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Migrating from Riak 0.9.x to 0.10

Overview

Riak has undergone significant restructuring in the transition from version 0.9.x to version 0.10. If you are using the binary builds, please skip directly to the Configuration and Clients sections. If you are building from source yourself, please review the whole of this document.

NOTE: If the only files you have changed in your Riak source clone are those underneath the “rel” directory (“rel/overlay/etc/app.config”, for example), the safest way to update is to make a fresh clone of the Riak repository, and then skip to the Configuration and Clients sections of this document for details about migrating your configurations and data.

Requirements

Erlang/OTP R13B04

Riak 0.10 uses new features (“NIFs”) provided by the latest Erlang/OTP release, R13B04. If you are building from source, you will need this release or a newer one.

Mercurial

Riak 0.10 has moved several of its components into external repositories. If you are building from source, you will need Mercurial installed to allow the Rebar build system to retrieve code from these external repositories.

Dependencies

Mochiweb, Webmachine, Erlang_js

mochiweb, webmachine, and erlang_js are now pulled into the “deps” subdirectory, instead of being included in the “apps” subdirectory. If you are pulling 0.10 code into a repository that formerly had 0.9.x in it, please remove the apps/mochiweb, apps/webmachine, and apps/erlang_js directories from your source tree.

There is a chance that your update will also leave an “apps/riak” directory hanging around. If it does, please remove this directory (Riak code has moved into the “apps/riak_core” and “apps/riak_kv” directories).

make deps

The “all” make target (and, by extension, the “rel” target as well), depend on a new “deps” target, which handles the fetching the dependencies (mochiweb, webmachine, erlang_js).

Source

Core/KV Split

We’ve drawn a line through 0.9.x Riak, and divided it into two things, one called “riak_core”, and the other called “riak_kv”.

The things that live in riak_core are those that deal with cluster membership. Ring-claiming and the like.

The things that live in riak_kv are those that deal with storing data. Get and Put FSMs, backends, etc.

Clients

We’ve also moved the clients out of the client_lib subdirectory, and into their own language-specific repositories on BitBucket. At http://bitbucket.org/basho/, you should find:

  • riak-python-client
  • riak-php-client
  • riak-erlang-client
  • riak-java-client
  • riak-javascript-client
  • riak-ruby-client

Configuration

app.config

Splitting the “riak” Erlang application into the “riak_core” and “riak_kv” Erlang applications means that configuration options for each component need to move around in etc/app.config.

Where before etc/app.config would have contained a section like:

{riak, [ %% many settings here ]},

Now, etc/app.config should contain two sections like:

{riak_core, [ %% core-specific settings ]}, {riak_kv, [ %% kv-specific settings ]},

The list of settings that moved to the riak_core section are:

  • choose_claim_fun
  • cluster_name - string, defaults to “default”
  • default_bucket_props
  • gossip_interval - integer, defaults to 60k msec
  • ring_creation_size - integer, defaults to 64
  • ring_state_dir - string
  • target_n_val - integer, defaults to 3
  • wants_claim_fun
  • web_ip - string. Used to be “riak_web_ip”
  • web_logdir - string.
  • web_port - integer. Used to be “riak_web_port”

IMPORTANT: Note the rename of “riak_web_*” to just “web_*”

The list of settings that moved to the riak_kv section are:

  • add_paths - list, defaults to []
  • handoff_concurrency - integer, defaults to 4
  • js_source_dir - string
  • js_vm_count - integer
  • mapred_name - string
  • raw_name - string
  • riak_kv_stat - boolean.
  • stats_urlpath - string
  • storage_backend - atom. Backend names are now prefixed as “riak_kv_” instead of just “riak_”.
  • pb_ip - string
  • pb_port - integer

IMPORTANT: The default backend has changed names from riak_dets_backend to riak_kv_dets_bakend. Other backends have changed names as well. This rename does not affect you if you are using the Innostore backend.

If you did not have any of these settings defined in etc/app.config, you still do not need to define them in your new etc/app.config.

Ring Storage

Periodically, Riak nodes save the state of their ring to disk. In 0.9, these files were named “data/ring/riak_ring.*”, but in 0.10, they’re named “data/ring/riak_core_ring.*”. Renaming the old files to the new scheme is all you need to do to make the switch.

If you referenced any Riak modules in your bucket properties, you will also need to change those references to point to the new module names after your cluster is running.

Your Data

The rest of your cluster’s data, stored in the “data” directory (“data/dets” or “data/innodb”, for example) should be safe to either leave in place, or copy to your new install location, depending on how you upgraded.