Nginx SSL configuration in Docker Swarm - Andrey Zhukov's Tech Blog

When you have several Nginx replicas in Docker Swarm and you need to share SSL certificate, you can use secrets.

Here is a short extract:

server {
    listen 443 ssl http2;
    server_name ...;
    ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
    ssl_ciphers EECDH+AESGCM:EECDH+AES;
    ssl_prefer_server_ciphers on;
    ssl_certificate /run/secrets/cert.crt;
    ssl_certificate_key /run/secrets/cert.key;
    ssl_trusted_certificate /run/secrets/fullchain.pem;
    ssl_dhparam /run/secrets/dh2048.pem;

    ...

version: '3.1'
services:
  ...
  nginx:
    ...
    ports:
      - "80:80"
      - "443:443"
    secrets:
      - cert.crt
      - cert.key
      - fullchain.pem
      - dh2048.pem

secrets:
  cert.crt:
    file: /path_to/cert.crt
  nginx.key:
    file: /path_to/cert.key
  fullchain.pem:
    file: /path_to/fullchain.pem
  dh2048.pem:
    file: /path_to/dh2048.pem