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Installation guide with CentOS 7
This page is provided for informational purposes and might not be up-to-date. The preferred way of installing NEMO is using docker and instructions can be found here
This guide is intended for setting up a production instance of NEMO, and assumes you have the CentOS 7 operating system installed, and nothing else.
You will need root privileges on the server to proceed.
The following components are recommended for running NEMO, and the installation process for each one will be explained.
- CentOS 7 (operating system)
- Python 3.6
- Gunicorn (Python WSGI server)
- Nginx (static content server and reverse proxy)
- SQLite (database)
There is nothing to prevent you from using NEMO in a different environment, however, the recommended components are tested and known to work well.
Download and install the following packages in order to compile Python. Also create a nemo user which will run the NEMO application and web server.
yum --assumeyes install gcc wget sqlite-devel openssl-devel git unzip make
useradd --comment "NEMO" nemo
su nemo
To compile and install SQLite... (the version in centos isn't compatible with django 2.2)
cd /home/nemo
wget https://www.sqlite.org/2019/sqlite-autoconf-3290000.tar.gz
tar -xzf sqlite-autoconf-3290000.tar.gz
cd /home/nemo/sqlite-autoconf-3290000
./configure --prefix=/home/nemo/sqlite
make
make install
rm -rf /home/nemo/sqlite-autoconf-3290000 /home/nemo/sqlite-autoconf-3290000.tar.gz
To compile and install Python...
cd /home/nemo
wget https://www.python.org/ftp/python/3.6.4/Python-3.6.4.tgz
tar xf Python-3.6.4.tgz
cd Python-3.6.4/
./configure --prefix=/home/nemo/python
make
make install
cd /home/nemo
rm -rf Python-3.6.4 Python-3.6.4.tgz
Python is now installed in the /home/nemo/python/ directory.
You'll need to set some environment variables to specify the location of the Python interpreter, and where NEMO should read its settings from.
All Django projects (including NEMO) read in their settings from one important file: settings.py. The Django documentation states you should specify the settings location using the environment variable DJANGO_SETTINGS_MODULE. The value of DJANGO_SETTINGS_MODULE should be in Python path syntax.
Additionally, the settings file should be on the Python import search path. You will probably also need to set PYTHONPATH to the directory that contains the settings file. For example, if the file settings.py resides in the directory /home/nemo/, you would set PYTHONPATH=/home/nemo and DJANGO_SETTINGS_MODULE=settings.
Edit /home/nemo/.bashrc to set environment variables to point to the correct Python interpreter and settings by adding:
PATH=/home/nemo/python/bin:/home/nemo/nginx:/home/nemo/sqlite/bin:$PATH
PYTHONPATH=/home/nemo
LD_LIBRARY_PATH=/home/nemo/sqlite/lib
LD_RUN_PATH=/home/nemo/sqlite/lib
DJANGO_SETTINGS_MODULE=settings
export PATH PYTHONPATH LD_LIBRARY_PATH LD_RUN_PATH DJANGO_SETTINGS_MODULE
Refresh the environment variables by closing the bash terminal and reopening it as the nemo user. Ensure the proper Python interpreter is available in your PATH environment variable using which python3... the first line of output should be /home/nemo/python/bin.
pip3 install NEMO gunicorn
Below is a template for NEMO settings that would be suitable for production. The settings must be customized appropriately for your organization. This is the single most important file for NEMO to run properly, and you should take your time to ensure it is correct. Furthermore, it's probably the most likely place where things can go wrong when configured improperly. So grab a coffee, take your time, and be thorough when crafting this file for your organization. In order to make things easier, several methods are described on the Initialization wiki page to test your configuration and ensure it's working properly.
The settings reference particular locations on disk that must exist, and external services that must be available for NEMO to work properly. A single, consolidated directory that contains all NEMO runtime information is recommended. Here is the suggested directory strcuture and contents:
/home/nemo/
|
|--- logs/ # Optional: store all log files. (Recommended approach: don't store logs locally... instead, send them to a central logging server via syslog so your disk never overflows)
|--- media/ # Images and files uploaded to NEMO are stored here
|--- nginx/ # Reverse proxy and static content server
| |--- configuration # Configuration file for Nginx
| |--- nginx # Nginx binary executable
|--- python/ # Python 3.6+ interpreter with NEMO package installed
|--- secrets/ # Contains all passwords, certificates, and keys that NEMO uses
| |--- nemo.example.org.key # Private TLS key used for encryption
| |--- nemo.example.org.crt # Public TLS certificate, signed by a certificate authority
| |--- Other certificates # Other certificates, such as public TLS certs for email or LDAPS authentication
|--- static/ # JavaScript, images, and CSS
|--- settings.py # NEMO settings file
|--- sqlite.db # SQLite database - this is automatically created by NEMO
Create a logs directory if you intend to store logs on the web server. Alternatively, you can configure NEMO to send logs to syslog, and redirect the output to a centralized log server... however, this is outside the scope installing NEMO and is not discussed here.
Create directories media, static, and secrets. Each of these directories will be referenced in the settings.py file.
An example can be found on the settings page
NEMO comes with static files, such as JavaScript and CSS, to improve the look and feel of the website. There are also static files included with the Django web framework, used in the /admin/ section of the site. These static files are dispersed throughout the source tree, and can be collected into a single place by specifying STATIC_ROOT in settings.py. These files are normally collected into a central location and served by a reverse proxy and static content server. The recommended default location is STATIC_ROOT = '/nemo/static/'. Then collect the files using this command:
django-admin collectstatic
Now that NEMO has been installed and configured, you'll need to create the database. An SQLite database will be suitable for most organizations. If your organization has hundreds of concurrent NEMO users then consider using PostgreSQL. The procedure to construct the database is the same for SQLite and Postgres:
django-admin makemigrations NEMO
django-admin migrate
If you are using SQLite, the file /home/nemo/sqlite.db should now exist.
