Start Application Without the X Bit Set

When one plays in many environments, ocassionally you can expect issues. For me one of those issues was starting Linux application from a shared drive. For reasons I won’t get into now, except to say security-related, executable (aka X) bit was removed. Thus it wasn’t possible to start application.

But, as always in Linux, there are multiple ways to skin a cat. For me the method that did wonders was usage of ld-linux library. For example, to start a.out application, one could use the following command:

/usr/lib64/ld-linux-x86-64.so.2 ./a.out

PS: This is for applications (e.g., files with ELF header). If you want to run a script without executable bit set, just call the interpreter directly, e.g.:

bash ./a.sh

Sleep Until the Next Full Second

For a bash script of mine I had to execute a certain command every second. While this command lasted less than a second, its duration was not always the same. Sometimes it would be done in 0.1 seconds, sometime in 0.5, and rarely in more than 1 second (that’s curl download for you). This variance made using a simple sleep command a bit suboptimal.

What I needed was a command that would wait until the next full second. What I needed up with was this

SLEEP_SEC=`printf "0.%03d" $((1000 - 10#$(date +%N | head -c 3)))`
if [[ "$SLEEP_SEC" == "0.000" ]]; then SLEEP_SEC="1.000"; fi
sleep $SLEEP_SEC

The first line is just taking the current nano-second count and trimming it to the first three digits that are then subtracted from 1000 and prefixed with 0.. This essentially gives millisecond precision count until the next full second. For example, if current nanosecond counter is 389123544, this would result in 0.611. And yes, you lose a bit of precision here as number gets truncated but the result will be precise enough.

If you wonder what is 10# doing here, it’s just ensuring numbers starting with 0 are not misdetected by bash as octal numbers.

The if conditional that follows is just to ensure there is at least 1 second of sleep if the previous command took less than 1 ms. Rare occurrence but cheap enough to protect against.

Finally, we send this to the sleep command which will do its magic and allow the script to continue as the next second starts. And yes, it’s not a millisecond precise despite all this calculation as sleep is not meant to be precise to start with. However, it is consistent and it triggers within the same 2-3 milliseconds almost every time. And that was plenty precise for me.

Disabling Horizontal Scroll on Logitech MX Master on Ubuntu 22.04

One feature that annoys the heck out of me on my MX Master is horizontal scroll. While usefulness of the horizontal scroll itself is already debatable, its positioning on MX Master is abhorrent. Side scroll wheels are extremely easy to hit by accident and they turn as soon as you even think about them. The only saving grace is that most applications don’t support them.

Under Windows, it’s easy to disable them in Logitech Options software. But Linux has no equivalent of this (and yes, I’m discounting LogiOps here, potentially unfairly so). Fortunately, Linux does offer a fine-grained control by default.

The first step is finding mouse ID under pointer devices (ignore it under keyboard).

xinput list

To verify you have the correct mouse and if you want to check which buttons horizontal scrool wheel occupies, you can use xinput test:

xinput test <id>

For MX master (and honestly pretty much any other mouse I tried), these values were 6 and 7. Thus we can simply disable them using xinput again.

xinput set-button-map <id> 1 2 3 4 5 0 0 8 9

And that has our horizontal scroll gone for good. Interestingly, while we can still see motion values, no application seems to react to those alone.

As this change will dissapear with reboot, I personally place them in .bash_profile so they get applied each time my user logs on.

PS: I also have my thumb button reconfigured.

Looping Ansible on Per-user Basis

When I moved my home network to Ansible, I had one problem repeating in many roles. How to do some action for every user?

For example, take setitng up a default .SSH configuration or Bash profile. While setting it for known users is easy enough, I wanted a role to setup things automatically for any user present on the system. Since searches of existing solutions didn’t fully apply to my solution, I decided to roll my own.

The first part is getting list of users and here is where good old passwd comes into play. However, one needs to filter it first for all accounts that cannot log into the system.

grep -v -e '/nologin$' -e '/bin/false$' -e '/bin/sync$' /etc/passwd

In Ansible, collecting this data would look something like this:

- name: Find all users
  shell: "grep -v -e '/nologin$' -e '/bin/false$' -e '/bin/sync$' /etc/passwd"
  register: grep_users_result
  changed_when: false
  failed_when: false

With user list in hand, we can now include the other task and forward it data it needs. In my case, that would be user name and its directory.

- name: Setup user
  include_tasks: peruser.yml
  vars:
    user_name: "{{ item.split(':').0 }}"
    user_directory: "{{ item.split(':').5 }}"
  with_items: "{{ grep_users_result.stdout_lines | list }}"

Finally, we can use those variables in a separate task file:

- name: "Setup .ssh directory ()"
  file:
    path: "/.ssh"
    state: directory
    owner: ""
    group: ""
    mode: "0700"

Easy peasy.

