Auto-Snapshot with dnf on Fedora | 在fedora上使用dnf自动快照

When I was using Arch Linux, one of my favorite packages was snap-pac, which works elegantly with pacman to create snapshots before and after any update.

当我在用 Arch Linux 的时候，我最喜欢的软件包之一是 snap-pac，它可以和 pacman 优雅地配合，在任何更新前后创建快照。

After I returned to Fedora, I wanted to implement a similar process for dnf. However, I found the solution is a little more complicated than on Arch, especially for dnf5. So, this article is a step-by-step guide to set it up.

回到 Fedora 后，我想为 dnf 实现类似的功能。然而，我发现解决方案比 Arch 上要复杂一些，特别是对于 dnf5。所以，这篇文章是一个手把手的设置指南。

1. Install necessary packages | 安装必要的软件包

sudo dnf install python3-dnf-plugin-snapper libdnf5-plugin-actions snapper -y

2. Setup snapper config | 设置 snapper 配置

sudo snapper -c root create-config /

If you want, you can also create snapshot for /home as well:

如果你愿意，也可以为 /home 创建快照：

sudo snapper -c home create-config /home

3. Setup dnf-snapper | 设置 dnf-snapper

sudo nano /etc/dnf/libdnf5-plugins/actions.d/snapper.actions

And copy and paste the following content:

然后复制并粘贴以下内容：

# Get the snapshot description
pre_transaction::::/usr/bin/sh -c echo\ "tmp.cmd=$(ps\ -o\ command\ --no-headers\ -p\ '${pid}')"

# Creates pre snapshots for root and home and stores snapshot numbers in variables
pre_transaction::::/usr/bin/sh -c echo\ "tmp.snapper_pre_root=$(snapper\ -c\ root\ create\ -c\ number\ -t\ pre\ -p\ -d\ '${tmp.cmd}')"
pre_transaction::::/usr/bin/sh -c echo\ "tmp.snapper_pre_home=$(snapper\ -c\ home\ create\ -c\ number\ -t\ pre\ -p\ -d\ '${tmp.cmd}')"

# Creates post snapshots for root and home if pre snapshot numbers exist
post_transaction::::/usr/bin/sh -c [\ -n\ "${tmp.snapper_pre_root}"\ ]\ &&\ snapper\ -c\ root\ create\ -c\ number\ -t\ post\ --pre-number\ "${tmp.snapper_pre_root}"\ -d\ "${tmp.cmd}"
post_transaction::::/usr/bin/sh -c [\ -n\ "${tmp.snapper_pre_home}"\ ]\ &&\ snapper\ -c\ home\ create\ -c\ number\ -t\ post\ --pre-number\ "${tmp.snapper_pre_home}"\ -d\ "${tmp.cmd}"

Now save and exit, and restart the computer if you can. Everything should work properly now.

现在保存并退出，如果可以的话重启电脑。一切都应该能正常工作了。

Conclusion | 总结

Using linux OS is an infinite loop of crash and recover. And snapshot is the only thing can help us take our breath and sleep at night.

使用 Linux 操作系统就是一个无限循环的崩溃和恢复。而快照是唯一能让我们在晚上松一口气，安然入睡的东西。

Reference | 参考

Getting snapper/btrfs-assistant to work with dnf5