Booting Fedora 36 on default btrfs partition structure from the grub prompt

One of the many logos from the many articles discussing Fedora 33’s stunning move to finally ditch XFS, after their unfortunate habit of talking much trash about btrfs for a number of years


I ran into an issue where I had an unpopulated grub menu on a Fedora 36 Workstation installation. It ended up only booting to the empty menu, but at least I could drop to a prompt to try and figure out how to get through it.

The usual booting with a live USB, mounting the affected drive to /mnt and the other partitions and bind mounts respectively, and rebuilding grub.cfg from chroot didn’t appear to be functional due to an error in the chroot environment that makes it unable to see /dev and use any of the usual tools to build the file.


All you really need to read in this article to boot from grub prompt is in the 2nd codeblock below (some people just here for the lols)

So booting from the grub prompt was necessary in order to be in an environment where /dev would be recognized and grub.cfg could be rebuilt – since grub.cfg isn’t anything that can be edited manually, unfortunately (it looks like it could be the way it’s named, but if you know anything about how grub works, you know it’s definitely not. Not even a little bit…)

I had written a while back about how to use the grub prompt in general here: The GRUB prompt: Demystified

The example I gave in the last article was done on Ubuntu. It looks like pretty much any other grub rescue operation using EXT4, XFS, etc. but it’s actually a homebrew ZFS initrd- I used to make my own ZFS built-in kernels regularly, and threw together a script for automating the process if you’re interested:

But lately I’ve been dabbling with Fedora so this article’s related to Fedora. It’s upstream for some great software, what can I say. I had an NVMe from a Thinkpad I’ve had for a couple years I tried to swap into a newer Thinkpad I was upgrading to, because Thinkpads. For some reason grub.cfg got hosed in the process and I couldn’t boot from it.

Not wanting to take too much time troubleshooting, I fresh-installed a new copy of Fedora 36 to another NVMe in the new laptop and copied as much as I could from /home and a package list from repoquery -a --installed run using chroot from the old NVMe in an external enclosure (gee willikers, I sure love my external NVMe with Thunderbolt 3, by golly).

Since I still had the old installation all set up, I thought I’d try and rescue it eventually, so when I got a moment I booted it from the external NVMe enclosure on another laptop with Thunderbolt using VMware Workstation and the enclosure as a physical disk .vmdk (hypervisors are awesome).

After failing with the tried-and-true live USB chroot rescue method, at least I could get into the grub menu without issue. That poor, empty menu, so lonely feeling with its 0 boot loader entries. I knew the OS was still there, but how to get into it without the entries? What’s a nerd to do? Start messing around with the prompt to explore how to crack open the damn thing!

Since this was btrfs, of course, it was a little different, and since each distro uses a different subvolume layout, none of the info about any of them translate to the others very well. At the time of writing, I didn’t see any definitive info on how to boot from grub prompt on stock btrfs Fedora Workstation, which is kind of surprising since it’s been btrfs default for 3-4 years now, since version 33.

There’s a great guide here about Ubutntu using btrfs on “nixventure”, which I admit I’d never heard of before, but appears very thorough, and I saw one from Debian (I believe) that I’m not going to reference because it was less remarkable, but Fedora there were just a bunch of forums with people flailing about trying to figure out the same thing I was, and ending up being unsuccessful and presumably giving up from the look of their abruptly truncated threads. So that was concerning, to say the last.

I even tried “rescatux” automated rescue tool, if you can believe that, because I was being lazy and kind of running out of ideas. I can’t say I give it a glowing review, but it tries. That statement probably indicates how well it worked for my needs. I had to suck it up and adapt what I knew about using the grub prompt to the new partition layout and filesystem. Thankfully, it all turned out well in the end.

Here’s some notes I took while I was working through the process:

# Fedora's variant of grub has some helpful btrfs-specific commands:

grub> help

. . . commands . . . 
btrfs-get-default-subvol (hd0,gpt3)
btrfs-list-subvols (hd0,gpt3)
. . . more commands . . .  

