X-Git-Url: https://git.saurik.com/redis.git/blobdiff_plain/5d8f25da3688a11daa1c2aa59322bb29eb78db16..af0b220756571bc8faf57a0c7b7389dd86a60376:/src/redis-trib.rb

diff --git a/src/redis-trib.rb b/src/redis-trib.rb
index 969cbfc3..1b83e19c 100755
--- a/src/redis-trib.rb
+++ b/src/redis-trib.rb
@@ -1,5 +1,26 @@
 #!/usr/bin/env ruby
 
+# TODO (temporary here, we'll move this into the Github issues once
+#       redis-trib initial implementation is complted).
+#
+# - 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 condiiton 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'
 
@@ -74,7 +95,9 @@ class ClusterNode
         nodes = @r.cluster("nodes").split("\n")
         nodes.each{|n|
             # name addr flags role ping_sent ping_recv link_status slots
-            name,addr,flags,role,ping_sent,ping_recv,link_status,slots = n.split(" ")
+            split = n.split
+            name,addr,flags,role,ping_sent,ping_recv,link_status = split[0..6]
+            slots = split[7..-1]
             info = {
                 :name => name,
                 :addr => addr,
@@ -87,8 +110,10 @@ class ClusterNode
             if info[:flags].index("myself")
                 @info = @info.merge(info)
                 @info[:slots] = {}
-                slots.split(",").each{|s|
-                    if s.index("-")
+                slots.each{|s|
+                    if s[0..0] == '['
+                        # Fixme: for now skipping migration entries
+                    elsif s.index("-")
                         start,stop = s.split("-")
                         self.add_slots((start.to_i)..(stop.to_i))
                     else
@@ -164,7 +189,7 @@ class ClusterNode
             x.count == 1 ? x.first.to_s : "#{x.first}-#{x.last}"
         }.join(",")
 
-        "[#{@info[:cluster_state].upcase}] #{self.to_s.ljust(25)} slots:#{slots}"
+        "[#{@info[:cluster_state].upcase}] #{self.info[:name]} #{self.to_s} slots:#{slots} (#{self.slots.length} slots)"
     end
 
     def info
@@ -197,8 +222,16 @@ class RedisTrib
         @nodes << node
     end
 
+    def get_node_by_name(name)
+        @nodes.each{|n|
+            return n if n.info[:name] == name.downcase
+        }
+        return nil
+    end
+
     def check_cluster
         puts "Performing Cluster Check (using node #{@nodes[0]})"
+        errors = []
         show_nodes
         # Check if all the slots are covered
         slots = {}
@@ -208,8 +241,10 @@ class RedisTrib
         if slots.length == 4096
             puts "[OK] All 4096 slots covered."
         else
-            puts "[ERR] Not all 4096 slots are covered by nodes."
+            errors << "[ERR] Not all 4096 slots are covered by nodes."
+            puts errors[-1]
         end
+        return errors
     end
 
     def alloc_slots
@@ -258,9 +293,7 @@ class RedisTrib
         end
     end
 
-    # redis-trib subcommands implementations
-
-    def check_cluster_cmd
+    def load_cluster_info_from_node(nodeaddr)
         node = ClusterNode.new(ARGV[1])
         node.connect(:abort => true)
         node.assert_cluster
@@ -272,15 +305,149 @@ class RedisTrib
             fnode.load_info()
             add_node(fnode)
         }
+    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 instanes 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
+
+    def move_slot(source,target,slot,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.
+        print "Moving slot #{slot} from #{source.info_string}: "; STDOUT.flush
+        target.r.cluster("setslot",slot,"importing",source.info[:name])
+        source.r.cluster("setslot",slot,"migrating",source.info[:name])
+        # Migrate all the keys from source to target using the MIGRATE command
+        while true
+            keys = source.r.cluster("getkeysinslot",slot,10)
+            break if keys.length == 0
+            keys.each{|key|
+                source.r.migrate(target.info[:host],target.info[:port],key,0,1000)
+                print "." if o[:verbose]
+                STDOUT.flush
+            }
+        end
+        puts
+        # Set the new node as the owner of the slot in all the known nodes.
+        @nodes.each{|n|
+            n.r.cluster("setslot",slot,"node",target.info[:name])
+        }
+    end
+
+    # redis-trib subcommands implementations
+
+    def check_cluster_cmd   
+        load_cluster_info_from_node(ARGV[1])
         check_cluster
     end
 
+    def reshard_cluster_cmd
+        load_cluster_info_from_node(ARGV[1])
+        errors = check_cluster
+        if errors.length != 0
+            puts "Please fix your cluster problems before resharding."
+            exit 1
+        end
+        numslots = 0
+        while numslots <= 0 or numslots > 4096
+            print "How many slots do you want to move (from 1 to 4096)? "
+            numslots = STDIN.gets.to_i
+        end
+        target = nil
+        while not target
+            print "What is the receiving node ID? "
+            target = get_node_by_name(STDIN.gets.chop)
+            if not target
+                puts "The specified node is not known, please retry."
+            end
+        end
+        sources = []
+        puts "Please enter all the source node IDs."
+        puts "  Type 'all' to use all the nodes as source nodes for the hash slots."
+        puts "  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"
+                if sources.length == 0
+                    puts "No source nodes given, operation aborted"
+                    exit 1
+                else
+                    break
+                end
+            elsif line == "all"
+                @nodes.each{|n|
+                    next if n.info[:name] == target.info[:name]
+                    sources << n
+                }
+                break
+            elsif not src
+                puts "The specified node is not known, please retry."
+            elsif src.info[:name] == target.info[:name]
+                puts "It is not possible to use the target node as source node."
+            else
+                sources << src
+            end
+        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)
+        print "Do you want to proceed with the proposed reshard plan (yes/no)? "
+        yesno = STDIN.gets.chop
+        exit(1) if (yesno != "yes")
+        reshard_table.each{|e|
+            move_slot(e[:source],target,e[:slot],:verbose=>true)
+        }
+    end
+
     def create_cluster_cmd
         puts "Creating cluster"
         ARGV[1..-1].each{|n|
             node = ClusterNode.new(n)
             node.connect(:abort => true)
             node.assert_cluster
+            node.load_info
             node.assert_empty
             add_node(node)
         }
@@ -298,7 +465,8 @@ end
 
 COMMANDS={
     "create" => ["create_cluster_cmd", -2, "host1:port host2:port ... hostN:port"],
-    "check" =>  ["check_cluster_cmd", 2, "host:port"]
+    "check" =>  ["check_cluster_cmd", 2, "host:port"],
+    "reshard" =>  ["reshard_cluster_cmd", 2, "host:port"]
 }
 
 # Sanity check