1.修改端口：我设置为 port 7001
2.放开配置：
 cluster-enabled yes
 cluster-config-file nodes-7001.conf //名称可自改
 cluster-node-timeout 15000

redis-trib.rb create --replicas 0 127.0.0.1:7001 127.0.0.1:7002 127.0.0.1:7003 127.0.0.1:7004 127.0.0.1:7005 127.0.0.1:7006

#!/usr/bin/env ruby
 
# TODO (temporary here, we'll move this into the Github issues once
# redis-trib initial implementation is completed).
#
# - Make sure that if the rehashing fails in the middle redis-trib will try
# to recover.
# - When redis-trib performs a cluster check, if it detects a slot move in
# progress it should prompt the user to continue the move from where it
# stopped.
# - Gracefully handle Ctrl+C in move_slot to prompt the user if really stop
# while rehashing, and performing the best cleanup possible if the user
# forces the quit.
# - When doing "fix" set a global Fix to true, and prompt the user to
# fix the problem if automatically fixable every time there is something
# to fix. For instance:
# 1) If there is a node that pretend to receive a slot, or to migrate a
# slot, but has no entries in that slot, fix it.
# 2) If there is a node having keys in slots that are not owned by it
# fix this condition moving the entries in the same node.
# 3) Perform more possibly slow tests about the state of the cluster.
# 4) When aborted slot migration is detected, fix it.
 
require 'rubygems'
require 'redis'
 
ClusterHashSlots = 16384
MigrateDefaultTimeout = 60000
MigrateDefaultPipeline = 10
RebalanceDefaultThreshold = 2
 
$verbose = false
 
def xputs(s)
 case s[0..2]
 when ">"
 color="29;1"
 when "[ER"
 color="31;1"
 when "[WA"
 color="31;1"
 when "[OK"
 color="32"
 when "[FA","***"
 color="33"
 else
 color=nil
 end
 
 color = nil if ENV['TERM'] != "xterm"
 print "\033[#{color}m" if color
 print s
 print "\033[0m" if color
 print "\n"
end
 
class ClusterNode
 def initialize(addr)
 s = addr.split(":")
 if s.length < 2
  puts "Invalid IP or Port (given as #{addr}) - use IP:Port format"
  exit 1
 end
 port = s.pop # removes port from split array
 ip = s.join(":") # if s.length > 1 here, it's IPv6, so restore address
 @r = nil
 @info = {}
 @info[:host] = ip
 @info[:port] = port
 @info[:slots] = {}
 @info[:migrating] = {}
 @info[:importing] = {}
 @info[:replicate] = false
 @dirty = false # True if we need to flush slots info into node.
 @friends = []
 end
 
 def friends
 @friends
 end
 
 def slots
 @info[:slots]
 end
 
 def has_flag"#{@info[:host]}:#{@info[:port]}"
 end
 
 def connect(o={})
 return if @r
 print "Connecting to node #{self}: " if $verbose
 STDOUT.flush
 begin
  @r = Redis.new(:host => @info[:host], :port => @info[:port], :timeout => 60)
  @r.ping
 rescue
  xputs "[ERR] Sorry, can't connect to node #{self}"
  exit 1 if o[:abort]
  @r = nil
 end
 xputs "OK" if $verbose
 end
 
 def assert_cluster
 info = @r.info
 if !info["cluster_enabled"] || info["cluster_enabled"].to_i == 0
  xputs "[ERR] Node #{self} is not configured as a cluster node."
  exit 1
 end
 end
 
 def assert_empty
 if !(@r.cluster("info").split("\r\n").index("cluster_known_nodes:1")) ||
  (@r.info['db0'])
  xputs "[ERR] Node #{self} is not empty. Either the node already knows other nodes (check with CLUSTER NODES) or contains some key in database 0."
  exit 1
 end
 end
 
 def load_info(o={})
 self.connect
 nodes = @r.cluster("nodes").split("\n")
 nodes.each{|n|
  # name addr flags role ping_sent ping_recv link_status slots
  split = n.split
  name,addr,flags,master_id,ping_sent,ping_recv,config_epoch,link_status = split[0..6]
  slots = split[8..-1]
  info = {
  :name => name,
  :addr => addr,
  :flags => flags.split(","),
  :replicate => master_id,
  :ping_sent => ping_sent.to_i,
  :ping_recv => ping_recv.to_i,
  :link_status => link_status
  }
  info[:replicate] = false if master_id == "-"
 
  if info[:flags].index("myself")
  @info = @info.merge(info)
  @info[:slots] = {}
  slots.each{|s|
   if s[0..0] == '['
   if s.index("->-") # Migrating
    slot,dst = s[1..-1].split("->-")
    @info[:migrating][slot.to_i] = dst
   elsif s.index("-<-") # Importing
    slot,src = s[1..-1].split("-<-")
    @info[:importing][slot.to_i] = src
   end
   elsif s.index("-")
   start,stop = s.split("-")
   self.add_slots((start.to_i)..(stop.to_i))
   else
   self.add_slots((s.to_i)..(s.to_i))
   end
  } if slots
  @dirty = false
  @r.cluster("info").split("\n").each{|e|
   k,v=e.split(":")
   k = k.to_sym
   v.chop!
   if k != :cluster_state
   @info[k] = v.to_i
   else
   @info[k] = v
   end
  }
  elsif o[:getfriends]
  @friends << info
  end
 }
 end
 
 def add_slots(slots)
 slots.each{|s|
  @info[:slots][s] = :new
 }
 @dirty = true
 end
 
 def set_as_replica(node_id)
 @info[:replicate] = node_id
 @dirty = true
 end
 
 def flush_node_config
 return if !@dirty
 if @info[:replicate]
  begin
  @r.cluster("replicate",@info[:replicate])
  rescue
  # If the cluster did not already joined it is possible that
  # the slave does not know the master node yet. So on errors
  # we return ASAP leaving the dirty flag set, to flush the
  # config later.
  return
  end
 else
  new = []
  @info[:slots].each{|s,val|
  if val == :new
   new << s
   @info[:slots][s] = true
  end
  }
  @r.cluster("addslots",*new)
 end
 @dirty = false
 end
 
 def info_string
 # We want to display the hash slots assigned to this node
 # as ranges, like in: "1-5,8-9,20-25,30"
 #
 # Note: this could be easily written without side effects,
 # we use 'slots' just to split the computation into steps.
 
