lab7

ansible/playbooks/deploy-monitoring.yml

@@ -0,0 +1,10 @@
+---
+- name: Deploy monitoring stack
+  hosts: webservers
+  become: true
+
+  roles:
+    - role: monitoring
+      tags:
+        - monitoring
+        - monitoring_deploy

ansible/roles/monitoring/defaults/main.yml

@@ -0,0 +1,12 @@
+---
+monitoring_project_dir: /opt/monitoring
+monitoring_loki_image: grafana/loki:3.0.0
+monitoring_promtail_image: grafana/promtail:3.0.0
+monitoring_grafana_image: grafana/grafana:12.3.1
+monitoring_loki_port: 3100
+monitoring_promtail_port: 9080
+monitoring_grafana_port: 3000
+monitoring_retention_period: 168h
+monitoring_grafana_admin_user: admin
+monitoring_grafana_admin_password: change-me-in-vault
+monitoring_compose_project_name: devops-monitoring

ansible/roles/monitoring/meta/main.yml

@@ -0,0 +1,4 @@
+---
+# Docker Engine and Compose plugin are required for monitoring stack deployment.
+dependencies:
+  - role: docker

ansible/roles/monitoring/tasks/main.yml

@@ -0,0 +1,77 @@
+---
+- name: Deploy Loki monitoring stack
+  tags:
+    - monitoring_deploy
+  block:
+    - name: Create monitoring directory tree
+      ansible.builtin.file:
+        path: "{{ item }}"
+        state: directory
+        mode: "0755"
+      loop:
+        - "{{ monitoring_project_dir }}"
+        - "{{ monitoring_project_dir }}/loki"
+        - "{{ monitoring_project_dir }}/promtail"
+        - "{{ monitoring_project_dir }}/grafana"
+        - "{{ monitoring_project_dir }}/grafana/provisioning"
+        - "{{ monitoring_project_dir }}/grafana/provisioning/datasources"
+
+    - name: Render Loki configuration
+      ansible.builtin.template:
+        src: loki-config.yml.j2
+        dest: "{{ monitoring_project_dir }}/loki/config.yml"
+        mode: "0644"
+
+    - name: Render Promtail configuration
+      ansible.builtin.template:
+        src: promtail-config.yml.j2
+        dest: "{{ monitoring_project_dir }}/promtail/config.yml"
+        mode: "0644"
+
+    - name: Render Grafana datasource provisioning
+      ansible.builtin.template:
+        src: grafana-datasource.yml.j2
+        dest: "{{ monitoring_project_dir }}/grafana/provisioning/datasources/loki.yml"
+        mode: "0644"
+
+    - name: Render monitoring docker-compose file
+      ansible.builtin.template:
+        src: docker-compose.yml.j2
+        dest: "{{ monitoring_project_dir }}/docker-compose.yml"
+        mode: "0644"
+
+    - name: Deploy monitoring stack with Docker Compose v2
+      community.docker.docker_compose_v2:
+        project_src: "{{ monitoring_project_dir }}"
+        files:
+          - docker-compose.yml
+        pull: always
+        remove_orphans: true
+        recreate: auto
+        state: present
+      register: monitoring_compose_result
+
+    - name: Wait for Loki readiness endpoint
+      ansible.builtin.uri:
+        url: "http://127.0.0.1:{{ monitoring_loki_port }}/ready"
+        status_code: 200
+        timeout: 10
+      register: monitoring_loki_ready
+      retries: 10
+      delay: 5
+      until: monitoring_loki_ready.status == 200
+
+    - name: Wait for Grafana health endpoint
+      ansible.builtin.uri:
+        url: "http://127.0.0.1:{{ monitoring_grafana_port }}/api/health"
+        status_code: 200
+        timeout: 10
+      register: monitoring_grafana_health
+      retries: 12
+      delay: 5
+      until: monitoring_grafana_health.status == 200
+
+  rescue:
+    - name: Show monitoring deployment diagnostics
+      ansible.builtin.debug:
+        var: monitoring_compose_result

