Assumptions:

  • you have a brand new EC2 instance running Amazon Linux AMI
  • your time zone is America/Chicago

Install Nginx PHP-FPM and MySQL

optional

sudo /bin/rpm -ivh http://ftp.uninett.no/linux/epel/6/i386/epel-release-6-8.noarch.rpm
sudo /bin/rpm -ivh http://rpms.famillecollet.com/enterprise/remi-release-6.rpm
sudo /bin/rpm -ivh http://nginx.org/packages/centos/6/noarch/RPMS/nginx-release-centos-6-0.el6.ngx.noarch.rpm

install nginx php mysql memcached memcache

sudo yum -y update
sudo ln -sf /usr/share/zoneinfo/America/Chicago /etc/localtime
sudo yum install -y gcc make nginx php-fpm php-devel php-mysql php-pdo php-pear php-mbstring php-cli php-odbc php-imap php-gd php-xml php-soap php-pecl-apc pcre-devel memcached php-pecl-memcached openssl-devel mysql-server mysql

sudo pecl install memcache

# auto start nginx php mysql memcached
sudo chkconfig nginx on
sudo chkconfig mysqld on
sudo chkconfig php-fpm on
sudo chkconfig memcached on

create files

create fcgi configuration file

sudo vi /etc/nginx/fcgi.conf

in vim:

fastcgi_param GATEWAY_INTERFACE CGI/1.1;
fastcgi_param SERVER_SOFTWARE nginx/$nginx_version;
 
fastcgi_param QUERY_STRING $query_string;
fastcgi_param REQUEST_METHOD $request_method;
fastcgi_param CONTENT_TYPE $content_type;
fastcgi_param CONTENT_LENGTH $content_length;
 
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
fastcgi_param SCRIPT_NAME $fastcgi_script_name;
fastcgi_param REQUEST_URI $request_uri;
fastcgi_param DOCUMENT_URI $document_uri;
fastcgi_param DOCUMENT_ROOT $document_root;
fastcgi_param SERVER_PROTOCOL $server_protocol;
 
fastcgi_param REMOTE_ADDR $remote_addr;
fastcgi_param REMOTE_PORT $remote_port;
fastcgi_param SERVER_ADDR $server_addr;
fastcgi_param SERVER_PORT $server_port;
fastcgi_param SERVER_NAME $server_name;
 
# PHP only, required if PHP was built with --enable-force-cgi-redirect
fastcgi_param REDIRECT_STATUS 200;

create nginx configuration file

sudo vi /etc/nginx/conf.d/default.conf

in vim:

server {
        listen       80;
        server_name  localhost;
        root         /var/www; # this has to be /var/www, not /var/www/html, or static files in flask projects won’t load
        index index.php index.html index.htm;
 
        location ~ .*\\.(php|php5)?$
        {
 
            fastcgi_pass  unix:/var/run/php-fpm/php-fpm.sock;
            fastcgi_index index.php;
            include fcgi.conf;
        }
 
        location ~ .*\\.(gif|jpg|jpeg|png|bmp|swf)$
        {
            expires      30d;
        }
        
        location ~ .*\\.(js|css)?$
        {
            expires      12h;
        }
 
        access_log off;
}

set php-fpm port

sudo vi /etc/php-fpm.d/www.conf

in vim:

;listen = 127.0.0.1:9000
listen = /var/run/php-fpm/php-fpm.sock
;listen.owner = nobody
listen.owner = nginx
;listen.group = nobody
listen.group = nginx
;listen.mode = 0666
listen.mode = 0664

;user = apache
user = nginx
;group = apache
group = nginx

enable memcached

sudo vi /etc/php.d/memcached.ini

in vim:

; Enable memcache extension module
extension=memcached.so

enable memcache

sudo vi /etc/php.ini

in vim:

extension=memcache.so

add a test web page

sudo vi /var/www/index.html

in vim:

<html>
<head>
    <title>Test Page</title>
</head>
<body>
    <h3>This is our test page</h3>
</body>
</html>

start service

sudo service php-fpm start
sudo service nginx start
sudo service mysqld start
sudo service memcached start