 # First step: we want an increasing array of integers
 # for instance: [1,2,3,4,5,8,9,20,21,22,23,24,25,30]
 slots = @info[:slots].keys.sort
 
 # As we want to aggregate adjacent slots we convert all the
 # slot integers into ranges (with just one element)
 # So we have something like [1..1,2..2, ... and so forth.
 slots.map!{|x| x..x}
 
 # Finally we group ranges with adjacent elements.
 slots = slots.reduce([]) {|a,b|
  if !a.empty"#{x.first}-#{x.last}"
 }.join(",")
 
 role = self.has_flag"master") "M" : "S"
 
 if self.info[:replicate] and @dirty
  is = "S: #{self.info[:name]} #{self.to_s}"
 else
  is = "#{role}: #{self.info[:name]} #{self.to_s}\n"+
  " slots:#{slots} (#{self.slots.length} slots) "+
  "#{(self.info[:flags]-["myself"]).join(",")}"
 end
 if self.info[:replicate]
  is += "\n replicates #{info[:replicate]}"
 elsif self.has_flag"master") && self.info[:replicas]
  is += "\n #{info[:replicas].length} additional replica(s)"
 end
 is
 end
 
 # Return a single string representing nodes and associated slots.
 # TODO: remove slaves from config when slaves will be handled
 # by Redis Cluster.
 def get_config_signature
 config = []
 @r.cluster("nodes").each_line{|l|
  s = l.split
  slots = s[8..-1].select {|x| x[0..0] != "["}
  next if slots.length == 0
  config << s[0]+":"+(slots.sort.join(","))
 }
 config.sort.join("|")
 end
 
 def info
 @info
 end
 
 def is_dirty"[ERR] Wrong number of arguments for specified sub command"
  exit 1
 end
 end
 
 def add_node(node)
 @nodes << node
 end
 
 def reset_nodes
 @nodes = []
 end
 
 def cluster_error(msg)
 @errors << msg
 xputs msg
 end
 
 # Return the node with the specified ID or Nil.
 def get_node_by_name(name)
 @nodes.each{|n|
  return n if n.info[:name] == name.downcase
 }
 return nil
 end
 
 # Like get_node_by_name but the specified name can be just the first
 # part of the node ID as long as the prefix in unique across the
 # cluster.
 def get_node_by_abbreviated_name(name)
 l = name.length
 candidates = []
 @nodes.each{|n|
  if n.info[:name][0...l] == name.downcase
  candidates << n
  end
 }
 return nil if candidates.length != 1
 candidates[0]
 end
 
 # This function returns the master that has the least number of replicas
 # in the cluster. If there are multiple masters with the same smaller
 # number of replicas, one at random is returned.
 def get_master_with_least_replicas
 masters = @nodes.select{|n| n.has_flag"master"}
 sorted = masters.sort{|a,b|
  a.info[:replicas].length <=> b.info[:replicas].length
 }
 sorted[0]
 end
 
 def check_cluster(opt={})
 xputs "> Performing Cluster Check (using node #{@nodes[0]})"
 show_nodes if !opt[:quiet]
 check_config_consistency
 check_open_slots
 check_slots_coverage
 end
 
 def show_cluster_info
 masters = 0
 keys = 0
 @nodes.each{|n|
  if n.has_flag"master")
  puts "#{n} (#{n.info[:name][0...8]}...) -> #{n.r.dbsize} keys | #{n.slots.length} slots | "+
   "#{n.info[:replicas].length} slaves."
  masters += 1
  keys += n.r.dbsize
  end
 }
 xputs "[OK] #{keys} keys in #{masters} masters."
 keys_per_slot = sprintf("%.2f",keys/16384.0)
 puts "#{keys_per_slot} keys per slot on average."
 end
 
 # Merge slots of every known node. If the resulting slots are equal
 # to ClusterHashSlots, then all slots are served.
 def covered_slots
 slots = {}
 @nodes.each{|n|
  slots = slots.merge(n.slots)
 }
 slots
 end
 
 def check_slots_coverage
 xputs "> Check slots coverage..."
 slots = covered_slots
 if slots.length == ClusterHashSlots
  xputs "[OK] All #{ClusterHashSlots} slots covered."
 else
  cluster_error   "[ERR] Not all #{ClusterHashSlots} slots are covered by nodes."
  fix_slots_coverage if @fix
 end
 end
 
 def check_open_slots
 xputs "> Check for open slots..."
 open_slots = []
 @nodes.each{|n|
  if n.info[:migrating].size > 0
  cluster_error    "[WARNING] Node #{n} has slots in migrating state (#{n.info[:migrating].keys.join(",")})."
  open_slots += n.info[:migrating].keys
  end
  if n.info[:importing].size > 0
  cluster_error    "[WARNING] Node #{n} has slots in importing state (#{n.info[:importing].keys.join(",")})."
  open_slots += n.info[:importing].keys
  end
 }
 open_slots.uniq!
 if open_slots.length > 0
  xputs "[WARNING] The following slots are open: #{open_slots.join(",")}"
 end
 if @fix
  open_slots.each{|slot| fix_open_slot slot}
 end
 end
 
 def nodes_with_keys_in_slot(slot)
 nodes = []
 @nodes.each{|n|
  next if n.has_flag"slave")
  nodes << n if n.r.cluster("getkeysinslot",slot,1).length > 0
 }
 nodes
 end
 
 def fix_slots_coverage
 not_covered = (0...ClusterHashSlots).to_a - covered_slots.keys
 xputs "> Fixing slots coverage..."
 xputs "List of not covered slots: " + not_covered.join(",")
 
 # For every slot, take action depending on the actual condition:
 # 1) No node has keys for this slot.
 # 2) A single node has keys for this slot.
 # 3) Multiple nodes have keys for this slot.
 slots = {}
 not_covered.each{|slot|
  nodes = nodes_with_keys_in_slot(slot)
  slots[slot] = nodes
  xputs "Slot #{slot} has keys in #{nodes.length} nodes: #{nodes.join(", ")}"
 }
 
 none = slots.select {|k,v| v.length == 0}
 single = slots.select {|k,v| v.length == 1}
 multi = slots.select {|k,v| v.length > 1}
 
 # Handle case "1": keys in no node.
 if none.length > 0
  xputs "The folowing uncovered slots have no keys across the cluster:"
  xputs none.keys.join(",")
  yes_or_die "Fix these slots by covering with a random node"
  none.each{|slot,nodes|
  node = @nodes.sample
  xputs "> Covering slot #{slot} with #{node}"
  node.r.cluster("addslots",slot)
  }
 end
 
 # Handle case "2": keys only in one node.
 if single.length > 0
  xputs "The folowing uncovered slots have keys in just one node:"
  puts single.keys.join(",")
  yes_or_die "Fix these slots by covering with those nodes"
  single.each{|slot,nodes|
  xputs "> Covering slot #{slot} with #{nodes[0]}"
  nodes[0].r.cluster("addslots",slot)
  }
 end
 