# so you get information like this:

grub> btrfs-list-subvols (hd0,gpt3)

ID 256 path home
ID 257 path root
ID 258 path var

# and this:

grub> btrfs-info (hd0,gpt3)

Label: 'fedora_treygouty' uuid: 7caff388-2bb3-434a-a927-096dac2dc892
        Total devices 1 FS bytes used 298520481792

# Intuitively, I thought this would work, but I was mistaken:

grub> linux /vmlinuz-5.17.9-300 <tab-tab works> root=UUID=7caff388-2bb3-434a-a927-096dac2dc892 ro rootflags=subvol=root

# You'd probably have to write all that out by hand, so be thankful I'm telling you ahead of time it didn't work for meCode language: PHP (php)

TL;DR #2 – you’re getting closer …

Anyway, I’ll cut to the chase and show how I did it. Note, again, for the record, this is the bare-minimum default partition structure on an Anaconda installed Fedora 36 Workstation setup. No LUKS or other encryption, no LVM.

Note: For the record, this is the first Anaconda (RedHat’s) installer where LVM hasn’t been enabled for the default partition configuration. LVM is marginally useful for btrfs, I’ve tried it before on OpenSUSE, but comparitively it’s much less of a crutch than it is for EXT4 or XFS filesystems. So if RH’s installer says don’t bother with LVM, don’t bother… It’s RH, you know how they LOVE their LVM, if they’re not recommending it it really must not be necessary. /rant

# Quick grub prompt recap --
# First, list your storage devices:

grub> ls

(proc) (hd0) (hd0,gpt3) (hd0,gpt2) (hd0,gpt1) (cd0) (cd0,msdos2) 

# If you're lucky like me and you only have one drive connected, /boot will be easy to find. /boot is almost always gpt2, and there's only one hard drive, so...:

grub> set root=(hd0,gpt2)

grub> ls /


# Set your vmlinuz and root device + partition. Here (hd0,gpt3) corresponds with /dev/sda3:

grub> linux /vmlinuz-5.17.9-300.fc36.x86_64 root=/dev/sda3 ro rootflags=subvol=root

# Then boot 'er up:

grub> boot
Code language: PHP (php)

That’s really all there is to it. It’s not too bad once you know what you’re doing. Since the process is so short, you might want to poke around some more to try and get more info, or to try and give your life meaning. There’s the (hd0,gpt2)/grub/grub.cfg file, or the /loader/entries folder – you can cat anything in either of those. Type help or something. Go wild.

Coincidentally, all the loaders were in the loader directory the entire time, but none of them would load all of the things. Such a bummer when one cannot load all of the things. So, frustrating, but glad it all worked out in the end. Hope this helps someone else, too.

VMware Upgrade renders Workstation 16.2.1 useless, thanks to Houdini-like disappearance of DLLs

Librarian replies to man inquiring about biography of famous escape artist, "I'm sorry sir, all of our books on Houdini have disappeared"
Picture depicts Houdinis as books disappearing from a library, while our problem depicts missing libraries themselves. Kinda makes you think, doesn’t it?


I just came across an issue many people have been experiencing after upgrading VMware Workstation to 16.2.1 in Windows. It looks like the installer has a bug that deletes two necessary files by accident, and their absence prevents the programs from running, beginning with vmware-tray.exe, which is the precursor to all things Workstation.

The lawnmowered files are two dynamic link libraries (“DLLs”) responsible for encryption. Their names are libssl-1_1.dll and libcrypto-1_1.dll. Thankfully, I’ve managed to gather them from a reliable source and have re-packaged them for your convenience. Below is an archive containing both missing files for you to download, in hopes that you may use them to remedy this rank insipidity:

The organization responsible for storing and distributing DLL files such as these is named, located at in lovely Tilf AB, Sweden. Their website offers a surprisingly painless, hassle-free download (full disclosure: no affiliation).

I actually visited a few other sites looking for these DLL files before I found, but all the other sites “provided” were dubious “utilities” containing code that made my antivirus software blush a deep shade of “seriously?”.

Speaking of malware, everything I am providing today has been scanned with Malwarebytes, the best antivirus software in the biz (full disclosure: no affiliation), which reports these DLLs, and obligatory license + attribution document, are as squeaky-clean as a newborn antelope (devouring placenta does have advantages). I installed them on my laptop, the one I’m using now, and it’s been smoother sailing than vacationing on Velveeta.

