Upgrading to Riak KV 2.0

When upgrading to Riak 2.0 from an earlier version, we strongly recommend reading each section of the following guide. This guide explains which default Riak behaviors have changed and specific steps to take for a successful upgrade.

For an overview of the new features and functionality included in version 2.0, check out our guide to Riak 2.0.

New Clients

To take advantage of the new features available in Riak 2.0, we recommend upgrading your application to an official Basho client that was built with those features in mind. There are official 2.0-compatible clients in the following languages:

While we strongly recommend using the newest versions of these clients, older versions will still work with Riak 2.0, with the drawback that those older clients will not able to take advantage of new features like data types or the new Riak Search.

Bucket Types

In versions of Riak prior to 2.0, the location of objects was determined by objects’ bucket and key, while all bucket-level configurations were managed by setting bucket properties.

In Riak 2.0, bucket types are both an additional namespace for locating objects and a new way of configuring bucket properties in a systematic fashion. More comprehensive details on usage can be found in the documentation on using bucket types. Here, we’ll list some of the things to be aware of when upgrading.

Bucket types and object location

With the introduction of bucket types, the location of all Riak objects is determined by:

  • bucket type
  • bucket
  • key

This means there are 3 namespaces involved in object location instead of 2. A full tutorial can be found in Using Bucket Types.

If your application was written using a version of Riak prior to 2.0, you should make sure that any endpoint in Riak targeting a bucket/key pairing is changed to accommodate a bucket type/bucket/key location.

If you’re using a pre-2.0-specific client and targeting a location specified only by bucket and key, Riak will use the default bucket configurations. The following URLs are equivalent in Riak 2.0:


If you use object locations that don’t specify a bucket type, you have three options:

Features that rely on bucket types

One reason we recommend using bucket types for Riak 2.0 and later is because many newer Riak features were built with bucket types as a precondition:

  • Strong consistency — Using Riak’s strong consistency subsystem requires you to set the consistent parameter on a bucket type to true
  • Riak Data Types — In order to use Riak Data Types, you must create bucket types specific to the Data Type you are using

Bucket types and downgrades

If you decide to use bucket types, please remember that you cannot downgrade your cluster to a version of Riak prior to 2.0 if you have both created and activated a bucket type.

New allow_mult Behavior

One of the biggest changes in version 2.0 regarding application development involves Riak’s default siblings behavior.

In versions prior to 2.0, the allow_mult setting was set to false by default for all buckets. So Riak’s default behavior was to resolve object replica conflicts between nodes on its own; relieving connecting clients of the need to resolve those conflicts.

In 2.0, allow_mult is set to true for any bucket type that you create and activate.

This means that the default when using bucket types is to handle conflict resolution on the client side using either traditional vector clocks or the newer dotted version vectors.

If you wish to set allow_mult to false in version 2.0, you have two options:

  • Set your bucket type’s allow_mult property to false.
  • Don’t use bucket types.

More information on handling siblings can be found in our documentation on conflict resolution.

Enabling Security

The authentication and authorization mechanisms included with Riak 2.0 should only be turned on after careful testing in a non-production environment. Security changes the way all applications interact with Riak.

When Downgrading is No Longer an Option

If you decide to upgrade to version 2.0, you can still downgrade your cluster to an earlier version of Riak if you wish, unless you perform one of the following actions in your cluster:

  • Index data to be used in conjunction with the new Riak Search.
  • Create and activate one or more bucket types. By extension, you will not be able to downgrade your cluster if you have used the following features, both of which rely on bucket types:

If you use other new features, such as Riak Security or the new configuration files, you can still downgrade your cluster, but you will no longer be able to use those features after the downgrade.

Upgrading Your Configuration System

Riak 2.0 offers a new configuration system that both simplifies configuration syntax and uses one configuration file, riak.conf, instead of the two files, app.config and vm.args, required by the older system. Full documentation of the new system can be found in Configuration Files.

If you’re upgrading to Riak 2.0 from an earlier version, you have two configuration options:

  1. Manually port your configuration from the older system into the new system.
  2. Keep your configuration files from the older system, which are still recognized in Riak 2.0.

If you choose the first option, make sure to consult the configuration files documentation, as many configuration parameters have changed names, some no longer exist, and others have been added that were not previously available.

If you choose the second option, Riak will automatically determine that the older configuration system is being used. You should be aware, however, that some settings must be set in an advanced.config file. For a listing of those parameters, see our documentation on advanced configuration.

If you choose to keep the existing app.config files, you must add the following additional settings in the riak_core section:

          [{allow_mult,false}, %% or the same as an existing setting
          %% other settings

This is to ensure backwards compatibility with 1.4 for these bucket properties.

Upgrading LevelDB

If you are using LevelDB and upgrading to 2.0, no special steps need to be taken, unless you wish to use your old app.config file for configuration. If so, make sure that you set the total_leveldb_mem_percent parameter in the eleveldb section of the file to 70.

{eleveldb, [
    %% ...
    {total_leveldb_mem_percent, 70},
    %% ...

If you do not assign a value to total_leveldb_mem_percent, Riak will default to a value of 15, which can cause problems in some clusters.

Information on upgrading Riak Search to 2.0 can be found in our Search upgrade guide.

Migrating from Short Names

Although undocumented, versions of Riak prior to 2.0 did not prevent the use of the Erlang VM’s -sname configuration parameter. As of 2.0 this is no longer permitted. Permitted in 2.0 are nodename in riak.conf and -name in vm.args. If you are upgrading from a previous version of Riak to 2.0 and are using -sname in your vm.args, the below steps are required to migrate away from -sname.

  1. Upgrade to Riak 1.4.12.
  2. Back up the ring directory on each node, typically located in /var/lib/riak/ring.
  3. Stop all nodes in your cluster.
  4. Run riak-admin reip <old_nodename> <new_nodename> on each node in your cluster, for each node in your cluster. For example, in a 5 node cluster this will be run 25 total times, 5 times on each node. The <old_nodename> is the current shortname, and the <new_nodename> is the new fully qualified hostname.
  5. Change riak.conf or vm.args, depending on which configuration system you’re using, to use the new fully qualified hostname on each node.
  6. Start each node in your cluster.