 # Handle case "3": keys in multiple nodes.
 if multi.length > 0
  xputs "The folowing uncovered slots have keys in multiple nodes:"
  xputs multi.keys.join(",")
  yes_or_die "Fix these slots by moving keys into a single node"
  multi.each{|slot,nodes|
  target = get_node_with_most_keys_in_slot(nodes,slot)
  xputs "> Covering slot #{slot} moving keys to #{target}"
 
  target.r.cluster('addslots',slot)
  target.r.cluster('setslot',slot,'stable')
  nodes.each{|src|
   next if src == target
   # Set the source node in 'importing' state (even if we will
   # actually migrate keys away) in order to avoid receiving
   # redirections for MIGRATE.
   src.r.cluster('setslot',slot,'importing',target.info[:name])
   move_slot(src,target,slot,:dots=>true,:fix=>true,:cold=>true)
   src.r.cluster('setslot',slot,'stable')
  }
  }
 end
 end
 
 # Return the owner of the specified slot
 def get_slot_owners(slot)
 owners = []
 @nodes.each{|n|
  next if n.has_flag"slave")
  n.slots.each{|s,_|
  owners << n if s == slot
  }
 }
 owners
 end
 
 # Return the node, among 'nodes' with the greatest number of keys
 # in the specified slot.
 def get_node_with_most_keys_in_slot(nodes,slot)
 best = nil
 best_numkeys = 0
 @nodes.each{|n|
  next if n.has_flag"slave")
  numkeys = n.r.cluster("countkeysinslot",slot)
  if numkeys > best_numkeys || best == nil
  best = n
  best_numkeys = numkeys
  end
 }
 return best
 end
 
 # Slot 'slot' was found to be in importing or migrating state in one or
 # more nodes. This function fixes this condition by migrating keys where
 # it seems more sensible.
 def fix_open_slot(slot)
 puts "> Fixing open slot #{slot}"
 
 # Try to obtain the current slot owner, according to the current
 # nodes configuration.
 owners = get_slot_owners(slot)
 owner = owners[0] if owners.length == 1
 
 migrating = []
 importing = []
 @nodes.each{|n|
  next if n.has_flag"slave"
  if n.info[:migrating][slot]
  migrating << n
  elsif n.info[:importing][slot]
  importing << n
  elsif n.r.cluster("countkeysinslot",slot) > 0 && n != owner
  xputs "*** Found keys about slot #{slot} in node #{n}!"
  importing << n
  end
 }
 puts "Set as migrating in: #{migrating.join(",")}"
 puts "Set as importing in: #{importing.join(",")}"
 
 # If there is no slot owner, set as owner the slot with the biggest
 # number of keys, among the set of migrating / importing nodes.
 if !owner
  xputs "> Nobody claims ownership, selecting an owner..."
  owner = get_node_with_most_keys_in_slot(@nodes,slot)
 
  # If we still don't have an owner, we can't fix it.
  if !owner
  xputs "[ERR] Can't select a slot owner. Impossible to fix."
  exit 1
  end
 
  # Use ADDSLOTS to assign the slot.
  puts "*** Configuring #{owner} as the slot owner"
  owner.r.cluster("setslot",slot,"stable")
  owner.r.cluster("addslots",slot)
  # Make sure this information will propagate. Not strictly needed
  # since there is no past owner, so all the other nodes will accept
  # whatever epoch this node will claim the slot with.
  owner.r.cluster("bumpepoch")
 
  # Remove the owner from the list of migrating/importing
  # nodes.
  migrating.delete(owner)
  importing.delete(owner)
 end
 
 # If there are multiple owners of the slot, we need to fix it
 # so that a single node is the owner and all the other nodes
 # are in importing state. Later the fix can be handled by one
 # of the base cases above.
 #
 # Note that this case also covers multiple nodes having the slot
 # in migrating state, since migrating is a valid state only for
 # slot owners.
 if owners.length > 1
  owner = get_node_with_most_keys_in_slot(owners,slot)
  owners.each{|n|
  next if n == owner
  n.r.cluster('delslots',slot)
  n.r.cluster('setslot',slot,'importing',owner.info[:name])
  importing.delete(n) # Avoid duplciates
  importing << n
  }
  owner.r.cluster('bumpepoch')
 end
 
 # Case 1: The slot is in migrating state in one slot, and in
 #  importing state in 1 slot. That's trivial to address.
 if migrating.length == 1 && importing.length == 1
  move_slot(migrating[0],importing[0],slot,:dots=>true,:fix=>true)
 # Case 2: There are multiple nodes that claim the slot as importing,
 # they probably got keys about the slot after a restart so opened
 # the slot. In this case we just move all the keys to the owner
 # according to the configuration.
 elsif migrating.length == 0 && importing.length > 0
  xputs "> Moving all the #{slot} slot keys to its owner #{owner}"
  importing.each {|node|
  next if node == owner
  move_slot(node,owner,slot,:dots=>true,:fix=>true,:cold=>true)
  xputs "> Setting #{slot} as STABLE in #{node}"
  node.r.cluster("setslot",slot,"stable")
  }
 # Case 3: There are no slots claiming to be in importing state, but
 # there is a migrating node that actually don't have any key. We
 # can just close the slot, probably a reshard interrupted in the middle.
 elsif importing.length == 0 && migrating.length == 1 &&
  migrating[0].r.cluster("getkeysinslot",slot,10).length == 0
  migrating[0].r.cluster("setslot",slot,"stable")
 else
  xputs "[ERR] Sorry, Redis-trib can't fix this slot yet (work in progress). Slot is set as migrating in #{migrating.join(",")}, as importing in #{importing.join(",")}, owner is #{owner}"
 end
 end
 
 # Check if all the nodes agree about the cluster configuration
 def check_config_consistency
 if !is_config_consistent"[ERR] Nodes don't agree about configuration!"
 else
  xputs "[OK] All nodes agree about slots configuration."
 end
 end
 
 def is_config_consistent"Waiting for the cluster to join"
 while !is_config_consistent"."
  STDOUT.flush
  sleep 1
 end
 print "\n"
 end
 
 def alloc_slots
 nodes_count = @nodes.length
 masters_count = @nodes.length / (@replicas+1)
 masters = []
 
 # The first step is to split instances by IP. This is useful as
 # we'll try to allocate master nodes in different physical machines
 # (as much as possible) and to allocate slaves of a given master in
 # different physical machines as well.
 #
 # This code assumes just that if the IP is different, than it is more
 # likely that the instance is running in a different physical host
 # or at least a different virtual machine.
 ips = {}
 @nodes.each{|n|
  ips[n.info[:host]] = [] if !ips[n.info[:host]]
  ips[n.info[:host]] << n
 }
 
