Refactor Terraform configs

README.md

@@ -403,6 +403,20 @@ kubectl delete namespace tarun-spring-app
 ```
 This ensures the namespace and all resources within it are deleted.
 
+## Deploying with Terraform
+
+The `terraform` directory provides the same Kubernetes resources using Terraform.
+The configuration is split across multiple `.tf` files for readability and Terraform automatically loads all of them.
+Run the following commands to apply them:
+
+```bash
+cd terraform
+terraform init
+terraform apply
+```
+
+Ensure your kubeconfig is accessible (by default `~/.kube/config`).
+
 ## Future Enhancements
 
 Below are some potential enhancements and next steps for this project:

terraform/configmap.tf

@@ -0,0 +1,22 @@
+resource "kubernetes_config_map" "spring_app_config" {
+  metadata {
+    name      = "spring-app-config"
+    namespace = kubernetes_namespace.spring.metadata[0].name
+  }
+
+  data = {
+    "application.properties" = <<EOT
+spring.application.name=spring-app
+spring.datasource.url=jdbc:h2:mem:todo-db
+spring.datasource.driverClassName=org.h2.Driver
+spring.datasource.username=$${DB_USERNAME:defaultUser}
+spring.datasource.password=$${DB_PASSWORD:defaultPass}
+spring.jpa.hibernate.ddl-auto=update
+spring.h2.console.enabled=true
+spring.h2.console.path=/h2-console
+spring.h2.console.settings.web-allow-others=true
+management.endpoints.web.exposure.include=prometheus
+management.endpoint.health.show-details=always
+EOT
+  }
+}

terraform/deployment.tf

@@ -0,0 +1,82 @@
+resource "kubernetes_deployment" "spring_app" {
+  metadata {
+    name      = "spring-app"
+    namespace = kubernetes_namespace.spring.metadata[0].name
+    labels = {
+      app = "spring-app"
+    }
+    annotations = {
+      "prometheus.io/scrape" = "true"
+      "prometheus.io/port"   = "8080"
+      "prometheus.io/path"   = "/actuator/prometheus"
+    }
+  }
+
+  spec {
+    replicas = 2
+
+    selector {
+      match_labels = {
+        app = "spring-app"
+      }
+    }
+
+    template {
+      metadata {
+        labels = {
+          app = "spring-app"
+        }
+      }
+
+      spec {
+        container {
+          name  = "spring-app"
+          image = "tarundhiman/spring-app:v3"
+
+          image_pull_policy = "IfNotPresent"
+
+          port {
+            container_port = 8080
+          }
+
+          volume_mount {
+            name       = "config-volume"
+            mount_path = "/config/application.properties"
+            sub_path   = "application.properties"
+          }
+
+          env {
+            name = "DB_USERNAME"
+            value_from {
+              secret_key_ref {
+                name = kubernetes_secret.spring_app_secret.metadata[0].name
+                key  = "username"
+              }
+            }
+          }
+
+          env {
+            name = "DB_PASSWORD"
+            value_from {
+              secret_key_ref {
+                name = kubernetes_secret.spring_app_secret.metadata[0].name
+                key  = "password"
+              }
+            }
+          }
+
+          args = ["--spring.config.location=file:/config/application.properties"]
+        }
+
+        volume {
+          name = "config-volume"
+          config_map {
+            name = kubernetes_config_map.spring_app_config.metadata[0].name
+          }
+        }
+
+        restart_policy = "Always"
+      }
+    }
+  }
+}

terraform/ingress.tf

@@ -0,0 +1,40 @@
+resource "kubernetes_ingress_v1" "spring_app_ingress" {
+  metadata {
+    name      = "spring-app-ingress"
+    namespace = kubernetes_namespace.spring.metadata[0].name
+  }
+
+  spec {
+    ingress_class_name = "nginx"
+
+    rule {
+      host = "spring-app.example.com"
+      http {
+        path {
+          path      = "/"
+          path_type = "Prefix"
+          backend {
+            service {
+              name = kubernetes_service.spring_app_service.metadata[0].name
+              port {
+                number = 80
+              }
+            }
+          }
+        }
+        path {
+          path      = "/prometheus"
+          path_type = "Prefix"
+          backend {
+            service {
+              name = kubernetes_service.prometheus_service.metadata[0].name
+              port {
+                number = 90
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+}

terraform/namespace.tf

@@ -0,0 +1,5 @@
