Nginx Maintenance Mode configuration

Question

How can i turn on maintenance mode on nginx, I am hosting multiple Angular apps with Nginx. All of them run in their own containers. Maintenance page is located at /var/www/maintenance/. My current config is bellow

server {
    listen 80;
    listen   443 ssl;
    server_name         example.eu;
    ssl_certificate /etc/letsencrypt/live/example.eu-0001/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/example.eu-0001/privkey.pem; # managed by Certbot
    

# user ssl certificate check
ssl_client_certificate /home/user/CA/certs/users/klient.crt;
#ssl_crl /home/user/CA/crl/ca.crl;
ssl_verify_client on;
  access_log /var/log/nginx/graylog_access.log;
  error_log /var/log/nginx/graylog_error.log;



location /abc/ {
root /var/webapps/;
 }


location = / {
proxy_pass http://localhost:5000/abcd;
 }

location /abcd {
rewrite ^/abcd(/css/|/js/|/img/)(.*)$ $1$2 break;
proxy_pass http://localhost:5000;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection keep-alive;
proxy_set_header Host $host;
proxy_cache_bypass $http_upgrade;
proxy_send_timeout 3600;
proxy_read_timeout 3600s;
proxy_set_header X-Forwarded-For $remote_addr;
proxy_set_header X-Forwarded-Proto "https";
 }


location /efgh/ {
rewrite ^/efgh(/css/|/js/|/img/)(.*)$ $1$2 break;
proxy_pass http://localhost:5005;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection keep-alive;
proxy_set_header Host $host;
proxy_cache_bypass $http_upgrade;
proxy_send_timeout 3600;
proxy_read_timeout 3600s;
proxy_set_header X-Forwarded-For $remote_addr;
proxy_set_header X-Forwarded-Proto "https";
 }






server {
    if ($host = example.eu) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


    listen   80;
    server_name         example.eu;
    return 404; # managed by Certbot


}

Answer 1

You can use something like this:

server {
    ...
    set $maintenance '';
    if ($maintenance) {
        rewrite ^ /maintenance/ last;
    }
    ...
    location /maintenance {
        internal;
        root /var/www;
    }
}

To enable maintenance mode set $maintenance variable to any non-empty string, for example

set $maintenance 1;

and reload (it is zero-downtime operation) nginx.