 # Select master instances
 puts "Using #{masters_count} masters:"
 interleaved = []
 stop = false
 while not stop do
  # Take one node from each IP until we run out of nodes
  # across every IP.
  ips.each do |ip,nodes|
  if nodes.empty"Requesting total of #{@replicas} replicas "      "(#{assigned_replicas} replicas assigned "      "so far with #{nodes_count} total remaining)."
   elsif assign == :unused
    puts "Assigning extra instance to replication "      "role too (#{nodes_count} remaining)."
   end
   end
 
   # Return the first node not matching our current master
   node = interleaved.find{|n| n.info[:host] != m.info[:host]}
 
   # If we found a node, use it as a best-first match.
   # Otherwise, we didn't find a node on a different IP, so we
   # go ahead and use a same-IP replica.
   if node
   slave = node
   interleaved.delete node
   else
   slave = interleaved.shift
   end
   slave.set_as_replica(m.info[:name])
   nodes_count -= 1
   assigned_replicas += 1
   puts "Adding replica #{slave} to #{m}"
 
   # If we are in the "assign extra nodes" loop,
   # we want to assign one extra replica to each
   # master before repeating masters.
   # This break lets us assign extra replicas to masters
   # in a round-robin way.
   break if assign == :unused
  end
  end
 end
 end
 
 def flush_nodes_config
 @nodes.each{|n|
  n.flush_node_config
 }
 end
 
 def show_nodes
 @nodes.each{|n|
  xputs n.info_string
 }
 end
 
 # Redis Cluster config epoch collision resolution code is able to eventually
 # set a different epoch to each node after a new cluster is created, but
 # it is slow compared to assign a progressive config epoch to each node
 # before joining the cluster. However we do just a best-effort try here
 # since if we fail is not a problem.
 def assign_config_epoch
 config_epoch = 1
 @nodes.each{|n|
  begin
  n.r.cluster("set-config-epoch",config_epoch)
  rescue
  end
  config_epoch += 1
 }
 end
 
 def join_cluster
 # We use a brute force approach to make sure the node will meet
 # each other, that is, sending CLUSTER MEET messages to all the nodes
 # about the very same node.
 # Thanks to gossip this information should propagate across all the
 # cluster in a matter of seconds.
 first = false
 @nodes.each{|n|
  if !first then first = n.info; next; end # Skip the first node
  n.r.cluster("meet",first[:host],first[:port])
 }
 end
 
 def yes_or_die(msg)
 print "#{msg} (type 'yes' to accept): "
 STDOUT.flush
 if !(STDIN.gets.chomp.downcase == "yes")
  xputs "*** Aborting..."
  exit 1
 end
 end
 
 def load_cluster_info_from_node(nodeaddr)
 node = ClusterNode.new(nodeaddr)
 node.connect(:abort => true)
 node.assert_cluster
 node.load_info(:getfriends => true)
 add_node(node)
 node.friends.each{|f|
  next if f[:flags].index("noaddr") ||
   f[:flags].index("disconnected") ||
   f[:flags].index("fail")
  fnode = ClusterNode.new(f[:addr])
  fnode.connect()
  next if !fnode.r
  begin
  fnode.load_info()
  add_node(fnode)
  rescue => e
  xputs "[ERR] Unable to load info for node #{fnode}"
  end
 }
 populate_nodes_replicas_info
 end
 
 # This function is called by load_cluster_info_from_node in order to
 # add additional information to every node as a list of replicas.
 def populate_nodes_replicas_info
 # Start adding the new field to every node.
 @nodes.each{|n|
  n.info[:replicas] = []
 }
 
 # Populate the replicas field using the replicate field of slave
 # nodes.
 @nodes.each{|n|
  if n.info[:replicate]
  master = get_node_by_name(n.info[:replicate])
  if !master
   xputs "*** WARNING: #{n} claims to be slave of unknown node ID #{n.info[:replicate]}."
  else
   master.info[:replicas] << n
  end
  end
 }
 end
 
 # Given a list of source nodes return a "resharding plan"
 # with what slots to move in order to move "numslots" slots to another
 # instance.
 def compute_reshard_table(sources,numslots)
 moved = []
 # Sort from bigger to smaller instance, for two reasons:
 # 1) If we take less slots than instances it is better to start
 # getting from the biggest instances.
 # 2) We take one slot more from the first instance in the case of not
 # perfect divisibility. Like we have 3 nodes and need to get 10
 # slots, we take 4 from the first, and 3 from the rest. So the
 # biggest is always the first.
 sources = sources.sort{|a,b| b.slots.length <=> a.slots.length}
 source_tot_slots = sources.inject(0) {|sum,source|
  sum+source.slots.length
 }
 sources.each_with_index{|s,i|
  # Every node will provide a number of slots proportional to the
  # slots it has assigned.
  n = (numslots.to_f/source_tot_slots*s.slots.length)
  if i == 0
  n = n.ceil
  else
  n = n.floor
  end
  s.slots.keys.sort[(0...n)].each{|slot|
  if moved.length < numslots
   moved << {:source => s, :slot => slot}
  end
  }
 }
 return moved
 end
 
 def show_reshard_table(table)
 table.each{|e|
  puts " Moving slot #{e[:slot]} from #{e[:source].info[:name]}"
 }
 end
 
 # Move slots between source and target nodes using MIGRATE.
 #
 # Options:
 # :verbose -- Print a dot for every moved key.
 # :fix -- We are moving in the context of a fix. Use REPLACE.
 # :cold -- Move keys without opening slots / reconfiguring the nodes.
 # :update -- Update nodes.info[:slots] for source/target nodes.
 # :quiet -- Don't print info messages.
 def move_slot(source,target,slot,o={})
 o = {:pipeline => MigrateDefaultPipeline}.merge(o)
 
