What's the difference between the kind of a tracing span?

[adinhodovic]

What's the difference in the above example between the two spans? And what does kind mean in the above example? There's two spans registered by Linkerd-proxy for each request and the only difference is the kind.

[ihcsim]

A typical request flow looks like this: ----> inbound server ----> inbound client ---> application ----> outbound server ----> outbound client --->. (Thanks @adleong for the explanation.) The span.kind and direction labels tell us which side the span is from. If you are interested, there is more info on how the proxy handles requests in this blog post.

[adinhodovic]

Thanks a lot, makes sense! Will read.