2017-01-01 01:23:11+0900 []  WARN: [control connection] Error connecting to 11.11.11.11: <ErrorMessage code=000a [Protocol error] message="Invalid or unsupported protocol version (2); the lowest supported version is 3 and the greatest is 4">

2017-01-01 01:23:11+0900 [] ERROR: Control connection failed to connect, shutting down Cluster: ('Unable to connect to any servers', {u'172.17.56.90': <ErrorMessage code=000a [Protocol error] message="Invalid or unsupported protocol version (2); the lowest supported version is 3 and the greatest is 4">})

2017-01-01 01:23:11+0900 []  WARN: ProcessingError while calling CreateClusterConfController: Unable to connect to cluster. Error is: Unable to connect to any servers

$ sudo -E pip install cqlsh

After 3.0, we’ll take this even further: we will release 3.x versions monthly.  Even releases will include both bugfixes and new features; odd releases will be bugfix-only.  You may have heard this referred to as “tick-tock” releases, after Intel’s policy of changing process and architecture independently.

The primary goal is to improve release quality.  Our current major “dot zero” releases require another five or six months to make them stable enough for production.  This is directly related to how we pile features in for 9 to 12 months and release all at once.  The interactions between the new features are complex and not always obvious.  2.1 was no exception, despite DataStax hiring a full time test engineering team specifically for Apache Cassandra.

We need to try something different.  Tick-tock releases will dramatically reduce the number of features in each version, which will necessarily improve our ability to quickly track down any regressions.  And “pausing” every other month to focus on bug fixes will help ensure that we don’t accumulate issues faster than we can fix them.