ansible-role-nginx/riak

Introduction

These example playbooks should help you get an idea of how to use the riak ansible module. These playbooks were tested on Ubuntu Precise (12.04) and CentOS 6.4, both on x86_64.

About Riak

Riak is distributed key-value store that is architected for:

• Availability: Riak replicates and retrieves data intelligently so it is available for read and write operations, even in failure conditions
• Fault-Tolerance: You can lose access to many nodes due to network partition or hardware failure without losing data
• Operational Simplicity: Add new machines to your Riak cluster easily without incurring a larger operational burden – the same ops tasks apply to small clusters as large clusters
• Scalability: Riak automatically distributes data around the cluster and yields a near-linear performance increase as you add capacity.

For more information, please visit http://docs.basho.com/riak/latest/

Requirements

This playbook requires ansible 1.2.

Hosts File Naming Conventions

In the hosts file, we use a host variable node_type to ease the cluster joining process. The following values of node_type can be used.

• primary - all nodes attempt to join this node.
• last - this node plans and commits changes to the cluster, in this example, the joining of the nodes.
• middle - all nodes in between primary and last

There is no concept of node roles in Riak proper, it is master-less.

You can build an entire cluster by first modifying the hosts file to fit your network.

Using the Playbooks

Here are the playbooks that you can use with the ansible-playbook commands:

• site.yml - creates a complete riak cluster, it calls setup_riak.yml and form_cluster.yml
• setup_riak.yml - installs riak onto nodes
• form_cluster.yml - forms a riak cluster
• rolling_restart.yml - demonstrates the ability to perform a rolling configuration change. Similar principals could apply to performing rolling upgrades of Riak itself.