Installing random files with these kinds of file names actually can be a little scary, considering all the ransomware thieves who were wreaking havoc across the US a couple years ago, but legitimate programs use cryptographic libraries just often as cyber-criminals, perhaps even more. So never you be a’ feared of them scary ol’ names, now, their bark a’ far worse than their soo-eey.

Come to think of it, in contrast to the wrath of cryptographic criminals a couple years ago, it seems that recently the media is more likely to associate “crypto” with blockchain currency. At least wealth is a more pleasant association than robbery… <dentist office music>

To install the files above after you download them, unzip the .7z file using 7zip archive software, and move the two .dll files contained therein to the folder located at C:\Program Files (x86)\VMware\VMware Workstation\<files go here>

I used an admin command prompt to move mine, but you could just as easily open your file explorer to drag-and-drop them, I’m sure. Once Meta gets off their behinds and releases the first telekinesis controller, we’ll all be able to will our files across our hard drives with sheer focus and determination, but until then it’s a flail across our mice and keyboards. Sorry to remind you we’re still savages with disappearing DLLs.

Mount Ubuntu 22.04 ZFS partitions using live ISO for disaster recovery

ZFS Send and Receive ·

My system runs ZFS and lately has been dropping to the initramfs / busybox prompt on boot. I had a hard time finding a fleshed-out guide on how to mount ZFS in a live environment for performing disaster recovery tasks like chroot and grub repair, so I thought I’d write something up.

My system was dropping to the busybox prompt after GRUB menu. I started experiencing the issue after a routine apt upgrade, I rebooted and wasn’t able to get any of my initramfs to boot. It seems a little strange, because usually the inability to boot will be limited to a new initramfs – e.g. an older version of the kernel will still have the ZFS drivers, or other necessary components to boot, while the newer versions (the ones just installed) will be lacking these necessary components for whatever reason.

First of all, burn yourself a copy of a live USB, and boot into it. Luckily, the newest version of Ubuntu (22.04 – Jammy Jellyfish) has the ZFS drivers and executables installed by default, unlike prior versions where you had to add the multiverse repo manually, download the packages, and enable the ZFS drivers using modprobe.

A peek at lsmod shows the ZFS drivers are indeed loaded, and lo-and-behold, there’s the zpool and zfs executables:

ubuntu@ubuntu:~$ lsmod | grep zfs
zfs                  3751936  29
zunicode              348160  1 zfs
zzstd                 487424  1 zfs
zlua                  155648  1 zfs
zavl                   20480  1 zfs
icp                   319488  1 zfs
zcommon               102400  2 zfs,icp
znvpair                94208  2 zfs,zcommon
spl                   122880  6 zfs,icp,zzstd,znvpair,zcommon,zavl

ubuntu@ubuntu:~$ which {zpool,zfs}

The drive I am diagnosing is the internal NVMe, so there’s no need to attach it. One question I had was how to mount the two pools, and in what order. By default, Ubuntu creates an rpool for the root partition, and a bpool for the boot partition.

Generally, on an EFI system, one would mount the root partition in a clean directory like /mnt first, and subsequently mount boot at /mnt/boot once it is provided by the previously mounted root partition, and then mount efi at /mnt/boot/efi once that’s provided by the boot partition. As you can see, the order of mounting these partitions is therefore of paramount importance, but as there are only 3 options, it’s not too complicated.

You’ll need to be root for basically all these commands. Using sudo su without a password will typically get you to a root prompt (#) in a live environment.

TL;DR – probably way more than you ever wanted to know about an lsblk device list:

First, we should identify the storage devices using lsblk -f (the -f flag includes the filesystem information, which is important for our purposes):

