One thing that annoyed me about my Mikrotik RB1100HAx4 router was the need to unplug darn thing when I wanted to reboot it. It does have reset button but the darn thing is just there for resetting configuration. Simple reboot was not the part of the repertoire.
Well, that changed with RouterOS 6.47. As of them there is a few more options under settings – most notably reset button configuration. Now action on reset button can be configured.
And it’s easy enough.
Terminal
/system routerboard reset-button set enabled=yes on-event="/log info message=(\"Reset button\")\r\n/system reboot"
PS: This works with vast majority of Mikrotik routers and switches. But not all so your mileage may wary.
With Ubuntu 20.04 Desktop there is a (still experimental) ZFS setup option in the addition to long time manual ZFS installation option. For Ubuntu Server we’re still dependent on the manual steps.
Steps here follow my 19.10 server guide but without the encryption steps. While I normally love having encryption enabled, there are situations where it gets in the way. Most notable example is a machine which you cannot access remotely to enter encryption key.
To start with installation we need to get to the root prompt. Just find Enter Shell behind Help menu item (Shift+Tab comes in handy) and you’re there.
The very first step is setting up a few variables – disk, pool, host name, and user name. This way we can use them going forward and avoid accidental mistakes. Make sure to replace these values with the ones appropriate for your system.
To start the fun we need debootstrap and zfsutils-linux package. Unlike desktop installation, ZFS package is not installed by default.
Terminal
apt install --yes debootstrap zfsutils-linux
General idea of my disk setup is to maximize amount of space available for pool with the minimum of supporting partitions. If you are planning to have multiple kernels, increasing boot partition size might be a good idea. Major change as compared to my previous guide is partition numbering. While having partition layout different than partition order had its advantages, a lot of partition editing tools would simply “correct” the partition order to match layout and thus cause issues down the road.
Assuming UEFI boot, two additional partitions are needed. One for EFI and one for booting. Unlike what you get with the official guide, here I don’t have ZFS pool for boot partition but a plain old ext4. I find potential fixup works better that way and there is a better boot compatibility. If you are thinking about mirroring, making it bigger and ZFS might be a good idea. For a single disk, ext4 will do.
Terminal
yes | mkfs.ext4 $DISK-part2 mkdir /mnt/install/boot mount $DISK-part2 /mnt/install/boot/
Bootstrapping Ubuntu on the newly created pool is next. As we’re dealing with server you can consider using --variant=minbase rather than the full Debian system. I personally don’t see much value in that as other packages get installed as dependencies anyhow. In any case, this will take a while.
Terminal
debootstrap focal /mnt/install/
zfs set devices=off $POOL
Our newly copied system is lacking a few files and we should make sure they exist before proceeding.
Finally we’re ready to “chroot” into our new system.
Terminal
mount --rbind /dev /mnt/install/dev mount --rbind /proc /mnt/install/proc mount --rbind /sys /mnt/install/sys chroot /mnt/install /usr/bin/env DISK=$DISK POOL=$POOL USER=$USER bash --login
Let’s not forget to setup locale and time zone. If you opted for minbase you can either skip this step or manually install locales and tzdata packages.
Now we get grub started and update our boot environment. Due to Ubuntu 19.10 having some kernel version kerfuffle, we need to manually create initramfs image. As before, boot cryptsetup discovery errors during mkinitramfs and update-initramfs as OK.
Since we’re dealing with computer that will most probably be used without screen, it makes sense to install OpenSSH Server.
Terminal
apt install --yes openssh-server
I also prefer to allow remote root login. Yes, you can create a sudo user and have root unreachable but that’s just swapping one security issue for another. Root user secured with key is plenty safe.
If you’re willing to deal with passwords, you can allow them too by changing both PasswordAuthentication and PermitRootLogin parameter. I personally don’t do this.
Terminal
sed -i '/^#PasswordAuthentication yes/s/^.//' /etc/ssh/sshd_config sed -i '/^#PermitRootLogin/s/^.//' /etc/ssh/sshd_config sed -i 's/^PermitRootLogin prohibit-password/PermitRootLogin yes/' /etc/ssh/sshd_config passwd
Short package upgrade will not hurt.
Terminal
apt dist-upgrade --yes
We can omit creation of the swap dataset but I personally find its good to have it just in case.
Consider enabling firewall. While you can go wild with firewall rules, I like to keep them simple to start with. All outgoing traffic is allowed while incoming traffic is limited to new SSH connections and responses to the already established ones.
Terminal
apt install --yes man iptables iptables-persistent
iptables -F iptables -X iptables -Z iptables -P INPUT DROP iptables -P FORWARD DROP iptables -P OUTPUT ACCEPT iptables -A INPUT -i lo -j ACCEPT iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT iptables -A INPUT -p tcp --dport 22 -j ACCEPT iptables -A INPUT -p icmp -j ACCEPT iptables -A INPUT -p ipv6-icmp -j ACCEPT
netfilter-persistent save
As install is ready, we can exit our chroot environment.
As it is the machine with the most redundancy, there are many tasks that fall onto my XigmaNAS server. One of those tasks is serving as a syslog destination for other devices.
However, you cannot get that behavior by default as its syslog server will start in secure mode (-ss) without opening any socket. And there is no easy GUI way to make it accept syslog messages.
But here comes the power of postinit actions. Just add the following in System⮞Advanced⮞Command scripts as the new PostInit entry:
PostInit
sed -i -e 's^ -ss^ -a 192.168.0.0/16^' /etc/rc.d/syslogd ; /etc/rc.d/syslogd restart
Your XigmaNAS server will now accept all messages coming from your local network.
PS: To troubleshoot settings, you can do the following on the command line:
Before I had CyberCard, I still had a need to monitor if my system was running off the UPS power. If my server could detect power out and shut down other devices, my battery life would keep server up for longer.
If you have Mikrotik’s router with two power supplies and an SSH connection to the same there is a trick you can use – Mikrotik can show you each power supply state. If you take care to plug one power supply into the UPS and the other one into the non-UPS outlet, you suddenly have a detector.
Even better, the voltage doesn’t go immediately to 0 V as soon as power is out so there is a delay built-in. So, script is as easy as detecting 0V on the output. Something like this.
