for which an updated repository hasn't been published yet. This often involves e.g. RPM Fusion or Dropbox.

You can remove no-longer-needed packages using:

$ sudo dnf autoremove

Please note that dnf decides that a package is no longer needed if you haven't explicitly asked to install it and nothing else requires it. That doesn't mean that package is not useful or that you don't use it. Only remove what you know you don't need. Please note that there's a known bug in PackageKit which doesn't mark packages as user-installed, see bug 1259865. If you use PackageKit (or GNOME Software, Apper, etc) for installation, this output might list even important apps and system packages, so beware.

Resolving post-upgrade issues

Only follow up these steps if you have troubles with your upgraded system. It should not be needed in the vast majority of upgrades.

Rebuilding RPM database

If you see warnings when working with RPM/DNF tools, your database might have gotten corrupted for some reason. It is possible to rebuild it and see if resolves your issues. Always back up /var/lib/rpm/ first. To rebuild the database, run:

$ sudo rpm --rebuilddb

Using distro-sync to resolve dependency issues

The system upgrade tool uses distro-sync method by default. If your system stayed partly unupgraded or you see some package dependency issues, you might try to fix it by running another distro-sync manually. This tries to make your installed packages exactly the same version as in currently enabled repositories, even if it meant downgrading some packages:

$ sudo dnf distro-sync

A stronger variant also allows to remove package for which package dependencies can't be satisfied. Always carefully review which packages are going to be removed before confirming this:

$ sudo dnf distro-sync --allowerasing

Relabel files with latest SELinux policy

If you see warnings that some actions were not allowed because of current SELinux policy, it might be a case of having some files incorrectly label with SELinux permissions. This might happen in case of some bug or if you had SELinux disabled in some point of time in the past. You can relabel the whole system by running:

$ sudo touch /.autorelabel

and rebooting. The next boot will take a long time and will check and fix all SELinux labels on all your files.