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Advantages of using Jaeger Agent

So I am exploring Jaeger for Tracing and I saw that we can directly send spans from the client to the collector in HTTP (PORT: 14268), if so then what is the advantage of using the jaeger agent.

When to go for the Jaeger Agent Approach and when to go with the direct HTTP Approach. What is the disadvantage of going with the Direct approach to the collector

Solution

  • From the official FAQ (https://www.jaegertracing.io/docs/latest/faq/#do-i-need-to-run-jaeger-agent):

    jaeger-agent is not always necessary. Jaeger client libraries can be configured to export trace data directly to jaeger-collector. However, the following are the reasons why running jaeger-agent is recommended:

    • If we want SDK libraries to send trace data directly to collectors, we must provide them with a URL of the HTTP endpoint. It means that our applications require additional configuration containing this parameter, especially if we are running multiple Jaeger installations (e.g. in different availability zones or regions) and want the data sent to a nearby installation. In contrast, when using the agent, the libraries require no additional configuration because the agent is always accessible via localhost. It acts as a sidecar and proxies the requests to the appropriate collectors.

    • The agent can be configured to enrich the tracing data with infrastructure-specific metadata by adding extra tags to the spans, such as the current zone, region, etc. If the agent is running as a host daemon, it will be shared by all applications running on the same host. If the agent is running as a true sidecar, i.e. one per application, it can provide additional functionality such as strong authentication, multi-tenancy (see this blog post), pod name, etc.

    • Agents allow implementing traffic control to the collectors. If we have thousands of hosts in the data center, each running many applications, and each application sending data directly to the collectors, there may be too many open connections for each collector to handle. The agents can load balance this traffic with fewer connections.