Cannot set resources for sidecar tasks

[akhayyat]

Nomad version

Nomad v0.11.1 (b434570)

Operating system and Environment details

Debian 10.3

Issue

When setting resource requirements for a Connect sidecar task using the service.connect.sidecar_task stanza, running the job results in the error:

Error submitting job: Put "https://localhost:4646/v1/jobs": EOF

The same job file without the sidecar_task.resources stanza runs fine.

Reproduction steps

Run a Docker job with some resource requirements defined under service.connect.sidecar_task.resources. See below for an example.

Job file (if appropriate)

job "echo" {
  datacenters = ["test"]
  group "echo" {
    network {
      mode = "bridge"
      port "http" {
        static = 8080
        to = 8080
      }
    }
    service {
      name = "echo"
      port = 8080
      connect {
        sidecar_service {}
        sidecar_task {
          resources {
            memory = 128
          }
        }
      }
    }
    task "echo" {
      user = 65534
      driver = "docker"
      config {
        image = "hashicorp/http-echo"
        args = [
          "-listen",
          ":8080",
          "-text",
          "hello world"
        ]
      }
      resources {
        memory = 10
      }
    }
  }
}

Nomad Client logs

2020-05-17T15:13:36.032Z [DEBUG] http: request complete: method=PUT path=/v1/jobs duration=267.105µs
2020-05-17T15:13:36.037Z [ERROR] http: http: panic serving [::1]:56382: runtime error: invalid memory address or nil pointer dereference
goroutine 56665 [running]:
net/http.(*conn).serve.func1(0xc000c18000)
        net/http/server.go:1772 +0x139
panic(0x2a07d20, 0x55da6a0)
        runtime/panic.go:973 +0x3e3
github.com/hashicorp/nomad/command/agent.ApiResourcesToStructs(0xc0004efe50, 0x0)
        github.com/hashicorp/nomad/command/agent/job_endpoint.go:1056 +0x60
github.com/hashicorp/nomad/command/agent.apiConnectSidecarTaskToStructs(0xc001961300, 0xc000c037a0)
        github.com/hashicorp/nomad/command/agent/job_endpoint.go:1269 +0x3c
github.com/hashicorp/nomad/command/agent.ApiConsulConnectToStructs(0xc0014f1080, 0xc000c18140)
        github.com/hashicorp/nomad/command/agent/job_endpoint.go:1192 +0x58
github.com/hashicorp/nomad/command/agent.ApiServicesToStructs(0xc0014f0fa0, 0x1, 0x4, 0xc0009426c8, 0x1, 0x1)
        github.com/hashicorp/nomad/command/agent/job_endpoint.go:1177 +0x1e1
github.com/hashicorp/nomad/command/agent.ApiTgToStructsTG(0xc000c565a0, 0xc001ade000, 0xc001ade0f0)
        github.com/hashicorp/nomad/command/agent/job_endpoint.go:783 +0x1cd
github.com/hashicorp/nomad/command/agent.ApiJobToStructJob(0xc001694840, 0x2759ce0)
        github.com/hashicorp/nomad/command/agent/job_endpoint.go:768 +0x4a7
github.com/hashicorp/nomad/command/agent.(*HTTPServer).jobUpdate(0xc000429090, 0x37b77c0, 0xc000687260, 0xc001d3fe00, 0x0, 0x0, 0x0, 0xc002027970, 0x8, 0xc002027930)  
        github.com/hashicorp/nomad/command/agent/job_endpoint.go:408 +0x1d8
github.com/hashicorp/nomad/command/agent.(*HTTPServer).JobsRequest(0xc000429090, 0x37b77c0, 0xc000687260, 0xc001d3fe00, 0x4d6f96, 0x5ec154a0, 0x1f0d59f, 0x368ac3774721)
        github.com/hashicorp/nomad/command/agent/job_endpoint.go:22 +0x84
github.com/hashicorp/nomad/command/agent.(*HTTPServer).wrap.func1(0x37b77c0, 0xc000687260, 0xc001d3fe00)
        github.com/hashicorp/nomad/command/agent/http.go:445 +0x176
net/http.HandlerFunc.ServeHTTP(0xc0004f6bc0, 0x37b77c0, 0xc000687260, 0xc001d3fe00)
        net/http/server.go:2012 +0x44
net/http.(*ServeMux).ServeHTTP(0xc0008ef4c0, 0x37b77c0, 0xc000687260, 0xc001d3fe00)
        net/http/server.go:2387 +0x1a5
github.com/hashicorp/nomad/vendor/github.com/NYTimes/gziphandler.GzipHandlerWithOpts.func1.1(0x37bb840, 0xc00159e0e0, 0xc001d3fe00)
        github.com/hashicorp/nomad/vendor/github.com/NYTimes/gziphandler/gzip.go:269 +0x1e6
net/http.HandlerFunc.ServeHTTP(0xc00092ec60, 0x37bb840, 0xc00159e0e0, 0xc001d3fe00)
        net/http/server.go:2012 +0x44
net/http.serverHandler.ServeHTTP(0xc0004d2620, 0x37bb840, 0xc00159e0e0, 0xc001d3fe00)
        net/http/server.go:2807 +0xa3
net/http.(*conn).serve(0xc000c18000, 0x37d28c0, 0xc001c03680)
        net/http/server.go:1895 +0x86c
created by net/http.(*Server).Serve
        net/http/server.go:2933 +0x35c

[shoenig]

Thanks for reporting this @akhayyat ! There is definitely a bug here - if both (or neither) resources.memory and resources.cpu are set, everything is fine. However if only one is set, there is an attempt to derefence a nil pointer on the other.

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