MILESTONE #1

Browse to your server and you should get the test page
http://ec2-54-208-30-174.compute-1.amazonaws.com/

reference

[1] http://nizhishuai.com/2014/04/19/article-148.html
[2] http://codingsteps.com/install-php-fpm-nginx-mysql-on-ec2-with-amazon-linux-ami/

Install Python 2.7.8

install dependencies

sudo yum -y groupinstall "development tools"
sudo yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel 

download and install python

cd ~
wget http://python.org/ftp/python/2.7.8/Python-2.7.8.tar.xz
tar xf Python-2.7.8.tar.xz
cd Python-2.7.8
./configure --prefix=/usr/local  --enable-shared LDFLAGS="-Wl,-rpath /usr/local/lib"
make && sudo make altinstall

note:

  • python 2.7.8 will be installed at /usr/local
  • It is critical that you use make altinstall when installing your custom version of Python. If using the normal make install, you will end up with two different versions of Python in the filesystem both named python. This can lead to problems that are very hard to diagnose.

download and install setuptools and pip

# get the setup script for setuptools:
cd ~
sudo wget https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py

# install setuptools for python 2.7
sudo /usr/local/bin/python2.7 ez_setup.py

# insall pip
sudo /usr/local/bin/easy_install-2.7 pip

install virtual environment

sudo /usr/local/bin/pip2.7 install virtualenv

reference

[3] http://toomuchdata.com/2014/02/16/how-to-install-python-on-centos/

Install Flask and testing app

install flask

sudo mkdir /var/www # optional, for Amazon Linux AMI, this is created by default
sudo mkdir /var/www/demoapp

# set the owner of demoapp directory to ec2-user
sudo chown -R ec2-user:ec2-user /var/www/demoapp/

cd /var/www/demoapp

# make sure this virtualenv is for python2.7.8 we just installed, if not, use virtualenv-2.7 instead

# create a new virtual environment called venv
virtualenv venv

# activate venv
. venv/bin/activate

# install flask in venv
pip install flask

install testing app

create main python script

vi hello.py

in vim:

from flask import Flask
app = Flask(__name__)

@app.route("/")
def hello():
    return "Hello World!"

if __name__ == "__main__":
    app.run(host='0.0.0.0', port=8080)

MILESTONE #2

Run the script of the testing app

python hello.py

Browse to your server’s port 8080 and see the app in action
http://ec2-54-208-30-174.compute-1.amazonaws.com:8080/

You should see ‘Hello World!’ in plain text

Install and configure uWSGI

install uwsgi

pip install uwsgi

# back up current nginx conf
sudo mv /etc/nginx/conf.d/default.conf /etc/nginx/conf.d/default.conf.bak

create demoapp configuration file

vi demoapp_nginx.conf

in vim:

server {
    listen      80;
    server_name localhost;
    charset     utf-8;
    client_max_body_size 75M;

    location / { try_files $uri @yourapplication; }
    location @yourapplication {
        include uwsgi_params;
        uwsgi_pass unix:/var/www/demoapp/demoapp_uwsgi.sock;
    }
} 
sudo ln -s /var/www/demoapp/demoapp_nginx.conf /etc/nginx/conf.d/

restart nginx and uwsgi

sudo service nginx restart
sudo restart uwsgi

MILESTONE #3

Browse to your server’s public ip address and you will see 502 Bad Gateway error
http://ec2-54-208-30-174.compute-1.amazonaws.com/

This is what we expected. It means that Nginx has an issue connecting to uWSGI, our Python application host.

In demoapp_nginx.conf we have this line:

uwsgi_pass unix:/var/www/demoapp/demoapp_uwsgi.sock;

It says that we would like Nginx and uWSGI to communicate using this socket file. But we haven’t configured uWSGI yet, and this file doesn’t exist, for now.

configure demoapp uwsgi configuration file

vi demoapp_uwsgi.ini # note that we are still in /var/www/demoapp

in vim:

[uwsgi]
#application's base folder
base = /var/www/demoapp

#python module to import
app = hello
module = %(app)

home = %(base)/venv
pythonpath = %(base)