 # We start marking the slot as importing in the destination node,
 # and the slot as migrating in the target host. Note that the order of
 # the operations is important, as otherwise a client may be redirected
 # to the target node that does not yet know it is importing this slot.
 if !o[:quiet]
  print "Moving slot #{slot} from #{source} to #{target}: "
  STDOUT.flush
 end
 
 if !o[:cold]
  target.r.cluster("setslot",slot,"importing",source.info[:name])
  source.r.cluster("setslot",slot,"migrating",target.info[:name])
 end
 # Migrate all the keys from source to target using the MIGRATE command
 while true
  keys = source.r.cluster("getkeysinslot",slot,o[:pipeline])
  break if keys.length == 0
  begin
  source.r.client.call(["migrate",target.info[:host],target.info[:port],"",0,@timeout,:keys,*keys])
  rescue => e
  if o[:fix] && e.to_s =~ /BUSYKEY/
   xputs "*** Target key exists. Replacing it for FIX."
   source.r.client.call(["migrate",target.info[:host],target.info[:port],"",0,@timeout,:replace,:keys,*keys])
  else
   puts ""
   xputs "[ERR] Calling MIGRATE: #{e}"
   exit 1
  end
  end
  print "."*keys.length if o[:dots]
  STDOUT.flush
 end
 
 puts if !o[:quiet]
 # Set the new node as the owner of the slot in all the known nodes.
 if !o[:cold]
  @nodes.each{|n|
  next if n.has_flag"slave")
  n.r.cluster("setslot",slot,"node",target.info[:name])
  }
 end
 
 # Update the node logical config
 if o[:update] then
  source.info[:slots].delete(slot)
  target.info[:slots][slot] = true
 end
 end
 
 # redis-trib subcommands implementations.
 
 def check_cluster_cmd(argv,opt)
 load_cluster_info_from_node(argv[0])
 check_cluster
 end
 
 def info_cluster_cmd(argv,opt)
 load_cluster_info_from_node(argv[0])
 show_cluster_info
 end
 
 def rebalance_cluster_cmd(argv,opt)
 opt = {
  'pipeline' => MigrateDefaultPipeline,
  'threshold' => RebalanceDefaultThreshold
 }.merge(opt)
 
 # Load nodes info before parsing options, otherwise we can't
 # handle --weight.
 load_cluster_info_from_node(argv[0])
 
 # Options parsing
 threshold = opt['threshold'].to_i
 autoweights = opt['auto-weights']
 weights = {}
 opt['weight'].each{|w|
  fields = w.split("=")
  node = get_node_by_abbreviated_name(fields[0])
  if !node || !node.has_flag"master")
  puts "*** No such master node #{fields[0]}"
  exit 1
  end
  weights[node.info[:name]] = fields[1].to_f
 } if opt['weight']
 useempty = opt['use-empty-masters']
 
 # Assign a weight to each node, and compute the total cluster weight.
 total_weight = 0
 nodes_involved = 0
 @nodes.each{|n|
  if n.has_flag"master")
  next if !useempty && n.slots.length == 0
  n.info[:w] = weights[n.info[:name]] "*** Please fix your cluster problems before rebalancing"
  exit 1
 end
 
 # Calculate the slots balance for each node. It's the number of
 # slots the node should lose (if positive) or gain (if negative)
 # in order to be balanced.
 threshold = opt['threshold'].to_f
 threshold_reached = false
 @nodes.each{|n|
  if n.has_flag"master")
  next if !n.info[:w]
  expected = ((ClusterHashSlots.to_f / total_weight) *
    n.info[:w]).to_i
  n.info[:balance] = n.slots.length - expected
  # Compute the percentage of difference between the
  # expected number of slots and the real one, to see
  # if it's over the threshold specified by the user.
  over_threshold = false
  if threshold > 0
   if n.slots.length > 0
   err_perc = (100-(100.0*expected/n.slots.length)).abs
   over_threshold = true if err_perc > threshold
   elsif expected > 0
   over_threshold = true
   end
  end
  threshold_reached = true if over_threshold
  end
 }
 if !threshold_reached
  xputs "*** No rebalancing needed! All nodes are within the #{threshold}% threshold."
  return
 end
 
 # Only consider nodes we want to change
 sn = @nodes.select{|n|
  n.has_flag"master") && n.info[:w]
 }
 
 # Because of rounding, it is possible that the balance of all nodes
 # summed does not give 0. Make sure that nodes that have to provide
 # slots are always matched by nodes receiving slots.
 total_balance = sn.map{|x| x.info[:balance]}.reduce{|a,b| a+b}
 while total_balance > 0
  sn.each{|n|
  if n.info[:balance] < 0 && total_balance > 0
   n.info[:balance] -= 1
   total_balance -= 1
  end
  }
 end
 
 # Sort nodes by their slots balance.
 sn = sn.sort{|a,b|
  a.info[:balance] <=> b.info[:balance]
 }
 
 xputs "> Rebalancing across #{nodes_involved} nodes. Total weight = #{total_weight}"
 
 if $verbose
  sn.each{|n|
  puts "#{n} balance is #{n.info[:balance]} slots"
  }
 end
 
 # Now we have at the start of the 'sn' array nodes that should get
 # slots, at the end nodes that must give slots.
 # We take two indexes, one at the start, and one at the end,
 # incrementing or decrementing the indexes accordingly til we
 # find nodes that need to get/provide slots.
 dst_idx = 0
 src_idx = sn.length - 1
 
 while dst_idx < src_idx
  dst = sn[dst_idx]
  src = sn[src_idx]
  numslots = [dst.info[:balance],src.info[:balance]].map{|n|
  n.abs
  }.min
 
  if numslots > 0
  puts "Moving #{numslots} slots from #{src} to #{dst}"
 
  # Actaully move the slots.
  reshard_table = compute_reshard_table([src],numslots)
  if reshard_table.length != numslots
   xputs "*** Assertio failed: Reshard table != number of slots"
   exit 1
  end
  if opt['simulate']
   print "#"*reshard_table.length
  else
   reshard_table.each{|e|
   move_slot(e[:source],dst,e[:slot],
    :quiet=>true,
    :dots=>false,
    :update=>true,
    :pipeline=>opt['pipeline'])
   print "#"
   STDOUT.flush
   }
  end
  puts
  end
 
  # Update nodes balance.
  dst.info[:balance] += numslots
  src.info[:balance] -= numslots
  dst_idx += 1 if dst.info[:balance] == 0
  src_idx -= 1 if src.info[:balance] == 0
 end
 end
 
 def fix_cluster_cmd(argv,opt)
 @fix = true
 @timeout = opt['timeout'].to_i if opt['timeout']
 
 load_cluster_info_from_node(argv[0])
 check_cluster
 end
 
 def reshard_cluster_cmd(argv,opt)
 opt = {'pipeline' => MigrateDefaultPipeline}.merge(opt)
 
 load_cluster_info_from_node(argv[0])
 check_cluster
 if @errors.length != 0
  puts "*** Please fix your cluster problems before resharding"
  exit 1
 end
 
 @timeout = opt['timeout'].to_i if opt['timeout'].to_i
 
 # Get number of slots
 if opt['slots']
  numslots = opt['slots'].to_i
 else
  numslots = 0
  while numslots <= 0 or numslots > ClusterHashSlots
  print "How many slots do you want to move (from 1 to #{ClusterHashSlots})"
  numslots = STDIN.gets.to_i
  end
 end
 
