Active/Passive Clusters

In a cluster configured as active/passive, high availability is sought between a master system, which primarily offers the services, and a passive standby system (N plus 1) or several standby systems (N plus M). If certain criteria on the active system are no longer met or are only met unreliably, the services are taken over by the passive node and started there. In jargon, a "failover" has taken place.

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Purposes

  • Webserver and Webservices with nginx, Apache, Apache Tomcat
  • Application-Server php-fpm, starman, ror, ...
  • Netzwerkservices such as VPN-endpoints and Firewall
  • File server with access via WebDAV, HTTPS , RPC-XML and (s)FTP
  • Clustered databases, MySQL, PostgreSQL, Redis, MongoDB...