This chapter covers
- What we mean by agents and instrumentation
- What type of agents exist, for what signal types
- What OpenTelemetry is and how you can benefit from it
- Criteria for selecting an agent
In this chapter we will focus on how to get the signals from the sources that we discussed in 3 to the destinations, which we will be focusing on in 5 and 6, respectively. Since observability is all about getting actionable insights from the signals that the systems under observation expose, without the agents and instrumentation there would be little to observe.
In a nutshell, in this chapter we will learn how to instrument code (and automate that task), as well as select and deploy agents that collect, aggregate, filter, downsample, redact, and route logs, metrics, and traces.
The telemetry industry is, at time of writing, in the midst of a tectonic shift. This transformation from vendor-specific or signal-specific instrumentation and agents to an industry standard called OpenTelemetry started in 2019. In the context of this book we consider vendor-specific as well as signal-specific agents as traditional agents, in contrast to OpenTelemetry.