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When installing Docker on Ubuntu, there are multiple options and configurations to consider both during and after installation. Here’s a comprehensive guide:

During Installation

1. Install from the Official Ubuntu Repository (Basic)

sudo apt update
sudo apt install docker.io -y

• Pros: Simple, stable.
• Cons: Might not have the latest version.

2. Install from Docker’s Official Repository (Recommended)

sudo apt update
sudo apt install ca-certificates curl gnupg
sudo install -m 0755 -d /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo tee /etc/apt/keyrings/docker.asc > /dev/null
sudo chmod a+r /etc/apt/keyrings/docker.asc
echo \
  "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] 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 update
sudo apt install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin -y

• Pros: Latest stable version, full feature set.
• Cons: Slightly longer setup.

3. Install from a DEB Package (Offline Installation)

wget https://download.docker.com/linux/ubuntu/dists/$(lsb_release -cs)/pool/stable/amd64/docker-ce_XX.YY.ZZ~3-0~ubuntu_amd64.deb
sudo dpkg -i docker-ce_XX.YY.ZZ~3-0~ubuntu_amd64.deb

• Pros: Useful for air-gapped environments.
• Cons: Manual updates required.

4. Install Using Snap (Not Recommended)

sudo snap install docker

• Pros: Easy installation and updates.
• Cons: Can have permission issues with volume mounts.

After Installation

1. Verify Installation

docker --version
docker info

2. Start and Enable Docker Service

sudo systemctl start docker
sudo systemctl enable docker

3. Run a Test Container

sudo docker run hello-world

4. Allow Non-root Users to Run Docker

sudo groupadd docker
sudo usermod -aG docker $USER
newgrp docker

• Pros: Run Docker without sudo.
• Cons: May have security risks.

5. Enable Docker to Start on Boot

sudo systemctl enable docker

6. Configure Docker Daemon Settings

• Edit the configuration file:

sudo nano /etc/docker/daemon.json

• Example configuration:

{
  "log-driver": "json-file",
  "log-opts": { "max-size": "10m", "max-file": "3" },
  "storage-driver": "overlay2",
  "insecure-registries": ["myregistry.local:5000"]
}

• Restart Docker:

sudo systemctl restart docker

7. Check Logs

sudo journalctl -u docker --no-pager

8. Install Docker Compose

sudo apt install docker-compose-plugin
docker compose version

9. Set Up a Private Docker Registry

docker run -d -p 5000:5000 --restart=always --name registry registry:2

10. Remove Docker (if needed)

sudo apt remove docker-ce docker-ce-cli containerd.io -y
sudo rm -rf /var/lib/docker /etc/docker

Optional Configurations

– Use Different Storage Drivers

docker info | grep "Storage Driver"

• Change driver (Example: overlay2):

sudo systemctl stop docker
sudo rm -rf /var/lib/docker
sudo nano /etc/docker/daemon.json
# Add:
{
  "storage-driver": "overlay2"
}

sudo systemctl restart docker

– Enable IPv6

sudo nano /etc/docker/daemon.json

{
  "ipv6": true,
  "fixed-cidr-v6": "2001:db8:1::/64"
}

sudo systemctl restart docker

– Configure Remote API

sudo nano /lib/systemd/system/docker.service
# Modify ExecStart:
ExecStart=/usr/bin/dockerd -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock

sudo systemctl daemon-reload
sudo systemctl restart docker

These steps cover all major aspects of Docker installation and configuration on Ubuntu.🚀