docker installation failed on Ubuntu 20.04 LTS(Vmware)

For the moment, you can use :

sudo apt-get install -y docker.io

And then check with :

docker -v

Docker has not released the repository for focal fossa (20.04) yet. As @Wared said, running

sudo apt install -y docker.io

will get docker from ubuntu repository.

I am able to use all my docker images that I used to in 18.04 successfully on 20.04 with this docker installation.

I know the question is about Ubuntu 20. But in case you are trying to install it on Linux Mint 20 (like me), the problem looks the same but the answer is different.

The installation guide tells you to add the PPA like this:

sudo add-apt-repository \
"deb [arch=amd64] https://download.docker.com/linux/ubuntu \
$(lsb_release -cs) \
stable"

However, the $(lsb_release -cs) part is the problem, because it passes the release name as a parameter to the repository command. In Ubuntu 20 that command outputs focal and everything goes well, but in Linux Mint that command outputs ulyana and it fails because docker does not have that release.

If you want to install it on mint, just replace that command with the focal string so you get the ubuntu focal version:

sudo add-apt-repository \
"deb [arch=amd64] https://download.docker.com/linux/ubuntu \
focal \
stable"