update unifi mongodb from 3.6 to 7.0 on Ubuntu 22.04, incl. migration from mmapv1 to wiredtiger

upgrade-to-mongo-7.0.sh

# i suggest to take a VM snapshot / backup just in case.

# first we install mongodb-database-tools from mongodb 4.4 which is still compatible with mmapv1
curl -fsSL https://pgp.mongodb.com/server-4.4.asc |  sudo gpg -o /usr/share/keyrings/mongodb-server-4.4.gpg --dearmor
echo "deb [ arch=amd64,arm64 signed-by=/usr/share/keyrings/mongodb-server-4.4.gpg ] https://repo.mongodb.org/apt/ubuntu jammy/mongodb-org/4.4 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-4.4.list
apt update
apt install mongodb-database-tools

# make backup of unifi mongodb
mkdir /root/backup
mongodump --port=27117 --out=/root/backup

# remove unifi and old mongodb installation
systemctl stop unifi
apt remove mongodb-server-core  mongodb-database-tools unifi -y

# add repo for mongodb 7.0
rm /etc/apt/sources.list.d/mongodb-org-4.4.list
curl -fsSL https://pgp.mongodb.com/server-7.0.asc |  sudo gpg -o /usr/share/keyrings/mongodb-server-7.0.gpg --dearmor
echo "deb [ arch=amd64,arm64 signed-by=/usr/share/keyrings/mongodb-server-7.0.gpg ] https://repo.mongodb.org/apt/ubuntu jammy/mongodb-org/7.0 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-7.0.list
apt update

# update to mongodb 7.0
apt install mongodb-org-server mongodb-org-tools -y

# create empty mongodb
mv /var/lib/unifi/db /var/lib/unifi/db.old
mkdir /var/lib/unifi/db
mongod --dbpath=/var/lib/unifi/db &

# restore database
mongorestore /root/backup/
killall mongod

# secure files
chown -R unifi:unifi /var/lib/unifi/db
chmod 700 /var/lib/unifi/db

# update to mongodb 7.0 and reinstall unifi
apt install mongodb-org-server unifi -y

#restart unifi (check if everything is working)
systemctl start unifi

# clean up
rm -R /root/backup /var/lib/unifi/db.old
rm /usr/share/keyrings/mongodb-server-4.4.gpg  /etc/apt/sources.list.d/mongodb-org-4.4.list
apt update
apt clean
apt autoremove

# gz now you have unifi working with mongodb 7.0 (you can now also upgrade to Ubuntu 24.04)