Lab10

k8s/HELM.md

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+
+# Lab 10 — Helm Package Manager
+
+![difficulty](https://img.shields.io/badge/difficulty-intermediate-yellow)
+![topic](https://img.shields.io/badge/topic-Helm-blue)
+![points](https://img.shields.io/badge/points-12%2B2.5-orange)
+![tech](https://img.shields.io/badge/tech-Helm-informational)
+
+> Package your Kubernetes applications with Helm for reusable, configurable deployments across environments.
+
+---
+
+## Chart Overview
+
+This Helm chart (`myapp`) converts Kubernetes manifests from Lab 9 into a reusable, configurable deployment system.
+
+### Structure
+
+```
+
+myapp/
+├── Chart.yaml
+├── values.yaml
+├── values-dev.yaml
+├── values-prod.yaml
+└── templates/
+├── deployment.yaml
+├── service.yaml
+└── hooks/
+├── pre-install-job.yaml
+└── post-install-job.yaml
+
+````
+
+### Key Components
+
+- **Deployment template** — runs the Python application with configurable replicas, image, and resources
+- **Service template** — exposes the application inside cluster (NodePort / ClusterIP)
+- **Values files** — environment-based configuration (dev/prod)
+- **Hooks** — lifecycle jobs executed before and after deployment
+
+---
+
+## Configuration Guide
+
+### Main values (`values.yaml`)
+
+- `replicaCount` — number of pods
+- `image.repository` — Docker image name
+- `image.tag` — image version
+- `service.port` — exposed port
+- `service.targetPort` — container port (5000)
+- `resources` — CPU/memory limits
+- `livenessProbe` — health check configuration
+- `readinessProbe` — readiness check configuration
+
+### Dev environment (`values-dev.yaml`)
+
+- 1 replica
+- lightweight CPU/memory limits
+- NodePort service
+- relaxed probes
+
+### Prod environment (`values-prod.yaml`)
+
+- 3–5 replicas
+- higher resource limits
+- LoadBalancer-ready configuration
+- stricter probes
+
+### Example usage
+
+```bash
+helm install myapp-dev ./myapp -f values-dev.yaml
+helm install myapp-prod ./myapp -f values-prod.yaml
+````
+
+---
+
+## Hook Implementation
+
+### Pre-install hook
+
+Executes before deployment starts.
+
+* Used for initialization / validation
+* Runs a Kubernetes Job
+
+### Post-install hook
+
+Executes after deployment completes.
+
+* Used for smoke tests or verification
+* Confirms application readiness
+
+### Hook execution order
+
+```
+Pre-install → Deploy resources → Post-install
+```
+
+### Hook weights
+
+* `-5` → pre-install (runs first)
+* `5` → post-install (runs last)
+
+### Deletion policy
+
+Hooks are configured with:
+
+```
+hook-delete-policy: hook-succeeded
+```
+
+This ensures:
+
+* cleanup after successful execution
+* no leftover Jobs in cluster
+
+---
+
+## Installation Evidence
+
+### Helm release list
+
+```bash
+helm list
+```
+
+📸 Screenshot: `lab10-set.png`
+
+---
+
+### Kubernetes resources
+
+```bash
+kubectl get all
+```
+
+📸 Screenshot: `lab10-set.png`
+
+---
+
+### Application running
+
+```bash
+kubectl get pods
+kubectl get svc
+```
+
+📸 Screenshot: `lab10-app.png`
+
+---
+
+### Hooks execution
+
+```bash
+kubectl get jobs
+kubectl logs job/<pre-install-job>
+kubectl logs job/<post-install-job>
+```
+
+📸 Screenshot: `lab10-hooks.png`
+
+---
+
+## Operations
+
+### Install
+
+```bash
+helm install myapp-release ./myapp
+```
+
+### Upgrade
+
+```bash
+helm upgrade myapp-release ./myapp
+```
+
+### Rollback
+
+```bash
+helm rollback myapp-release 1
+```
+
+### Uninstall
+
+```bash
+helm uninstall myapp-release
+```
+
+---
+
+## Testing & Validation
+
+### Chart validation
+
+```bash
+helm lint ./myapp
+```
+
+### Template rendering
+
+```bash
+helm template myapp ./myapp
+```
+
+### Dry-run install
+
+```bash
+helm install test ./myapp --dry-run --debug
+```
+
+### Result
+
+* Deployment successfully created
+* Service exposed via NodePort
+* Application accessible in browser via `http://localhost:8080`
+
+---
+
+## Summary
+
+This Helm chart demonstrates:
+
+* templating Kubernetes manifests
+* environment-based configuration
+* lifecycle hooks (pre/post install)
+* production-ready structure
+* reusable deployment patterns
+
+Helm significantly improves maintainability, scalability, and repeatability of Kubernetes deployments.
+
+---
+
+## Screenshots
+
+### Cluster setup & Helm state
+
+![lab10-set](lab10-set.png)
+
+### Application running
+
+![lab10-app](lab10-app.png)
+
+### Hooks execution
+
+![lab10-hooks](lab10-hooks.png)