 # Get the target instance
 if opt['to']
  target = get_node_by_name(opt['to'])
  if !target || target.has_flag"slave")
  xputs "*** The specified node is not known or not a master, please retry."
  exit 1
  end
 else
  target = nil
  while not target
  print "What is the receiving node ID"
  target = get_node_by_name(STDIN.gets.chop)
  if !target || target.has_flag"slave")
   xputs "*** The specified node is not known or not a master, please retry."
   target = nil
  end
  end
 end
 
 # Get the source instances
 sources = []
 if opt['from']
  opt['from'].split(',').each{|node_id|
  if node_id == "all"
   sources = "all"
   break
  end
  src = get_node_by_name(node_id)
  if !src || src.has_flag"slave")
   xputs "*** The specified node is not known or is not a master, please retry."
   exit 1
  end
  sources << src
  }
 else
  xputs "Please enter all the source node IDs."
  xputs " Type 'all' to use all the nodes as source nodes for the hash slots."
  xputs " Type 'done' once you entered all the source nodes IDs."
  while true
  print "Source node ##{sources.length+1}:"
  line = STDIN.gets.chop
  src = get_node_by_name(line)
  if line == "done"
   break
  elsif line == "all"
   sources = "all"
   break
  elsif !src || src.has_flag"slave")
   xputs "*** The specified node is not known or is not a master, please retry."
  elsif src.info[:name] == target.info[:name]
   xputs "*** It is not possible to use the target node as source node."
  else
   sources << src
  end
  end
 end
 
 if sources.length == 0
  puts "*** No source nodes given, operation aborted"
  exit 1
 end
 
 # Handle soures == all.
 if sources == "all"
  sources = []
  @nodes.each{|n|
  next if n.info[:name] == target.info[:name]
  next if n.has_flag"slave")
  sources << n
  }
 end
 
 # Check if the destination node is the same of any source nodes.
 if sources.index(target)
  xputs "*** Target node is also listed among the source nodes!"
  exit 1
 end
 
 puts "\nReady to move #{numslots} slots."
 puts " Source nodes:"
 sources.each{|s| puts " "+s.info_string}
 puts " Destination node:"
 puts " #{target.info_string}"
 reshard_table = compute_reshard_table(sources,numslots)
 puts " Resharding plan:"
 show_reshard_table(reshard_table)
 if !opt['yes']
  print "Do you want to proceed with the proposed reshard plan (yes/no)"
  yesno = STDIN.gets.chop
  exit(1) if (yesno != "yes")
 end
 reshard_table.each{|e|
  move_slot(e[:source],target,e[:slot],
  :dots=>true,
  :pipeline=>opt['pipeline'])
 }
 end
 
 # This is an helper function for create_cluster_cmd that verifies if
 # the number of nodes and the specified replicas have a valid configuration
 # where there are at least three master nodes and enough replicas per node.
 def check_create_parameters
 masters = @nodes.length/(@replicas+1)
 if masters < 3
  puts "*** ERROR: Invalid configuration for cluster creation."
  puts "*** Redis Cluster requires at least 3 master nodes."
  puts "*** This is not possible with #{@nodes.length} nodes and #{@replicas} replicas per node."
  puts "*** At least #{3*(@replicas+1)} nodes are required."
  exit 1
 end
 end
 
 def create_cluster_cmd(argv,opt)
 opt = {'replicas' => 0}.merge(opt)
 @replicas = opt['replicas'].to_i
 
 xputs "> Creating cluster"
 argv[0..-1].each{|n|
  node = ClusterNode.new(n)
  node.connect(:abort => true)
  node.assert_cluster
  node.load_info
  node.assert_empty
  add_node(node)
 }
 check_create_parameters
 xputs "> Performing hash slots allocation on #{@nodes.length} nodes..."
 alloc_slots
 show_nodes
 yes_or_die "Can I set the above configuration"
 flush_nodes_config
 xputs "> Nodes configuration updated"
 xputs "> Assign a different config epoch to each node"
 assign_config_epoch
 xputs "> Sending CLUSTER MEET messages to join the cluster"
 join_cluster
 # Give one second for the join to start, in order to avoid that
 # wait_cluster_join will find all the nodes agree about the config as
 # they are still empty with unassigned slots.
 sleep 1
 wait_cluster_join
 flush_nodes_config # Useful for the replicas
 check_cluster
 end
 
 def addnode_cluster_cmd(argv,opt)
 xputs "> Adding node #{argv[0]} to cluster #{argv[1]}"
 
 # Check the existing cluster
 load_cluster_info_from_node(argv[1])
 check_cluster
 
 # If --master-id was specified, try to resolve it now so that we
 # abort before starting with the node configuration.
 if opt['slave']
  if opt['master-id']
  master = get_node_by_name(opt['master-id'])
  if !master
   xputs "[ERR] No such master ID #{opt['master-id']}"
  end
  else
  master = get_master_with_least_replicas
  xputs "Automatically selected master #{master}"
  end
 end
 
 # Add the new node
 new = ClusterNode.new(argv[0])
 new.connect(:abort => true)
 new.assert_cluster
 new.load_info
 new.assert_empty
 first = @nodes.first.info
 add_node(new)
 
 # Send CLUSTER MEET command to the new node
 xputs "> Send CLUSTER MEET to node #{new} to make it join the cluster."
 new.r.cluster("meet",first[:host],first[:port])
 
 # Additional configuration is needed if the node is added as
 # a slave.
 if opt['slave']
  wait_cluster_join
  xputs "> Configure node as replica of #{master}."
  new.r.cluster("replicate",master.info[:name])
 end
 xputs "[OK] New node added correctly."
 end
 
 def delnode_cluster_cmd(argv,opt)
 id = argv[1].downcase
 xputs "> Removing node #{id} from cluster #{argv[0]}"
 
 # Load cluster information
 load_cluster_info_from_node(argv[0])
 
 # Check if the node exists and is not empty
 node = get_node_by_name(id)
 
 if !node
  xputs "[ERR] No such node ID #{id}"
  exit 1
 end
 
 if node.slots.length != 0
  xputs "[ERR] Node #{node} is not empty! Reshard data away and try again."
  exit 1
 end
 
 # Send CLUSTER FORGET to all the nodes but the node to remove
 xputs "> Sending CLUSTER FORGET messages to the cluster..."
 @nodes.each{|n|
  next if n == node
  if n.info[:replicate] && n.info[:replicate].downcase == id
  # Reconfigure the slave to replicate with some other node
  master = get_master_with_least_replicas
  xputs "> #{n} as replica of #{master}"
  n.r.cluster("replicate",master.info[:name])
  end
  n.r.cluster("forget",argv[1])
 }
 
