Websites: https://experiments.jcsda.org/ and https://skylab.jcsda.org/
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About
Our web applications, https://experiments.jcsda.org and https://skylab.jcsda.org run on two individual AWS EC2 instances in us-east-1. They are Voila applications running on port 8866 on an nginx web server on ports 80/443. The web apps are simply python notebooks in the diag-plots repository with r2d2 and solo as the only dependencies. These packages are located in /home/ubuntu. Python3 virtual environments, e.i. "venv" are not used for the web apps. All python code is installed to the system python. It was the only way we could figure out to get the notebooks to work with Viola and nginx over https.
The Viola middleware service strips the cells from each notebook at runtime and displays only the user interface graphics required for the drop down menus and image viewing. Every time someone visits one of these web pages, a new Python3 kernel is started in memory. Over time, this leads to OutOfMemoryErrors from the OS and the web apps freeze up and the instance will have to be rebooted as detailed below.
The error logs a Voila application with python notebooks and each run from their own instance. The logs on these instances are located at /var/log/nginx/error.log and can be accessed by executing
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journalctl -u voila. |
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service |
The https nginx configurations are at /etc/nginx/sites-enabled/experiments.jcsda.org and /etc/nginx/sites-enabled/skylab.jcsda.org.
WARNING: Do not change the https nginx configurations unless you know what you are doing.
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server {
server_name experiments.jcsda.org;
proxy_buffering off;
location / {
proxy_pass http://localhost:8866;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
proxy_read_timeout 86400;
}
client_max_body_size 100M;
error_log /var/log/nginx/error.log;
listen 443 ssl; # managed by Certbot
ssl_certificate /etc/letsencrypt/live/experiments.jcsda.org/fullchain.pem; # managed by Certbot
ssl_certificate_key /etc/letsencrypt/live/experiments.jcsda.org/privkey.pem; # managed by Certbot
include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot
}
server {
if ($host = experiments.jcsda.org) {
return 301 https://$host$request_uri;
} # managed by Certbot
listen 80;
server_name experiments.jcsda.org;
return 301 https://$host$request_uri;
# return 404; # managed by Certbot
} |
Procedures
Reboot EC2 Instance
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Voila documentation: https://voila.readthedocs.io/en/stable/deploy.html#running-voila-on-a-private-server
WARNING: these These instructions are old and some steps might be outdated or simply not correct for the current web apps.
Start a new EC2 instance using the console:
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