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Deep Dive into OpenStack Ceilometer

Understanding OpenStack's Telemetry and Monitoring Service

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Understanding OpenStack Ceilometer

Ceilometer is OpenStack’s telemetry and monitoring service that collects measurements of resource usage and provides data for billing and performance monitoring.

It integrates with various OpenStack services to gather metrics and events for comprehensive cloud resource management.


What is Ceilometer?


The Telemetry Service

Ceilometer is OpenStack’s monitoring and metering service, providing the following capabilities:

By collecting and analyzing resource usage data, Ceilometer enables effective cloud resource management and cost control.


Ceilometer Architecture Overview (Diagram Description)

graph LR A[OpenStack Ceilometer] A --> B[Core Features] A --> C[Service Integration] A --> D[Data Collection] A --> E[Monitoring] B --> B1[Resource Monitoring] B --> B2[Event Tracking] B --> B3[Alarm Management] C --> C1[Nova Integration] C --> C2[Neutron Integration] C --> C3[Cinder Integration] D --> D1[Metrics Collection] D --> D2[Event Collection] D --> D3[Data Storage] E --> E1[Performance Monitoring] E --> E2[Usage Tracking] E --> E3[Alert Generation] style A stroke:#333,stroke-width:1px,fill:#f5f5f5 style B stroke:#333,stroke-width:1px,fill:#a5d6a7 style C stroke:#333,stroke-width:1px,fill:#64b5f6 style D stroke:#333,stroke-width:1px,fill:#ffcc80 style E stroke:#333,stroke-width:1px,fill:#ce93d8


Ceilometer Architecture and Components

Ceilometer’s architecture consists of several key components that work together to provide comprehensive monitoring and metering capabilities.

Each component plays a specific role in the data collection and processing pipeline.


Core Components

Component Role Description
Compute Agent Instance Metrics
  • Collects Nova instance metrics
  • Monitors CPU and memory usage
  • Tracks instance lifecycle events
  • Reports resource utilization
Central Agent Service Metrics
  • Collects metrics from various services
  • Monitors storage and network usage
  • Tracks service-specific events
  • Reports service metrics
Notification Agent Event Collection
  • Processes system notifications
  • Collects event-based data
  • Handles real-time events
  • Manages event processing
Collector Data Storage
  • Stores collected metrics
  • Manages data persistence
  • Handles data aggregation
  • Coordinates with storage backends


Data Flow

Ceilometer’s data collection flow:

  1. Metric Generation: OpenStack services generate metrics
  2. Agent Collection: Agents collect metrics via API calls
  3. Data Storage: Collector stores data in backend storage
  4. Alarm Processing: Aodh processes threshold-based alarms
  5. Billing Integration: Usage data is used for billing

This flow enables monitoring and metering of cloud resources.


Key Features and Capabilities

Ceilometer provides comprehensive monitoring and metering capabilities that enable effective resource management and cost control.

These features make it a powerful tool for cloud operations.


Core Features

Feature Description Benefits
Resource Monitoring Track resource usage across services
  • Comprehensive visibility
  • Resource optimization
  • Capacity planning
Event Tracking Monitor system events and changes
  • Change tracking
  • Audit compliance
  • System analysis
Alarm Management Configure and manage alerts
  • Proactive monitoring
  • Issue detection
  • Automated responses


Service Integration

Ceilometer integrates with the following services:

These integrations provide comprehensive monitoring and billing capabilities.


Implementation and Usage

Effective implementation of Ceilometer requires proper configuration and integration with other OpenStack services.

Here are key considerations and best practices for utilizing Ceilometer effectively.


Basic Setup

Component Description Configuration
API Service Ceilometer API endpoint
  • Enable API service
  • Configure authentication
  • Set up endpoints
Agents Metric collection agents
  • Configure compute agent
  • Set up central agent
  • Enable notification agent
Storage Metric storage backend
  • Configure database
  • Set up Gnocchi
  • Enable data retention


Common Operations

These commands are used to manage Ceilometer.


Advanced Configuration (Production Hardening)


Telemetry Stack Options

Component Role When to Use
Ceilometer Metric/event collection and notifications Always (foundation of telemetry)
Gnocchi Time‑series metrics storage and API Performance/capacity trending at scale
Aodh Threshold alarms and actions Real‑time alerting on metric thresholds
Panko Event storage/query Audit/change tracking (optional)


Performance Tuning


High Availability (HA)

Layer Recommendation Notes
API 2+ API nodes behind L7 load balancer Stateless; health checks and rate limits
Agents Multiple compute/central/notification agents Idempotent; safe to run in parallel
Message Bus HA RabbitMQ (quorum queues) Monitor queue depth, consumers
Storage Gnocchi with HA backend (Ceph/Swift) Archive policy per SLO and cost


Security & Compliance


Observability & Billing


Troubleshooting Playbook (Quick Checks)


Key Points

Ceilometer Essentials
  • Core Functionality
    - Resource monitoring
    - Event tracking
    - Alarm management
    - Billing integration
  • Key Features
    - Metric collection
    - Event processing
    - Alert generation
    - Data storage
  • Best Practices
    - Proper agent configuration
    - Storage optimization
    - Alarm management
    - Service integration


References