# 01 — Docker Swarm Init (Test)

## Context
- **Repo:** `iklim.co` root
- **Environment:** test
- **Server:** single node — same machine is both Swarm manager and worker
- **Sizing:** Terraform test app node is `cpx42`; see `../../hetzner-sizing-report.md`
- Pipeline trigger: push to `test-env` branch → Gitea runner executes directly on the test server
- `init/swarm-init.sh` already exists in the repo and is called by the pipeline

## Prerequisites
- Docker Engine installed on test server
- User running the pipeline has Docker access (group `docker` or root)

## Step 1 — Verify / update `init/swarm-init.sh`

Check that the script handles idempotent init:

```bash
grep -n "swarm init" init/swarm-init.sh
```

The script must contain logic similar to:

```bash
if ! docker info --format '{{.Swarm.LocalNodeState}}' | grep -q "active"; then
  docker swarm init --advertise-addr $(hostname -I | awk '{print $1}')
  echo "✅ Swarm initialized"
else
  echo "ℹ️  Swarm already active, skipping init"
fi
```

If this guard is missing, add it. Without it, the step fails on second deploy.

## Step 2 — Run via pipeline

The pipeline step `Initialize Docker Swarm` in `.gitea/workflows/deploy-test.yml` already calls:

```bash
/bin/bash init/swarm-init.sh
```

No manual action needed after the script is correct.

## Step 3 — Apply node label

The `type=service` label is required for placement constraints in `docker-stack-infra.yml`.
Run once after Swarm init (Ansible handles this in automated setup):

```bash
docker node update --label-add type=service $(docker node ls -q)
```

## Step 4 — Verify

SSH into the test server and run:

```bash
docker node ls
```

Expected: one node, `STATUS=Ready`, `AVAILABILITY=Active`, `MANAGER STATUS=Leader`.

```bash
docker node inspect self --format '{{.Spec.Labels}}'
```

Expected: `map[type:service]`.

## Notes
- Single-node Swarm: node is simultaneously manager and worker (`AVAILABILITY=Active`, not drained).
- Placement constraints `node.role == manager` and `node.labels.type == service` both resolve to this machine.
- No worker-join or manager-join steps needed for test.
- Docker Swarm overlay network `iklimco-net` is created automatically on first `docker stack deploy`.