What are Helm Plugins and how to use them?

Question

Accepted Answer

**Helm Plugins** — extending Helm functionality through plugins.

**Popular plugins:**
- **helm-diff** — shows diff before apply.
- **helm-secrets** — working with SOPS/Sealed Secrets.
- **helmfile** — declarative management.
- **helm-unittest** — template testing.

**Installation:**
```bash
helm plugin install https://github.com/databus23/helm-diff
helm plugin install https://github.com/jkroepke/helm-secrets --version v4.5.1
helm plugin install https://github.com/helm-unittest/helm-unittest
```

**helm-diff:**
```bash
helm diff upgrade my-release ./mychart -f values.yaml
# Output:
# mychart/templates/deployment.yaml has changed:
#   - image: myapp:1.0
#   + image: myapp:2.0
```

**helm-secrets (SOPS):**
```bash
# Encryption
helm secrets enc secrets.yaml

# Usage
helm secrets upgrade my-release ./mychart -f values.yaml -f secrets://secrets.yaml

# Decode (read only)
helm secrets view secrets.yaml
```

**helm-unittest:**
```yaml
# tests/deployment_test.yaml
suite: deployment tests
tests:
  - it: should set correct image
    set:
      image.tag: "2.0"
    asserts:
      - equal:
          path: spec.template.spec.containers[0].image
          value: "nginx:2.0"

- it: should have correct labels
    asserts:
      - isSubset:
          path: metadata.labels
          content:
            app: myapp
```
```bash
helm unittest ./mychart
```

**helmfile (declarative):**
```yaml
# helmfile.yaml
releases:
  - name: myapp
    chart: ./mychart
    values:
      - values.yaml
    set:
      - name: replicaCount
        value: 3
  - name: redis
    chart: bitnami/redis
    version: 18.0.0
    namespace: production
```
```bash
helmfile sync
```

DevOps: What are Helm Plugins and how to use them?