PreUpgrade是用户在一个已存的发布上运行的应用，它解决并下载必要的包来升级到最新的Fedora发行。虽然PreUpgrade开始下载必要的包，但是用户可以自由地继续使用他们的系统。这类似于实时升级。附加信息请参阅PreUpgrade特性页面。
Preupgrade可以直接升级到最新的Fedora。它没有必要去升级到中间版本。例子，它可能直接从Fedora 38到Fedora 40。
准备系统
While preupgrade provides a generally hassle free upgrade experience. 在处理前，以下步骤是推荐的。
- 备份 - Before performing any system maintenance, it is recommended that you back up all important data before proceeding.
- 升级 - Apply available updates Fedora updates before proceeding. As the root user, issue the following command.
yum update
- 安装 - As of Fedora 10, the preupgrade utility is included in a default Fedora install. However, the package can be installed manually using the
yumcommand.yum install preupgrade
执行升级
通常情况，当您系统升级可用，
PackageKitpreupgrade手动升级，看看下面的步骤。
- 以root运行命令
preupgrade开启Preupgrade。如果你喜欢命令行，可以试试preupgrade-cli。 - On the Choose desired release screen, select the Fedora release you want to upgrade to , and click the Apply button.
- 当所有软件包下载完了，将会重启并启动Fedora安装器并升级到下一个发行。
远程升级
preupgradegkiu有一个开关，允许通过VNC远程升级。如果你使用preupgrade远程升级，你更可能要有一个静态IP和机器打交道。通过preupgrade命令处理：
preupgrade-cli --vnc[=密码] --ip=[IP地址] --netmask=[子网掩码] --gateway=[IP地址] --dns=[DNS服务器] "Fedora 15 (Lovelock)"
升级后的通用任务
升级完成后，推荐去用来完成处理的附加步骤。
删除不支持的软件包
有些套件可能不再支持新版本。您可能希望删除这些包，因为他们将不会再获得安全更新。他们支持的包可能会导致后来的冲突。可以用下面的命令确定：
package-cleanup --orphans
检查.rpmsave和.rpmnew文件
After completing the upgrade process, you may notice file names ending with .rpmsave and .rpmnew. Don't be alarmed. The upgrade process will always preserve any locally modified configuration files. The file names ending with .rpmsave contain your local configuration changes. While the file names ending with .rpmnew represent the configuration file originally packages with the software.
You should examine all .rpmsave and .rpmnew files created by the upgrade. Depending on the differences, you may need to manually merge configuration files. You can locate all matching files using the find command.
find / -print | egrep "rpm(new|save)$"
You may wish to speed up repeat searches as you edit, by running the updatedb command first, and then using locate for subsequent searches.
updatedb locate --regex "rpm(new|save)$"
校验升级
运行
yum repolist
确定仓库设置正确。然后运行
yum distro-sync
在源里同步包和版本。
疑难解答
/boot没有足够的空间
Fedora 13 and above has a 500 MB default boot partition. The default /boot filesystem size of 200MB for previous releases can be a problem for users upgrading from that release. In many cases, the diskspace that is likely free is just enough for preupgrade to find enough space to download the installer to but not quite enough for it to run the installer and install the new kernel after reboot. This section outlines several tips that have been known to work. As always when performing administrative tasks, be sure to back-up any data before proceeding.
There are two basic methods to make preupgrade work in this situation. In the first method, you need to free up sufficient space for the installer to install the new kernel packages. In the second method, you need to temporarily fill up enough of the space on /boot to force preupgrade to download the installer after rebooting.
方法1：释放空间
首先，try to remove any kernel packages not currently in use on your system. The kernel-prune.py script can be used to identify kernels that may be safely removed. If you choose to remove additional kernels, be prepared with installation media should you be unable to return to your previously installed system.
The installer will need approximately 26M of free space in /boot. Use the following command to determine the amount of free space in the /boot partition:
df -h /boot
To identify kernels that may be safely removed, run the following from a command line:
curl -O 'http://skvidal.fedorapeople.org/misc/kernel-prune.py' chmod a+x kernel-prune.py ./kernel-prune.py
Now, to actually remove the kernel versions listed by the above command, run the following as root:
# PKGS=`./kernel-prune.py` # echo $PKGS # yum remove $PKGS
其次, adjust the number of reserved filesystem blocks using the command tune2fs. You'll first need to identify the block device for your /boot file system. In the example below, /dev/sda1 is the block device for the /boot filesystem.
# mount | grep "/boot" /dev/sda1 on /boot type ext4 (rw)
Now, adjust the number of reserved blocks for the /boot filesystem using the command tune2fs. Normally, a small amount of space on ext filesystem formatted partitions is 'reserved' and can only be used by the system administrator; this is to prevent an entirely full partition from rendering a system unbootable, and allow the administrator some space in which to work in order to clean up 'full' partitions. However, neither of this cases really applies to the /boot filesystem, so removing this reserved space is safe.
# tune2fs -r 0 /dev/sda1
最后, try removing unnecessary files from the /boot filesystem. This will largely depend on how your system is set up. Removing the incorrect files may result in a unbootable system. Some candidates for removal include /boot/efi and /boot/grub/splash.xpm.gz.
方法2：升级前用户下载安装程序
This method requires you to have a wired connection to the internet during the install. If you are on wireless and cannot connect via an ethernet cable you will have to use Method 1 instead.
