Generate a Voldemort partition scheme for a given size of cluster.

en_cluster_partitions.rb

#!/usr/bin/env ruby
#
# gen_cluster_partitions.rb
# Generate a Voldemort partition scheme for a given size of cluster.
#
usage = "Usage: gen_cluster_partitions.rb <name of cluster> < # of cluster nodes> < # of partitions per node>"

if ARGV[0]
  cluster_name = ARGV[0] 
else
  puts "Missing Cluster name"
  puts usage
  exit 1
end

if ARGV[1]
  number_of_nodes = ARGV[1].to_i
else
  puts "Missing # of cluster nodes"
  puts usage
  exit 1
end

if ARGV[2]
  partitions_per_node = ARGV[2].to_i
else
  puts "Missing # of partitions per node"
  puts usage
  exit 1
end

def gen_cluster_partitions(cluster_name, number_of_nodes, partitions_per_node)
  #Build an array of node id's
  nodes = (0...(number_of_nodes)).to_a

  n = number_of_nodes
  partition_ids = (0...(n * partitions_per_node)).to_a

  # use known seed so this is repeatable
  srand(92873498274)
  partition_ids.shuffle!

  p = partitions_per_node
  cluster = []
  id = 0
  nodes.each do |host_number|
    host_number_s = host_number.to_s
    host_name     = "v#{cluster_name}#{host_number_s}"

    ids = partition_ids[id*p...(id+1)*p]
    partition_array = ids.sort!.join(",")

    cluster_node = {
      "node_id"    => host_number_s,
      "node_name"  => host_name,
      "partitions" => partition_array
    }

    cluster << cluster_node

    # Move onto the next group
    id = id.next
  end
return cluster
end

cluster = gen_cluster_partitions(cluster_name, number_of_nodes, partitions_per_node)

cluster.each do|node_hash|
  puts node_hash.inspect
end