# 14 — Deployment Process

## Summary

A production deploy is: build a new image, push to Gitea, update the
Deployment's image field with the new SHA, Kubernetes rolls new pods in.
No downtime if the change is backward-compatible. Rollback is
`kubectl rollout undo`. This chapter walks through the full process,
plus alternate paths (config-only changes, manifest changes, hotfixes).

## TL;DR for a code change

```bash
# 1. Commit + get SHA
cd /Users/treyt/Desktop/code/honeyDue/honeyDueAPI-go
git add . && git commit -m "..." && SHA=$(git rev-parse --short HEAD)

# 2. Login to Gitea registry
set -a; source deploy/registry.env; set +a
printf '%s' "$REGISTRY_TOKEN" | docker login "$REGISTRY" -u "$REGISTRY_USERNAME" --password-stdin

# 3. Build + push amd64 image
docker buildx build --platform linux/amd64 --target api \
  -t "gitea.treytartt.com/admin/honeydue-api:${SHA}" --push .

# 4. Roll it in
export KUBECONFIG=~/.kube/honeydue-k3s.yaml
kubectl set image deployment/api -n honeydue \
  api="gitea.treytartt.com/admin/honeydue-api:${SHA}"

# 5. Watch
kubectl rollout status -n honeydue deployment/api

# 6. Log out
docker logout "$REGISTRY"
```

~3–5 minutes end to end for api.

## The build

### Step 1 — Prepare

```bash
cd /Users/treyt/Desktop/code/honeyDue/honeyDueAPI-go
git status                        # clean working tree?
git log -1 --oneline              # this is the SHA that'll ship
```

### Step 2 — Login to Gitea

```bash
set -a; source deploy/registry.env; set +a
printf '%s' "$REGISTRY_TOKEN" | \
  docker login "$REGISTRY" -u "$REGISTRY_USERNAME" --password-stdin
```

**Note**: `docker login` without `--password-stdin` writes the token to
shell history. Don't skip the `printf` trick.

### Step 3 — Build + push

```bash
SHA=$(git rev-parse --short HEAD)

# For API
docker buildx build \
  --platform linux/amd64 \
  --target api \
  -t "gitea.treytartt.com/admin/honeydue-api:${SHA}" \
  --push .

# For Worker
docker buildx build \
  --platform linux/amd64 \
  --target worker \
  -t "gitea.treytartt.com/admin/honeydue-worker:${SHA}" \
  --push .

# For Admin (Next.js)
docker buildx build \
  --platform linux/amd64 \
  --target admin \
  -t "gitea.treytartt.com/admin/honeydue-admin:${SHA}" \
  --push .
```

- `--platform linux/amd64` — cross-compile from operator's arm64 to
  Hetzner nodes' amd64
- `--target X` — select a stage from the multi-stage Dockerfile
- `--push` — push to registry in one step; don't leave image in local
  Docker

First build is slow (~3–5 min cold). Subsequent builds hit BuildKit
layer cache and complete in ~30–60s if only app code changed.

### Build platform note

If `docker buildx` isn't configured:

```bash
docker buildx create --name honeydue-builder --use
docker buildx inspect --bootstrap
```

This creates a BuildKit container that supports cross-platform builds.
The `--bootstrap` line spins it up immediately so errors surface now
instead of on first build.

## The deploy

### For a single service

```bash
export KUBECONFIG=~/.kube/honeydue-k3s.yaml

kubectl set image deployment/api -n honeydue \
  api="gitea.treytartt.com/admin/honeydue-api:${SHA}"
```

This updates the Deployment's image field. Kubernetes:
1. Creates a new ReplicaSet with the new image (annotation records
   rev)
2. Starts a new pod (per `maxSurge: 1`)
3. Waits for readinessProbe to pass on the new pod (up to 240s for
   cold api boot)
4. Once ready, removes a pod from the old ReplicaSet
5. Repeats until all pods are on the new ReplicaSet
6. Marks rollout complete

### Watching the rollout

```bash
kubectl rollout status -n honeydue deployment/api
```

Outputs progress; returns when complete or timed out. Default timeout
is 10 minutes.