#socket file's location
socket = /var/www/demoapp/%n.sock

#permissions for the socket file
chmod-socket = 666
#chown-socket = nginx:nginx
# if chown-socket, uwsgi needs to be run using sudo, which will make the log's owner root

#the variable that holds a flask application inside the module imported at line #6
callable = app

#location of log files
logto = /var/log/uwsgi/%n.log 

note:

  • Nginx versions from other repositories may use a user www-data instead of nginx

create directory for uwsgi log

sudo mkdir -p /var/log/uwsgi
sudo chown -R ec2-user:ec2-user /var/log/uwsgi

MILESTONE #4

Execute uWSGI and pass it the newly created configuration file

uwsgi --ini /var/www/demoapp/demoapp_uwsgi.ini

Browse to your server. Now nginx should be able to connect to uWSGI process
http://ec2-54-208-30-174.compute-1.amazonaws.com/

You should see ‘Hello World!’ in plain text

configure uwsgi emperor

note:

  • uWSGI Emperor is for reading configuration files and spawning uWSGI processes.

create emperor configuration file

sudo vi /etc/init/uwsgi.conf

in vim:

description "uWSGI"
start on runlevel [2345]
stop on runlevel [06]
respawn

env UWSGI=/var/www/demoapp/venv/bin/uwsgi
env LOGTO=/var/log/uwsgi/emperor.log

exec $UWSGI --master --emperor /etc/uwsgi/vassals --die-on-term --uid nginx --gid nginx --logto $LOGTO

create necessary folders

sudo mkdir /etc/uwsgi && sudo mkdir /etc/uwsgi/vassals
sudo ln -s /var/www/demoapp/demoapp_uwsgi.ini /etc/uwsgi/vassals 

set the owner of the application and log folders

sudo chown -R nginx:nginx /var/www/demoapp/
sudo chown -R nginx:nginx /var/log/uwsgi/ 

start uwsgi

sudo start uwsgi

reference

[4] http://vladikk.com/2013/09/12/serving-flask-with-nginx-on-ubuntu/


Add A Second Application

### Assumptions * the name of the app to be added is twist

configure demoapp

remove demoapp configuration file

sudo rm /etc/nginx/conf.d/demoapp_nginx.conf

restore previously back-uped configuration file

sudo mv /etc/nginx/conf.d/default.conf.bak /etc/nginx/conf.d/default.conf

modify default configuration file

sudo vi /etc/nginx/conf.d/default.conf

in vim:

...
location = /demoapp { rewrite ^ /demoapp/; }
location /demoapp { try_files $uri @demoapp; }
location @demoapp {
  include uwsgi_params;
  uwsgi_param SCRIPT_NAME /demoapp;
  uwsgi_modifier1 30;
  uwsgi_pass unix:/var/www/demoapp/demoapp_uwsgi.sock;
}
...

restart nginx and uwsgi

sudo service nginx restart
sudo restart uwsgi

MILESTONE #5

Browse to your server to check if demoapp has correct url prefix demoapp
http://ec2-54-208-30-174.compute-1.amazonaws.com/demoapp

add the new app

upload twist to /home/ec2-user/

move it to /var/www/

sudo mv /home/ec2-user/twist /var/www/twist
cd /var/www/twist 

modify nginx configuration

sudo vi /etc/nginx/conf.d/default.conf

in vim:

...
location = /twist { rewrite ^ /twist/; }
location /twist { try_files $uri @twist; }
location @twist {
  include uwsgi_params;
  uwsgi_param SCRIPT_NAME /twist;
  uwsgi_modifier1 30;
  uwsgi_pass unix:/var/www/twist/twist_uwsgi.sock;
}
...

create twist_uwsgi.ini

vi twist_uwsgi.ini

in vim:

[uwsgi]
#application's base folder
base = /var/www/twist

#python module to import
app = twist
module = %(app)

# home should still be the path of virtual environment
home = /var/www/demoapp/venv
pythonpath = %(base)

#socket file's location
socket = /var/www/twist/%n.sock

#permissions for the socket file
chmod-socket    = 666

#the variable that holds a flask application inside the module imported at line #6
callable = app