k8s/myapp/.helmignore

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+# Patterns to ignore when building packages.
+# This supports shell glob matching, relative path matching, and
+# negation (prefixed with !). Only one pattern per line.
+.DS_Store
+# Common VCS dirs
+.git/
+.gitignore
+.bzr/
+.bzrignore
+.hg/
+.hgignore
+.svn/
+# Common backup files
+*.swp
+*.bak
+*.tmp
+*.orig
+*~
+# Various IDEs
+.project
+.idea/
+*.tmproj
+.vscode/

k8s/myapp/Chart.yaml

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+apiVersion: v2
+name: myapp
+description: A Helm chart for Kubernetes
+
+# A chart can be either an 'application' or a 'library' chart.
+#
+# Application charts are a collection of templates that can be packaged into versioned archives
+# to be deployed.
+#
+# Library charts provide useful utilities or functions for the chart developer. They're included as
+# a dependency of application charts to inject those utilities and functions into the rendering
+# pipeline. Library charts do not define any templates and therefore cannot be deployed.
+type: application
+
+# This is the chart version. This version number should be incremented each time you make changes
+# to the chart and its templates, including the app version.
+# Versions are expected to follow Semantic Versioning (https://semver.org/)
+version: 0.1.0
+
+# This is the version number of the application being deployed. This version number should be
+# incremented each time you make changes to the application. Versions are not expected to
+# follow Semantic Versioning. They should reflect the version the application is using.
+# It is recommended to use it with quotes.
+appVersion: "1.16.0"

k8s/myapp/templates/_helpers.tpl

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+{{/*
+Expand the name of the chart.
+*/}}
+{{- define "myapp.name" -}}
+{{- default .Chart.Name .Values.nameOverride | trunc 63 | trimSuffix "-" }}
+{{- end }}
+
+{{/*
+Create a default fully qualified app name.
+We truncate at 63 chars because some Kubernetes name fields are limited to this (by the DNS naming spec).
+If release name contains chart name it will be used as a full name.
+*/}}
+{{- define "myapp.fullname" -}}
+{{- if .Values.fullnameOverride }}
+{{- .Values.fullnameOverride | trunc 63 | trimSuffix "-" }}
+{{- else }}
+{{- $name := default .Chart.Name .Values.nameOverride }}
+{{- if contains $name .Release.Name }}
+{{- .Release.Name | trunc 63 | trimSuffix "-" }}
+{{- else }}
+{{- printf "%s-%s" .Release.Name $name | trunc 63 | trimSuffix "-" }}
+{{- end }}
+{{- end }}
+{{- end }}
+
+{{/*
+Create chart name and version as used by the chart label.
+*/}}
+{{- define "myapp.chart" -}}
+{{- printf "%s-%s" .Chart.Name .Chart.Version | replace "+" "_" | trunc 63 | trimSuffix "-" }}
+{{- end }}
+
+{{/*
+Common labels
+*/}}
+{{- define "myapp.labels" -}}
+helm.sh/chart: {{ include "myapp.chart" . }}
+{{ include "myapp.selectorLabels" . }}
+{{- if .Chart.AppVersion }}
+app.kubernetes.io/version: {{ .Chart.AppVersion | quote }}
+{{- end }}
+app.kubernetes.io/managed-by: {{ .Release.Service }}
+{{- end }}
+
+{{/*
+Selector labels
+*/}}
+{{- define "myapp.selectorLabels" -}}
+app.kubernetes.io/name: {{ include "myapp.name" . }}
+app.kubernetes.io/instance: {{ .Release.Name }}
+{{- end }}
+
+{{/*
+Create the name of the service account to use
+*/}}
+{{- define "myapp.serviceAccountName" -}}
+{{- if .Values.serviceAccount.create }}
+{{- default (include "myapp.fullname" .) .Values.serviceAccount.name }}
+{{- else }}
+{{- default "default" .Values.serviceAccount.name }}
+{{- end }}
+{{- end }}

k8s/myapp/templates/deployment.yaml

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+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: {{ include "myapp.fullname" . }}
+spec:
+  replicas: {{ .Values.replicaCount }}
+  selector:
+    matchLabels:
+      app: {{ include "myapp.name" . }}
+  template:
+    metadata:
+      labels:
+        app: {{ include "myapp.name" . }}
+    spec:
+      containers:
+        - name: app
+          image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
+          ports:
+            - containerPort: {{ .Values.service.targetPort }}
+          resources:
+            {{- toYaml .Values.resources | nindent 12 }}
+          livenessProbe:
+            httpGet:
+              path: {{ .Values.livenessProbe.path }}
+              port: {{ .Values.service.targetPort }}
+            initialDelaySeconds: {{ .Values.livenessProbe.initialDelaySeconds }}
+            periodSeconds: {{ .Values.livenessProbe.periodSeconds }}
+          readinessProbe:
+            httpGet:
+              path: {{ .Values.readinessProbe.path }}
+              port: {{ .Values.service.targetPort }}
+            initialDelaySeconds: {{ .Values.readinessProbe.initialDelaySeconds }}
+            periodSeconds: {{ .Values.readinessProbe.periodSeconds }}