I would recommend Ubuntu as the distro of choice because most docker images function best with it. Official recomendation is for Ubuntu 18.04 but for me 20.04 has worked fine.

Step 0 : SSH into the machine (VM or bare-metal and follow these instructions)

Code to Upgrade packages:

sudo apt-get update && sudo apt-get upgrade -y

Steps to Install Docker

sudo apt-get install \\
    apt-transport-https \\
    ca-certificates \\
    curl \\
    gnupg \\
    lsb-release

curl -fsSL <https://download.docker.com/linux/ubuntu/gpg> | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg

echo \\ 
"deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] <https://download.docker.com/linux/ubuntu> \\
$(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

sudo apt-get update

sudo apt-get install docker-ce docker-ce-cli containerd.io

To verify if Docker is working:

sudo docker run hello-world

Configure Firewall

Clear all already set iptables if set by your cloud provider and configure firewall via UFW (personal preference)

Also make sure to allow ports which you are actively using for caprover from your router or cloud provider's console.

sudo ufw allow 22,80,443,3000,996,7946,4789,2377/tcp; sudo ufw allow 7946,4789,2377/udp;

Installing Caprover

Just run the following line, sit back and enjoy!

sudo docker run -p 80:80 -p 443:443 -p 3000:3000 -v /var/run/docker.sock:/var/run/docker.sock -v /captain:/captain caprover/caprover

NOTE: Do not change the port mappings. CapRover only works on the specified ports.