# lsblk -f
     squash 4.0                                                    0   100% /rofs
     squash 4.0                                                    0   100% /snap/bare/5
     squash 4.0                                                    0   100% /snap/core20/1405
     squash 4.0                                                    0   100% /snap/snapd/15177
     squash 4.0                                                    0   100% /snap/snap-store/575
     squash 4.0                                                    0   100% /snap/gtk-common-themes/1534
     squash 4.0                                                    0   100% /snap/firefox/1232
     squash 4.0                                                    0   100% /snap/snapd-desktop-integration/10
     squash 4.0                                                    0   100% /snap/gnome-3-38-2004/99
sda  iso966 Jolie Ubuntu 22.04 LTS amd64
│                       2022-04-19-10-23-19-00                              
│    iso966 Jolie Ubuntu 22.04 LTS amd64
│                       2022-04-19-10-23-19-00                     0   100% /cdrom
│    vfat   FAT12 ESP   8D6C-A9F8                                           
     ext4   1.0   writable
                        bb277d84-75cc-473b-b327-fd885d85889a   24.5G     0% /var/crash
zd0  btrfs              b6239f8a-058b-4a6c-8258-b9a7b50f6c23                
     btrfs              d6074499-b9aa-47e0-a08a-58e27c73e771                
zd32 btrfs              c68aa9ca-933a-48cb-9adb-22fd6a8ca8c8                
     btrfs              f52702bd-c805-4edc-87d1-6fb877ee6738                
│    vfat   FAT32       B045-5C3B                                           
│    swap   1           584b9b78-7d8d-4a5a-9263-d6f6a48adc6b                
│    zfs_me 5000  bpool 11241115695889536197                                
     zfs_me 5000  rpool 16130566787573079380                                
│    vfat   FAT32       EC9D-0344                                           
│    ntfs               A4EEBDB4EEBD7F5C                                    
     ntfs               989EE7E99EE7BDBECode language: PHP (php)

OK, there’s a lot there, so what are we looking at? Well, the first 9 devices that say loop are snaps, since we’re on Ubuntu. Those are responsible for storing some of the programs being run by the OS. Each one gets their own virtual storage device, sometimes referred to as an “overlay”. They create a fair amount of clutter in our device list, but that’s about all. You can ignore them.

Then, /dev/sda is our copy of Ubuntu ISO we booted from – you can see how it says cdrom there, and iso9660 (the cdrom spec). It’s read-only, so we couldn’t do anything with it if we wanted to, and we don’t, so let’s move on…

There’s a device for log and crash log, so that’s kind of interesting. I imagine the live ISO makes those since you can’t write to the USB drive, seeing as the ISO is a virtual CD-ROM, and CD-ROMs are read-only. Then there’s a bunch of what are called “zvols” (the zd0, zd16, etc. devices – see those?). Those are devices created with ZFS that are isolated from the rest of the filesystem. zvols are virtual block devices you can use just like any other block device, but in this context they’re typically either formatted with a different filesystem, or mounted via iSCSI for block-level filesharing (filesystem-sharing?). You can see these ones say btrfs, they were actually created for use with container runtimes, namely podman and systemd-container, both of which support btrfs very well and ZFS either nominally or not at all.

Now we get to nvme1n1 – this is the first NVMe drive listed. Generally 0 would be listed first, but for some reason it’s listed second. n1 is the number of the drive (the second NVMe drive in the laptop), after that the partitions are listed as p1, p2, p3, and so on. Here’s the drive in isolation:

│    vfat   FAT32       B045-5C3B                                           
│    swap   1           584b9b78-7d8d-4a5a-9263-d6f6a48adc6b                
│    zfs_me 5000  bpool 11241115695889536197                                
     zfs_me 5000  rpool 16130566787573079380  

The canonical address for this drive is: /dev/nvme1n1p{1,2,3,4} . The /dev (device) folder, while not listed in this output, is important to reference, as the full path is required for mounting a partition. Typically one would only mount a single partition at a time, but you could conceivably chain them in a single command by using curly braces, as shown. This is not common, as you will probably need to mount different partitions in different locations (e.g. /mnt, /mnt/boot), and usually either in descending order, or with no pattern at all.

If you remember back at the start, I mentioned the rpool and bpool. These are seen on /dev/nvme1n1p4 and /dev/nvme1n1p3 respectively. If the disk were formatted in a block filesystem such as EXT4 (Ubuntu’s default filesystem), the root partition could be mounted by attaching /dev/nvme0n1p4 to an empty folder. The command would therefore be:

# mount /dev/nvme1n1p4 /mntCode language: PHP (php)

And then you’d be able to ls /mnt and see the files contained on your newly mounted root partition. E.g.:

# ls /mnt
Qogir  boot   dev  home  lib32  libx32  mnt  proc  run   snap  sys  usr
bin    cdrom  etc  lib   lib64  media   opt  root  sbin  srv   tmp  varCode language: PHP (php)

But this NVMe is formatted using ZFS. So what to do? That’s the process I was having difficulty finding that inspired this blog post.

