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🐙 Docker Swarm on the SaveinCloud platform

This guide aims to guide the creation of a Docker Swarm cluster on the SaveinCloud platform, explaining the available options, essential commands, best practices, and management with Portainer.

🛠️ Installation via Marketplace​

  1. Access the SaveinCloud panel.
  2. Click on MARKETPLACE.
  3. Search for Docker Swarm Cluster.

You will see a screen with options such as:

imagem

🔢 Docker Version​

Select the desired Docker version (e.g., 28.1.1-almalinux-9).

⚙️ Manager Nodes / Worker Nodes​

Define how many Manager and Worker instances your cluster will have.

🧠 Understanding the Fields: Manager Nodes and Worker Nodes​

🧑‍✈️ Manager Nodes​

Managers are the nodes responsible for:

  • Managing the global state of the cluster
  • Coordinating tasks, services, and scaling
  • Making orchestration decisions (for example, restarting containers in case of failure)

Recommendations:

  • Use an odd number of managers to avoid ties (1, 3, 5...)
  • For high availability, ideally have 3 managers
  • Managers can also run containers (but you can disable this with --availability drain)

🧑‍🔧 Worker Nodes​

Workers are the nodes that:

  • Execute the tasks and containers assigned by managers
  • Do not participate in orchestration decisions
  • Are ideal for horizontally scaling your services

Recommendations:

  • Add more workers as your application load increases
  • Workers can be easily replaced if they fail, without compromising the cluster
tip

💡 You can start with 1 manager and 1 worker for testing, and increase as needed.
For production, the recommended minimum is 3 managers + 2 workers.

🧹 Clean Cluster​

Creates an empty cluster, without pre-configured services.

📦 Deploy Stack YML​

Allows you to automatically upload a docker-compose.yml file to deploy your stack as soon as the cluster is created.

✅ Install Portainer UI​

Installs the graphical panel for Swarm management and applies SSL certificates with Let's Encrypt.

tip

💡 Portainer will be accessible at:

https://<nome-do-ambiente>.sp1.br.saveincloud.net.br:4848/

🧪 Stack Example​

Basic example of docker-compose.yml to use with docker stack deploy:

version: "3.8"
services:
  app:
    image: nginxdemos/hello
    ports:
      - 80:80
    deploy:
      replicas: 3

🔐 Security in Docker Swarm​

warning

⚠️ Never expose the 2377 port of the Swarm cluster to the internet!

  • Use a private network between nodes.
  • Block administrative ports.
  • Use SSH key authentication.

📊 Management with Portainer​

Access Portainer, click on Environments > Add environment and connect to the local socket to manage the cluster with a visual interface.

📚 Related Resources​

✅ Final Checklist​

  • Cluster started via marketplace
  • Workers and managers active
  • Portainer installed and accessible
  • Deployment completed successfully