Native ZFS Encryption Speed (Ubuntu 22.10)

There is a newer version of this post.

I guess it’s that time of year when I do ZFS encryption testing on the latest Ubuntu. Is ZFS speed better, worse, or the same?

Like the last time, I did testing on Framework laptop with i5-1135G7 processor and 64GB of RAM. The only change is that I am writing a bit more data during the test this time. Regardless, this is still mostly an exercise in relative numbers. Overall, the procedure is still basically the same as before.

With all that out of way, you can probably just look at the 22.04 figures and be done. While there are some minor differences between 22.10 and 22.04, there is nothing big enough to change any recommendation here. Even ZFS version reflects this as we see only a tiny bump from zfs-2.1.2-1ubuntu2 to zfs-2.1.5-1ubuntu2.

ZFS GCM is still the fastest when it comes to writing and it wins over LUKS by a wide margin. It was a surprise when I saw it with 22.04 and it’s a surprise still. The surprise is not that ZFS is fast but why the heck is LUKS so slow. When it comes to reading speed, LUKS is still slightly faster but not by a wide margin.

With everything else the same, I would say ZFS GCM is a clear winner here with LUKS coming close second if you don’t mind slower write speed. I would expect both to be indistinguishable when it comes to real-world scenarios most of the time.

Using CCM encryption doesn’t make much sense at all. While encryption speed seems to benefit from disabling AES (part of which I suspect to be an artefact of my test environment), it’s just a smidgen faster than GCM. Considering that any upgrade in future is going to bring AES instruction set, I would say GCM is the way forward.

Of course, the elephant in the room is the fact the native ZFS encryption doesn’t actually cover all metadata. The only alternative that can help you with that is running ZFS on top of LUKS encryption. I honestly go back and forth between two with current preference being toward LUKS on laptop and the native ZFS encryption on servers where encrypted send/receive is a killer feature.

You can take a peek at the raw data and draw your own conclusions. As always, just keep in mind that these are just limited synthetic tests intended just to give you ballpark figure. Your mileage may vary.

Encrypted ZFS on Ubuntu 22.10

Ubuntu 22.10 in release notes brought one unpleasant news: “The option to install using zfs as a file system and encryption has been disabled due to a bug”. The official recommendation is to “simply” install Ubuntu 22.04 and upgrade from there. However, if you are willing to go over a lot of manual steps, that’s not necessary.

Those familiar with my previous installation guides will note two things. First, steps below will use LUKS encryption instead of the native ZFS option. I’ve been going back and forth on this one as I do like native ZFS encryption but in setups with hibernation enabled (and this one will be one of those), having both swap with LUKS and native ZFS would require user to type password twice. Not a great user experience.

Second, my personal preferences will “leak through”. This guide will clearly show dislike of snap system and use of way too big swap partition to facilitate hibernation under even the worst-case scenario. Your preferences might vary and thus you might want to adjust guide as necessary. The important part is disk and boot partition setup, everything else is just extra fluff.

Without further ado, let’s proceed with the install.

After booting into Ubuntu desktop installation (via “Try Ubuntu” option) we want to open a terminal. Since all further commands are going to need root credentials, we can start with that.

sudo -i

The very first step should be setting up a few variables - disk, hostname, and username. This way we can use them going forward and avoid accidental mistakes. Just make sure to replace these values with ones appropriate for your system. I like to use upper-case for ZFS pool as that’s what will appear as password prompt. It just looks nicer and ZFS doesn’t care either way.

DISK=/dev/disk/by-id/<diskid>
HOST=<hostname>
USER=<username>

For my setup I want 4 partitions. First two partitions will be unencrypted and in charge of booting. While I love encryption, I decided not to encrypt boot partition in order to make my life easier as you cannot integrate boot partition password prompt with the later data password prompt thus requiring you to type password twice. Both swap and ZFS partitions are fully encrypted.

Also, my swap size is way too excessive since I have 64 GB of RAM and I wanted to allow for hibernation under the worst of circumstances (i.e., when RAM is full). Hibernation usually works with much smaller partitions but I wanted to be sure and my disk was big enough to accommodate.