End TL;DR – here’s the ZFS-specific stuff again:

First, after you confirm that you have your ZFS modules loaded by referencing your list of loaded kernel modules, and confirming that your ZFS executables are available in PATH (here’s the syntax again so you don’t have to scroll back):

# lsmod | grep zfs 
zfs                  3751936  29
zunicode              348160  1 zfs
zzstd                 487424  1 zfs
zlua                  155648  1 zfs
zavl                   20480  1 zfs
icp                   319488  1 zfs
zcommon               102400  2 zfs,icp
znvpair                94208  2 zfs,zcommon
spl                   122880  6 zfs,icp,zzstd,znvpair,zcommon,zavl

# which {zpool,zfs}
/usr/sbin/zfsCode language: PHP (php)

Here’s where it’s different than your typical mount. You use zpool to import rpool, but you need to mount it using an alternate root (at /mnt) – otherwise it’ll try to mount itself over your live environment! Then confirm that the import worked.

# zpool import -f rpool -R /mnt

# ls /mnt
Qogir  boot   dev  home  lib32  libx32  mnt  proc  run   snap  sys  usr
bin    cdrom  etc  lib   lib64  media   opt  root  sbin  srv   tmp  varCode language: PHP (php)

OK, that went well. You can see that now we have a /mnt/boot folder, which is boot inside rpool – that’s where initramfs lives, but they’re stored in the bpool. We needed that folder to be available to mount our bpool into. So, let’s import bpool into /mnt/boot as an alternate root (if we didn’t, it’d try and overwrite our currently mounted /boot partition:

# zpool import -f bpool -R /mnt/boot

# ls /mnt/boot
config-5.15.32-xanmod1       memtest86+_multiboot.bin
grub                         vmlinuz
initrd.img                   vmlinuz-5.15.32-xanmod1
initrd.img-5.15.32-xanmod1   vmlinuz-5.15.34-xanmod1
initrd.img-5.15.34-xanmod1   vmlinuz-5.15.36-xanmod1
initrd.img-5.17.0-xanmod1    vmlinuz-5.17.0-xanmod1
initrd.img-5.17.1-xanmod1    vmlinuz-5.17.1-xanmod1
initrd.img-5.17.3-xanmod1    vmlinuz-5.17.3-xanmod1
initrd.img-5.17.5-xanmod1    vmlinuz-5.17.5-xanmod1
initrd.img.old               vmlinuz-5.17.9-xanmod1
memtest86+.bin               vmlinuz-5.17.9-xanmod1-x64v2
memtest86+.elf               vmlinuz.oldCode language: PHP (php)

That looks like a bunch of initramfs files to me! Good, so that means those kickstarter runtimes that load from grub are available.

If you look in that list, you’ll also see both efi and grub folders. Both of those are empty and waiting for storage to be attached. The efi partition lives in the first partition of the same NVMe drive, and is formatted with FAT, and grub is a bind-mount (you can see it in /etc/fstab):

# mount -t msdos /dev/nvme1n1p1 /mnt/boot/efi

Can also use UUID from lsblk if prefer (just use one or other, not both): 
# mount -t msdos UUID=B045-5C3B /mnt/boot/efi

# ls /mnt/boot/efi
efi  grub  system~1  (confirm it's mounted)

# grep grub /mnt/etc/fstab
/boot/efi/grub	/boot/grub	none	defaults,bind	0	0
(we'll bind-mount this in next step)Code language: PHP (php)

Then you’ll want to mount a few system folders inside your drive’s filesystem so you can access them inside the chroot (required for things to work OK):

# for i in proc dev sys dev/pts; do mount -v --bind /$i /mnt/$i; done

mount: /proc bound on /mnt/proc.
mount: /dev bound on /mnt/dev.
mount: /sys bound on /mnt/sys.
mount: /dev/pts bound on /mnt/dev/pts.