ansible/roles/monitoring/templates/docker-compose.yml.j2

@@ -0,0 +1,67 @@
+name: {{ monitoring_compose_project_name }}
+
+services:
+  loki:
+    image: {{ monitoring_loki_image }}
+    container_name: devops-loki
+    command: -config.file=/etc/loki/config.yml
+    ports:
+      - "{{ monitoring_loki_port }}:{{ monitoring_loki_port }}"
+    volumes:
+      - ./loki/config.yml:/etc/loki/config.yml:ro
+      - loki-data:/loki
+    labels:
+      logging: "promtail"
+      app: "devops-loki"
+    healthcheck:
+      test: ["CMD-SHELL", "wget -qO- http://localhost:{{ monitoring_loki_port }}/ready >/dev/null 2>&1 || curl -fsS http://localhost:{{ monitoring_loki_port }}/ready >/dev/null 2>&1"]
+      interval: 15s
+      timeout: 5s
+      retries: 10
+      start_period: 20s
+
+  promtail:
+    image: {{ monitoring_promtail_image }}
+    container_name: devops-promtail
+    command: -config.file=/etc/promtail/config.yml
+    ports:
+      - "{{ monitoring_promtail_port }}:{{ monitoring_promtail_port }}"
+    volumes:
+      - ./promtail/config.yml:/etc/promtail/config.yml:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+    depends_on:
+      loki:
+        condition: service_healthy
+    labels:
+      logging: "promtail"
+      app: "devops-promtail"
+
+  grafana:
+    image: {{ monitoring_grafana_image }}
+    container_name: devops-grafana
+    ports:
+      - "{{ monitoring_grafana_port }}:{{ monitoring_grafana_port }}"
+    environment:
+      GF_AUTH_ANONYMOUS_ENABLED: "false"
+      GF_SECURITY_ADMIN_USER: "{{ monitoring_grafana_admin_user }}"
+      GF_SECURITY_ADMIN_PASSWORD: "{{ monitoring_grafana_admin_password }}"
+      GF_USERS_ALLOW_SIGN_UP: "false"
+    volumes:
+      - grafana-data:/var/lib/grafana
+      - ./grafana/provisioning:/etc/grafana/provisioning:ro
+    depends_on:
+      loki:
+        condition: service_healthy
+    labels:
+      logging: "promtail"
+      app: "devops-grafana"
+    healthcheck:
+      test: ["CMD-SHELL", "wget -qO- http://localhost:{{ monitoring_grafana_port }}/api/health >/dev/null 2>&1 || curl -fsS http://localhost:{{ monitoring_grafana_port }}/api/health >/dev/null 2>&1"]
+      interval: 15s
+      timeout: 5s
+      retries: 10
+      start_period: 30s
+
+volumes:
+  loki-data:
+  grafana-data:

ansible/roles/monitoring/templates/grafana-datasource.yml.j2

@@ -0,0 +1,10 @@
+apiVersion: 1
+
+datasources:
+  - name: Loki
+    uid: loki
+    type: loki
+    access: proxy
+    url: http://loki:{{ monitoring_loki_port }}
+    isDefault: true
+    editable: true

ansible/roles/monitoring/templates/loki-config.yml.j2

@@ -0,0 +1,43 @@
+auth_enabled: false
+
+server:
+  http_listen_port: {{ monitoring_loki_port }}
+  log_level: info
+
+common:
+  path_prefix: /loki
+  replication_factor: 1
+  ring:
+    kvstore:
+      store: inmemory
+
+schema_config:
+  configs:
+    - from: "2024-01-01"
+      store: tsdb
+      object_store: filesystem
+      schema: v13
+      index:
+        prefix: index_
+        period: 24h
+
+storage_config:
+  tsdb_shipper:
+    active_index_directory: /loki/index
+    cache_location: /loki/index_cache
+  filesystem:
+    directory: /loki/chunks
+
+compactor:
+  working_directory: /loki/compactor
+  compaction_interval: 10m
+  retention_enabled: true
+  delete_request_store: filesystem
+
+limits_config:
+  retention_period: {{ monitoring_retention_period }}
+  reject_old_samples: true
+  reject_old_samples_max_age: {{ monitoring_retention_period }}
+
+analytics:
+  reporting_enabled: false

ansible/roles/monitoring/templates/promtail-config.yml.j2

@@ -0,0 +1,29 @@
+server:
+  http_listen_port: {{ monitoring_promtail_port }}
+  grpc_listen_port: 0
+
+positions:
+  filename: /tmp/positions.yaml
+
+clients:
+  - url: http://loki:{{ monitoring_loki_port }}/loki/api/v1/push
+
+scrape_configs:
+  - job_name: docker
+    docker_sd_configs:
+      - host: unix:///var/run/docker.sock
+        refresh_interval: 5s
+    pipeline_stages:
+      - docker: {}
+    relabel_configs:
+      - source_labels: ["__meta_docker_container_name"]
+        regex: "/(.*)"
+        target_label: container
+      - source_labels: ["__meta_docker_container_label_app"]
+        target_label: app
+      - source_labels: ["__meta_docker_container_label_com_docker_compose_service"]
+        target_label: service
+      - source_labels: ["__meta_docker_container_log_stream"]
+        target_label: stream
+      - target_label: job
+        replacement: docker

app_python/README.md

@@ -54,6 +54,25 @@ Configuration is done via environment variables:
 
 All configuration is read in `app.py` at startup, so restart the application after changing environment variables.
 
+## Structured Logging (Lab 7)
+
+The service writes JSON logs to `stdout` for centralized log collection (Loki/Promtail).
+
+Example:
+
+```json
+{"timestamp":"2026-03-12T20:45:10.123456+00:00","level":"INFO","logger":"devops-info-service","message":"HTTP request handled","method":"GET","path":"/health","status_code":200,"client_ip":"127.0.0.1","duration_ms":1.11}
+```
+
+Each request log includes:
+
+- `method`
+- `path`
+- `status_code`
+- `client_ip`
+- `duration_ms`
+- `user_agent`
+
 ## Docker
 
 How to use the containerized application (patterns):
@@ -66,4 +85,3 @@ How to use the containerized application (patterns):
 Notes:
 - The container exposes port `5002` by default (see `app.py`).
 - The image runs as a non-root user for improved security.
-