More detailed:

```bash
# Watch pods transition
kubectl get pods -n honeydue -l app.kubernetes.io/name=api -w

# Watch events
kubectl get events -n honeydue --sort-by=.lastTimestamp -w
```

### For all three services

```bash
for svc in api worker admin; do
  kubectl set image deployment/$svc -n honeydue \
    $svc="gitea.treytartt.com/admin/honeydue-${svc}:${SHA}"
done

# Watch all rollouts
for svc in api worker admin; do
  kubectl rollout status -n honeydue deployment/$svc
done
```

## Config-only changes (no new image)

When you change `prod.env` but code is unchanged:

```bash
# 1. Update prod.env locally
# 2. Regenerate ConfigMap
kubectl create configmap honeydue-config -n honeydue \
  --from-env-file=deploy/prod.env \
  --dry-run=client -o yaml | kubectl apply -f -

# 3. Pods do NOT auto-reload env vars. Restart them.
kubectl rollout restart -n honeydue deployment/api deployment/admin deployment/worker
```

`rollout restart` triggers a rolling update with the *same* image but
forces pod recreation. New pods pick up the updated ConfigMap.

### Why not auto-reload?

Kubernetes has no built-in mechanism to restart pods on ConfigMap change.
There's no `envFromWatch` equivalent. Third-party operators like
Reloader can do it, but we don't run one.

For sensitive config (like the `SECRET_KEY`), this is actually good —
pods don't cycle unexpectedly when someone tweaks the ConfigMap.

## Secret changes

Same flow as config:

```bash
# Rotate a value
kubectl patch secret honeydue-secrets -n honeydue \
  --type=merge -p "{\"data\":{\"SECRET_KEY\":\"$(echo -n 'newvalue' | base64)\"}}"

# Restart pods
kubectl rollout restart -n honeydue deployment/api deployment/worker
```

## Manifest changes

When you add/modify a deployment YAML:

```bash
kubectl apply -f deploy-k3s/manifests/api/deployment.yaml
```

If the change is a spec field that Kubernetes considers a new pod
template (e.g., changing resource limits, env, volumes), pods roll.
If the change is a scalar like replicas, no pod churn — just new pods
added/removed.

## Rollback

### Last-known-good rollback

```bash
kubectl rollout undo deployment/api -n honeydue
```

Reverts to the previous ReplicaSet (the one with the previous image).
Takes ~30s to stabilize.

### Rollback to a specific revision

```bash
# See revision history
kubectl rollout history deployment/api -n honeydue

# Revert to specific revision number
kubectl rollout undo deployment/api -n honeydue --to-revision=3
```

Kubernetes keeps up to 10 ReplicaSet revisions by default
(`spec.revisionHistoryLimit`).

### Hard rollback (deploy an older image)

```bash
kubectl set image deployment/api -n honeydue \
  api="gitea.treytartt.com/admin/honeydue-api:<older-sha>"
```

Useful when you want to go back further than the revision history, or
to a specific known-good SHA.

## Rolling update semantics

```yaml
strategy:
  type: RollingUpdate
  rollingUpdate:
    maxUnavailable: 0
    maxSurge: 1
```

For api (3 replicas):
- `maxUnavailable: 0` — no pod is removed until replacement is ready
- `maxSurge: 1` — up to 4 pods exist simultaneously during rollout

Timeline (approximate, warm state):
- t=0: kubectl set image
- t=0: k8s creates new RS with 1 pod
- t=30s (or so): new pod readiness probe passes
- t=30s: k8s terminates 1 old pod
- t=60s: next new pod ready
- t=60s: another old pod terminates
- ...continues until all on new RS

For cold-boot (e.g., first deploy on a rebuilt cluster), the
MigrateWithLock advisory lock extends this to several minutes. But the
rollout is serialized — only one pod starts per iteration, so the lock
queue is small.

## Hotfix workflow

When we need to ship a fix fast and skip the usual steps:

1. Fix in code
2. Build + push
3. `kubectl set image` on the affected service only
4. Monitor with `kubectl logs -f`

Don't skip CI/tests in a real org; for solo operator this is the tradeoff.

## Integration with Gitea

Currently no CI/CD. The operator builds from the workstation and pushes
manually. Future:

- Gitea Actions (Drone-like CI) could trigger on push to `main`
- Build + push step could run in a GitHub Actions-compatible workflow
- Auto-deploy on tag push, manual promote to prod

**TODO** (Chapter 20).

## What the old Swarm deploy script did

Contrast: `deploy/scripts/deploy_prod.sh` (Swarm-era) did:

1. Validate every config file (placeholder detection, APNS key format,
   B2 all-or-none)
2. Buildx to amd64
3. Push to Gitea (we retrofitted this from GHCR)
4. SCP bundle to manager node
5. `docker secret create` + `docker config create` with versioned names
6. `docker stack deploy --with-registry-auth`
7. Poll stack services until convergence (420s timeout)
8. Prune old secret/config versions
9. Healthcheck the final URL; auto-rollback on failure
10. Log out of registries

Our current k3s deploy is more manual but simpler. We'd write a similar
script for k3s if deploys become frequent:

```bash
# deploy-k3s/scripts/04-deploy.sh (not yet updated for Gitea)
```

See the scaffold in `deploy-k3s/scripts/`.