# mount -v --bind /mnt/boot/efi/grub /mnt/boot/grub
mount: /mnt/boot/efi/grub bound on /mnt/boot/grub.Code language: PHP (php)

chrooting”: Now that all 3 partitions are mounted together in a cohesive filesystem tree, and you’ve got all your necessary bind mounts, one of the most effective ways to diagnose issues as if you’re running the affected disk, is to chroot into the filesystem. Run # chroot /mnt and now you’ll see /mnt as / (root), and you can run your programs as if you booted the computer using that drive (from the terminal, anyway):

# chroot /mnt

# apt update (failed)

# cd /etc
# ls -la resolv.conf
lrwxrwxrwx 1 root root 39 Feb 17 12:09 resolv.conf -> ../run/systemd/resolve/stub-resolv.confCode language: PHP (php)

If your network connection fails inside the chroot like mine did, go to /etc and delete resolv.conf if it’s a symlink to systemd-resolved (as shown above). Then point /etc/resolv.conf to a known good dns forwarder (e.g.,, etc.)

# echo 'nameserver' > resolv.conf

# apt update (works)

# apt list --installed | grep dkms

dkms/jammy,now 2.8.7-2ubuntu2 all [installed,automatic]
zfs-dkms/jammy-proposed,now 2.1.4-0ubuntu0.1 all [installed]Code language: PHP (php)

I was really hoping zfs-dkms got uninstalled somehow, because I thought that might have been why my initramfs files didn’t have zfs modules. So unfortunately I still have to keep looking to figure out what’s wrong…

Note, you’ll probably see this error a lot, but it’s safe to ignore:

ERROR couldn't connect to zsys daemon: connection error: desc = "transport: Error while dialing dial unix /run/zsysd.sock: connect: connection refused" 

Let’s try upgrading the packages and see what shakes out:

# apt upgrade 

The following packages were automatically installed and are no longer required:
  linux-headers-5.15.32-xanmod1 linux-headers-5.15.34-xanmod1
  linux-headers-5.15.36-xanmod1 linux-headers-5.17.0-xanmod1
  linux-headers-5.17.1-xanmod1 linux-headers-5.17.3-xanmod1
  linux-headers-5.17.5-xanmod1 linux-image-5.15.32-xanmod1
  linux-image-5.15.34-xanmod1 linux-image-5.15.36-xanmod1
  linux-image-5.17.0-xanmod1 linux-image-5.17.1-xanmod1
  linux-image-5.17.3-xanmod1 linux-image-5.17.5-xanmod1
Use 'sudo apt autoremove' to remove them.Code language: PHP (php)

That was … interesting … and then the issue presented itself next while I ran apt autoremove:

Setting up linux-image-5.17.9-xanmod1 (5.17.9-xanmod1-0~git20220518.d88d798) ...
 * dkms: running auto installation service for kernel 5.17.9-xanmod1     [ OK ] 
update-initramfs: Generating /boot/initrd.img-5.17.9-xanmod1
<span style="text-decoration: underline;"><strong>zstd: error 25 : Write error : No space left on device (cannot write compressed</strong> </span>

(emphasis added)Code language: HTML, XML (xml)

bpool has no space left. That’s almost certainly the problem. I’m going to remove a couple kernels and rebuild all my initramfs, that ought to do it. I’m also noticing my bpool is full of snapshots. List current snapshots with this first command, and then destroy them with the second one:

// This lists the snapshots:
# zfs list -H -o name -t snapshot | grep bpool look like pool/BOOT/ubuntu_pd3ehl<strong>@autozsys_xxxx</strong>, 
<strong>snapshots have @ symbol - no @ symbol, not a snapshot, don't delete it!</strong>

// This destroys the snapshots:
# zfs list -H -o name -t snapshot | grep bpool | xargs -n1 zfs destroy -r 
What this does:
(list only snapshots by full name) | (list only bpool) | (delete by ea line)
It's the same as what's above, but with the delete command, destroy. 

