Vote container not starting + fix

[davidem]

Description

Vote container not starting. Running latest example-voting-app on up-to-date Docker Desktop on a Mac

Steps to reproduce the issue, if relevant:

1. git clone latest version
2. docker-compose up --build -d
3. docker-compose ps

Describe the results you received:
"docker-compose ps" shows "Exit 1" on vote_1 container. Rest is Up:

$ docker-compose ps
          Name                        Command               State                       Ports                    
-----------------------------------------------------------------------------------------------------------------
7_microservices_result_1   nodemon server.js                Up       0.0.0.0:5858->5858/tcp, 0.0.0.0:5001->80/tcp
7_microservices_vote_1     python app.py                    Exit 1                                               
7_microservices_worker_1   /bin/sh -c dotnet src/Work ...   Up                                                   
db                         docker-entrypoint.sh postgres    Up       5432/tcp                                    
redis                      docker-entrypoint.sh redis ...   Up       0.0.0.0:32769->6379/tcp 

'docker-compose logs' shows the following error:

OSError: [Errno 8] Exec format error

Describe the results you expected:
Well... Up instead of Exit 1 😎

Additional information you deem important (e.g. issue happens only occasionally):
I've fixed it... see below.

Output of docker version:

Client: Docker Engine - Community
 Version:           18.09.2
 API version:       1.39
 Go version:        go1.10.8
 Git commit:        6247962
 Built:             Sun Feb 10 04:12:39 2019
 OS/Arch:           darwin/amd64
 Experimental:      false

Server: Docker Engine - Community
 Engine:
  Version:          18.09.2
  API version:      1.39 (minimum version 1.12)
  Go version:       go1.10.6
  Git commit:       6247962
  Built:            Sun Feb 10 04:13:06 2019
  OS/Arch:          linux/amd64
  Experimental:     true

Output of docker info:

Containers: 5
 Running: 5
 Paused: 0
 Stopped: 0
Images: 33
Server Version: 18.09.2
Storage Driver: overlay2
 Backing Filesystem: extfs
 Supports d_type: true
 Native Overlay Diff: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
 Volume: local
 Network: bridge host ipvlan macvlan null overlay
 Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 9754871865f7fe2f4e74d43e2fc7ccd237edcbce
runc version: 09c8266bf2fcf9519a651b04ae54c967b9ab86ec
init version: fec3683
Security Options:
 seccomp
  Profile: default
Kernel Version: 4.9.125-linuxkit
Operating System: Docker for Mac
OSType: linux
Architecture: x86_64
CPUs: 2
Total Memory: 5.818GiB
Name: linuxkit-025000000001
ID: F4NW:FVGS:ZLTR:PEZA:T625:TSHW:4PB6:XX4C:WOVM:UIGB:TWSE:NYAA
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): true
 File Descriptors: 66
 Goroutines: 83
 System Time: 2019-05-15T21:29:37.0272169Z
 EventsListeners: 2
HTTP Proxy: gateway.docker.internal:3128
HTTPS Proxy: gateway.docker.internal:3129
Registry: https://index.docker.io/v1/
Labels:
Experimental: true
Insecure Registries:
 127.0.0.0/8
Live Restore Enabled: false
Product License: Community Engine

Additional environment details (AWS, Docker for Mac, Docker for Windows, VirtualBox, physical, etc.):
Docker Desktop on macOS 10.14.4.

The Fix
I've added a 'shebang' to 'example-voting-app/vote/app.py':

#!/usr/bin/env python2.7

Now it runs like expected:

$ docker-compose ps
          Name                        Command               State                      Ports                    
----------------------------------------------------------------------------------------------------------------
7_microservices_result_1   nodemon server.js                Up      0.0.0.0:5858->5858/tcp, 0.0.0.0:5001->80/tcp
7_microservices_vote_1     python app.py                    Up      0.0.0.0:5000->80/tcp                        
7_microservices_worker_1   /bin/sh -c dotnet src/Work ...   Up                                                  
db                         docker-entrypoint.sh postgres    Up      5432/tcp                                    
redis                      docker-entrypoint.sh redis ...   Up      0.0.0.0:32769->6379/tcp 

[davidem]

Strange, I can't seem to reproduce the error on a fresh install.

[ProsperWare]

this should be started with docker stack deploy -c docker-stack.yml app

[davidem]

@ProsperWare : thanks for the reply, but: I was under the impression that you can use any of the common methods to start the application (compose, stack, k8s, etc). So when I have an issue using 'docker compose', saying I need to use 'docker stack deploy' surprises me... especially when the documentation clearly states you can use either method.

Anyway: I had an issue, fixed it, thought I'd share it, but couldn't reproduce it myself on a fresh install. I'll close the case.

[robeatoz]

I had the same issue on Docker for Windows and I fixed it with two changes:

• Add the shebang #!/usr/bin/env python2.7, like @davidem already wrote
• Use the Unix style line endings for app.py, see https://stackoverflow.com/a/55272071/4471199

[wusatosi]

I had the same issue on Docker for Windows and I fixed it with two changes:

• Add the shebang #!/usr/bin/env python2.7, like @davidem already wrote
• Use the Unix style line endings for app.py, see https://stackoverflow.com/a/55272071/4471199

I'm unable to fix my setup, I've converted windows style line ending to unix style line ending, and added
#!/usr/bin/env python2.7
to the head of my app.py, but the container failed to boot with exit code 127, showing

vote_1    |  * Serving Flask app "app" (lazy loading)\r
vote_1    |  * Environment: production
vote_1    |    WARNING: This is a development server. Do not use it in a production deployment.
vote_1    |    Use a production WSGI server instead.
vote_1    |  * Debug mode: on
vote_1    |  * Running on http://0.0.0.0:80/ (Press CTRL+C to quit)
vote_1    |  * Restarting with stat
': No such file or directoryte 'python2.7
examplevotingapp_vote_1 exited with code 127

any ideas?

[davidem]

': No such file or directoryte 'python2.7
...
any ideas?

Do you have python 2.7 installed? 😎
Never mind... stupid remark... see below

[wusatosi]

': No such file or directoryte 'python2.7
...
any ideas?

Do you have python 2.7 installed? 😎

do I need to install that on the host machine?

[davidem]

do I need to install that on the host machine?

No... strike my comment... I was stupid 🤭

Can you post the first few lines of app.py?

Another option: remove everything and start from scratch. Unless you've made significant changes.

[wusatosi]

do I need to install that on the host machine?

No... strike my comment... I was stupid 🤭

Can you post the first few lines of app.py?

Another option: remove everything and start from scratch. Unless you've made significant changes.

In the Docker Quickstart Terminal

$ cat vote/app.py
#!/usr/bin/env python2.7

from flask import Flask, render_template, request, make_response, g
from redis import Redis
import os
import socket
import random
import json

I think should add the shebang and make an pull request 😏

[davidem]

hmm... looks ok. Strange. And you're using the original Dockerfile to build 'vote'? I mean: it 's still using python:2.7-alpine?

[wusatosi]

hmm... looks ok. Strange. And you're using the original Dockerfile to build 'vote'? I mean: it 's still using python:2.7-alpine?

Yes... I did not change the Dockerfile, more strangly, if I compile and build it as an single image, it runs smoothly without any warning. even with the shebang removed, I think it is an docker-compose issue.