What is application monitoring?

The importance of monitoring in the application lifecycle

Monitoring is not a one-time activity, but an ongoing process that is crucial, especially after an application is deployed to production. It allows development and operations (DevOps) teams to gain insight into the actual performance of an application in a production environment, respond quickly to incidents, measure the impact of changes, and make optimization and development decisions based on real data.

Key areas of monitoring

Effective application monitoring should cover several key areas:

• Availability (Availability): Checking whether an application is available and responsive to user requests (known as uptime monitoring, health checks).
• Performance: Measures key performance indicators such as application response time, throughput (number of requests per second), latency, and performance of individual components (e.g., database queries, external API calls).
• Resource Utilization (Resource Utilization): Monitors the consumption of infrastructure resources by an application (CPU, RAM, disk, network) to identify potential bottlenecks or the need to scale.
• Errors and Exceptions (Errors and Exceptions): Gather and analyze information about errors and exceptions occurring in an application to help quickly diagnose and fix problems.
• End-User Experience (EUX): Measuring actual user experience, such as by monitoring page load times in the browser (Real User Monitoring – RUM) or simulating user interactions (Synthetic Monitoring).
• Application Logs: Collect and analyze application-generated logs for event tracking, problem diagnosis and auditing.

Application monitoring tools (APM)

There are a number of APM (Application Performance Monitoring) class tools that help in comprehensive application monitoring. Popular solutions include:

• Commercial: Datadog, Dynatrace, New Relic, AppDynamics (Cisco), Splunk APM.
• Open-source: Prometheus (combined with Grafana for visualization), Jaeger (for distributed tracking – distributed tracing), ELK Stack/OpenSearch (Elasticsearch/OpenSearch, Logstash, Kibana – for logs and metrics), Grafana Loki (for logs).

These tools offer functionality such as metrics collection, transaction tracking (tracing), code profiling, log analysis, data visualization (dashboards) and alerting when problems are detected.

Monitoring as part of DevOps and SRE

Continuous monitoring is a fundamental practice in DevOps culture and Site Reliability Engineering (SRE). It provides essential feedback to the CI/CD loop, allows for measuring Service Level Indicators (SLIs) and ensuring compliance with Service Level Objectives (SLOs).

Summary

Application monitoring is an essential process that provides insight into the performance of production applications. It allows you to proactively detect and resolve problems, optimize performance and guarantee a high-quality user experience. Using the right monitoring tools and metrics is key to maintaining stable, reliable and efficient IT systems.