## Common deploy failures

| Symptom | Likely cause |
|---|---|
| `ImagePullBackOff` | Image not in registry, or pull secret expired |
| Stuck at "Progressing" | Readiness probe not passing; check pod logs |
| `CrashLoopBackOff` immediately | App won't start; check pod logs for panic/exit reason |
| `CrashLoopBackOff` after migration | Cache service, Redis connection, or post-init code issue |
| Old pods never terminate | New pods not ready; rollout doesn't progress |
| Rollout succeeds but app is broken | Readiness probe is too lenient; passes on broken app |

### Debugging commands

```bash
# Describe the deployment (shows events, conditions)
kubectl describe deployment api -n honeydue

# Describe the latest pod
kubectl describe pod -n honeydue -l app.kubernetes.io/name=api

# Logs from currently-running pods
kubectl logs -n honeydue -l app.kubernetes.io/name=api --tail=100 --prefix

# Logs from the last-terminated pod
kubectl logs -n honeydue <pod> --previous

# Events in the namespace (newest first)
kubectl get events -n honeydue --sort-by=.lastTimestamp

# Pause a rollout (stops new pods from being created)
kubectl rollout pause deployment/api -n honeydue

# Resume
kubectl rollout resume deployment/api -n honeydue
```

## Zero-downtime considerations

For zero-downtime deploys, the new image must be:

1. **Backward-compatible** with the current database schema (schema
   migrations run before new code)
2. **Backward-compatible** with in-flight API requests (don't remove
   endpoints mid-deploy; deprecate first)
3. **Backward-compatible** with Redis data structures (don't change
   cache key formats abruptly)

For breaking changes:
1. Deploy intermediate version that handles both old and new
2. Once rolled out everywhere, deploy breaking-change version
3. Two deploys, same day or different days

We don't have this discipline yet; our API has too few clients to
worry about. As mobile clients proliferate, this becomes more important.

## Blue-green / canary (not yet)

Kubernetes supports advanced rollout strategies:
- **Canary**: route 5% of traffic to new version, scale up gradually
- **Blue-green**: run new version alongside old, flip traffic all at
  once

These require Traefik's TraefikService CRD with weighted routing, or
a service mesh. **TODO** if traffic scale justifies.

## Cleanup: the old Swarm config

`deploy/` directory contains the Swarm-era config. It's still there but
unused. After we're confident in k3s (a few weeks? month?), remove it:

```bash
rm -rf deploy/
```

Keep the useful files in `deploy-k3s/` only.

## Operator cheat sheet

```bash
# Full build + deploy
cd /Users/treyt/Desktop/code/honeyDue/honeyDueAPI-go
SHA=$(git rev-parse --short HEAD)
set -a; source deploy/registry.env; set +a
printf '%s' "$REGISTRY_TOKEN" | docker login "$REGISTRY" -u admin --password-stdin
docker buildx build --platform linux/amd64 --target api -t "gitea.treytartt.com/admin/honeydue-api:${SHA}" --push .
docker buildx build --platform linux/amd64 --target worker -t "gitea.treytartt.com/admin/honeydue-worker:${SHA}" --push .
docker buildx build --platform linux/amd64 --target admin -t "gitea.treytartt.com/admin/honeydue-admin:${SHA}" --push .
docker logout gitea.treytartt.com

export KUBECONFIG=~/.kube/honeydue-k3s.yaml
for svc in api worker admin; do
  kubectl set image deployment/$svc -n honeydue "$svc=gitea.treytartt.com/admin/honeydue-${svc}:${SHA}"
done

for svc in api worker admin; do
  kubectl rollout status -n honeydue deployment/$svc
done
```

## References

- [Kubernetes Deployment rolling update][rolling]
- [kubectl rollout][rollout]
- [Docker buildx][buildx]

[rolling]: https://kubernetes.io/docs/concepts/workloads/controllers/deployment/#rolling-update-deployment
[rollout]: https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#rollout
[buildx]: https://docs.docker.com/build/buildx/