Lastly, while blkdiscard does nice job of removing old data from the disk, I would always recommend also using dd if=/dev/urandom of=$DISK bs=1M status=progress if your disk was not encrypted before.

blkdiscard -f $DISK
sgdisk --zap-all                      $DISK
sgdisk -n1:1M:+127M -t1:EF00 -c1:EFI  $DISK
sgdisk -n2:0:+896M  -t2:8300 -c2:Boot $DISK
sgdisk -n3:0:+65G   -t3:8200 -c3:Swap $DISK
sgdisk -n4:0:0      -t4:8309 -c4:ZFS  $DISK
sgdisk --print                        $DISK

Once partitions are created, we want to setup our LUKS encryption.

cryptsetup luksFormat -q --type luks2 \
    --cipher aes-xts-plain64 --key-size 512 \
    --pbkdf argon2i $DISK-part4
cryptsetup luksFormat -q --type luks2 \
    --cipher aes-xts-plain64 --key-size 512 \
    --pbkdf argon2i $DISK-part3

Since creating encrypted partition doesn’t mount them, we do need this as a separate step. Notice I use host name as the name of the main data partition.

cryptsetup luksOpen $DISK-part4 $HOST
cryptsetup luksOpen $DISK-part3 swap

Finally, we can setup our ZFS pool with an optional step of setting quota to roughly 80% of disk capacity. Adjust exact value as needed.

zpool create -o ashift=12 -o autotrim=on \
    -O compression=lz4 -O normalization=formD \
    -O acltype=posixacl -O xattr=sa -O dnodesize=auto -O atime=off \
    -O canmount=off -O mountpoint=none -R /mnt/install ${HOST^} /dev/mapper/$HOST
zfs set quota=1.5T ${HOST^}

I used to be fan of using just a main dataset for everything but these days I use more conventional “separate root dataset” approach.

zfs create -o canmount=noauto -o mountpoint=/ ${HOST^}/Root
zfs mount ${HOST^}/Root

And a separate home partition will not be forgotted.

zfs create -o canmount=noauto -o mountpoint=/home ${HOST^}/Home
zfs mount ${HOST^}/Home
zfs set canmount=on ${HOST^}/Home

With all datasets in place, we can finish setting the main dataset properties.

zfs set devices=off ${HOST^}

Now it’s time to format swap.

mkswap /dev/mapper/swap

And then boot partition.

yes | mkfs.ext4 $DISK-part2
mkdir /mnt/install/boot
mount $DISK-part2 /mnt/install/boot

And finally EFI partition.

mkfs.msdos -F 32 -n EFI -i 4d65646f $DISK-part1
mkdir /mnt/install/boot/efi
mount $DISK-part1 /mnt/install/boot/efi

At this time, I also like to disable IPv6 as I’ve noticed that on some misconfigured IPv6 networks it takes ages to download packages. This step is both temporary (i.e., IPv6 is disabled only during installation) and fully optional.

sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1
sudo sysctl -w net.ipv6.conf.default.disable_ipv6=1
sudo sysctl -w net.ipv6.conf.lo.disable_ipv6=1

To start the fun we need debootstrap package. Starting this step, you must be connected to the Internet.

apt update && apt install --yes debootstrap

Bootstrapping Ubuntu on the newly created pool comes next. This will take a while.

debootstrap $(basename `ls -d /cdrom/dists/*/ | grep -v stable | head -1`) /mnt/install/

We can use our live system to update a few files on our new installation.

echo $HOST > /mnt/install/etc/hostname
sed "s/ubuntu/$HOST/" /etc/hosts > /mnt/install/etc/hosts
sed '/cdrom/d' /etc/apt/sources.list > /mnt/install/etc/apt/sources.list
cp /etc/netplan/*.yaml /mnt/install/etc/netplan/

If you are installing via WiFi, you might as well copy your wireless credentials. Don’t worry if this returns errors - that just means you are not using wireless.

mkdir -p /mnt/install/etc/NetworkManager/system-connections/
cp /etc/NetworkManager/system-connections/* /mnt/install/etc/NetworkManager/system-connections/

Atlast, we’re ready to “chroot” into our new system.

mount --rbind /dev  /mnt/install/dev
mount --rbind /proc /mnt/install/proc
mount --rbind /sys  /mnt/install/sys
chroot /mnt/install \
    /usr/bin/env DISK=$DISK USER=$USER \
    bash --login

With our newly installed system running, let’s not forget to setup locale and time zone.

locale-gen --purge "en_US.UTF-8"
update-locale LANG=en_US.UTF-8 LANGUAGE=en_US
dpkg-reconfigure --frontend noninteractive locales
dpkg-reconfigure tzdata

Now we’re ready to onboard the latest Linux image.

apt update
apt install --yes --no-install-recommends linux-image-generic linux-headers-generic

Followed by the boot environment packages.

apt install --yes zfs-initramfs cryptsetup keyutils grub-efi-amd64-signed shim-signed

Now it’s time to setup crypttab so our encrypted partitions are decrypted on boot.