#location of log files
logto = /var/log/uwsgi/%n.log 

symlink it to /var/uwsgi/vassals

sudo ln -s /var/www/twist/twist_uwsgi.ini /etc/uwsgi/vassals 

set owner of twist nginx

sudo chown -R nginx:nginx /var/www/twist/ 

restart nginx and uwsgi

sudo service nginx restart
sudo restart uwsgi

MILESTONE #6

Browse to your server’s public ip address with prefix twist and see Internal Server Error message
http://ec2-54-208-30-174.compute-1.amazonaws.com/twist/

This is absolutely OK. The issue here is that tweepy hasn’t been installed. You can see more details about the error message in twist_uswgi.log

Unfortunately, it is not convenient to insall tweepy, because the virtual environment is in demoapp, which has been set owner nginx, you (as ec2-user) cannot play with it.

At this point, you have two options.

option 1:

change the owner of the virtual environment

sudo chown -R ec2-user:ec2-user /var/www/demoapp/venv

option 2:

install a new virtualenv and change configurations accordingly

Note that you don’t need to change settings for nginx.
You need to change settings for [appname]_uwsgi.ini and for uwsgi emperor

deactivate current virtualenv

deactivate

install new virtualenv

cd ~
virtualenv venv
. ./venv/bin/activate

install tweepy

pip install flask uwsgi tweepy

modify demoapp uwsgi configuration file

cd /var/www/demoapp
sudo vi demoapp_uwsgi.ini

in vim:

home = /home/ec2-user/venv/

modify twist uwsgi configuration file

cd ../twist
sudo vi twist_uwsgi.ini

in vim:

home = /home/ec2-user/venv/

modify emperor configuration file

sudo vi /etc/init/uwsgi.conf

in vim:

env UWSGI=/home/ec2-user/venv/bin/uwsgi

now we have a problem; permission denied when starting emperor

execvp(): Permission denied [core/emperor.c line 1434]

fix 1: run emperor as root (works)
fix 2: set owner of newly installed venv nginx (not work)
fix 3: set permission of newly installed venv 777 (not work)

fix 1

sudo vi /etc/init/uwsgi.conf

in vim:

...
exec $UWSGI --master --emperor /etc/uwsgi/vassals --die-on-term --uid root --gid root --logto $LOGTO
...

MILESTONE #7

Browse to your server’s with prefix twist and see twist app in action
http://ec2-54-208-30-174.compute-1.amazonaws.com/twist/

In the future

In the future if new apps need to be installed, repeat steps between MILESTONE #5 and MILESTONE #6, replacing twist with your app’s name.

Below is an example of adding a new app called accessibility, and the python script is called acc.py.

add the new app

upload accessibility to /home/ec2-user/

move it to /var/www/

sudo mv /home/ec2-user/accessibility /var/www/accessibility
cd /var/www/accessibility

modify nginx configuration

sudo vi /etc/nginx/conf.d/default.conf

in vim:

...
location = /accessibility { rewrite ^ /accessibility/; }
location /accessibility { try_files $uri @accessibility; }
location @accessibility {
  include uwsgi_params;
  uwsgi_param SCRIPT_NAME /accessibility;
  uwsgi_modifier1 30;
  uwsgi_pass unix:/var/www/accessibility/accessibility_uwsgi.sock;
}
...

create accessibility_uwsgi.ini

vi accessibility_uwsgi.ini

in vim:

[uwsgi]
#application's base folder
base = /var/www/accessibility

#python module to import
app = acc
module = %(app)

home = /home/ec2-user/venv
pythonpath = %(base)

#socket file's location
socket = /var/www/accessibility/%n.sock

#permissions for the socket file
chmod-socket    = 666

#the variable that holds a flask application inside the module imported at line #6
callable = app

#location of log files
logto = /var/log/uwsgi/%n.log 

symlink it to /var/uwsgi/vassals

sudo ln -s /var/www/accessibility/accessibility_uwsgi.ini /etc/uwsgi/vassals 

set owner of accessibility nginx

sudo chown -R nginx:nginx /var/www/accessibility/ 

restart nginx and uwsgi

sudo service nginx restart
sudo restart uwsgi