ERR_EMPTY_RESPONSE for localhost when running Docker - apache

Question

Here's my Dockerfile:
# CentOs base image
FROM centos:centos6.8
# install python, pip, apache and other packages
RUN yum -y update; yum clean all
RUN yum -y install epel-release; yum clean all
RUN yum -y install centos-release-scl; yum clean all
RUN yum -y install python27; yum clean all
RUN yum -y install python-devel.x86_64; yum clean all
RUN yum -y install python-pip; yum clean all
RUN yum -y install gcc; yum clean all
RUN yum -y install httpd httpd-devel mod_ssl; yum clean all
# Make a non root user so I can run mod_wsgi without root
# USER adm
# install Python modules needed by the Python app
COPY requirements.txt /usr/src/app/
RUN pip install --no-cache-dir -r /usr/src/app/requirements.txt
# copy files required for the app to run
COPY . /usr/src/app/
# tell the port number the container should expose
EXPOSE 80
# run the application
# CMD ["mod_wsgi", "start-server run_apache_server.wsgi"]
# CMD ["cat", "/etc/passwd"]
# CMD ["cat", "/etc/group"]
# CMD ["find", "/"]
CMD ["/bin/sh", "-c", "/usr/bin/mod_wsgi-express start-server run_apache_server.wsgi --user adm --group apache"]
I can run the app:
$ docker run -d -P --name myapp jacobirr/pleromatest
And see tcp port 80:
$ docker port myapp
80/tcp -> 0.0.0.0:32769
Here's my requirements.txt:
Flask==0.10.1
Flask-Restless==0.13.1
Flask-SQLAlchemy==0.16
Jinja2==2.7
MarkupSafe==0.18
SQLAlchemy==0.8.2
Werkzeug==0.9.2
gunicorn==17.5
itsdangerous==0.22
mimerender==0.5.4
python-dateutil==2.1
python-mimeparse==0.1.4
requests==1.2.3
six==1.3.0
wsgiref==0.1.2
setuptools==5.4.2
mod_wsgi==4.5.15
Why can't I get to localhost:32769 in the browser? I suspect this is related to:
•the user/group running apache?
•the fact that I'm installing mod_wsgi but it's nowhere on the docker "filesystem" so I have to use mod_wsgi-express?
Update:
'1' Netstat shows:
[root#9003b0d64916 app]# netstat -l
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 *:irdmi *:* LISTEN
Active UNIX domain sockets (only servers)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ACC ] STREAM LISTENING 113181 /tmp/mod_wsgi-localhost:8000:0/wsgi.1.0.1.sock
'2' httpd seems to be running in my container:
[root#9003b0d64916 mod_wsgi-localhost:8000:0]# ps aux | grep httpd
root 1 0.0 0.2 64060 5084 ? Ss 21:17 0:00 httpd (mod_wsgi-express) -f /tmp/mod_wsgi-localhost:8000:0/httpd.conf -k start -DFOREGROUND
adm 6 0.0 0.6 350928 13936 ? Sl 21:17 0:00 (wsgi:localhost:8000:0) -f /tmp/mod_wsgi-localhost:8000:0/httpd.conf -k start -DFOREGROUND
adm 7 0.0 0.1 64192 3248 ? S 21:17 0:00 httpd (mod_wsgi-express) -f /tmp/mod_wsgi-localhost:8000:0/httpd.conf -k start -DFOREGROUND

Answer 1

From all your outputs, your httpd / uwsgi process is definitely bound to 8000, and this is the port you need to expose on the container.
This line in netstat, is showing a bind on 8000, and nothing else.
tcp 0 0 *:irdmi *:* LISTEN
It is not obvious here, but if you use the --numeric-ports argument, it will not convert the 8000 into its known port.
In your docker file, again you should
EXPOSE 8000
When launching your container, you can also specify the port to use on the host machine:
docker run -p 8080:8000 --name ...
After this, you should be able to use your browser to hit
localhost:8080 -> container:8000

Answer 2

Add this to your Dockerfile, just before CMD:
WORKDIR /usr/src/app/
Assuming that your start-apache-server file is in that directory. This will help wsgi to find the needed file.