dokku: connect() failed (113: No route to host) while connecting to upstream

Seemingly randomly, nginx will give this error and view will report a 502 Bad Gateway error. Dokku logs don’t indicate any issues but the dokku nginx:error-logs <appname> returns this:

2015/12/22 09:53:29 [error] 31348#0: *4059 connect() failed (113: No route to host) while connecting to upstream, client: 108.30.150.109, server: <servername>, request: "GET / HTTP/1.1", upstream: "<ip address>", host: "<hostname>"

The output of uname -a.

Linux nycda 3.13.0-57-generic #95-Ubuntu SMP Fri Jun 19 09:28:15 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

The output of free -m

             total       used       free     shared    buffers     cached
Mem:           490        187        302         13         22         86
-/+ buffers/cache:         79        410
Swap:            0          0          0

The output of docker version.

Client:
 Version:      1.9.1
 API version:  1.21
 Go version:   go1.4.2
 Git commit:   a34a1d5
 Built:        Fri Nov 20 13:12:04 UTC 2015
 OS/Arch:      linux/amd64

Server:
 Version:      1.9.1
 API version:  1.21
 Go version:   go1.4.2
 Git commit:   a34a1d5
 Built:        Fri Nov 20 13:12:04 UTC 2015
 OS/Arch:      linux/amd64

The output of docker -D info.

Containers: 21
Images: 59
Server Version: 1.9.1
Storage Driver: aufs
 Root Dir: /var/lib/docker/aufs
 Backing Filesystem: extfs
 Dirs: 101
 Dirperm1 Supported: false
Execution Driver: native-0.2
Logging Driver: json-file
Kernel Version: 3.13.0-57-generic
Operating System: Ubuntu 14.04.3 LTS
CPUs: 1
Total Memory: 490 MiB
Name: nycda
ID: JGKG:C4PX:RQRD:BMJV:QTH2:FPM5:IE3D:SHIW:2RU2:WGWE:72AX:2J2U
WARNING: No swap limit support

The output of docker run -ti gliderlabs/herokuish:latest herokuish version

herokuish: 0.3.4
buildpacks:
  heroku-buildpack-clojure   v70
  heroku-buildpack-go        v18
  heroku-buildpack-gradle    v12
  heroku-buildpack-grails    v19
  heroku-buildpack-java      v40
  heroku-buildpack-multi     26fa21a
  heroku-buildpack-nodejs    v86
  heroku-buildpack-php       v80
  heroku-buildpack-play      v24
  heroku-buildpack-python    v68
  heroku-buildpack-ruby      v140
  heroku-buildpack-scala     v63

The output of dokku version.

v0.4.4-75-gcfe7604

The output of dokku plugin.

  00_dokku-standard    0.4.0 enabled    dokku core standard plugin
  20_events            0.4.0 enabled    dokku core events logging plugin
  apps                 0.4.0 enabled    dokku core apps plugin
  backup               0.4.0 enabled    dokku core backup plugin
  build-env            0.4.0 enabled    dokku core build-env plugin
  certs                0.4.0 enabled    dokku core certificate management plugin
  checks               0.4.0 enabled    dokku core checks plugin
  common               0.4.0 enabled    dokku core common plugin
  config               0.4.0 enabled    dokku core config plugin
  docker-options       0.4.0 enabled    dokku core docker-options plugin
  domains              0.4.0 enabled    dokku core domains plugin
  enter                0.4.0 enabled    dokku core enter plugin
  git                  0.4.0 enabled    dokku core git plugin
  logs                 0.4.0 enabled    dokku core logs plugin
  named-containers     0.4.0.1 enabled    dokku core named containers plugin
  nginx-vhosts         0.4.0 enabled    dokku core nginx-vhosts plugin
  plugin               0.4.0 enabled    dokku core plugin plugin
  postgres             1.0.0 enabled    dokku postgres service plugin
  ps                   0.4.0 enabled    dokku core ps plugin
  shell                0.4.0 enabled    dokku core shell plugin
  tags                 0.4.0 enabled    dokku core tags plugin
  tar                  0.4.0 enabled    dokku core tar plugin