 # Finally shutdown the node
 xputs "> SHUTDOWN the node."
 node.r.shutdown
 end
 
 def set_timeout_cluster_cmd(argv,opt)
 timeout = argv[1].to_i
 if timeout < 100
  puts "Setting a node timeout of less than 100 milliseconds is a bad idea."
  exit 1
 end
 
 # Load cluster information
 load_cluster_info_from_node(argv[0])
 ok_count = 0
 err_count = 0
 
 # Send CLUSTER FORGET to all the nodes but the node to remove
 xputs "> Reconfiguring node timeout in every cluster node..."
 @nodes.each{|n|
  begin
  n.r.config("set","cluster-node-timeout",timeout)
  n.r.config("rewrite")
  ok_count += 1
  xputs "*** New timeout set for #{n}"
  rescue => e
  puts "ERR setting node-timeot for #{n}: #{e}"
  err_count += 1
  end
 }
 xputs "> New node timeout set. #{ok_count} OK, #{err_count} ERR."
 end
 
 def call_cluster_cmd(argv,opt)
 cmd = argv[1..-1]
 cmd[0] = cmd[0].upcase
 
 # Load cluster information
 load_cluster_info_from_node(argv[0])
 xputs "> Calling #{cmd.join(" ")}"
 @nodes.each{|n|
  begin
  res = n.r.send(*cmd)
  puts "#{n}: #{res}"
  rescue => e
  puts "#{n}: #{e}"
  end
 }
 end
 
 def import_cluster_cmd(argv,opt)
 source_addr = opt['from']
 xputs "> Importing data from #{source_addr} to cluster #{argv[1]}"
 use_copy = opt['copy']
 use_replace = opt['replace']
  
 # Check the existing cluster.
 load_cluster_info_from_node(argv[0])
 check_cluster
 
 # Connect to the source node.
 xputs "> Connecting to the source Redis instance"
 src_host,src_port = source_addr.split(":")
 source = Redis.new(:host =>src_host, :port =>src_port)
 if source.info['cluster_enabled'].to_i == 1
  xputs "[ERR] The source node should not be a cluster node."
 end
 xputs "*** Importing #{source.dbsize} keys from DB 0"
 
 # Build a slot -> node map
 slots = {}
 @nodes.each{|n|
  n.slots.each{|s,_|
  slots[s] = n
  }
 }
 
 # Use SCAN to iterate over the keys, migrating to the
 # right node as needed.
 cursor = nil
 while cursor != 0
  cursor,keys = source.scan(cursor, :count => 1000)
  cursor = cursor.to_i
  keys.each{|k|
  # Migrate keys using the MIGRATE command.
  slot = key_to_slot(k)
  target = slots[slot]
  print "Migrating #{k} to #{target}: "
  STDOUT.flush
  begin
   cmd = ["migrate",target.info[:host],target.info[:port],k,0,@timeout]
   cmd << :copy if use_copy
   cmd << :replace if use_replace
   source.client.call(cmd)
  rescue => e
   puts e
  else
   puts "OK"
  end
  }
 end
 end
 
 def help_cluster_cmd(argv,opt)
 show_help
 exit 0
 end
 
 # Parse the options for the specific command "cmd".
 # Returns an hash populate with option => value pairs, and the index of
 # the first non-option argument in ARGV.
 def parse_options(cmd)
 idx = 1 ; # Current index into ARGV
 options={}
 while idx < ARGV.length && ARGV[idx][0..1] == '--'
  if ARGV[idx][0..1] == "--"
  option = ARGV[idx][2..-1]
  idx += 1
 
  # --verbose is a global option
  if option == "verbose"
   $verbose = true
   next
  end
 
  if ALLOWED_OPTIONS[cmd] == nil || ALLOWED_OPTIONS[cmd][option] == nil
   puts "Unknown option '#{option}' for command '#{cmd}'"
   exit 1
  end
  if ALLOWED_OPTIONS[cmd][option] != false
   value = ARGV[idx]
   idx += 1
  else
   value = true
  end
 
  # If the option is set to [], it's a multiple arguments
  # option. We just queue every new value into an array.
  if ALLOWED_OPTIONS[cmd][option] == []
   options[option] = [] if !options[option]
   options[option] << value
  else
   options[option] = value
  end
  else
  # Remaining arguments are not options.
  break
  end
 end
 
 # Enforce mandatory options
 if ALLOWED_OPTIONS[cmd]
  ALLOWED_OPTIONS[cmd].each {|option,val|
  if !options[option] && val == :required
   puts "Option '--#{option}' is required "+     "for subcommand '#{cmd}'"
   exit 1
  end
  }
 end
 return options,idx
 end
end
 
#################################################################################
# Libraries
#
# We try to don't depend on external libs since this is a critical part
# of Redis Cluster.
#################################################################################
 
# This is the CRC16 algorithm used by Redis Cluster to hash keys.
# Implementation according to CCITT standards.
#
# This is actually the XMODEM CRC 16 algorithm, using the
# following parameters:
#
# Name   : "XMODEM", also known as "ZMODEM", "CRC-16/ACORN"
# Width   : 16 bit
# Poly   : 1021 (That is actually x^16 + x^12 + x^5 + 1)
# Initialization  : 0000
# Reflect Input byte  : False
# Reflect Output CRC  : False
# Xor constant to output CRC : 0000
# Output for "123456789" : 31C3
 
module RedisClusterCRC16
 def RedisClusterCRC16.crc16(bytes)
 crc = 0
 bytes.each_byte{|b|
  crc = ((crc<<8) & 0xffff) ^ XMODEMCRC16Lookup[((crc8)^b) & 0xff]
 }
 crc
 end
 
