# Procedure: Add, Update, or Remove a Tool from a Cluster

> Step-by-step guide for modifying `appSpec` entries in cluster values files.
>
> **Layer:** 1-T (Tool-Mediated). Use `argo-app-tool` where available; manual YAML edits acceptable with checklist.
>
> **Blast radius:** Single cluster, single tool. Auto-sync means changes deploy immediately after merge to the env branch (`main` for prd, `develop` for stg, `pre-prod` for int).

---

## Prerequisites

Before starting, confirm:

1. The tool's **chart** exists in `devops-infra-helm-charts/helm-templates/<chartDir>/` on the correct branch.
2. The tool's **values override** exists in `devops-infra-helm-charts/helm-overrides/<cluster>/<valuesDir>/custom-values.yaml` on the correct branch.
3. You know which **cluster** and **environment** the tool should deploy to.

Both this repo and `devops-infra-helm-charts` use the same branch convention:

| Environment | Branch |
| ----------- | ------ |
| Production (prd) | `main` |
| Staging (stg) | `develop` |
| Integration (int) | `pre-prod` |

If either the chart or override doesn't exist on the target branch, the work starts in `devops-infra-helm-charts` first. See [devops-infra-helm-charts procedures](https://github.com/Meesho/devops-infra-helm-charts).

---

## Add a new tool

### Step 1: Identify the target values file

```text
values/<env>/incubator-infra-<cluster>-values.yaml
```

Example: `values/prd/incubator-infra-k8s-central-prd-ase1-values.yaml`

### Step 2: Verify chart and values exist in the sister repo

```bash
# Chart directory
ls /path/to/devops-infra-helm-charts/helm-templates/<chartDir>/

# Values override
ls /path/to/devops-infra-helm-charts/helm-overrides/<cluster>/<valuesDir>/custom-values.yaml
```

If either is missing, stop. Create them in `devops-infra-helm-charts` first.

### Step 3: Compute the auto-generated Application name

Apply the munging rules from [coding-guidelines/infra-argo.md](../global/coding-guidelines/infra-argo.md):

```text
<name>-<mungedCluster>-<env>
```

Example: `kyverno` on `k8s-farmiso-prd-ase1` → `kyverno-farmiso-prd`

Verify:
- Name is <= 253 characters.
- Name doesn't collide with an existing Application (grep the values file).

### Step 4: Add the appSpec entry

Append to the `appSpec` list in the values file:

```yaml
  - name: kyverno
    namespace: kyverno-farmiso-prd
    chartDir: kyverno
    valuesDir: kyverno
```

Only add `nameOverride` if Step 3 revealed a collision or length issue.

Only add `additionalValueFiles` if the tool requires region-shared overlays.

### Step 5: Validate locally

```bash
# Render the generic chart with the updated values
helm template generic-argo-apps-chart/ \
  -f values/prd/incubator-infra-<cluster>-values.yaml | grep -A 20 "name: kyverno"

# Verify no YAML syntax errors
yamllint values/prd/incubator-infra-<cluster>-values.yaml
```

### Step 6: Open PR

- Target branch: `main` (prd) / `develop` (stg) / `pre-prod` (int)
- Required: Platform team review
- Pre-commit hooks must pass (TruffleHog, CAC, Yaak)

### Step 7: After merge

ArgoCD auto-syncs from the env branch. The new Application will appear in ArgoCD within minutes. Verify in the ArgoCD UI that:
- The Application is created with the expected name.
- It syncs successfully.
- The target namespace is created.

---

## Update an existing tool

### Change chart version

Update `chartDir` to point to the new chart directory:

```yaml
  - name: contour-internal-0
    chartDir: contour-v1.33.3          # was: contour
```

Verify the new `chartDir` exists in `helm-templates/`.

### Change values directory

Update `valuesDir`:

```yaml
  - name: vmagent
    valuesDir: victoria-metrics-agent-new   # was: victoria-metrics-agent
```

Verify the new `valuesDir` exists in `helm-overrides/<cluster>/`.

### Change namespace

Update `namespace`. This is a destructive operation — ArgoCD will create the new namespace and deploy there, but the old namespace's resources are **not automatically cleaned up**.

```yaml
  - name: ai-gateway
    namespace: ai-gateway-prd          # was: ai-gateway
```

After merge, manually clean up the old namespace if no other tools use it.

---

## Remove a tool from a cluster

### Step 1: Delete the appSpec entry

Remove the entire `- name: ...` block from the values file.

### Step 2: Verify no other entries depend on it

Check if any other appSpec entries reference the same namespace or have dependencies on this tool.

### Step 3: Open PR

After merge, the ArgoCD Application will be deleted by the finalizer (`resources-finalizer.argocd.argoproj.io`), which will also clean up the deployed resources.

**Warning:** If the Application has `CreateNamespace=true` in syncOptions and the namespace is shared with other tools, removing the Application will NOT delete the namespace. Namespace cleanup is manual.

---

## Multi-cluster rollout

When adding a tool to multiple clusters:

1. Add the appSpec entry to each cluster's values file in the **same PR**.
2. Verify chart/values exist for **each** cluster — valuesDir names may differ per cluster.
3. Each cluster should have its own override directory in `devops-infra-helm-charts/helm-overrides/<cluster>/<valuesDir>/`.

---

## Checklist

- [ ] `chartDir` exists in `devops-infra-helm-charts/helm-templates/`
- [ ] `valuesDir` exists in `devops-infra-helm-charts/helm-overrides/<cluster>/`
- [ ] Auto-generated Application name <= 253 characters
- [ ] No name collision with existing appSpec entries
- [ ] `nameOverride` used only if justified
- [ ] `helm template` renders without errors
- [ ] `yamllint` passes
- [ ] Pre-commit hooks pass