Make sure you understand what's going on with this command, as you can delete stuff you don't want to <em>really</em> easily. Please be careful.  Code language: PHP (php)

… looks pretty good to me – much more tidy:

# ls /boot
config-5.15.0-33-generic       memtest86+.elf
config-5.15.40-xanmod1-tt      memtest86+_multiboot.bin
initrd.img                     vmlinuz
initrd.img-5.15.0-33-generic   vmlinuz-5.15.0-33-generic
initrd.img-5.15.40-xanmod1-tt  vmlinuz-5.15.40-xanmod1-tt
initrd.img.old                 vmlinuz.old
memtest86+.binCode language: PHP (php)

Install some generic kernel to make sure you have one available, check that zfs-initramfs is installed if all you’re going to use is generic kernel (or zfs-dkms if using xanmod, other 3rd-party kernel). E.g. I got rid of my xanmod kernels just so I wouldn’t have to deal with building custom dkms modules:

# apt list --installed | grep xanmod

linux-headers-5.15.40-xanmod1-tt/unknown,now 5.15.40-xanmod1-tt-0~git20220515.867e3cb amd64 [installed,automatic]
linux-image-5.15.40-xanmod1-tt/unknown,now 5.15.40-xanmod1-tt-0~git20220515.867e3cb amd64 [installed,automatic]
linux-xanmod-tt/unknown,now 5.15.40-xanmod1-tt-0 amd64 [installed]
xanmod-repository/unknown,now 1.0.5 all [installed]

# apt remove linux-headers-5.15.40-xanmod1-tt linux-image-5.15.40-xanmod1-tt xanmod-repository linux-xanmod-tt zfs-dkms
 . . . 
The following packages will be REMOVED:
  linux-headers-5.15.40-xanmod1-tt linux-image-5.15.40-xanmod1-tt
  linux-xanmod-tt xanmod-repository zfs-dkms
Do you want to continue? [Y/n] 
 . . .
# apt autoremove -y

... install a couple kernels...

# apt install -y linux-{image,headers}-5.15.0-28-generic linux-{image,headers}-5.15.0-33-generic

 . . . using versions that are most current & 2nd most current now . . . 
 Code language: PHP (php)

Then update all the initramfs one last time, just in case. I’ll probably re-install grub, too, just bc, but one thing at a time…

# update-initramfs -uvk all  

. . . lots of output . . . that's how you know it's working . . . Code language: PHP (php)

Let’s re-install grub and run update-grub

# grub-install --bootloader-id=ubuntu --recheck --target=x86_64-efi --efi-directory=/boot/efi --no-floppy

Installing for x86_64-efi platform.
grub-install: warning: EFI variables cannot be set on this system.
grub-install: warning: You will have to complete the GRUB setup manually.
Installation finished. No error reported.Code language: PHP (php)

When you get this error, it just means you can’t set the UEFI boot order while you’re in a chroot. I also like to run update-grub for good measure (this is grub2-mkconfig -o /boot/grub/grub.cfg on most other systems if that’s more familiar sounding to you). Update-grub rebuilds the entries in your grub menu, along with their parameters detailed in /etc/default/grub.

Speaking of which, you can always take a peek at /etc/default/grub before you run this command – just in case.

# which update-grub

# cat /usr/sbin/update-grub

// update-grub:
set -e
exec grub-mkconfig -o /boot/grub/grub.cfg "$@"

# update-grub
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/init-select.cfg'
Generating grub configuration file ...
Found linux image: vmlinuz-5.15.0-33-generic in rpool/ROOT/ubuntu_pd3ehl
Found initrd image: initrd.img-5.15.0-33-generic in rpool/ROOT/ubuntu_pd3ehl
Found linux image: vmlinuz-5.15.0-28-generic in rpool/ROOT/ubuntu_pd3ehl
Found initrd image: initrd.img-5.15.0-28-generic in rpool/ROOT/ubuntu_pd3ehl
Found linux image: vmlinuz-5.15.0-33-generic in rpool/ROOT/ubuntu_pd3ehl@autozsys_yg50xc
 . . . snapshot menu entries . . . Code language: PHP (php)

Now leave the chroot now, remove the system folder redirects and bind mounts, and reboot, like so:

# exit

# for i in proc dev/pts dev sys boot/grub; do umount -v /mnt/$i; done
umount: /mnt/proc unmounted
umount: /mnt/dev/pts unmounted
umount: /mnt/dev unmounted
umount: /mnt/sys unmounted
umount: /mnt/boot/grub unmounted

# umount -v /dev/nvme1n1p1
umount: /mnt/boot/efi (/dev/nvme1n1p1) unmounted

# zpool export bpool

# zpool export rpoolCode language: PHP (php)

One last quick thing you can do before rebooting is check out efibootmgr and see which order your system will start up in. This is a little easier and more predictable, as you can make sure you boot from the right efi file, rather than mashing the startup menu button to make sure it loads the correct disk / efi.