echo "$HOST UUID=$(blkid -s UUID -o value $DISK-part4) none \
    luks,discard,initramfs,keyscript=decrypt_keyctl" >> /etc/crypttab
echo "swap UUID=$(blkid -s UUID -o value $DISK-part3) none \
    swap,luks,discard,initramfs,keyscript=decrypt_keyctl" >> /etc/crypttab
cat /etc/crypttab

To mount all those partitions, we need also some fstab entries. The last entry is not strictly needed. I just like to add it in order to hide our LUKS encrypted ZFS from file manager.

echo "PARTUUID=$(blkid -s PARTUUID -o value $DISK-part2) \
    /boot ext4 noatime,nofail,x-systemd.device-timeout=5s 0 1" >> /etc/fstab
echo "PARTUUID=$(blkid -s PARTUUID -o value $DISK-part1) \
    /boot/efi vfat noatime,nofail,x-systemd.device-timeout=5s 0 1" >> /etc/fstab
echo "UUID=$(blkid -s UUID -o value /dev/mapper/swap) \
    none swap defaults 0 0" >> /etc/fstab
echo "/dev/disk/by-uuid/$(blkid -s UUID -o value /dev/mapper/$HOST) \
    none auto nosuid,nodev,nofail 0 0" >> /etc/fstab
cat /etc/fstab

If hibernation is desired, a few settings need to be added.

sed -i 's/.*AllowSuspend=.*/AllowSuspend=yes/' \
    /etc/systemd/sleep.conf
sed -i 's/.*AllowHibernation=.*/AllowHibernation=yes/' \
    /etc/systemd/sleep.conf
sed -i 's/.*AllowSuspendThenHibernate=.*/AllowSuspendThenHibernate=yes/' \
    /etc/systemd/sleep.conf
sed -i 's/.*HibernateDelaySec=.*/HibernateDelaySec=13min/' \
    /etc/systemd/sleep.conf

Since we’re doing laptop setup, we can also setup lid switch. I like to set it as suspend-then-hibernate.

sed -i 's/.*HandleLidSwitch=.*/HandleLidSwitch=suspend-then-hibernate/' \
    /etc/systemd/logind.conf
sed -i 's/.*HandleLidSwitchExternalPower=.*/HandleLidSwitchExternalPower=suspend-then-hibernate/' \
    /etc/systemd/logind.conf

Lastly, I adjust swappiness a bit.

echo "vm.swappiness=10" >> /etc/sysctl.conf

And then, we can get grub going. Do note we also setup booting from swap (hibernation support) here too.

sed -i "s/^GRUB_CMDLINE_LINUX_DEFAULT.*/GRUB_CMDLINE_LINUX_DEFAULT=\"quiet splash \
    nvme.noacpi=1 \
    RESUME=UUID=$(blkid -s UUID -o value /dev/mapper/swap)\"/" \
    /etc/default/grub
update-grub
grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=Ubuntu \
    --recheck --no-floppy
update-initramfs -u -k all

Next step is to create boot environment.

KERNEL=`ls /usr/lib/modules/ | cut -d/ -f1 | sed 's/linux-image-//'`
update-initramfs -c -k $KERNEL

Finally, we can install our desktop environment.

apt install --yes ubuntu-desktop-minimal

Once installation is done, I like to remove snap and banish it from ever being installed.

apt remove --yes snapd
echo 'Package: snapd'    > /etc/apt/preferences.d/snapd
echo 'Pin: release *'   >> /etc/apt/preferences.d/snapd
echo 'Pin-Priority: -1' >> /etc/apt/preferences.d/snapd

Since Firefox is only available as snapd package, we can install it manually.

add-apt-repository --yes ppa:mozillateam/ppa
cat << 'EOF' | sed 's/^    //' | tee /etc/apt/preferences.d/mozillateamppa
    Package: firefox*
    Pin: release o=LP-PPA-mozillateam
    Pin-Priority: 501
EOF
apt update && apt install --yes firefox

While at it, I might as well get Chrome too.

cd /tmp
wget --inet4-only https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb
apt install ./google-chrome-stable_current_amd64.deb

For Framework Laptop I use here, we need one more adjustment due to Dell audio needing a special care. Note that owners of Gen12 boards need a few more adjustments.

echo "options snd-hda-intel model=dell-headset-multi" >> /etc/modprobe.d/alsa-base.conf

Of course, we need to have a user too.

adduser --disabled-password --gecos '' $USER
usermod -a -G adm,cdrom,dialout,dip,lpadmin,plugdev,sudo,tty $USER
echo "$USER ALL=NOPASSWD:ALL" > /etc/sudoers.d/$USER
passwd $USER

I like to add some extra packages and do one final upgrade before calling it done.

add-apt-repository --yes universe
apt update && apt dist-upgrade --yes

It took a while but we can finally exit our debootstrap environment.

