For more than five years, DC/OS has enabled some of the largest, most sophisticated enterprises in the world to achieve unparalleled levels of efficiency, reliability, and scalability from their IT infrastructure. But now it is time to pass the torch to a new generation of technology: the D2iQ Kubernetes Platform (DKP). Why? Kubernetes has now achieved a level of capability that only DC/OS could formerly provide and is now evolving and improving far faster (as is true of its supporting ecosystem). That’s why we have chosen to sunset DC/OS, with an end-of-life date of October 31, 2021. With DKP, our customers get the same benefits provided by DC/OS and more, as well as access to the most impressive pace of innovation the technology world has ever seen. This was not an easy decision to make, but we are dedicated to enabling our customers to accelerate their digital transformations, so they can increase the velocity and responsiveness of their organizations to an ever-more challenging future. And the best way to do that right now is with DKP.
Cassandra-Mesos is a Mesos framework. It is also available as a DCOS package that provisions a Cassandra ring onto a Mesos cluster.
Starting with the 0.2.0 release, you can configure the framework to launch rings that include the information Cassandra needs to perform multi-datacenter replication.
Why is multi-datacenter configuration useful?
Cassandra is a distributed database that runs on multiple nodes to provide high availability. This avoids a single point of failure, where the database's ability to serve data could be taken offline if a single node fails.
However, in many scenarios, datacenter operators want to protect against instances where several nodes co-located either on the same physical rack or in the same physical datacenter all fail simultaneously. By configuring Cassandra nodes to be rack- and datacenter-aware, Cassandra attempts to replicate data in an intelligent manner to mitigate against rack and datacenter failures. By default, applications writing to a rack- and datacenter-aware cluster receive successful write confirmation only if write quorum is achieved within the datacenter. (For more details on write consistency levels, see the Cassandra documentation.)
Enabling Datacenter Awareness with Cassandra-Mesos
An alpha version of Cassandra-Mesos is available in the Mesosphere Universe and can be easily installed onto a DCOS cluster. Please see the Cassandra service tutorial to learn how to set up your own Cassandra-Mesos installation on the Mesosphere Datacenter Operating System.
If you want to get started with a multi-datacenter deployment, in-depth configuration documentation is available on the Cassandra-Mesos framework documentation. Configuration values are passed in as an options file when running dcos package install cassandra or as environment variables when you launch the Cassandra-Mesos framework manually.
In a future release, Cassandra-on-Mesos will schedule tasks on specific racks in specific datacenters, allowing fine-grained control over automated replication between racks and between datacenters in distant locations.