So I've been reading across the web on this, but can't find a good guide on how to set this up. I gave my parent's a Raspberry Pi 3 that I have installed pi-hole and zerotier on to give them some network wide ad-blocking, as well as giving me a VPN tunnel into their network so I can do remote troubleshooting if necessary.

I'm trying to figure out a way to schedule automatic updates for this pi to happen on a weekly basis (ie. Monday morning at like 4:00AM), so that it updates overnight when no-one is online since it is their DNS resolver. I want all 3 of the base OS, Pi-Hole, and the zerotier client to get updated. Looks like I should be able to install unattended-upgrades on the system to do it with, but figuring out how to set the schedule as I want is confusing me.

Any help would be great.

  • Another option is to install and configure unattended-upgrades. Unless you have PPAs setting it up is not that difficult.
    – user68186
    Commented Dec 10, 2021 at 22:24
  • FWIW: I looked into this once. I decided against it for one simple reason: the reboot function in unattended upgrades did not work. IIRC, it was broken/failed in Ubuntu & Debian, and not even implemented in RPi. Since upgrades often require a reboot, this means that automatic or unattended upgrades must also include a reboot - whether it's required or not. Failure to reboot when required will occasionally leave your system in a state of chaos.
    – Seamus
    Commented Dec 11, 2021 at 5:12
  • @Seamus You can roll your own reboot script and use cron to schedule it. I did it for Ubuntu and it works fine in RasPi OS.
    – user68186
    Commented Dec 11, 2021 at 13:21
  • @user68186: Of course you can. But if unattended-upgrades isn't capable of determining if a reboot is required, what is the point, exactly?
    – Seamus
    Commented Dec 11, 2021 at 16:19
  • 1
    @user68186: I don't think unattended-upgrades is a good idea - certainly it's not for me personally. This opinion is based on a risk-reward comparison for my RPi use-case. I'm just not that bothered to spend a few minutes every week or so to manually update & upgrade. YMMV.
    – Seamus
    Commented Jan 8, 2022 at 8:22

2 Answers 2



Setting up automatic updates can lead to broken system. If this happens and the Pi does not boot (after an attempted reboot) the next update won't fix the problem. It has happened to me.

The best practice is to wait a week or two after an update is released to make sure there are no show-stopper bugs or regressions. This is not possible if you use unattended upgrade.

You may want to make periodic disk images as backups in an attached USB drive. This way you can restore the MicroSD card from the image file using another computer and the Imager app.

Install unattended-upgrades

Open a terminal and enter the command:

sudo apt install unattended-upgrades

The default setting will look for updates every night and install them.

Basic Configuration

Edit the file: /etc/apt/apt.conf.d/50unattended-upgrades uncomment (remove //) or add the following lines

Unattended-Upgrade::Origins-Pattern {
        "origin=Raspberry Pi Foundation,codename=${distro_codename},label=Raspberry Pi Foundation";

The last two lines with Raspbian and Raspberry Pi are the most important ones. I am not sure if you need the Debian ones. I have them and so far I have not had any issues. YMMV.


To set up autoremove, look for these lines in the above file:

// Do automatic removal of unused packages after the upgrade
// (equivalent to apt-get autoremove)
//Unattended-Upgrade::Remove-Unused-Dependencies "false";

Uncomment the third line above and make it look like:

Unattended-Upgrade::Remove-Unused-Dependencies "true";

Reboot if needed

Periodically updates need restarting the Pi to take effect. This is particularly true for kernel updates. look for these lines in the above file:

// Automatically reboot *WITHOUT CONFIRMATION* if
//  the file /var/run/reboot-required is found after the upgrade
//Unattended-Upgrade::Automatic-Reboot "false";

Uncomment the third line above and make it look like:

Unattended-Upgrade::Automatic-Reboot "true";

If you want to reboot the Pi at a fixed time at night, such as at 2:00 AM only if a reboot is needed look for these lines

// If automatic reboot is enabled and needed, reboot at the specific
// time instead of immediately
//  Default: "now"
//Unattended-Upgrade::Automatic-Reboot-Time "02:00";

Uncomment the fourth line above and make it look like:

Unattended-Upgrade::Automatic-Reboot-Time "02:00";

Note: Some have said that reboot does not work in unattended-upgrades. If you find this is the case, see a workaround below under the Advanced Configuration.

Reference: https://www.linuxcapable.com/how-to-enable-configure-unattended-upgrades-on-debian-11/

Also see Configuring `unattended-upgrades` on Raspbian Stretch

Advanced Configuration

Reduce Upgrade Frequency

Upgrade takes place every morning by the default configuration. To change it to weekly upgrade, edit the file /etc/apt/apt.conf.d/20auto-upgrades:

APT::Periodic::Unattended-Upgrade "7";

Note, unattended-upgades does not allow for setting a specific day, such as Monday, for the upgrade. The "7" above sets the interval of upgrades to 7 days.

Change the upgrade time of the day

The default time of unattended upgrade is randomly set between 6 and 7 AM. The default randomization is needed so that every computer using this app do not overload the upgrade repositories by trying to get updates exactly at the same time.

To set the upgrade time to 4:00 AM, use the following command to create the file /etc/systemd/system/apt-daily-upgrade.timer.d/override.conf:

sudo systemctl edit apt-daily-upgrade.timer

This will open a blank file if none exists. Enter the following lines:


Save and exit the editor. See the Debian documentation for the explanation.

