Ubuntu 18.4 - Right click doesn't work on the touchpad

A very quick fix, for a very silly default behaviour...

By default, Ubuntu has been set up to respond to two finger taps  as a secondary / right click. Ah there's nothing like trying to alienate Windows users eh?

To fix this behaviour, you need to install the Gnome Tweaks tool.

You can do this in the terminal with:

$ sudo apt install gnome-tweak-tool

Or just hit the Windows key and type 'tweak' and select Gnome Tweak

Once installed, run the app, go to Keyboard and Mouse and chnage the Mouse Click Options to Area.

Boom! Right click is behaving like it should :)

Setting up Redis Sentinel as a service in Ubuntu

There are plenty of excellent documents on how to set up a Redis Master/Slave system, but very little on Sentinel.

Once you have Sentinel running reliably on the commend line, you will want to get Sentinel working as a service.

First, open up a new file:
vim /etc/systemd/system/sentinel.service

In there you probably want something like:

[Unit]
Description=Sentinel for Redis
After=network.target

[Service]
LimitNOFILE=64000
User=redis
Group=redis
ExecStart=/usr/local/bin/redis-sentinel /etc/redis/<your configuration file>.conf --daemonize no

[Install]
WantedBy=multi-user.target

You then need to make sure that the user you are using to run the service (in this case redis) has permissions for both the configuration file 

chown redis:redis /etc/redis/<your configuration file>.conf

and the log files you have set up in your configuration file

chown redis:redis /var/log/redis/<your log file>.log

Test everything works as expected by:

systemctl start sentinel

then 

systemctl status sentinel

You should get something that looks like:

If you do, then everything is good and you can set your service to start automatically with:

systemctl enable sentinel