dozzle/docs/guide/swarm-mode.md

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Swarm Mode

Swarm Mode

Dozzle supports Docker Swarm Mode starting from version 8. When using Swarm Mode, Dozzle will automatically discover services and custom groups. Dozzle does not use Swarm API internally as it is limited. Instead, Dozzle implements its own grouping using swarm labels. Additionally, Dozzle merges stats for containers in a group. This means that you can see logs and stats for all containers in a group in one view. However, it does mean each host needs to be set up with Dozzle.

How Does It Work?

When deployed in Swarm Mode, Dozzle will create a secured mesh network between all the nodes in the swarm. This network is used to communicate between the different Dozzle instances. The mesh network is created using mTLS with a private TLS certificate. This means that all communication between the different Dozzle instances is encrypted and safe to deploy anywhere.

Dozzle supports Docker stacks, services and custom groups for joining logs together. com.docker.stack.namespace and com.docker.compose.project labels are used for grouping containers. For services, Dozzle uses the service name as the group name which is com.docker.swarm.service.name.

How to Enable Swarm Mode?

To deploy on every node in the swarm, you can use mode: global. This will deploy Dozzle on every node in the swarm. Here is an example using Docker Stack:

services:
  dozzle:
    image: amir20/dozzle:latest
    environment:
      - DOZZLE_MODE=swarm
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    ports:
      - 8080:8080
    networks:
      - dozzle
    deploy:
      mode: global
networks:
  dozzle:
    driver: overlay

Note that the DOZZLE_MODE environment variable is set to swarm. This tells Dozzle to automatically discover other Dozzle instances in the swarm. The overlay network is used to create the mesh network between the different Dozzle instances.

Warning

There is no way to use socket-proxy in swarm mode. This is not a limitation of Dozzle, but rather a limitation of Docker itself as all services in a swarm are behind a load balancer which means Dozzle cannot connect to a specific service. You can use network_mode: host but not recommended. If you know how to use socket-proxy in swarm mode, please let us know!

Setting Up Simple Authentication in Swarm Mode

To set up simple authentication, you can use Docker secrets to store users.yml file. Here is an example using Docker Stack:

services:
  dozzle:
    image: amir20/dozzle:latest
    environment:
      - DOZZLE_LEVEL=debug
      - DOZZLE_MODE=swarm
      - DOZZLE_AUTH_PROVIDER=simple
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    secrets:
      - source: users
        target: /data/users.yml

    ports:
      - "8080:8080"
    networks:
      - dozzle
    deploy:
      mode: global

networks:
  dozzle:
    driver: overlay
secrets:
  users:
    file: users.yml

In this example, users.yml file is stored in a Docker secret. It is the same as the simple authentication example.

Adding Standalone Agents to Swarm Mode

From version v8.8.x, Dozzle supports adding standalone Agents when running in Swarm Mode.

Simply add the remote agent to your Swarm compose in the same way you normally would.

Note

While remote agents are supported, remote connections such as socket proxy are not supported.

services:
  dozzle:
    image: amir20/dozzle:latest
    environment:
      - DOZZLE_MODE=swarm
      - DOZZLE_REMOTE_AGENT=agent:7007
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    ports:
      - 8080:8080
    networks:
      - dozzle
    deploy:
      mode: global
networks:
  dozzle:
    driver: overlay

The remote agent(s) will now display alongside the other nodes in Dozzle.