exit

Let’s clean all mounted partitions and get ZFS ready for next boot.

umount /mnt/install/boot/efi
umount /mnt/install/boot
mount | grep -v zfs | tac | awk '/\/mnt/ {print $3}' | xargs -i{} umount -lf {}
zpool export -a

With reboot, we should be done and our new system should boot with a password prompt.

reboot

Once we log into it, we need to adjust boot image and test hibernation. If you see your desktop after waking it up, all is good.

sudo update-initramfs -u -k all
sudo systemctl hibernate

If you get Failed to hibernate system via logind: Sleep verb "hibernate" not supported go into BIOS and disable secure boot (Enforce Secure Boot option). Unfortunately, secure boot and hibernation still don’t work together but there is some work in progress to make it happen in future. At this time, you need to select one or the other.

PS: If you already installed system with secure boot and hibernation is not working, run update-initramfs -c -k all and try again.

PPS: There are versions of this guide using the native ZFS encryption for other Ubuntu versions: 22.04, 21.10, and 20.04.

PPPS: For LUKS-based ZFS setup, check the following posts: 20.04, 19.10, 19.04, and 18.10.

Manually Installing Ubuntu 22.04 on Surface Go (with Hibernation)

Just a few months ago I had a post about installing Ubuntu 22.04 on Surface Go. And that guide is still valid. However, while using my Surface Go during vacation, I noticed I miss hibernation. Yes, deep sleep is nice enough but hibernation is much sweeter deal when you expect your device to wake up after a longer time period.

Do note I am a huge fan of encryption and thus this guide will have both data and swap encrypted thus complicating setup a bit.

As always, all starts with a creation of Ubuntu installation media and booting into it. If done from Windows, you can use the original instructions for both. If you already have Linux installed, you can check how to do it from grub. Either way, I’ll asume you have it all booted and that you selected “Try Ubuntu” when offered.

From there we need to get into Terminal and become a root user.

sudo -i

The very next step should be setting up a few variables - host, user name, and disk. This way we can use them going forward and avoid accidental mistakes.

DISK=/dev/mmcblk0
HOST=smeagol
USER=josip

Disk setup is a bit more wasteful than what you would get following the original guide. While EFI and boot partitions are the same size, the swap partition has been increased to match RAM size (4 GB in my case). While you don’t necessarily need it that big, it will help with hibernation if you do. And yes, I’m cheating a bit since the final swap size will be a bit under as encryption headers will take a bit of space. If you really need all MMC space you can get, system will work (most of the time) fine with 2 GB too.

blkdiscard -f $DISK
sgdisk --zap-all                     $DISK
sgdisk -n1:1M:+63M -t1:EF00 -c1:EFI  $DISK
sgdisk -n2:0:+640M -t2:8300 -c2:Boot $DISK
sgdisk -n3:0:+4G   -t3:8200 -c3:Swap $DISK
sgdisk -n4:0:0     -t4:8309 -c4:Root $DISK
sgdisk --print                       $DISK

While one could encrypt boot partition too, I usually don’t do it as it prevents double prompt (grub has to unlock boot partition separately of others) and that is too annoying for my taste. I do encrypt both data and swap of course. Make sure they use the same password if you don’t want to always enter password twice.

cryptsetup luksFormat -q --type luks2 \
    --cipher aes-xts-plain64 --key-size 256 \
    --pbkdf argon2i ${DISK}p4

cryptsetup luksFormat -q --type luks2 \
    --cipher aes-xts-plain64 --key-size 256 \
    --pbkdf argon2i ${DISK}p3

Once encryption is done, we need to load the devices. For the main partition I like to use hostname as it’s displayed in the prompt.

cryptsetup luksOpen ${DISK}p4 ${HOST}

cryptsetup luksOpen ${DISK}p3 swap

Now we can format (and mount) all partitions.

yes | mkfs.ext4 /dev/mapper/${HOST}
mkdir /mnt/install
mount /dev/mapper/${HOST} /mnt/install/

mkswap /dev/mapper/swap

yes | mkfs.ext4 ${DISK}p2
mkdir /mnt/install/boot
mount ${DISK}p2 /mnt/install/boot/

mkfs.msdos -F 32 -n EFI -i 4d65646f ${DISK}p1
mkdir /mnt/install/boot/efi
mount ${DISK}p1 /mnt/install/boot/efi

To start the fun we need the debootstrap package. Do make sure you have Wireless network connected at this time as otherwise operation will not succeed.

apt update ; apt install --yes debootstrap

And then we can get basic OS on the disk. This will take a while.

debootstrap $(basename `ls -d /cdrom/dists/*/ | grep -v stable | head -1`) /mnt/install/

