How to install and configure Docker on Centos 8 (VM instead of using Docker Desktop)

docker-on-centos-8.txt

# Install docker
# from: https://docs.docker.com/engine/install/centos/
sudo yum install -y yum-utils
sudo yum-config-manager \
    --add-repo \
    https://download.docker.com/linux/centos/docker-ce.repo
sudo yum install docker-ce docker-ce-cli containerd.io
# check fingerprint 060A 61C5 1B55 8A7F 742B 77AA C52F EB6B 621E 9F35
# OR if error on install, sometimes specific version of containerd.io is needed
sudo dnf install https://download.docker.com/linux/centos/7/x86_64/stable/Packages/containerd.io-1.2.6-3.3.el7.x86_64.rpm
sudo yum install docker-ce docker-ce-cli
sudo systemctl start docker

# Allow user access
sudo usermod -aG docker tim

# Allow firewall in
sudo firewall-cmd --permanent --new-service docker-host
sudo firewall-cmd --permanent --service docker-host --add-port 2375/tcp
sudo firewall-cmd --permanent --add-service docker-host

# Setup docker
# from: https://docs.docker.com/engine/install/linux-postinstall/
sudo systemctl enable docker

sudo systemctl edit docker.service
# add and save:
[Service]
ExecStart=
ExecStart=/usr/bin/dockerd -H fd:// -H tcp://127.0.0.1:2375

sudo systemctl daemon-reload
sudo systemctl restart docker.service

# Configure firewalld for container internet access
# from: https://forums.centos.org/viewtopic.php?f=54&t=74270

sudo firewall-cmd --permanent --zone=trusted --add-interface=docker0
sudo firewall-cmd --reload

# an alternative using the "public" zone instead: https://serverfault.com/questions/987686/no-network-connectivity-to-from-docker-ce-container-on-centos-8/994704#994704

# Maybe enable IP forwarding?
# from: https://docs.docker.com/network/bridge/#enable-forwarding-from-docker-containers-to-the-outside-world
sudo vim /etc/sysctl.conf
# add and save:
net.ipv4.ip_forward = 1
net.ipv6.conf.all.forwarding = 1

sudo sysctl -p
sudo iptables -P FORWARD ACCEPT

# Mount home or src directory
sudo dnf install nfs-utils
sudo vim /etc/fstab
# add and save
10.1.2.1:/usr/home/tim/src /usr/home/tim/src    nfs     defaults        0 0

sudo mount -a

# Add extra repo
sudo dnf install epel-release
sudo dnf install htop

## Troubleshooting

# No DNS queries inside container?
# if using a custom network (docker-compose does this) then add the generated bridge to the trusted firewall zone:
sudo firewall-cmd --permanent --zone=trusted --add-interface=br-abcdef # find name with `docker network list` or ifconfig
sudo firewall-cmd --reload

# Files not found in mounted volume?
# re-mount the NFS mount
sudo mount -a

# No network access in host or during image build?
# pf is blocking because vm was started before pf initialised during boot
# on freebsd:
doas service pf reload