stack-orchestrator/docs/deployment_patterns.md

Deployment Patterns

GitOps Pattern

For production deployments, we recommend a GitOps approach where your deployment configuration is tracked in version control.

Overview

• spec.yml is your source of truth: Maintain it in your operator repository
• Don't regenerate on every restart: Run deploy init once, then customize and commit
• Use restart for updates: The restart command respects your git-tracked spec.yml

Workflow

1. Initial setup: Run deploy init once to generate a spec.yml template
2. Customize and commit: Edit spec.yml with your configuration (hostnames, resources, etc.) and commit to your operator repo
3. Deploy from git: Use the committed spec.yml for deployments
4. Update via git: Make changes in git, then restart to apply

# Initial setup (run once)
laconic-so --stack my-stack deploy init --output spec.yml

# Customize for your environment
vim spec.yml  # Set hostname, resources, etc.

# Commit to your operator repository
git add spec.yml
git commit -m "Add my-stack deployment configuration"
git push

# On deployment server: deploy from git-tracked spec
laconic-so --stack my-stack deploy create \
  --spec-file /path/to/operator-repo/spec.yml \
  --deployment-dir my-deployment

laconic-so deployment --dir my-deployment start

Updating Deployments

When you need to update a deployment:

# 1. Make changes in your operator repo
vim /path/to/operator-repo/spec.yml
git commit -am "Update configuration"
git push

# 2. On deployment server: pull and restart
cd /path/to/operator-repo && git pull
laconic-so deployment --dir my-deployment restart

The restart command:

• Pulls latest code from the stack repository
• Uses your git-tracked spec.yml (does NOT regenerate from defaults)
• Syncs the deployment directory
• Restarts services

Anti-patterns

Don't do this:

# BAD: Regenerating spec on every deployment
laconic-so --stack my-stack deploy init --output spec.yml
laconic-so deploy create --spec-file spec.yml ...

This overwrites your customizations with defaults from the stack's commands.py.

Do this instead:

# GOOD: Use your git-tracked spec
git pull  # Get latest spec.yml from your operator repo
laconic-so deployment --dir my-deployment restart

Private Registry Authentication

For deployments using images from private container registries (e.g., GitHub Container Registry), configure authentication in your spec.yml:

Configuration

Add a registry-credentials section to your spec.yml:

registry-credentials:
  server: ghcr.io
  username: your-org-or-username
  token-env: REGISTRY_TOKEN

Fields:

• server: The registry hostname (e.g., ghcr.io, docker.io, gcr.io)
• username: Registry username (for GHCR, use your GitHub username or org name)
• token-env: Name of the environment variable containing your API token/PAT

Token Environment Variable

The token-env pattern keeps credentials out of version control. Set the environment variable when running deployment start:

export REGISTRY_TOKEN="your-personal-access-token"
laconic-so deployment --dir my-deployment start

For GHCR, create a Personal Access Token (PAT) with read:packages scope.

Ansible Integration

When using Ansible for deployments, pass the token from a credentials file:

- name: Start deployment
  ansible.builtin.command:
    cmd: laconic-so deployment --dir {{ deployment_dir }} start
  environment:
    REGISTRY_TOKEN: "{{ lookup('file', '~/.credentials/ghcr_token') }}"

How It Works

1. laconic-so reads the registry-credentials config from spec.yml
2. Creates a Kubernetes docker-registry secret named {deployment}-registry
3. The deployment's pods reference this secret for image pulls

Cluster and Volume Management

Stopping Deployments

The deployment stop command has two important flags:

# Default: stops deployment, deletes cluster, PRESERVES volumes
laconic-so deployment --dir my-deployment stop

# Explicitly delete volumes (USE WITH CAUTION)
laconic-so deployment --dir my-deployment stop --delete-volumes

Volume Persistence

Volumes persist across cluster deletion by design. This is important because:

• Data survives cluster recreation: Ledger data, databases, and other state are preserved
• Faster recovery: No need to re-sync or rebuild data after cluster issues
• Safe cluster upgrades: Delete and recreate cluster without data loss

Only use --delete-volumes when:

• You explicitly want to start fresh with no data
• The user specifically requests volume deletion
• You're cleaning up a test/dev environment completely

Shared Cluster Architecture

In kind deployments, multiple stacks share a single cluster:

• First deployment start creates the cluster
• Subsequent deployments reuse the existing cluster
• deployment stop on ANY deployment deletes the shared cluster
• Other deployments will fail until cluster is recreated

To stop a single deployment without affecting the cluster:

laconic-so deployment --dir my-deployment stop --skip-cluster-management

Stacks sharing a cluster must agree on mount topology. See Volume Persistence in k8s-kind.

cluster-id vs deployment-id

Each deployment's deployment.yml carries two identifiers with different roles:

• cluster-id — which kind cluster this deployment attaches to. Used for the kube-config context name (kind-{cluster-id}) and for kind lifecycle ops. Inherited from the running cluster at deploy create time when one exists; freshly generated otherwise. Shared across every deployment that joins the same cluster.
• deployment-id — this particular deployment's identity. Generated fresh on every deploy create and never inherited. Flows into app_name, the prefix on every k8s resource name this deployment creates (PVs, ConfigMaps, Deployments, PVCs, …). Distinct per deployment even when the cluster is shared.

The split prevents silent resource-name collisions between deployments sharing a cluster: two deployments of the same stack, or any two deployments that happen to declare a volume with the same name, still produce distinct {deployment-id}-{vol} PV names.

Backward compatibility: deployment.yml files written before the deployment-id field existed fall back to using cluster-id as the deployment-id. Existing resource names stay stable across this upgrade — no PV renames, no re-bind, no data orphaning. The next deploy create writes both fields going forward.

Namespace ownership: on top of distinct resource names, SO stamps the k8s namespace with a laconic.com/deployment-dir annotation on first creation. A subsequent deployment start from a different deployment directory that would land in the same namespace fails with a DeployerException pointing at the namespace: spec override. Catches operator-error cases where the same deployment dir is effectively registered twice.

Caddy ingress image lifecycle

The Caddy ingress controller lives in the cluster-scoped caddy-system namespace and is installed on first deployment start. Its image is configurable per deployment:

# spec.yml
caddy-ingress-image: ghcr.io/laconicnetwork/caddy-ingress:v1.2.3

Defaults to ghcr.io/laconicnetwork/caddy-ingress:latest when not set.

On subsequent deployment start, if the running Caddy image differs from the spec value, laconic-so patches the Caddy Deployment to the new image. The Deployment uses strategy: Recreate (the hostPort 80/443 binding blocks a rolling update from ever completing), so expect ~10–30s of ingress downtime while the old pod terminates and the new one starts.

Cluster-scoped caveat: caddy-system is shared by every deployment on the cluster. Setting caddy-ingress-image in any one deployment's spec rolls the controller for all of them — last deployment start wins. Treat it as a cluster-level knob; keep the value consistent across the deployments sharing a cluster.

Volume Persistence in k8s-kind

k8s-kind has 3 storage layers:

• Docker Host: The physical server running Docker
• Kind Node: A Docker container simulating a k8s node
• Pod Container: Your workload

Volumes with paths are mounted from Docker Host → Kind Node → Pod via kind extraMounts. Kind applies extraMounts only at cluster creation — they cannot be added to a running cluster.

spec.yml volume	Storage Location	Survives Pod Restart	Survives Cluster Restart
vol: (empty)	Kind Node PVC	✅	❌
vol: ./data/x	Docker Host	✅	✅
vol: /abs/path	Docker Host	✅	✅

Recommendation: Always use paths for data you want to keep. Relative paths (e.g., ./data/rpc-config) resolve to $DEPLOYMENT_DIR/data/rpc-config on the Docker Host.