Our newly copied system is lacking a few files and we should make sure they exist before proceeding.

echo $HOST > /mnt/install/etc/hostname
sed "s/ubuntu/$HOST/" /etc/hosts > /mnt/install/etc/hosts
sed '/cdrom/d' /etc/apt/sources.list > /mnt/install/etc/apt/sources.list
cp /etc/netplan/*.yaml /mnt/install/etc/netplan/

If you are installing via WiFi, you might as well copy your wireless credentials

mkdir -p /mnt/install/etc/NetworkManager/system-connections/
cp /etc/NetworkManager/system-connections/* /mnt/install/etc/NetworkManager/system-connections/

Finally we’re ready to “chroot” into our new system.

mount --rbind /dev  /mnt/install/dev
mount --rbind /proc /mnt/install/proc
mount --rbind /sys  /mnt/install/sys
chroot /mnt/install \
    /usr/bin/env DISK=$DISK HOST=$HOST USER=$USER \
    bash --login

For the new system we need to setup the locale and the time zone.

locale-gen --purge "en_US.UTF-8"
update-locale LANG=en_US.UTF-8 LANGUAGE=en_US
dpkg-reconfigure --frontend noninteractive locales

dpkg-reconfigure tzdata

Now we’re ready to onboard the latest Linux image. And yes, there is a Surface Go specific kernel, but it seems that 5.17 you get with OEM kernels is as good.

apt update
apt install --yes --no-install-recommends linux-oem-22.04

Then we install boot environment packages.

apt install --yes initramfs-tools cryptsetup keyutils grub-efi-amd64-signed shim-signed

Since we’re dealing with encrypted data, we should auto mount it via crypttab. If there are multiple encrypted drives or partitions, keyscript really comes in handy to open them all with the same password…

echo "${HOST} UUID=$(blkid -s UUID -o value ${DISK}p4)  none \
    luks,discard,initramfs,keyscript=decrypt_keyctl" >> /etc/crypttab
echo "swap UUID=$(blkid -s UUID -o value ${DISK}p3) none \
    swap,luks,discard,initramfs,keyscript=decrypt_keyctl" >> /etc/crypttab
cat /etc/crypttab

To mount partitions, we need to do some fstab setup too:

echo "UUID=$(blkid -s UUID -o value /dev/mapper/${HOST}) \
    / ext4 noatime,nofail,x-systemd.device-timeout=5s 0 1" >> /etc/fstab
echo "PARTUUID=$(blkid -s PARTUUID -o value ${DISK}p2) \
    /boot ext4 noatime,nofail,x-systemd.device-timeout=5s 0 1" >> /etc/fstab
echo "PARTUUID=$(blkid -s PARTUUID -o value ${DISK}p1) \
    /boot/efi vfat noatime,nofail,x-systemd.device-timeout=5s 0 1" >> /etc/fstab
echo "UUID=$(blkid -s UUID -o value /dev/mapper/swap) \
    none swap defaults 0 0" >> /etc/fstab
cat /etc/fstab

While defaults are actually matching most of the needed values, I like to explicilty list them and manually configure the time after which sleep will be followed by automatic hybernation (10 minutes in my case).

sed -i 's/.*AllowSuspend=.*/AllowSuspend=yes/' \
    /etc/systemd/sleep.conf
sed -i 's/.*AllowHibernation=.*/AllowHibernation=yes/' \
    /etc/systemd/sleep.conf
sed -i 's/.*AllowSuspendThenHibernate=.*/AllowSuspendThenHibernate=yes/' \
    /etc/systemd/sleep.conf
sed -i 's/.*HibernateDelaySec=.*/HibernateDelaySec=10min/' \
    /etc/systemd/sleep.conf

Lid switch can be then easily setup to use suspend-then-hibernate.

sed -i 's/.*HandleLidSwitch=.*/HandleLidSwitch=suspend-then-hibernate/'
    /etc/systemd/logind.conf
sed -i 's/.*HandleLidSwitchExternalPower=.*/HandleLidSwitchExternalPower=suspend-then-hibernate/'
    /etc/systemd/logind.conf

I also like to adjust swappiness to make system a bit more lively.

echo "vm.swappiness=10" >> /etc/sysctl.conf

With all that out of way, we can finally update our boot environment.

