Agent-based vs Agentless Monitoring
Applications Manager supports both agent-based monitoring and agentless monitoring to monitor the performance and health of servers, applications, databases, and system resources. Each monitoring approach has its own advantages and is suitable for different environments. Understanding the differences helps administrators choose the most appropriate monitoring method based on their infrastructure, security policies, and monitoring requirements.
What is agent-based monitoring?
Agent-based monitoring involves deploying a lightweight monitoring agent, the Applications Manager's FSO (Full Stack Observability) Agent, on the target server or application host. The FSO Agent, which supports both Windows and Linux operating systems, runs locally on the monitored system along with its sub-agents to collect server performance metrics such as CPU utilization, memory usage, disk and file system statistics, as well as application logs for monitoring and analysis.
The collected data is then securely transmitted to the Applications Manager server, where it is processed, visualized, and displayed in the monitoring console. Since the data collection occurs locally on the monitored system, the monitoring server does not need to frequently poll the server directly.
Advantages of agent-based monitoring
- Improved security — The monitored server communicates with the Applications Manager server through an outbound connection, eliminating the need to expose server ports externally.
- Reduced monitoring load — Since the agent collects metrics locally, the workload on the Applications Manager server is reduced.
- Monitoring continuity — The agent can continue collecting monitoring data even if the Applications Manager server becomes temporarily unavailable, and forward the data once connectivity is restored.
- No dependency on remote protocols — Agent-based monitoring does not require enabling protocols such as SSH, WMI, or SNMP on the monitored system.
- Better support for secured environments — Useful in environments where credential sharing or inbound connections are restricted.
Limitations of agent-based monitoring
- The monitoring agent must be installed on each server.
- Agents may require periodic updates or maintenance.
When to use agent-based monitoring
- When monitoring servers in secure or restricted environments
- When administrative credentials cannot be shared
- When inbound firewall access to servers is restricted
- When deeper system-level or application-level monitoring is required
- When monitoring distributed or remote environments
What is agentless monitoring?
Agentless monitoring allows the Applications Manager server to directly communicate with the target server or application to collect monitoring data. This approach does not require installing any monitoring software on the monitored system. It collects metrics using standard management protocols and interfaces such as SSH, WMI, SNMP, REST APIs, JMX, and database connections. The Applications Manager server periodically queries the monitored systems to collect performance metrics and display them in the monitoring console.
Advantages of agentless monitoring
- No software installation required — Servers and applications can be monitored without deploying agents.
- Faster deployment — Monitoring can be configured quickly since no agent installation is required.
- Simplified maintenance — Administrators do not need to manage agents across multiple servers.
- Support for multiple technologies — Applications Manager supports monitoring a wide range of servers and applications using standard protocols.
Limitations of agentless monitoring
- Administrative credentials are required to access the monitored system.
- Remote management protocols such as SSH, WMI, or SNMP must be enabled.
- Firewall rules may need to allow communication between the Applications Manager server and monitored systems.
- If the Applications Manager server becomes unavailable, monitoring data may not be collected during that time.
When to use agentless monitoring
- When installing agents on servers is not preferred
- When monitoring standard system metrics such as CPU, memory, or disk usage
- When remote management protocols are already enabled in the environment
- When quick monitoring setup is required
Agent-based vs Agentless monitoring: A high-level comparison
| Aspect | Agent-Based Monitoring | Agentless Monitoring |
|---|
| Monitoring mode | Uses a lightweight agent (FSO Agent) to collect data locally. | Applications Manager collects data remotely without an agent. |
| Data collection method | Agent collects and sends data to Applications Manager. | Applications Manager polls the monitored system to collect data. |
| Installation requirement | Agent must be installed on the server. | No installation required. |
| Protocols used | Does not depend on remote monitoring protocols since the agent collects data locally. | Uses remote monitoring protocols such as SSH, WMI, SNMP, Telnet, etc. |
| Security | Agent initiates outbound communication to the Applications Manager server, improving security in restricted environments. | Applications Manager server requires inbound access to the monitored system. |
| Credential requirement | Does not require sharing server credentials for monitoring. | Requires server credentials to access the monitored system. |
| Deployment complexity | Requires agent setup and maintenance. | Faster and easier to deploy since no installation is required. |
| Reliability | Agent can collect data even if the Applications Manager server is temporarily unreachable. | Monitoring depends on the availability of the Applications Manager server to collect data. |
| Best usecase | Secure environments and deeper monitoring. | Quick setup and standard monitoring needs. |
Choosing the right monitoring approach
Both agent-based and agentless monitoring methods have their own advantages and limitations. The appropriate approach depends on the infrastructure, security policies, and monitoring requirements of your environment.
In many cases, organizations use a combination of both approaches. Agent-based monitoring can be used for secure servers and deeper system monitoring, while agentless monitoring can be used for quick deployment and standard server monitoring.
Applications Manager provides the flexibility to use either approach, ensuring comprehensive visibility into the performance and health of your servers and applications.
