Good citizenship:

Resource recovery policies:

Security:

Image management policies:

Software Installation/Development:

Updating only security packages

While updating all packages is recommended, if you would just like to install security updates, you can do the following:

Ubuntu 16 and 18 and 20
grep security /etc/apt/sources.list | sudo tee /etc/apt/security.sources.list
sudo apt-get upgrade -o Dir::Etc::SourceList=/etc/apt/security.sources.list


CentOS 7 and up
sudo yum update --security