+resource "kubernetes_namespace" "spring" {
+  metadata {
+    name = "tarun-spring-app"
+  }
+}

terraform/prometheus.tf

@@ -0,0 +1,137 @@
+resource "kubernetes_service_account" "prometheus" {
+  metadata {
+    name      = "prometheus"
+    namespace = kubernetes_namespace.spring.metadata[0].name
+  }
+}
+
+resource "kubernetes_cluster_role" "prometheus" {
+  metadata {
+    name = "prometheus-clusterrole"
+  }
+
+  rule {
+    api_groups = [""]
+    resources  = ["pods", "endpoints", "services"]
+    verbs      = ["get", "list", "watch"]
+  }
+}
+
+resource "kubernetes_cluster_role_binding" "prometheus" {
+  metadata {
+    name = "prometheus-clusterrolebinding"
+  }
+
+  subject {
+    kind      = "ServiceAccount"
+    name      = kubernetes_service_account.prometheus.metadata[0].name
+    namespace = kubernetes_namespace.spring.metadata[0].name
+  }
+
+  role_ref {
+    kind      = "ClusterRole"
+    name      = kubernetes_cluster_role.prometheus.metadata[0].name
+    api_group = "rbac.authorization.k8s.io"
+  }
+}
+
+resource "kubernetes_config_map" "prometheus_config" {
+  metadata {
+    name      = "prometheus-config"
+    namespace = kubernetes_namespace.spring.metadata[0].name
+  }
+
+  data = {
+    "prometheus.yml" = <<EOT
+global:
+  scrape_interval: 15s
+
+scrape_configs:
+  - job_name: 'spring-app'
+    metrics_path: /actuator/prometheus
+    scheme: http
+    kubernetes_sd_configs:
+      - role: pod
+    relabel_configs:
+      - source_labels: [__meta_kubernetes_pod_label_app]
+        action: keep
+        regex: spring-app
+EOT
+  }
+}
+
+resource "kubernetes_deployment" "prometheus" {
+  metadata {
+    name      = "prometheus-deployment"
+    namespace = kubernetes_namespace.spring.metadata[0].name
+    labels = {
+      app = "prometheus"
+    }
+  }
+
+  spec {
+    replicas = 1
+
+    selector {
+      match_labels = {
+        app = "prometheus"
+      }
+    }
+
+    template {
+      metadata {
+        labels = {
+          app = "prometheus"
+        }
+      }
+
+      spec {
+        service_account_name = kubernetes_service_account.prometheus.metadata[0].name
+        container {
+          name  = "prometheus"
+          image = "prom/prometheus:v2.22.0"
+          args = [
+            "--config.file=/etc/prometheus/prometheus.yml",
+            "--web.route-prefix=/prometheus",
+            "--web.external-url=http://spring-app.example.com/prometheus"
+          ]
+          port {
+            container_port = 9090
+          }
+          volume_mount {
+            name       = "prometheus-config-volume"
+            mount_path = "/etc/prometheus"
+          }
+        }
+
+        volume {
+          name = "prometheus-config-volume"
+          config_map {
+            name = kubernetes_config_map.prometheus_config.metadata[0].name
+          }
+        }
+      }
+    }
+  }
+}
+
+resource "kubernetes_service" "prometheus_service" {
+  metadata {
+    name      = "prometheus-service"
+    namespace = kubernetes_namespace.spring.metadata[0].name
+  }
+
+  spec {
+    selector = {
+      app = "prometheus"
+    }
+
+    port {
+      name        = "http"
+      port        = 90
+      target_port = 9090
+    }
+
+    type = "ClusterIP"
+  }
+}

terraform/provider.tf

@@ -0,0 +1,12 @@
+terraform {
+  required_providers {
+    kubernetes = {
+      source  = "hashicorp/kubernetes"
+      version = "~> 2.29"
+    }
+  }
+}
+
+provider "kubernetes" {
+  config_path = var.kubeconfig
+}

terraform/secret.tf

@@ -0,0 +1,11 @@
+resource "kubernetes_secret" "spring_app_secret" {
+  metadata {
+    name      = "spring-app-secret"
+    namespace = kubernetes_namespace.spring.metadata[0].name
+  }
+  data = {
+    username = base64decode("c2F0")
+    password = base64decode("cGFzc3dvcmQ=")
+  }
+  type = "kubernetes.io/basic-auth"
+}

terraform/service.tf

@@ -0,0 +1,19 @@
+resource "kubernetes_service" "spring_app_service" {
+  metadata {
+    name      = "spring-app-service"
+    namespace = kubernetes_namespace.spring.metadata[0].name
+  }
+
+  spec {
+    selector = {
+      app = "spring-app"
+    }
+
+    port {
+      port        = 80
+      target_port = 8080
+    }
+
+    type = "ClusterIP"
+  }
+}

terraform/variables.tf

@@ -0,0 +1,5 @@
+variable "kubeconfig" {
+  description = "Path to the kubeconfig file"
+  type        = string
+  default     = "~/.kube/config"
+}