Application monitoring describes a category of tools, techniques, and software applications used to ensure that technical teams—such as DevOps teams—are aware of key metrics and events related to a wide range of areas, including application health, performance, network traffic, resource utilization, and security.
Application monitoring complements application delivery by enabling these teams to predict and prevent potential problems, identify and resolve issues in real time, and improve decision-making.
Application monitoring goes beyond merely checking if an application is active or inactive. It focuses on maintaining optimal performance by helping the user to quickly identify any abnormalities, security breaches, or performance hiccups. The goal of application monitoring is to help the user to maintain nearly perfect delivery of results, such as delivering a near-perfect user experience, which has become synonymous with business success.
Application monitoring is important and covers a wide range of functionality. As a result, software with these capabilities has a wide range of names, including application monitoring, application performance monitoring (APM), and application performance management (also APM) software. We use application monitoring in this article to describe core capabilities that apply across these categories.
How does application monitoring work?
Application monitoring gathers telemetry—or metrics and event records generated by an application and the environment it’s running in. For example, tools such as log analysis and cloud monitoring services generate telemetry that helps detect operational bottlenecks, such as CPU spikes or memory leaks, which can lead to resource depletion and unexpected downtime.
Application monitoring then provides this information in a variety of ways to technical team members. For instance, application monitoring capabilities may provide information in a graphical user interface (GUI), such as in graph format; displayed as text on screen, via a command-line interface (CLI); or as text delivered in response to an application query sent via an application programming interface (API).
Application monitoring also aggregates information and compares information from multiple sources, thus adding value when compared to the user simply inspecting various metrics and events directly. For example, application monitoring makes it easy for the user to set alerts when a specific result, trend, or combination of these is detected. It also streamlines the process of managing alerts as a group, a task which a user would have difficulty doing on their own.
Ten best practices for application monitoring
By following these best practices as you set up or update your application monitoring system, you can establish a reliable monitoring solution that ensures consistent performance, enhances user satisfaction, and minimizes disruptions.
Clearly define the objectives and key performance indicators (KPIs) you want to monitor.
Select monitoring tools and software that align with your application's technology stack and requirements.
Identify the metrics that matter most to your setup. Application monitoring tools typically offer insights into various components of your software and hardware, including CPU usage, errors, and potentially defective RAM.
Establish alerting thresholds for crucial metrics to notify your team when issues occur. To avoid unneeded effort and confusion, set realistic thresholds and ensure that applications are appropriately tuned.
Analyze user experience metrics. This can help you identify areas for improvement and make informed decisions to enhance your users' experience.
Keep track of the health of your application's infrastructure by monitoring your server, network, and infrastructure metrics.
Implement end-to-end monitoring to track data flow and connections between various components and services within your application.
Include security monitoring in your application monitoring strategy. It will help you detect and respond to any security incidents or threats promptly and effectively.
In addition, incorporate root cause analysis into your monitoring strategy. It's crucial not just to fix surface-level issues but to identify and address the underlying causes of problems.
While non-visualized data is highly effective for systems automation, use visual representations such as graphs for anomaly detection and decision-making by people, particularly when working with large datasets.
All application monitoring solutions are most effective when used within a framework of best practices, such as those described above. Other professionals will assume that you and your organization are following these standard or recommended practices. If you aren't, not only are you likely to experience more (and more severe) problems, but you also risk confusion and frustration when you need help solving them.
Why is application monitoring useful?
Application monitoring provides a great deal of value to technical teams, such that it's considered indispensable in delivering applications. Most technical teams use multiple and overlapping application monitoring tools, techniques, and software applications in their work.
The usefulness of application monitoring can be seen by examining four major—and usually overlapping—ways in which application monitoring tools are used:
Performance monitoring involves tracking metrics such as response times, throughput, resource utilization, and latency. It’s used to assess key performance indicators (KPIs) of an application, including performance, availability, resource usage, and efficiency.
Availability/uptime monitoring focuses on ensuring high availability by monitoring each component of the application stack individually, such as proxies, web servers, databases, and storage systems. This can also include simulating user interactions, such as user log-in or access to database-driven content.
Security monitoring helps users to effectively identify and mitigate potential security threats and risks within an application by closely observing application behavior, user activities, and network traffic in real time.
Error monitoring detects and reports glitches, errors, or exceptions within an application. Error monitoring capabilities also provide detailed error logs and stack traces, to support effective debugging and troubleshooting.
Application monitoring is critical to meeting organizational goals in important areas such as cost reduction, user experience, revenue generation, and enhancing security, as well as in broader goals such as scalability planning and reputation management.
Identifying common issues with apps
In application monitoring, several issues require attentive observation and management. Having an overall awareness of these issues is important to developing a sense of where to start looking when symptoms present themselves—whether these be issues reported by application monitoring software or user-visible problems in application availability and performance.
Here are major types of issues and some of the indicators that cause them:
Bot activity
A high volume of requests
Repetitive access patterns
Unusual source IP addresses
Multiple failed login attempts in a short period
Extremely short or unusually long session durations
You can learn more about bot management in HAProxy by reading our blog post, Bot Protection With HAProxy.
Server nearing full capacity
Consistently high CPU utilization (nearing 100%)
High memory usage or out of memory errors
Running out of disk space
High network utilization
Cloud and cluster failure
Resource allocation limits reached
Frequent service, pod, or node crashes
Communication issues within cloud service or cluster
Operating system (OS) failure
Repeated OS crashes or kernel panic logs
Unusual CPU, memory, or I/O usage
OS-specific error messages
Hardware failure
Physical disk errors
Overheating or power supply issues
Failure of network components such as NICs, switches, or routers
The challenge of tracing app issues
Unfortunately, many problems are hard to trace back to the underlying cause. For instance, a server nearing its capacity will likely cause intermittent failures that are hard to trace back to their origin. Application monitoring plays a crucial role in identifying issues and in helping to find the underlying cause of a given issue.
Does HAProxy offer application monitoring?
HAProxy products support a wide range of application monitoring features, while also providing telemetry to other application monitoring tools.
First, the HAProxy Stats Page provides a dashboard that serves as a GUI for the operational state of services proxied by HAProxy. Second, HAProxy Data Plane API allows users to configure load balancing and fetch real-time stats via API calls. Third, HAProxy and HAProxy Enterprise collect a vast expanse of application health data, which users can export to external application monitoring solutions compatible with Prometheus, the most-used open source standard for application monitoring data.
Most importantly, HAProxy Fusion Control Plane provides advanced application observability, monitoring, and management to users of HAProxy Enterprise, while easily integrating with other monitoring frameworks. To learn more about application monitoring in HAProxy, check out our alerts and errors documentation.