Example

# In spec.yml
volumes:
  rpc-config: ./data/rpc-config  # Persists to $DEPLOYMENT_DIR/data/rpc-config
  chain-data: ./data/chain       # Persists to $DEPLOYMENT_DIR/data/chain
  temp-cache:                    # Empty = Kind Node PVC (lost on cluster delete)

The Antipattern

Empty-path volumes appear persistent because they survive pod restarts (data lives in Kind Node container). However, this data is lost when the kind cluster is recreated. This "false persistence" has caused data loss when operators assumed their data was safe.

Shared Clusters: Use kind-mount-root

Because kind extraMounts can only be set at cluster creation, the first deployment to start locks in the mount topology. Later deployments that declare new extraMounts have them silently ignored — their PVs fall through to the kind node's overlay filesystem and lose data on cluster destroy.

The fix is an umbrella mount. Set kind-mount-root in the spec, pointing at a host directory all stacks will share:

# spec.yml
kind-mount-root: /srv/kind

volumes:
  my-data: /srv/kind/my-stack/data   # visible at /mnt/my-stack/data in-node

SO emits a single extraMount (<kind-mount-root> → /mnt). Any new host subdirectory under the root is visible in the node immediately — no cluster recreate needed to add stacks.

All stacks sharing a cluster must agree on kind-mount-root and keep their host paths under it.

Mount Compatibility Enforcement

laconic-so deployment start validates mount topology:

• On first cluster creation without an umbrella mount: prints a warning (future stacks may require a full recreate to add mounts).
• On cluster reuse: compares the new deployment's extraMounts against the live mounts on the control-plane container. Any mismatch (wrong host path, or mount missing) fails the deploy.

Static files in compose volumes → auto-ConfigMap

Compose volumes that bind a host file or flat directory into a container (e.g. ../config/test/script.sh:/opt/run.sh) are used to inject static content that ships with the stack. k8s doesn't have a native notion of this — the canonical way to inject static content is a ConfigMap.

At deploy start, laconic-so auto-generates a namespace-scoped ConfigMap per host-path compose volume (deduped by source) and mounts it into the pod instead of routing the bind through the kind node:

Source shape	Behavior
Single file	ConfigMap with one key (the filename); pod mount uses subPath so the single key lands at the compose target path
Flat directory (no subdirs, ≤ ~700 KiB)	ConfigMap with one key per file; pod mount exposes all keys at the target path
Directory with subdirs, or over budget	Rejected at deploy create — embed in the container image, split into multiple ConfigMaps, or use an initContainer
:rw on any host-path bind	Rejected at deploy create — use a named volume with a spec-configured host path for writable data

The deployment dir layout is unchanged: compose files stay verbatim and spec.yml is not rewritten. Source files remain under {deployment_dir}/config/{pod}/ (as copied by deploy create); the ConfigMap is built from them at deploy start and no kind extraMount is emitted for these paths.

This works identically on kind and real k8s (ConfigMaps are cluster-native; no node-side landing pad required), and two deployments of the same stack sharing a cluster get their own per-namespace ConfigMaps — no aliasing.

Writable / generated data → named volume + host path

For volumes the workload writes to (databases, ledgers, caches, logs), use a named volume backed by a spec-configured host path under kind-mount-root:

# compose
volumes:
  - my-data:/var/lib/foo

# spec.yml
kind-mount-root: /srv/kind
volumes:
  my-data: /srv/kind/my-stack/data

Works on both kind (via the umbrella mount) and real k8s (operator provisions /srv/kind/my-stack/data on each node).

Migrating an Existing Cluster

If a cluster was created without an umbrella mount and you need to add a stack that requires new host-path mounts, the cluster must be recreated:

1. Back up ephemeral state (DBs, caches) from PVs that lack host mounts — these are in the kind node overlay FS and do not survive kind delete.
2. Update every stack's spec to set a shared kind-mount-root and place host paths under it.
3. Stop all deployments, destroy the cluster, recreate it by starting any stack (umbrella now active), and restore state.