Xubuntu Server Ubgrade 16.04 to 18.04 to 20.04

As I have been busy the past few months, I failed to notice that 16.04 went past it's support window and hasn't been getting updates. Here are the steps that I went through to get current and fix the issues that I encountered

Perform the Upgrade

I upgraded using the GUI to walk me thru the steps

• upgrade to 18.04
• sudo do-release-upgrade -f DistUpgradeViewGtk3
• reboot
• upgrade to 20.04
• sudo do-release-upgrade -f DistUpgradeViewGtk3
• When prompted for debian-sys-maint password find it here:
• sudo cat /etc/mysql/debian.cnf

Getting Unifi Web working again

127.0.0.1:8443 was giving a 404 error

• Check the logs
• tail -n 50 /usr/lib/unifi/logs/server.log
• [2021-10-24TXX:XX:XX,XXX] <db-server> INFO  db     - DbServer stopped
• tail -n 50 /usr/lib/unifi/logs/mongod.log
• 2021-10-24TXX:XX:XX.XXX-XXXX F CONTROL  [initandlisten] ** IMPORTANT: UPGRADE PROBLEM: The data files need to be fully upgraded to version 3.4 before attempting an upgrade to 3.6; see http://dochub.mongodb.org/core/3.6-upgrade-fcv for more details.

So I needed to upgrade the mongo data files, but can't do that in version 3.6 so I used a combination of the following posts

• https://community.ui.com/questions/Unifi-controller-on-Ubuntu-18-04/93b00b88-7542-40ba-bb0b-a80a84415e1d
• https://docs.mongodb.com/manual/release-notes/3.6/#upgrade-procedures
• https://stackoverflow.com/questions/48318487/error-while-upgrading-mongodb-from-3-2-to-3-6

Here are the actual steps that I used:

• sudo apt-get install docker.io
• sudo docker run --name mongo-migrate -v /var/lib/unifi/db:/data/db -p 127.0.0.1:27888:27017 -d mongo:3.4
• mongo localhost:27888
• db.adminCommand( { getParameter: 1, featureCompatibilityVersion: 1 } )
• db.adminCommand( { setFeatureCompatibilityVersion: "3.4" } )
• exit
• sudo docker stop mongo-migrate
• sudo chown -R unifi:unifi /var/lib/unifi/db
• sudo systemctl restart unifi

Fixing MythTV

I was seeing the following Fatal Error when accessing mythweb:

!!NoTrans: You are missing a php extension for mysql interaction. Please install php-mysqli or similar!!

I solved this error with the following steps:

• apt-get install php7.4
• sudo a2dismod php7.0
• sudo a2enmod php7.4
• sudo systemctl restart apache2

It then became this error:

!!NoTrans: MasterServerIP or MasterServerPort not found! You may need to check your mythweb.conf file or re-run mythtv-setup!!

I determined this to be an error with mysql

• tail -n 100 /var/log/mysql/error.log
• 2021-10-24TXX:XX:XX.XXXXXXZ 0 [ERROR] [MY-000067] [Server] unknown variable 'query_cache_limit=1M'.
• 2021-10-24TXX:XX:XX.XXXXXXZ 0 [ERROR] [MY-000067] [Server] unknown variable 'query_cache_size=16M'.
• sudo vi /etc/mysql/my.cnf
• commented out the 2 lines regarding query_cache
• sudo systemctl restart mysql

This got mysql running but, mythweb still had the same error. I tried a reboot of the server, but that didn't seem to help. It turns out that I needed to change the bind_address

• sudo vi /etc/mysql/my.cnf
• bind-address            = 127.0.0.1,192.168.X.X

VNC

I needed to fix my vnc setup and came across this:

• vnc4server is no longer in the repo
• tightvncserver works with the exception of window buttons. This is due to it not supporting Render: https://bugs.launchpad.net/ubuntu/+source/xfwm4/+bug/1860921
• Solution: Use tigervncserver

Here are the steps that I used:

• sudo apt-get install tigervnc-standalone-server
• touch ${HOME}/.Xresources
• tigervncserver :1 -geometry 1366x768 -depth 24 -localhost no

Let's Encrypt

Update 2021-12-14: Apparently, the upgrade broke my Let's Encrypt certificate, but fixing it was easy enough, I just needed to install 2 packages: sudo apt-get install certbot python3-certbot-apache