Suggestion for dual booting ubuntu 18.04 and 20.04

Question

I have a work laptop with 18.04 pre-installed, however I want to use 20.04, I cannot erase and install as they have installed some monitoring service on 18.04, I was thinking of dual booting it with 20.04 but I'm confused on which option should I choose while installing, as all of disk is allocated to 18.04

1. Install along with ubuntu 18.04
2. Reduce partition size for 18.04 and create new partition for 20.04

At some point I will have to remove Ubuntu 20.04 and restore to original condition.

Please suggest which option will be better?

Answer 1

The options you have are:

1. Having two separate installations side by side, as you propose. Whichever method works fine. What you have to do is first take decisions related to partitioning design. E.g., whether you need separate swap partitions (unlikely).
2. Use a VM with 20.04 inside 18.04. This is "less invasive" than the first, and much easier to take back to the original configuration (simply remove the VM). Plus, you can run both OSs at the same time. If the resources in your system are enough to make this work reasonably, this is likely a better option.

I am assuming that both options agree with the intended use of your system.

Related (most are somewhat "aged"):

1. https://medium.com/@manujarvinen/setting-up-a-multi-boot-of-5-linux-distributions-ca1fcf8d502
2. Ubuntu 18.04 and 20.04 on the same computer
3. https://ubuntuforums.org/showthread.php?t=2382905
4. Dual booting two Ubuntu versions
5. https://superuser.com/questions/251270/can-i-install-two-ubuntu-versions-on-the-same-machine
6. Installing 2 versions of Ubuntu on same hard drive?
7. How to use manual partitioning during installation?