Docker Swarm

Description

Docker Swarm is Docker's built-in clustering and container-orchestration mode. It groups multiple Docker hosts into a single virtual host that can schedule services, replicate tasks, and route traffic via an internal mesh.

Overview

This role bootstraps and manages a Docker Swarm cluster across the hosts in the Ansible group svc-swarm-node. The manager is the single host in svc-swarm-manager; every other group member joins as a worker. Membership is expressed via group membership only, never via duplicated lists in group_vars. Inventory node labels are pushed to the cluster after the join phase.

Cosmos

The diagram places Docker Swarm in the Infinito.Nexus cosmos: the components it deploys (capabilities), the central services it consumes (dependencies), and its outward reach (federation and bridged external networks).

flowchart LR
    subgraph role [svc-swarm-node 💻]
        svc_node["node"]
    end
    subgraph dependents [Dependents]
        dpt_svc_registry_cache["svc-registry-cache 🐳"]
        dpt_svc_registry_docker["svc-registry-docker 🐳"]
        dpt_svc_swarm_manager["svc-swarm-manager 💻"]
    end
    svc_node -- "1:1" --> dpt_svc_registry_cache
    svc_node -- "1:1" --> dpt_svc_registry_docker
    svc_node -. "0..1" .-> dpt_svc_swarm_manager

Solid 1:1 edges are fixed relationships; dashed 0..1 edges are conditional (enabled only in matching deployments); red 0..0 edges are turned off in this role. Node markers show the role's deploy modes (💻 host, 🐳 compose, 🐝 swarm); ❌ marks a service that is explicitly turned off, and ⚙️ an Ansible role dependency declared in meta/main.yml.

Features

Single-manager bootstrap: Initialises the cluster on the manager with the configured advertise address; idempotent on re-runs.
Auto-derived workers: svc-swarm-node - svc-swarm-manager yields the worker set; no separate worker_nodes list to drift.
Token publishing: Manager-fetched worker/manager join tokens are published as facts to every cluster member.
Node labels: Per-host labels declared via swarm_node_labels in inventory are applied to the joining node.
Mode-selection trigger: Membership in svc-swarm-node resolves DEPLOYMENT_MODE = swarm for every web-app role on that host.

Quick Setup

Development

Clone, set up the workstation, and deploy Docker Swarm onto the local stack:

git clone https://github.com/infinito-nexus/core.git
cd core
make onboard
make compose-deploy mode=reinstall apps=svc-swarm-node full_cycle=false

Production

Install Docker Swarm directly onto the target machine: clone the repository, install the OS prerequisites and the repository toolchain, then deploy against localhost over a local connection (no SSH, no container):

git clone https://github.com/infinito-nexus/core.git
cd core
bash scripts/install/package.sh
make install
source scripts/meta/env/load.sh

APP=svc-swarm-node
DOMAIN=<your-domain>
TLS_MODE=self_signed
SSH_PUBLIC_KEY="<your-ssh-public-key>"
INVENTORY=inventories/production
infinito administration inventory provision "$INVENTORY" \
  --inventory-file "$INVENTORY/devices.yml" \
  --host localhost \
  --include "$APP" \
  --vars "{\"TLS_MODE\": \"$TLS_MODE\", \"DOMAIN_PRIMARY\": \"$DOMAIN\", \"users\": {\"administrator\": {\"authorized_keys\": [\"$SSH_PUBLIC_KEY\"]}}}"
infinito administration deploy dedicated "$INVENTORY/devices.yml" \
  --password-file "$INVENTORY/.password" \
  --diff -vv

Credits

Implemented by Kevin Veen-Birkenbach. Part of the Infinito.Nexus Project and maintained by Kevin Veen-Birkenbach. Licensed under the Infinito.Nexus Community License (Non-Commercial).