Running Sentry On-Premise with Digital Ocean & Docker

This article will go through the steps needed to get Sentry On-Premise working on a Digital Ocean preconfigured Docker droplet with TLS. Running Sentry yourself will eliminate bandwidth costs because your droplets will be sending data through Digital Ocean's network rather than across the internet. It will potentially cost less because a droplet with minimum system requirements is $15 a month versus the $26 team tier available from Sentry.

Installing Sentry On-Premise

Start by creating a new Digital Ocean droplet. It must have at least 3 gigs of RAM and make sure the "Private networking" option is selected. Once the droplet is created then ssh as root into the droplet.

ssh root@your-droplet-ip-address

Notice: This article is setting up everything on the droplet as the root user. This is not a good practice and that is outside the scope of this article.

Create a new folder which will be used as the install location for Sentry On-Premise

$ mkdir /home/root/ && mkdir /home/root/apps

Ensure that you are in /home/root/apps and clone the Sentry On-Premise Github Repository. Next, generate a secret required for Sentry On-Premise. Inside the onpremise directory (created from git clone) run the following command to generate a new secret.

docker run sentry config generate-secret-key

Docker will fetch the images needed to generate the secret and a new secret will be displayed in the terminal. Copy it and we'll add it to the config file. A config file can be created by copying the existing example config.

cp ./sentry/config.example.yml ./sentry/config.yml

Open the new config.yml file, find system.secret-key: '!!changeme!!', and replace "!!changeme!!" with the secret generated from before. That's it for configuring sentry! Next, run the install script to install all of the dependencies. It will prompt to create a user account which will be used to login into the sentry dashboard.

. ./

Running Sentry

Once everything has installed, run docker-compose up -d to get everything up and running. You won't be able to visit the sentry dashboard yet because port 9000 is blocked by default on droplets. You can open the port by running ufw allow 9000. You can now visit http://doplet-ip-address:9000 and should see the Sentry login screen! However, it's not a good security practice to send error information without TLS. In the next section, NGINX will be used to handle TLS and proxy traffic through port 80 to port 9000. For now, disable port 9000 ufw deny 9000.

Configuring and Running NGINX

First, start off my updating package indexes apt-get update and then install NGINX apt-get install nginx-full.

NGINX needs to be configured correctly to know which certificate and key to look for and which port should be forwarded to 80. Edit /etc/nginx/nginx.config and copy/paste the code below into it. All instances of of "" to the correct domain name. The certificate and private key of the domain will need to be added in the locations as specified under the SSL Configuration section.

events {}

http {
  # set REMOTE_ADDR from any internal proxies
  # see
  real_ip_header X-Forwarded-For;
  real_ip_recursive on;

  # SSL configuration -- change these certs to match yours
  ssl_certificate      /etc/ssl/;
  ssl_certificate_key  /etc/ssl/;

  # NOTE: These settings may not be the most-current recommended
  # defaults
  ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
  ssl_prefer_server_ciphers on;
  ssl_session_cache shared:SSL:128m;
  ssl_session_timeout 10m;

  server {
    listen   80;

    location / {
      if ($request_method = GET) {
        rewrite  ^ https://$host$request_uri? permanent;
      return 405;

  server {
    listen   443 ssl;

    proxy_set_header   Host                 $http_host;
    proxy_set_header   X-Forwarded-Proto    $scheme;
    proxy_set_header   X-Forwarded-For      $remote_addr;
    proxy_redirect     off;

    # keepalive + raven.js is a disaster
    keepalive_timeout 0;

    # use very aggressive timeouts
    proxy_read_timeout 5s;
    proxy_send_timeout 5s;
    send_timeout 5s;
    resolver_timeout 5s;
    client_body_timeout 5s;

    # buffer larger messages
    client_max_body_size 5m;
    client_body_buffer_size 100k;

    location / {
      proxy_pass        http://localhost:9000;

      add_header Strict-Transport-Security "max-age=31536000";

Locking down the ports and opening the correct ones is the last step. Allow https, http and port 22, but otherwise block everything else. For whatever reason, ports 2376 and 2375 are open on the docker droplet. Run the following command to correctly configure the ports.

ufw allow https && \
  ufw allow http && \
  ufw deny 2375 && \
  ufw deny 2375/tcp && \
  ufw deny 2376  && \
  ufw deny 2376/tcp

Restart nginx systemctl restart nginx for everything to take effect. Visit to see the Sentry dashboard!