Add Other Repositories

So far unattended-upgrades is configured to upgrade applications that exist only in the official repositories. Sometimes we install software that are in special repositories not included in the default system.

I have no experience with Pi-Hole, and the Zerotier. As far as I can tell Pi-Hole does not use the apt system for upgrade. As a result it cannot be (easily) included in the unattended-upgrades configuration.

As far as I can tell Zerotier adds a PPA in the file /etc/apt/sources.list.d/zerotier.list The line in that file looks like something like:

http://download.zerotier.com/debian/RELEASE RELEASE main

Where RELEASE is the OS nickname, maybe buster or bullseye for Pi.

You would like to add a origin and archive to the file /etc/apt/apt.conf.d/50unattended-upgrades. To find what those are for your PPAs open the folder /var/lib/apt/lists/, that is the storage area for state information for each package resource. What you are looking for is the files that begins with "Zerotier" and ends with "Release" in the name.

As I don't have Zerotier, I will give the example of "Google Chrome"

Open one with your text editor, ie for Google Chrome:

sudo nano /var/lib/apt/lists/dl.google.com_linux_chrome_deb_dists_stable_Release

You will see something like:

Origin: Google, Inc. 
Label: Google 
Suite: stable 
Codename: stable 
Version: 1.0 
Date: Thu, 17 Nov 2011 19:09:01 +0000 Architectures: i386 amd64 
Components: main 
Description: Google chrome-linux repository.

The origin is obvious (Origin: Google, Inc.) and the archive will be whatever is in the line Suite (Suite: stable).

If either Origin or Suite is missing then they will be the empty string. But note that if both are missing then probably it will not be possible to use that source with unattended upgrades without including other sources with the same issue.

After you noted those 2 lines you need to edit the /etc/apt/apt.conf.d/50unattended-upgrades file and add the lines using this format "o=<origin>,a=<archive>"; for this example’s sake:

"o=Google Inc.,a=stable";

See commented out similar lines in the file to determine where the above line should go.

Reboot using crontab

Some have reported that automated reboot configuration in unattended-upgrades do not work as intended. If that is the case you may want to use a bash script and crontab to reboot the Pi if and when needed by unattended-upgrade.

Stop Unattended-Upgrades from restarting the computer

Right now Unattended-Upgrades is setup to restart the computer at 2:00AM if the update requires a restart. This step will stop this behavior.

Step: edit the file /etc/apt/apt.conf.d/50unattended-upgrades

Inside the file look for the line:

unattended-Upgrade::Automatic-Reboot "true";

and make it look like:

Unattended-Upgrade::Automatic-Reboot "false";

Create a bash script to check if restart is required and do it if needed

The script below checks if the file reboot-required exists and if so, it reboots the computer immediately. Let's call this file reboot_if_needed.sh.

if [ -f /var/run/reboot-required ]; then
        echo $(date) Sytem restart required by: $(cat /var/run/reboot-required.pkgs)
        /sbin/reboot now

Save this file as /opt/bin/reboot_if_needed.sh

Make this file executable:

sudo chmod +x `/opt/bin/reboot_if_needed.sh`


When the script runs and the file var/run/reboot-required exists it will output some text that will be captured in a log file /var/log/reboot_history.log. Then the system will restart.

Schedule reboot_if_needed.sh every night at 2:00 AM

Note, even though script is to run every night, the Pi will not be rebooted every night. It will be rebooted only when it is required by the upgrade.

We want to run the script with administrator privileges. So we use sudo:

sudo crontab -e

This command will open the crontab file for the root user if one exists, or create a blank new file. Add the following line at the end of the file:

0 02 * * * /opt/bin/reboot_if_needed.sh >> /var/log/reboot_history.log

Save the file and exit the text editor.

For more details on rebooting with crontab for unattended-upgrades see this answer in Ask Ubuntu

I have unattended-upgrade running for about a year in Buster, and a few weeks in Bullseye. Once my system got screwed up by a bad update. Otherwise it has been working fine.

Hope this helps

  • Thanks for all this. In the end, I decided that I was going to roll my own with a simple script, as I want specific control over day and time that using unattended-upgrade wouldn't provide (I get I could edit the daily timer file, but it just seems wrong to edit a file named "daily" to not be). But this did give me a of source information I used, and learned a ton, so thanks.
    – Evan M.
    Commented Jan 13, 2022 at 17:58
  • @EvanM. You are welcome. Rolling your own gives you more control and I am all for it if it works for you. Writing this answer helped me decide to make a few changes in my unattended upgrade config as well. Hopefully this answer will help someone else.
    – user68186
    Commented Jan 13, 2022 at 19:29

There are automatic update programs such as unattended-upgrades, but I have never used one.

Upgrading the Pi is a hazardous undertaking; it usually works, but occasionally it causes corrupted OS. There are many reports on this site, and it has happened to me a few times. It appears that many are caused by ageing SD Cards, which have a limited life.

As a consequence my upgrade process is to first BACKUP then upgrade.

Bullseye does have apt-daily-upgrade (at least in the Desktop version) but AFAIK this is just a notification of available updates, which need to be manually initiated. It appears to run at ~0600.

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