33 lines
1.3 KiB
Markdown
33 lines
1.3 KiB
Markdown
# Docker Swarm Stack Skill
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Use this skill when adding, reviewing, or modifying Docker Swarm stack files in this repository.
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## Workflow
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1. Confirm the service belongs in the Swarm repo.
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2. Create or update a Swarm-compatible stack YAML file.
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3. Create or update `.env.example` with placeholders only.
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4. Use Docker secrets/configs for sensitive runtime values.
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5. Define overlay networks and named volumes explicitly.
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6. Add `deploy:` settings only when they are meaningful.
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7. Validate YAML/Compose rendering where possible.
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8. Explain deployment commands, required secrets, required networks, and rollback notes.
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## Swarm Standards
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- Use 2-space YAML indentation.
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- Prefer explicit image tags over unpinned `latest` when stability matters.
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- Use `deploy.restart_policy` for Swarm-managed services.
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- Use `placement.constraints` when a service must run on a specific node or node label.
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- Do not use `container_name`; it is ignored or problematic in Swarm.
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- Be careful with `depends_on`; Swarm does not honor Compose startup ordering the same way local Compose does.
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- Prefer external secrets for sensitive values.
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## Validation Command Pattern
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```bash
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docker compose --env-file <service>.env.example -f <stack-file>.yml config
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```
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Do not run `docker stack deploy` unless explicitly asked.
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