IPMI

IPMI allows us to access a physical server removetly, as if we were in the colo with a monitor and keyboard plugged in. At least in theory. We used to use a simple serial cable to achieve this feat. However, new servers are no longer beings shipped with serial ports and motherboard/bios software no longer support them. Instead, we are expected to use IPMI.

IPMI provides a million ways to connect, but we are enabling two. Both are configured to use a local, non-routable IP address.

• web-based access (we will setup nginx to proxy from a public address to the non-routable address)
• serial over LAN access, using ipmiutil which will be run from a server in the cabinet

Unfortunately, IPMI is complex and varies considerably from computer to computer. Here are the steps used to connect john.

BIOS/Setup

When you first boot the computer, IPMI has to be enabled and assigned an IP address.

We use a non-routable IP address so the only way to connect to IPMI is via a machine in the colo itself.

Below are the screen shots of the bios and their settings.

Enable http redirections

On robideau, we have the following nginx configuration to allow web-based proxying:

#server {
#  listen 80;
#  server_name ipmi.john.mayfirst.org;
#  root /var/www/html;
#  location /.well-known/acme-challenge {
#    try_files $uri $uri/ =404;
#  }
#  location / {
#    return 301 https://$host$request_uri;
#  }
#}

server {
  listen 443;
  server_name ipmi.john.mayfirst.org;
  location /.well-known {
    root /var/www/html;
  }
  location / {
    access_log off;
    proxy_pass http://192.168.56.3:80;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header Host $host;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "Upgrade";
  }

  ssl on;
  ssl_certificate_key /etc/letsencrypt/live/ipmi.john.mayfirst.org/privkey.pem;
  ssl_certificate /etc/letsencrypt/live/ipmi.john.mayfirst.org/fullchain.pem;

  ssl_ciphers 'AES128+EECDH:AES128+EDH:!aNULL';

  ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
  ssl_session_cache shared:SSL:10m;

  ssl_prefer_server_ciphers on;
  ssl_dhparam /etc/ssl/dhparam.pem;

  add_header Strict-Transport-Security max-age=63072000;
  add_header X-Content-Type-Options nosniff;
}

The commented out section must be un-commented initially to allow lets encrypt to create a proper initial certificate.

Also, you need to create dlparams with:

openssl dhparam -out /etc/ssl/dhparam.pem 2048