private
 XMODEMCRC16Lookup = [
 0x0000,0x1021,0x2042,0x3063,0x4084,0x50a5,0x60c6,0x70e7,
 0x8108,0x9129,0xa14a,0xb16b,0xc18c,0xd1ad,0xe1ce,0xf1ef,
 0x1231,0x0210,0x3273,0x2252,0x52b5,0x4294,0x72f7,0x62d6,
 0x9339,0x8318,0xb37b,0xa35a,0xd3bd,0xc39c,0xf3ff,0xe3de,
 0x2462,0x3443,0x0420,0x1401,0x64e6,0x74c7,0x44a4,0x5485,
 0xa56a,0xb54b,0x8528,0x9509,0xe5ee,0xf5cf,0xc5ac,0xd58d,
 0x3653,0x2672,0x1611,0x0630,0x76d7,0x66f6,0x5695,0x46b4,
 0xb75b,0xa77a,0x9719,0x8738,0xf7df,0xe7fe,0xd79d,0xc7bc,
 0x48c4,0x58e5,0x6886,0x78a7,0x0840,0x1861,0x2802,0x3823,
 0xc9cc,0xd9ed,0xe98e,0xf9af,0x8948,0x9969,0xa90a,0xb92b,
 0x5af5,0x4ad4,0x7ab7,0x6a96,0x1a71,0x0a50,0x3a33,0x2a12,
 0xdbfd,0xcbdc,0xfbbf,0xeb9e,0x9b79,0x8b58,0xbb3b,0xab1a,
 0x6ca6,0x7c87,0x4ce4,0x5cc5,0x2c22,0x3c03,0x0c60,0x1c41,
 0xedae,0xfd8f,0xcdec,0xddcd,0xad2a,0xbd0b,0x8d68,0x9d49,
 0x7e97,0x6eb6,0x5ed5,0x4ef4,0x3e13,0x2e32,0x1e51,0x0e70,
 0xff9f,0xefbe,0xdfdd,0xcffc,0xbf1b,0xaf3a,0x9f59,0x8f78,
 0x9188,0x81a9,0xb1ca,0xa1eb,0xd10c,0xc12d,0xf14e,0xe16f,
 0x1080,0x00a1,0x30c2,0x20e3,0x5004,0x4025,0x7046,0x6067,
 0x83b9,0x9398,0xa3fb,0xb3da,0xc33d,0xd31c,0xe37f,0xf35e,
 0x02b1,0x1290,0x22f3,0x32d2,0x4235,0x5214,0x6277,0x7256,
 0xb5ea,0xa5cb,0x95a8,0x8589,0xf56e,0xe54f,0xd52c,0xc50d,
 0x34e2,0x24c3,0x14a0,0x0481,0x7466,0x6447,0x5424,0x4405,
 0xa7db,0xb7fa,0x8799,0x97b8,0xe75f,0xf77e,0xc71d,0xd73c,
 0x26d3,0x36f2,0x0691,0x16b0,0x6657,0x7676,0x4615,0x5634,
 0xd94c,0xc96d,0xf90e,0xe92f,0x99c8,0x89e9,0xb98a,0xa9ab,
 0x5844,0x4865,0x7806,0x6827,0x18c0,0x08e1,0x3882,0x28a3,
 0xcb7d,0xdb5c,0xeb3f,0xfb1e,0x8bf9,0x9bd8,0xabbb,0xbb9a,
 0x4a75,0x5a54,0x6a37,0x7a16,0x0af1,0x1ad0,0x2ab3,0x3a92,
 0xfd2e,0xed0f,0xdd6c,0xcd4d,0xbdaa,0xad8b,0x9de8,0x8dc9,
 0x7c26,0x6c07,0x5c64,0x4c45,0x3ca2,0x2c83,0x1ce0,0x0cc1,
 0xef1f,0xff3e,0xcf5d,0xdf7c,0xaf9b,0xbfba,0x8fd9,0x9ff8,
 0x6e17,0x7e36,0x4e55,0x5e74,0x2e93,0x3eb2,0x0ed1,0x1ef0
 ]
end
 
# Turn a key name into the corrisponding Redis Cluster slot.
def key_to_slot(key)
 # Only hash what is inside {...} if there is such a pattern in the key.
 # Note that the specification requires the content that is between
 # the first { and the first } after the first {. If we found {} without
 # nothing in the middle, the whole key is hashed as usually.
 s = key.index "{"
 if s
 e = key.index "}",s+1
 if e && e != s+1
  key = key[s+1..e-1]
 end
 end
 RedisClusterCRC16.crc16(key) % 16384
end
 
#################################################################################
# Definition of commands
#################################################################################
 
COMMANDS={
 "create" => ["create_cluster_cmd", -2, "host1:port1 ... hostN:portN"],
 "check" => ["check_cluster_cmd", 2, "host:port"],
 "info" => ["info_cluster_cmd", 2, "host:port"],
 "fix" => ["fix_cluster_cmd", 2, "host:port"],
 "reshard" => ["reshard_cluster_cmd", 2, "host:port"],
 "rebalance" => ["rebalance_cluster_cmd", -2, "host:port"],
 "add-node" => ["addnode_cluster_cmd", 3, "new_host:new_port existing_host:existing_port"],
 "del-node" => ["delnode_cluster_cmd", 3, "host:port node_id"],
 "set-timeout" => ["set_timeout_cluster_cmd", 3, "host:port milliseconds"],
 "call" => ["call_cluster_cmd", -3, "host:port command arg arg .. arg"],
 "import" => ["import_cluster_cmd", 2, "host:port"],
 "help" => ["help_cluster_cmd", 1, "(show this help)"]
}
 
ALLOWED_OPTIONS={
 "create" => {"replicas" => true},
 "add-node" => {"slave" => false, "master-id" => true},
 "import" => {"from" => :required, "copy" => false, "replace" => false},
 "reshard" => {"from" => true, "to" => true, "slots" => true, "yes" => false, "timeout" => true, "pipeline" => true},
 "rebalance" => {"weight" => [], "auto-weights" => false, "use-empty-masters" => false, "timeout" => true, "simulate" => false, "pipeline" => true, "threshold" => true},
 "fix" => {"timeout" => MigrateDefaultTimeout},
}
 
def show_help
 puts "Usage: redis-trib <command> <options> <arguments ...>\n\n"
 COMMANDS.each{|k,v|
 o = ""
 puts " #{k.ljust(15)} #{v[2]}"
 if ALLOWED_OPTIONS[k]
  ALLOWED_OPTIONS[k].each{|optname,has_arg|
  puts "   --#{optname}" + (has_arg " <arg>" : "")
  }
 end
 }
 puts "\nFor check, fix, reshard, del-node, set-timeout you can specify the host and port of any working node in the cluster.\n"
end
 
# Sanity check
if ARGV.length == 0
 show_help
 exit 1
end
 
rt = RedisTrib.new
cmd_spec = COMMANDS[ARGV[0].downcase]
if !cmd_spec
 puts "Unknown redis-trib subcommand '#{ARGV[0]}'"
 exit 1
end
 
# Parse options
cmd_options,first_non_option = rt.parse_options(ARGV[0].downcase)
rt.check_arity(cmd_spec[1],ARGV.length-(first_non_option-1))
 
# Dispatch
rt.send(cmd_spec[0],ARGV[first_non_option..-1],cmd_options)