[MESOS-7697] Mesos scheduler v1 HTTP API may generate 404 errors for temporary conditions

• Type: Bug
• Status: Accepted
• Priority: Major
• Resolution: Unresolved
• Component/s: HTTP API, libprocess
• Labels: mesosphere
• Epic Link: Scheduler API v1 improvements
• Assignee: Unassigned
• Reporter: James DeFelice
• Created: 20/Jun/17 14:22
• Updated: 09/May/19 21:49

Description

Returning a 404 error for a condition that's a known temporary condition is confusing from a client's perspective. A client wants to know how to recover from various error conditions. A 404 error condition should be distinct from a "server is not yet ready, but will be shortly" condition (which should probably be reported as a 503 "unavailable" error).

https://github.com/apache/mesos/blob/72752fc6deb8ebcbfbd5448dc599ef3774339d31/src/scheduler/scheduler.cpp#L593

    if (response->code == process::http::Status::NOT_FOUND) {
      // This could happen if the master libprocess process has not yet set up
      // HTTP routes.
      LOG(WARNING) << "Received '" << response->status << "' ("
                   << response->body << ") for " << call.type();
      return;
    }