bin/rebalance-cluster-expansion.sh

   1 #!/bin/bash -e
   2
   3 #
   4 #   Copyright 2013 LinkedIn, Inc
   5 #
   6 #  Licensed under the Apache License, Version 2.0 (the "License");
   7 #  you may not use this file except in compliance with the License.
   8 #  You may obtain a copy of the License at
   9 #
  10 #      http://www.apache.org/licenses/LICENSE-2.0
  11 #
  12 #  Unless required by applicable law or agreed to in writing, software
  13 #  distributed under the License is distributed on an "AS IS" BASIS,
  14 #  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15 #  See the License for the specific language governing permissions and
  16 #  limitations under the License.
  17
  18 # This script generates a final cluster.xml and a plan for the cluster expansion.
  19 # The final cluster is placed in output_dir/
  20 # Argument = -c current_cluster -s current_stores -i interim_cluster -o output dir
  21 #
  22 # This script steals partitions from other nodes and assigns them to the new nodes
  23 # in the cluster. While stealing partitions, the script doesn't make an effort to balance
  24 # the cluster. However, because the repartitioner is invoked multiple distinct times,
  25 # the most balanced such expansion is chosen. #To further rebalance the cluster,
  26 # use the rebalance-shuffle script.
  27 #
  28 # In a typical workflow one would chain this script with the rebalance-shuffle script.
  29 # by running this script first and then the shuffle to achieve better balancing.
  30 #
  31 # This script uses getopts which means only single character switches are allowed.
  32 # Using getopt would allow for multi charcter switch names but would come at a
  33 # cost of not being cross compatible.
  34
  35 # Function to display usage
  36 usage_and_exit() {
  37   echo "ERROR: $1."
  38   cat <<EOF
  39
  40   Usage: $0 options
  41   OPTIONS:
  42    -h     Show this message
  43    -c     Current cluster that describes the cluster
  44    -s     Current stores that describes the store. If you do not have info about the stores yet, look
  45           under 'voldemort_home/config/tools/' for some store examples.
  46    -i     Interim Cluster that corresponds to cluster expansion.
  47    -o     Output dir where all interim and final files will be stored.
  48 EOF
  49 exit 1
  50 }
  51
  52 # initialize  variables to an empty string
  53 current_cluster=""
  54 current_stores=""
  55 interim_cluster=""
  56 output_dir=""
  57
  58 # Figure out voldemort home directory
  59 dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
  60 vold_home="$(dirname "$dir")"
  61
  62 # Parse options
  63 while getopts “hc:s:i:o:” OPTION
  64 do
  65   case $OPTION in
  66   h)
  67     usage_and_exit
  68     exit 1
  69     ;;
  70   c)
  71     current_cluster=$OPTARG
  72     echo "[rebalance-cluster-expansion] Will rebalance on the cluster described in '$current_cluster'."
  73     ;;
  74   s)
  75     current_stores=$OPTARG
  76     echo "[rebalance-cluster-expansion] Will rebalance on the stores described in '$current_stores'."
  77     ;;
  78   i)
  79     interim_cluster=$OPTARG
  80     echo "[rebalance-cluster-expansion] Will rebalance on the interim cluster described in '$interim_cluster'."
  81     ;;
  82   o)
  83     output_dir=$OPTARG
  84     mkdir -p $output_dir
  85     echo "[rebalance-cluster-expansion] Using '$output_dir' for all interim and final files generated."
  86     ;;
  87   ?)
  88     usage_and_exit
  89   ;;
  90      esac
  91 done
  92
  93 if [[ -z $current_cluster ]] || [[ -z $current_stores ]] \
  94     || [[ -z $interim_cluster ]] || [[ -z $output_dir ]]
  95 then
  96      printf "\n"
  97      echo "[rebalance-cluster-expansion] Missing argument. Check again."
  98      usage_and_exit
  99      exit 1
 100 fi
 101
 102 if [ ! -e $current_cluster ]; then
 103     usage_and_exit "File '$current_cluster' does not exist."
 104 fi
 105
 106 if [ ! -e $current_stores ]; then
 107     usage_and_exit "File '$current_stores' does not exist."
 108 fi
 109
 110 if [ ! -e $interim_cluster ]; then
 111     usage_and_exit "File '$interim_cluster' does not exist."
 112 fi
 113
 114
 115 # The final cluster.xml for cluster expansion is generated in two steps.
 116 # Step 1: Current cluster.xml is fed to the repartitioner along with the interim cluster xml.
 117 #         The repartitioner tries to balance the ring by moving the partitions around.
 118 # Step 2: A plan is generated on how to reach from the original cluster topology to
 119 #         the one that is generated in step 1.
 120 #
 121
 122 attempts=50
 123
 124 # Step 1
 125 mkdir -p $output_dir/step1/
 126 $vold_home/bin/run-class.sh voldemort.tools.RepartitionerCLI \
 127                             --current-cluster $current_cluster \
 128                             --current-stores $current_stores \
 129                             --interim-cluster $interim_cluster \
 130                             --attempts $attempts \
 131                             --output-dir $output_dir/step1/$i
 132
 133 if [ ! -e $output_dir/step1/final-cluster.xml ]; then
 134     usage_and_exit "File '$final-cluster.xml' does not exist."
 135 fi
 136
 137 # Step 2
 138 mkdir -p $output_dir/step2/
 139 $vold_home/bin/run-class.sh voldemort.tools.RebalancePlanCLI \
 140                             --current-cluster $current_cluster \
 141                             --current-stores $current_stores \
 142                             --final-cluster $output_dir/step1/final-cluster.xml \
 143                             --output-dir $output_dir/step2/
 144
 145 echo "[rebalance-cluster-expansion] Placing final-cluster.xml in '$output_dir'"
 146 cp $output_dir/step2/final-cluster.xml $output_dir/final-cluster.xml
 147 echo "[rebalance-cluster-expansion] Placing plan.out in '$output_dir'"
 148 cp $output_dir/step2/plan.out $output_dir/plan.out
 149 echo "[rebalance-cluster-expansion] Placing final-cluster.xml.analysis in '$output_dir'"
 150 cp $output_dir/step1/final-cluster.xml.analysis $output_dir/final-cluster.xml.analysis