Table of contents

OpenTelemetry Agent Management Protocol

Managing the OpenTelemetry a large number of OpenTelemetry collectors isn’t always easy. In my informal conversations at events like OpenTelemetry community day at KubeCon, most operators are still manually editing the configuration templates for their collectors, and then restarting the process to get it to pick up. If you’re running one collector or even five this isn’t that arduous (in the case of five collectors it’s likely each one has some unique settings), but for hundreds of collector processes on a large cloud this will get tedious fast. For those medium-to-large collector implementations there’s hope: the Agent Management Protocol.

The OpenTelemetry Open Agent Management Protocol (OpAMP) is an emerging standard aimed at managing telemetry agents, such as the OpenTelemetry Collector, at scale. OpAMP is designed to allow dynamic configuration, credential management, and remote updates, ensuring observability infrastructure can adapt to changing needs without downtime. While still in development, the protocol holds significant potential for streamlining the management of distributed telemetry agents.

OpAMP provides a standard framework for remotely managing telemetry agents. Although current implementations primarily focus on the OpenTelemetry Collector, the protocol is flexible enough to manage various telemetry-related components, including instrumentation agents or future SDK-level integrations. The primary goal is to allow real-time configuration changes, package updates, and secure connection management without manual intervention.

1. Dynamic Configuration Management:

   OpAMP supports dynamic configuration changes for telemetry agents, such as modifying how data is collected or processed. This is especially useful for managing configurations like sampling rates and trace selection strategies.

2. Package Management for Auto-Updates:

   The protocol allows agents to receive new versions or updates through downloadable packages, including checksums for integrity verification. A supervisor process can handle package downloads, restart the agent with the new version, and roll back to a stable version if issues arise.

3. Credential Management:

   OpAMP facilitates the management of client-side TLS certificates and other credentials. Credentials can be rotated dynamically, either through server-initiated updates or client-initiated requests, ensuring secure communication across agents and servers.

4. Tail-Based Sampling:

   Tail-based sampling, a feature OpAMP aims to support, allows agents to decide which traces to retain after they are fully captured, rather than at the start. This strategy helps reduce the amount of irrelevant telemetry data, though it requires specialized architectures to handle sampling decisions across distributed collectors.

OpAMP supports multiple deployment models to fit different environments, including:

• Integrated Client Model:

  In this model, the OpAMP client runs within the same process as the OpenTelemetry Collector. The client communicates with the OpAMP server to receive updates and reconfigures the collector without restarting the entire process.

• Supervisor Process Model:

  The supervisor approach runs the OpAMP client as a separate process alongside the collector. It monitors the collector’s health, applies configuration changes, and ensures that the collector restarts if it crashes or fails to start after updates. This model provides greater fault tolerance, especially in Kubernetes environments where the client and collector can run as sidecars in the same pod.

• Remote Configuration and Management:

  Administrators can adjust configurations across a fleet of agents without restarting them. For example, switching from head-based to tail-based sampling or changing export endpoints can be performed on the fly.

• Resilient Agent Operation:

  The supervisor model ensures that agents stay operational, even if configurations cause issues. If a new configuration leads to a crash, the supervisor can revert to the previous stable configuration.

• Credential Rotation for Secure Communication:

  TLS certificates and other credentials can be dynamically rotated, ensuring secure and compliant communication between agents and backends.

Some advanced use cases, such as tail-based sampling, present challenges due to the need for stateful processing and coordinated decision-making across multiple collectors. While the protocol provides a foundation for such features, implementing them in a distributed environment requires careful architectural design.

OpAMP is still evolving, with many features in beta or under active development. In the coming quarters, more user-facing tools are expected, including graphical interfaces for managing collector configurations. As vendors begin to adopt the protocol, end-users can expect smoother agent management and the ability to make configuration changes in real-time.

The Open Agent Management Protocol (OpAMP) is evolving as a key component for managing fleets of telemetry agents, such as the OpenTelemetry Collector, at scale. As of late 2023, the protocol is still in its beta phase, with development focused on enabling dynamic configuration, remote updates, and secure credential management across distributed agents.

Recent Progress:

OpAMP is being implemented in two modes for the OpenTelemetry Collector:

1. Collector Extension: A lightweight client-side implementation embedded within the collector to support essential OpAMP operations.
2. Supervisor Process: An external process that works alongside the collector to handle more advanced features, such as reverting failed configurations and coordinating updates. This supervisor ensures the collector remains operational by restarting or rolling back if new configurations cause issues.

One key development area is tail-based sampling, which requires careful architectural design to coordinate sampling decisions across multiple agents and avoid bottlenecks. The protocol’s potential for dynamic configuration management is also expanding, with planned improvements for user-facing tools, including a graphical interface for managing collector settings.

Looking ahead, the next few quarters are expected to bring more production-ready implementations. This may include interfaces for real-time configuration changes through OpAMP and better integration within platforms like Kubernetes via sidecars or the OpenTelemetry Operator.

OpAMP represents a significant step forward in managing telemetry agents at scale, offering dynamic configuration, secure credential handling, and automated updates. Although the protocol is still maturing, it promises to simplify the management of observability infrastructure, making it more adaptable and resilient. Organizations implementing OpenTelemetry can look forward to enhanced capabilities for managing their telemetry systems remotely and efficiently.