Building a Multi-Node Docker Swarm

1. Environment Setup

2. Docker CE Installation

Install Docker CE on all nodes following the official documentation.

3. Configure All Nodes

# Update Docker daemon configuration
cat > /etc/docker/daemon. <<EOF
{
    "live-restore": false
}
EOF

# Restart Docker service
systemctl restart docker

# Configure firewall rules
firewall-cmd --permanent --add-port={2377/tcp,7946/tcp,7946/udp,4789/udp}
firewall-cmd --reload

# Install bash completion
dnf install bash-completion -y
</pre>

4. Initialize Swarm on Manager Node

# Initialize swarm on controller node
docker swarm init


5. Join Worker Nodes to Swarm

# On worker1 and worker2, execute the join command
docker swarm join \
--token SWMTKN-1-5yz0ag8l4mqj1gw20kl6fn4j38gj9rs4oefi6pgyuz40wsjotp-1tpgymi77j5idqanazqbpsmoj 10.32.161.124:2377


6. Verify Cluster Nodes

# Check node status on manager
docker node ls


7. Create Services and Deploy Applications

# Create a service with 2 replicas
docker service create --name web_service --replicas=2 -p 80:80 nginx:stable-alpine

# List services
docker service ls

# Inspect service details
docker service inspect web_service --pretty

# Check service tasks
docker service ps web_service

# Test service access
for i in {124..126}; do curl -I 10.32.161.$i; done

# Scale service to 3 instances
docker service scale web_service=3

# Verify updated service tasks
docker service ps web_service


8. Install Portainer CE

# Download deployment file
curl -L https://downloads.portainer.io/ce2-19/portainer-agent-stack.yml -o portainer-agent-stack.yml

# Deploy Portainer stack
docker stack deploy -c portainer-agent-stack.yml portainer

# Check stack services
docker stack ps portainer


Access Portainer at: http://Manager_IP:9000/
Default credentials: admin