Ubuntu20 安装docker

### Add Docker's official GPG key:
 
```
sudo apt-get update
sudo apt-get install ca-certificates curl gnupg
sudo install -m 0755 -d /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
sudo chmod a+r /etc/apt/keyrings/docker.gpg
```
 
### Add the repository to Apt sources:
 
```
echo \
  "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu \
  $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | \
  sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
sudo apt-get update
```
 
### Install the Docker packages.
 
```
sudo apt-get install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
```
 
### If you want to run Docker as a non-root user
 
```
sudo groupadd docker
sudo usermod -aG docker $USER
newgrp docker
```
 
### Verify that the Docker Engine installation is successful
 
```
docker run hello-world
```