You will need to log in to NEMO in order to access and manage it. Create a "super user" with this command:
django-admin createsuperuser
You will be prompted for a username, first name, last name, email address, and password. Enter the appropriate information. Note, that even though you enter a password, NEMO is designed to not store passwords in the database, therefore the password you enter is discarded. It will not work when you try to log in. NEMO relies exclusively on external authentication sources (such as LDAP or Kerberos) for authentication. Usernames are stored in NEMO, and these are authenticated against the external authentication source(s). So, your NEMO username must match the username of the external authentication source.
The Gunicorn documentation recommends using Nginx as a reverse proxy and static content server, and this guide follows that reference architecture. Installing Nginx will ensure you have a robust and secure production deployment of NEMO.
Navigate to the NEMO home directory:
cd /home/nemo
Use the script below to install Nginx at /home/nemo/nginx. You can copy and paste it into a file called compile_nginx.sh, make it executable with chmod 700 compile_nginx.sh, then run it with ./compile_nginx.sh. (Note: eventually, the ability to download, compile, and deploy Nginx will be built into the command line nemo executable).
NGINX_VERSION=1.12.2
OPENSSL_VERSION=1.1.0f
set -e # Exit the script if an error is encountered
rm -rf build
mkdir build
cd build
wget https://nginx.org/download/nginx-$NGINX_VERSION.tar.gz
tar xf nginx-$NGINX_VERSION.tar.gz
cd nginx-$NGINX_VERSION
wget https://www.openssl.org/source/openssl-$OPENSSL_VERSION.tar.gz
tar xf openssl-$OPENSSL_VERSION.tar.gz
mv openssl-$OPENSSL_VERSION $OPENSSL_VERSION
wget https://github.com/stnoonan/spnego-http-auth-nginx-module/archive/master.zip
unzip master.zip
mv spnego-http-auth-nginx-module-master spnego-http-auth-nginx-module
./configure \
--prefix=. \
--sbin-path=nginx \
--conf-path=configuration \
--pid-path=process_identifier \
--error-log-path=error_log \
--http-log-path=http_log \
--user=nobody \
--group=nobody \
--without-http_gzip_module \
--without-http_rewrite_module \
--with-cc-opt="-O2" \
--with-http_ssl_module \
--with-openssl=$OPENSSL_VERSION \
--add-module=spnego-http-auth-nginx-module
make
cd ../..
rm -rf nginx
mkdir nginx
cp build/nginx-$NGINX_VERSION/objs/nginx nginx/
touch nginx/configuration
rm -rf build
Grant Nginx the ability to bind to port 443 with this command:
sudo setcap cap_net_bind_service=+eip /home/nemo/nginx/nginx
Now that Nginx is installed, edit the configuration file (that was automatically created) at /home/nemo/nginx/configuration. You can use this configuration:
user nemo nemo;
worker_processes 2; # The number of processes should be less than or equal to the number of actual CPUs
worker_priority 15; # renice workers to reduce priority compared to system processes for machine health. Worst case nginx will get ~25% system resources at nice=15
events {
worker_connections 1024;
}
error_log /home/nemo/logs/nginx/main_error.log;
http {
error_log /home/nemo/logs/nginx/http_error.log;
server_tokens off; # Don't send the nginx version number in error pages and server header
# Timeouts, do not keep connections open longer then necessary to reduce resource usage and deny Slowloris type attacks.
client_body_timeout 4s; # Maximum time between packets the client can pause when sending nginx any data
client_header_timeout 4s; # Maximum time the client has to send the entire header to nginx
keepalive_timeout 75s; # Timeout which a single keep-alive client connection will stay open
send_timeout 24s; # Maximum time between packets nginx is allowed to pause when sending the client data
log_format meaningful '$time_iso8601 $remote_addr $request_method $request_uri "$http_user_agent" $http_referer $request_length $bytes_sent $request_time';
ssl_protocols TLSv1.2;
ssl_prefer_server_ciphers on;
ssl_ciphers 'ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256';
ssl_session_timeout 1d;
ssl_session_cache shared:SSL:50m;
ssl_session_tickets off;
types {
application/javascript js;
text/css css;
image/x-icon ico;
text/plain txt;
application/json map;
application/font-woff woff;
application/font-woff2 woff2;
application/vnd.ms-fontobject eot;
application/x-font-ttf ttf;
image/svg+xml svg;
image/png png;
}
server {
server_name nemo.example.org;
listen 0.0.0.0:443 ssl;
location / {
proxy_set_header Host $host;
proxy_set_header X-Forwarded-Host $server_name;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto https;
proxy_set_header X-Real-IP $remote_addr;
proxy_pass http://127.0.0.1:8000;
}
location /static/ { alias /home/nemo/static/; }
location /favicon.ico { alias /home/nemo/static/favicon.ico; }
ssl_certificate /home/nemo/secrets/nemo.example.org.crt;
ssl_certificate_key /home/nemo/secrets/nemo.example.org.key;
access_log /home/nemo/logs/nginx/proxy_server_access.log meaningful;
error_log /home/nemo/logs/nginx/proxy_server_error.log info;
}
}