Chef has recently released Chef Server HA 2.0 which is a complete redesign of their Architecture designed for Mission Critical implementations that also require performance and reliability.
Chef Server HA now provides high degrees of fault tolerance, support for virtualized environments, synchronous search writes, increased indexing and native backup and restore tools that do not impact service availability.
All of these capabilities were designed to meet the demands of the growing Enterprise user base. Existing users will have to migrate their data to the new HA 2.0 environment to take advantage of all the new features.
In the deployment of Chef Server HA 2.0, Chef has made several architectural changes over Chef Server. A new Two-tiered approach has been leveraged in 2.0, by creating separate Frontend and Backend groups Chef can now scale horizontally to handle demand. The Frontend nodes allow for distributing API and Management console access to one or chef server nodes. While the Backend group which is composed of a three node cluster with one leader and two followers nodes. Process all writes which are written to the search engine and the database simultaneously. You should also be aware that Apache Solr has been replaced with Elasticsearch on the frontend nodes but will maintain API compatibility with Solr for the time being.
Chef Server HA 2.0 does not provide for cluster security so the Backend group should be run in a trusted environment. Other communication between cluster nodes could occur over common application ports with username & password authentication without encryption. Because of this, you are going to want to use host base firewalls and/or network ACL’s when deploying to keep attackers from eavesdropping on your clusters communications.
Chef has also provided a rich set of CLI commands giving DevOps engineers the tools required to automate the process of scaling the frontend group and managing the backend group. Including the ability to force a new database leader should you lose the current one.
Chef Server HA 2.0 is a premium feature however, you can get started in your Lab for free as long as you have less than 25 nodes.