Install Mikrotik CHR on a Digital Ocean droplet (Ubuntu 20.04 tested working 29/03/2022)

make-chr.sh

#!/bin/bash
#
# Digital Ocean Ubuntu 18.04 x64 Droplet with "Regular Intel" CPU.
# Running:
# git clone https://gist.github.com/54fc09734a3911e91eeeb43434f117df.git
# cd 54fc09734a3911e91eeeb43434f117df/
# chmod +x make-chr.sh
# ./make-chr.sh
#
# Once the reboot is done, login with root/CHANGEME and change the password!
# You might get a "Segmentation fault" on line 56 while the image is being written.
# Most of the time this is absolutely fine. Reboot the droplet and attempt to login using Winbox.
# If it didn't work, just trash the droplet and try it again.
#
wget http://download2.mikrotik.com/routeros/6.37/chr-6.37.img.zip -O chr.img.zip  && \
gunzip -c chr.img.zip > chr.img  && \
apt-get update && \
apt install -y qemu-utils pv && \
qemu-img convert chr.img -O qcow2 chr.qcow2 && \
qemu-img resize chr.qcow2 1073741824 && \
modprobe nbd && \
qemu-nbd -c /dev/nbd0 chr.qcow2 && \
echo "Give some time for qemu-nbd to be ready" && \
sleep 2 && \
partprobe /dev/nbd0 && \
sleep 5 && \
mount /dev/nbd0p2 /mnt && \
ADDRESS=`ip addr show eth0 | grep global | cut -d' ' -f 6 | head -n 1` && \
GATEWAY=`ip route list | grep default | cut -d' ' -f 3` && \
PASSWORD="CHANGEME" && \
echo "/ip address add address=$ADDRESS interface=[/interface ethernet find where name=ether1]
/ip route add gateway=$GATEWAY
/ip service disable telnet
/user set 0 name=root password=$PASSWORD
/ip dns set servers=1.1.1.1,1.0.0.1
/system package update install
 " > /mnt/rw/autorun.scr && \
umount /mnt && \
echo "Magic constant is 65537 (second partition address). You can check it with fdisk before appliyng this" && \
echo "This scary sequence removes seconds partition on nbd0 and creates new, but bigger one" && \
echo -e 'd\n2\nn\np\n2\n65537\n\nw\n' | fdisk /dev/nbd0 && \
e2fsck -f -y /dev/nbd0p2 || true && \
resize2fs /dev/nbd0p2 && \
sleep 1 && \
echo "Compressing to gzip, this can take several minutes" && \
mount -t tmpfs tmpfs /mnt && \
pv /dev/nbd0 | gzip > /mnt/chr-extended.gz && \
sleep 1 && \
killall qemu-nbd && \
sleep 1 && \
echo u > /proc/sysrq-trigger && \
echo "Warming up sleep" && \
sleep 1 && \
echo "Writing raw image, this will take time" && \
zcat /mnt/chr-extended.gz | pv > /dev/vda && \
echo "Don't forget your password: $PASSWORD" && \
echo "Sleep 5 seconds (if lucky)" && \
sleep 5 || true && \
echo "sync disk" && \
echo s > /proc/sysrq-trigger && \
echo "Ok, reboot" && \
echo b > /proc/sysrq-trigger

What is the problem @eklascode? Does it work or not?

EDIT: Just tested this yet again on a Digital Ocean Ubuntu 20.04 x64 Droplet with "Regular Intel" CPU and it worked absolutely fine.

Digital Ocean supports custom images: https://docs.digitalocean.com/products/images/custom-images/ which should be used instead of this script where possible. MikroTik CHR disk images have been tested to work with this method. The script will remain here as historical reference.

These are my customizations and I have successfully installed them on Ubuntu 20.04
Good luck
#!/bin/bash
wget https://download.mikrotik.com/routeros/7.14.1/chr-7.14.1.img.zip -O chr.img.zip &&
gunzip -c chr.img.zip > chr.img &&
apt-get update &&
apt install -y qemu-utils pv &&
qemu-img convert chr.img -O qcow2 chr.qcow2 &&
qemu-img resize chr.qcow2 1073741824 &&
modprobe nbd &&
qemu-nbd -c /dev/nbd0 chr.qcow2 &&
echo "Give some time for qemu-nbd to be ready" &&
sleep 2 &&
partprobe /dev/nbd0 &&
sleep 5 &&
mount /dev/nbd0p2 /mnt &&
ADDRESS=ip addr show eth0 | grep global | cut -d' ' -f 6 | head -n 1 &&
GATEWAY=ip route list | grep default | cut -d' ' -f 3 &&
echo "/ip address add address=$ADDRESS interface=[/interface ethernet find where name=ether1]
/ip route add gateway=$GATEWAY
/ip service disable telnet
/ip dns set servers=1.1.1.1,1.0.0.1
" > /mnt/rw/autorun.scr &&
umount /mnt &&
echo "Magic constant is 65537 (second partition address). You can check it with fdisk before appliyng this" &&
echo "This scary sequence removes seconds partition on nbd0 and creates new, but bigger one" &&
echo -e 'd\n2\nn\np\n2\n65537\n\nw\n' | fdisk /dev/nbd0 &&
e2fsck -f -y /dev/nbd0p2 || true &&
resize2fs /dev/nbd0p2 &&
sleep 1 &&
echo "Compressing to gzip, this can take several minutes" &&
mount -t tmpfs tmpfs /mnt &&
pv /dev/nbd0 | gzip > /mnt/chr-extended.gz &&
sleep 1 &&
killall qemu-nbd &&
sleep 1 &&
echo u > /proc/sysrq-trigger &&
echo "Warming up sleep" &&
sleep 1 &&
echo "Writing raw image, this will take time" &&
zcat /mnt/chr-extended.gz | pv > /dev/vda &&
echo "Don't forget your password: $PASSWORD" &&
echo "Sleep 5 seconds (if lucky)" &&
sleep 5 || true &&
echo "sync disk" &&
echo s > /proc/sysrq-trigger &&
echo "Ok, reboot" &&
echo b > /proc/sysrq-trigger

@nhan6310 excuse me, i want to ask, i have followed your guide, but in the last part, at the "zcat /mnt/chr-extended.gz | pv > /dev/vda &&",
i got an error "pv: write failed: No space left on device"
how can i solve this?

god dammit it works flawlessly on ubuntu 24.04. i was using docker compose to run L2TP, but somehow it doesn't work as a vpn server. with your solution it's working. thank you!

Extra notes: you need to login as admin@<IP_ADDRESS> to access with empty password.