Some stuff I was messing with trying cover all the bases. efibootmgr reference:

# efibootmgr -v
Boot0000* ubuntu	HD(1,GPT,544a9120-eef7-4aae-8311-cd6ca6929213,0x800,0x100000)/File(\EFI\ubuntu\shimx64.efi)
 . . . 
# efibootmgr -B Boot0000 -b 0

# efibootmgr --create /dev/nvme1n1 --part 1 --write-signature --loader /EFI/GRUB/grubx64.efi --label "GRUB" --verbose
BootCurrent: 0002
Timeout: 0 seconds
BootOrder: 0000,0001,0002
Boot0001* UEFI: Samsung SSD 980 1TB, Partition 1	HD(1,GPT,6afa5e93-54a5-4628-978f-313a0dcfe27b,0x800,0xfa000)/File(\EFI\Microsoft\Boot\bootmgfw.efi)..BO
Boot0002* UEFI: Samsung Flash Drive DUO 1100, Partition 2	PciRoot(0x0)/Pci(0x14,0x0)/USB(16,0)/HD(2,GPT,a09db2b8-b5f6-43ae-afb1-91e0a90189a1,0x6cc954,0x2130)..BO
Boot0003  Windows Boot Manager	HD(1,GPT,6afa5e93-54a5-4628-978f-313a0dcfe27b,0x800,0xfa000)/File(\EFI\Microsoft\Boot\bootmgfw.efi)WINDOWS.........x...B.C.D.O.B.J.E.C.T.=.{.9.d.e.a.8.6.2.c.-.5.c.d.d.-.4.e.7.0.-.a.c.c.1.-.f.3.2.b.3.4.4.d.}....................
Boot0000* GRUB	HD(1,GPT,a09db2b8-b5f6-43ae-afb2-91e0a90189a1,0x40,0x6cc914)/File(\EFI\GRUB\grubx64.efi)/dev/nvme1n1Code language: PHP (php)

A troubleshooting tip: If you have issues using the pool names with zpool for some reason, the UUIDs are listed in lsblk. While technically interchangeable, the UUID can coax some commands into to working correctly when the name can’t.

If it doesn’t boot from the ZFS drive again, boot it into the live ISO and go through everything all over … 😉 Good luck!!

dpdk 22.03 rpm packages for Fedora 36: a dependency of openvswitch

open vswitch with DPDK: architecture and performance - ppt download

I meant to post this over a month ago, but got sidetracked, so I’m coming in a little late. Unfortunately, it looks like even though Fedora 36 has officially been released, the dpdk 22.03 rpms still aren’t available.

Back when I compiled these, I realized there were no official dpdk 22.03 rpms available in the yum repos, despite being required for openvswitch. So I compiled them so I could install openvswitch for use with virt-manager.

Dpdk on Fedora has an official maintainer, they probably just got sidetracked themselves – I can relate. But I had these packages already and wanted to help other people install openvswitch, so I posted the resulting packages in a github repo case other people want to download it.

So if you (like me) want to run openvswitch on your fancy new officially-released non-beta Fedora 36 workstation (or server, or silverblue, kinoite or iot using rpm-ostree), and you don’t want to wait or downgrade, you’d have to either have to compile dpdk 22.03 for yourself, or now you can download them from my repo.

I’ve got all the instructions to go through the build process if you’d like to get your hands dirty with compilation (it’s pretty straightforward):

The .rpm files are also there if you don’t care for all the fuss of compilation. You can use them as openvswitch dependencies, just install them before you try and install openvswitch using dnf.

I should have made this post sooner so people knew the rpms were available, but at least I put a note or two in on reddit in a couple key places (now that I think about it, probably just /r/fedora). Nothing beats the officialism of posting a fancy notice on your wordpress blog, though, amirite?

Speaking of which, I think I will be looking at a way of integrating this blog with my repo – I’m hoping I can figure out a way to produce and update posts on wordpress automatically by creating a gist or a new repo. Then the two would be more tightly integrated, and could avoid this whole getting sidetracked issue…

The less people get sidetracked, the sooner they use software…