KERNEL=`ls /usr/lib/modules/ | cut -d/ -f1 | sed 's/linux-image-//'`
update-initramfs -u -k $KERNEL

Grub update is the last part we need to make system bootable. And no, the second initramfs update is not optional as it needs to pickup RESUME variable.

sed -i "s/^GRUB_CMDLINE_LINUX_DEFAULT.*/GRUB_CMDLINE_LINUX_DEFAULT=\"quiet splash \
    RESUME=UUID=$(blkid -s UUID -o value /dev/mapper/swap)\"/" \
    /etc/default/grub
update-grub
grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=Ubuntu \
    --recheck --no-floppy
update-initramfs -u -k all

Finally we install out GUI environment. I personally like ubuntu-desktop-minimal but you can opt for ubuntu-desktop.

apt install --yes ubuntu-desktop-minimal

Since this will not install any browser, you can add Firefox package too (apt install firefox) but I like to download Chrome.

cd /tmp
wget --inet4-only https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb
sudo apt install ./google-chrome-stable_current_amd64.deb

Having power button do a hibernate action requires a bit more effort. And while you can use suspend-then-hibernate here too, I personally prefer to have it linked to straight hibernate.

gsettings set org.gnome.settings-daemon.plugins.power power-button-action nothing
echo 'event=button/power' > /etc/acpi/events/power
echo 'action=sudo systemctl hibernate' >> /etc/acpi/events/power

Short package upgrade will not hurt.

add-apt-repository universe
apt update ; apt dist-upgrade --yes

The only remaining task before restart is to create the user, assign a few extra groups to it, and make sure its home has correct owner.

adduser --disabled-password --gecos '' -u 1002 $USER
usermod -a -G adm,cdrom,dialout,dip,lpadmin,plugdev,sudo,tty $USER
echo "$USER ALL=NOPASSWD:ALL" > /etc/sudoers.d/$USER
passwd $USER

As install is ready, we can exit our chroot environment.

exit

And now we can unmount our disk, followed by a reboot.

umount /mnt/install/boot/efi
umount /mnt/install/boot
mount | tac | awk '/\/mnt/ {print $3}' | xargs -i{} umount -lf {}

reboot

If everything went fine, we can now hibernate.

systemctl hibernate

If you see hibernate not supported message, turn off the secure boot. At this time hibernation is not supported when secure boot is turned on.

OBS Studio Tray Icon Change

When customizing one’s desktop, there are always few applications that resist the change. This time I was fighting OBS Studio under Ubuntu and its dreadful tray icon. It just didn’t fit with my desktop theme.

I searched around and found essentially nothing. Yes, there were pages upon pages of people having the same problem and then other people giving them generalized advice but without anything actionable.

To make long story short, it took understanding Qt theming to find a solution for me. It’s not an ideal solution since it does require modification to the theme that could be lost in the future update but the trick was in getting icons added to the /usr/share/icons/hicolor/ directory.

I simply took my chosen 16x16 icons and placed them at the following locations:

• /usr/share/icons/hicolor/16x16/status/obs-tray.png
• /usr/share/icons/hicolor/16x16/status/obs-tray-active.png
• /usr/share/icons/hicolor/16x16/status/obs-tray-paused.png

For a good measure I also changed their 24x24 and 32x32 variants and that was it. OBS now picked up my icons without an error.

PS: And no, adding them to .icons will not work since it’ll break the rest of the system’s theme. And yes, one could go around that by copying the whole theme to the directory but I found it easier just to copy a few files to the system directory instead.

Small(er) Ubuntu Server 22.04 Install on Vultr

For my new Ubuntu Server deployment I decided to go with Intel High Frequency Vultr instance, mostly due to its larger disk allotment. However, going with default Vultr’s deployment image, I ended up with 18 GB of disk occupied. And yes, I could have removed extra stuff I didn’t need (e.g. /usr/local/cuda/ was the prime candidate). However, I decided to go a different route - manual installation.

Getting the Ubuntu ISO is easy enough as a wide selection is already available behind ISO Library tab on Server Image selection page. Combine that with noVNC console and you can just click your way through. However, one can also find Shell option within the Help menu giving you access to the bash prompt and allowing for more control.

While noVNC is decent, the lack of copy/paste makes it unwieldy when more then a few commands need to be entered. So, my first task was to SSH into the installation and continue from there. To do this, we have to allow for password login and set the password.

sed -i 's/^#PermitRootLogin.*$/PermitRootLogin yes/' /etc/ssh/sshd_config
systemctl restart sshd
passwd

Now we can connect using any SSH client and do the rest of steps from there.

I like to start by setting a few variables. Here I needed only DISK and HOST.

DISK=/dev/vda
HOST=^^ubuntu^^

Assuming this is a fresh VM, the disk should already be empty but I like to clean it again (just in case) and create a single partition. On servers I quite often skip swap partition and that’s the case here too.

blkdiscard -f $DISK
echo -e "o\nn\np\n1\n\n\nw" | fdisk $DISK
fdisk -l $DISK

Now we can format our partition and mount it into /mnt/install/.

