When chef-client is run manually node[:Cassandra][Keyspaces] populates properly from discover_cassandra_schema() and then the cassandra_maintenance.sh.erb template is generated properly. When Chef is run in the background (we keep it in cron) it does not populate, and the template is blank. I suspect it might have something to do with the way 's…

cassandra_helpers.rb

# relevent bits from my library

  def discover_cassandra_schema
  # Discover schema information for this host so we can dynamically generate
  # maintenance scripts and collectd config.
  #
  # This depends on the discover-cassandra-schema.sh script.  Eventually
  # I will us the Cassandra Ruby gem to get this data directly.

    # Gets schema data into an array in and the form of keyspace.columnfamily
    schema_data = `/var/tmp/discover-cassandra-schema.sh`.split("\n")

    schema = {}
    keyspaces = []
    columnfamilies = []

    schema_data.each do |x|
      keyspaces << x.split(".")[0]
    end

    keyspaces.uniq.each do |ks|
      schema_data.each do |cf|
        if cf.include?("#{ks}")
          columnfamilies << cf.split(".")[1]
        end
      end
      schema["#{ks}"] = columnfamilies
      columnfamilies = []
    end
    return schema
  end

cassandra_maintenance.sh.erb

#/bin/bash
# Generated by Chef for <%= @node[:fqdn] %>
logFile="/var/log/cassandra/mainenance.log"

<% @node[:Cassandra][:Keyspaces].each do |ks| -%>
<%   ks[1].each do |cf| -%>
echo "<%= ks[0] %>.<%= cf %> repair started at $(date)" >> $logFile
nodetool -h <%= node[:fqdn] %> -p <%= @node[:Cassandra][:JMX_PORT] %> repair <%= ks[0] %> <%= cf %>
echo "<%= ks[0] %>.<%= cf %> repair completed at $(date)" >> $logFile

echo "<%= ks[0] %>.<%= cf %> compaction started at $(date)" >> $logFile
nodetool -h <%= node[:fqdn] %> -p <%= @node[:Cassandra][:JMX_PORT] %> compact <%= ks[0] %> <%= cf %>
echo "<%= ks[0] %>.<%= cf %> compaction completed at $(date)" >> $logFile

echo "<%= ks[0] %>.<%= cf %> cleanup started at $(date)" >> $logFile
nodetool -h <%= node[:fqdn] %> -p <%= @node[:Cassandra][:JMX_PORT] %> cleanup <%= ks[0] %> <%= cf %>
echo "<%= ks[0] %>.<%= cf %> cleanup completed at $(date)" >> $logFile

<%   end -%>
<% end -%>

default.rb

# Relevant bits from the recipe.
class ::Chef::Recipe
  include ::CassandraHelpers
end

# Drop the schema discovery script.  Make sure it loads before the run.
a = cookbook_file "/var/tmp/discover-cassandra-schema.sh" do
  source "discover-cassandra-schema.sh"
  mode "0775"
  owner "root"
  group "root"
end
a.run_action(:create)

# This depends on the script above existing.
node.normal[:Cassandra][:Keyspaces] = discover_cassandra_schema()

template "/var/tmp/cassandra-maintenance.sh" do
  source "cassandra-maintenance.sh.erb"
  mode "0775"
  owner "root"
  group "root"
end

discover-cassandra-schema.sh

#/bin/bash

getKeyspaces() {
  echo "show keyspaces;" > /var/tmp/ks.cmd
  keyspaces=( $(cassandra-cli -h $HOSTNAME -p 9160 -f /var/tmp/ks.cmd 2>&1 | grep Keyspace | grep -v 'system\|OpsCenter' | awk {' print $2 '} | sed 's/://' ) )
  rm -f /var/tmp/ks.cmd
}

getColumnfamilies() {
  echo "describe $keyspace;" > /var/tmp/cf.cmd
  columnfamilies=( $(cassandra-cli -h $HOSTNAME -p 9160 -f /var/tmp/cf.cmd 2>&1 | grep ColumnFamily | awk {' print $2 '} | sed 's/://' ) )
  rm -f /var/tmp/cf.cmd
}

getKeyspaces
for keyspace in "${keyspaces[@]}"; do
  getColumnfamilies
  for columnfamily in "${columnfamilies[@]}"; do
    echo "$keyspace.$columnfamily"
  done
done