首先, find out how much space is available on the /boot filesystem. df is the command you want for this:
$ df /boot Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda1 198337 30543 157554 17% /boot
其次, create a file that takes up enough space that preupgrade decides it cannot install stage2 now. Preupgrade needs approximately 120MB for the installer image so we'll make sure we have a bit less than 100MB. For the example filesystem, that means we need to fill up 60MB. Here's how to do that as root:
# dd if=/dev/zero of=/boot/preupgrade_filler bs=1024 count=61440 # df /boot Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda1 198337 92224 95873 50% /boot
再次, run preupgrade as normal. In the early stages, before downloading packages, preupgrade should tell you that there wasn't enough room to download part of the installer but it can download it after reboot if you have a wired connection to the network. You can click continue for that. When preupgrade is done don't reboot immediately. Instead, remove the /boot/preupgrade_filler file and make sure your computer is connected to the network via an ethernet cable. Then you can reboot.
# rm /boot/preupgrade_filler
最后, the computer should boot into the installer, connect to the internet via the ethernet cable and start downloading the stage2 installer image. Then it should continue upgrading as normal.
升级安装后不会重新启动
解释
If you have a multiboot configuration, the /boot menu that grub uses might be different from the /boot menu that preupgrade modifies. In this case, you will need to point grub to the appropriate file to complete upgrade upon reboot. If this is not done, once preupgrade has completed downloading and installing files, upon reboot no change will be visible. The system will simply reboot as to the older version.
Preupgrade boots into an upgrade kernel as an intermediate step. Once the system has been upgraded, preupgrade replaces the temporary upgrade kernel option with an option for the upgraded kernel. In other words, there are two modifications made to the bootloader: a temporary upgrade option, followed by an option that is permanent until the next upgrade.
The grub bootloader can be used to boot from its command line, or /boot/grub/menu.lst can be modified to create a boot menu option. (Example screenshot of grub boot menu.) (For further detail on grub, refer to the grub manual.)
Either grub option can be used for either preupgrade step. To be comprehensive, the following describes both the command line option and doing so by editing the menu.lst file.
However, since the upgrade should only be run once, and the upgraded system will probably require repeated booting, the most expedient approach is probably to manually boot the upgrade via the grub command line, then once the upgrade has completed, to add an option to menu.lst add the upgraded Fedora installation to the grub boot menu. This would correspond to using Method 1, Steps 1 - 3, followed by Method 2, Step 4.
方法1：手动从GRUB命令行启动
步骤 1: 确定分区的位置
Identify the drive and partition of your Fedora /boot folder. (See Grub Naming Convention for details.) For example, if you installed Fedora entirely on the fourteenth partition of a second hard drive, /boot would be located on root (hd1,13)
步骤 2: 从此分区引导
Upon reboot, enter 'c' to enter the grub command line. Using the appropriate drive and partition numbers, enter the following commands:
root (hd1,13) kernel /boot/upgrade/vmlinuz initrd /boot/upgrade/initrd.img boot
This will boot the upgrade installation.
步骤 3: 选择安装映像
The upgrade installation will then run an ncurses dialog. After selecting language and keyboard types, select hard drive for installation method. The next dialog box will require partition and directory information of the installation image. Select the partition from the drop-down menu. (Note that the numbering will be one off from the grub partition. In other words root (hd1,13) will appear as /dev/sdf14.) Finally, enter the location of the install image file: /boot/upgrade/install.img.
The installation will run normally at this point. After completing the upgrade, you will need to either boot the upgraded system manually by entering the newly installed kernel and initrd.img files at the grub command line, or add an entry to the menu.lst file. This step is detailed in the next section.
As an alternative to entering the commands at the grub command prompt upon reboot, you can also edit grub's menu.lst file to add an option that will allow you to select booting to the upgrade process from grub's boot menu. Since the upgrade should only be run once, after you've upgraded you will then need to re-edit menu.lst, remove the upgrade boot menu option, and add a boot entry for the new kernel.
步骤 1: 确定分区位置
Identify the drive and partition of your Fedora /boot folder. Grub Naming Convention. For example, if you installed Fedora entirely on the fourteenth partition of a second hard drive, /boot would be located on root (hd1,13)
步骤 2: 编辑menu.lst
Locate and open the /boot/grub/menu.lst file that grub actually uses. If this file is on another partition, check the /media files.
Using the appropriate drive and partition information in the root line format, add the following entry to the menu.lst file:
title Fedora Upgrade root (hd*,*) kernel /boot/upgrade/vmlinuz initrd /boot/upgrade/initrd.img savedefault boot
保存并重启。从GRUB引导菜单选择Fedora Upgrade。
步骤 3: 选择安装映像
The upgrade installation will then run an ncurses dialog. After selecting language and keyboard types, select hard drive for installation method. The next dialog box will require partition and directory information of the installation image. Select the partition from the drop-down menu. (Note that the numbering will be one off from the grub partition. In other words root (hd1,13) will appear as /dev/sdf14.)
Finally, enter the location of the install image file: /boot/upgrade/install.img. The installation will run normally at this point.
步骤 4: 清理menu.lst
After completing the upgrade, you will need to either boot the upgraded system manually by entering the newly installed kernel and initrd.img files at the grub command line, or by adding an entry to the menu.lst file.
The following is an example of a grub entry for a Fedora Core 10 installation, located on the fourteenth partition of the second hard drive.
title Fedora Core 10 (on /dev/sdb14) root (hd1,13) kernel /boot/vmlinuz-2.6.27.5-117.fc10.x86_64 ro quiet splash initrd /boot/initrd-2.6.27.5-117.fc10.x86_64 savedefault boot
Locate the updated kernel and initrd files located in the /boot folder of the Fedora partition, and create an entry with modified title, kernel, and initrd lines that will match those of the upgrade.
最后，从menu.lst移除升级引导入口。