# mkfs.ext4 ${DISK}1
# mkdir /mnt/install
# mount ${DISK}1 /mnt/install/

We will need to install debootstrap to get our installation going.

# apt update ; apt install --yes debootstrap

And now we can finally move installation files to our disk.

debootstrap $(basename `ls -d /cdrom/dists/*/ | grep -v stable | head -1`) /mnt/install/

Before proceeding, we might as well update a few settings.

echo $HOST > /mnt/install/etc/hostname
sed "s/ubuntu/$HOST/" /etc/hosts > /mnt/install/etc/hosts
sed '/cdrom/d' /etc/apt/sources.list > /mnt/install/etc/apt/sources.list
cp /etc/netplan/*.yaml /mnt/install/etc/netplan/

Finally we get to chroot into our newly installed system.

mount --rbind /dev  /mnt/install/dev
mount --rbind /proc /mnt/install/proc
mount --rbind /sys  /mnt/install/sys
chroot /mnt/install \
    /usr/bin/env DISK=$DISK HOST=$HOST \
    bash --login

While optional, I like to update locale settings and set the time zone.

locale-gen --purge "en_US.UTF-8"
update-locale LANG=en_US.UTF-8 LANGUAGE=en_US
dpkg-reconfigure --frontend noninteractive locales
dpkg-reconfigure tzdata

Installing kernel is next.

apt update
apt install --yes --no-install-recommends linux-image-generic linux-headers-generic

Followed by our boot environment packages.

apt install --yes initramfs-tools grub-pc

Setting FSTab will ensure disk is mounted once done.

echo "PARTUUID=$(blkid -s PARTUUID -o value ${DISK}1) \
    / ext4 noatime,nofail,x-systemd.device-timeout=5s 0 1" > /etc/fstab
cat /etc/fstab

Of course, boot wouldn’t be possible without getting images ready.

KERNEL=`ls /usr/lib/modules/ | cut -d/ -f1 | sed 's/linux-image-//'`
update-initramfs -u -k $KERNEL

And finally, boot needs Grub installed to MBR.

update-grub
grub-install ${DISK}

While we could boot our system already, it’s a bit too bare for my taste so I’ll add a basic set of packages.

apt install --yes ubuntu-server-minimal man

Once done, a small update will not hurt.

apt update ; apt dist-upgrade --yes

Of course, we need to ensure we can boot into our system. While one could use passwd to set the root password, I like to use keys for access.

mkdir /root/.ssh
echo '^^ssh-ed25519 AAAA...^^' > /root/.ssh/authorized_keys
chmod 600 -R /root/.ssh

With all set, we can exit our chroot environment.

exit

We might as well unmount our custom install.

mount | tac | awk '/\/mnt/ {print $3}' | xargs -i{} umount -lf {}

And finally we get to reboot. Please note that you should also go to VM Settings and unmount custom ISO to avoid getting into installation again.

reboot

If all steps worked, you will face a pristine Ubuntu installation measuring something around 5 GB. To make it even smaller, one can turn off the swap.

swapoff -a
vi /etc/fstab
rm /swapfile

Regardless, your system is now ready for abuse. :)

You Need to Load the Kernel First

I update my Linux servers regularly. What I do less regularly is restarting them. So I was not really surprised when one of them failed to boot with “you need to load the kernel first” message. What I usually do is: select the old kernel, boot the darn thing up, and then refresh grub. However, this time I overdid it so even the attempt to boot the old kernel produced the same message. It was time for troubleshooting.

While I knew which kernels wouldn’t boot, I didn’t actually know which kernels I have available. Fortunately, grub has a command line mode hidden behind ‘c’ key press. There I selected my disk and listed all files:

ls
set root=(hd1,2)
ls /

It helps if you know how your partitions are setup for this to work but, in the worst case scenario, you can also go over each partition to find vmlinuz files. This is also the reason why I leave the boot partition unencrypted. Had my boot partition been encrypted, this step would be impossible and more involved recovery would be needed.

In this case, I was able to find vmlinuz files and I saw that the newest kernel I had installed was 5.4.0.117. Armed with that knowledge I went back to the main grub screen.

On the main screen I went to the edit option hidden behind ‘e’ keypress. There it was simple to edit existing commands (both linux and initrd) to update the kernel version to match the one I had on my disk, followed by F10 keypress. Voila! My linux was booting.

Mind you, this wasn’t a permanent solution since the next reboot would leave me with the same issue. What I needed was to update grub (and I might as well update initramfs while I’m at it).

From the prompt, two commands were enough to make my next reboot a boring affair.

sudo update-initramfs -k all -u
sudo update-grub

And that’s it. Now my grub and my kernels are back in sync. At least for a while.