A couple of points of information for the Cloud SQL Lab in Chapter 3.7:
1. The sudo apt-get install mysql-client doesn’t work use default-mysql-client instead
2. If you find that wget isn’t installed on your VM instance, use the ‘sudo apt install wget’ to download it
Nice catch! It looks like Compute Engine has updated its default image to Debian 10, where the mysql package name has changed and wget is no longer included.
If you prefer, you can change the boot disk to use Debian 9, and the original commands shown in the lab should work.