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Diffstat (limited to 'zookeeper/init/on-start.sh')
-rwxr-xr-x | zookeeper/init/on-start.sh | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/zookeeper/init/on-start.sh b/zookeeper/init/on-start.sh new file mode 100755 index 0000000..392b82a --- /dev/null +++ b/zookeeper/init/on-start.sh @@ -0,0 +1,73 @@ +#! /bin/bash + +# Copyright 2016 The Kubernetes Authors All rights reserved. +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +# This script configures zookeeper cluster member ship for version of zookeeper +# >= 3.5.0. It should not be used with the on-change.sh script in this example. +# As of April-2016 is 3.4.8 is the latest stable. + +# Both /opt and /tmp/zookeeper are assumed to be volumes shared with the parent. +CFG=/opt/zookeeper/conf/zoo.cfg.dynamic +CFG_BAK=/opt/zookeeper/conf/zoo.cfg.bak +MY_ID_FILE=/tmp/zookeeper/myid +HOSTNAME=$(hostname) + +while read -ra LINE; do + PEERS=("${PEERS[@]}" $LINE) +done + +# Don't add the first member as an observer +if [ ${#PEERS[@]} -eq 1 ]; then + # We need to write our index in this list of servers into MY_ID_FILE. + # Note that this may not always coincide with the hostname id. + echo 1 > "${MY_ID_FILE}" + echo "server.1=${PEERS[0]}:2888:3888;2181" > "${CFG}" + # TODO: zkServer-initialize is the safe way to handle changes to datadir + # because simply starting will create a new datadir, BUT if the user changed + # pod template they might end up with 2 datadirs and brief split brain. + exit +fi + +# Every subsequent member is added as an observer and promoted to a participant +echo "" > "${CFG_BAK}" +i=0 +for peer in "${PEERS[@]}"; do + let i=i+1 + if [[ "${peer}" == *"${HOSTNAME}"* ]]; then + MY_ID=$i + MY_NAME=${peer} + echo $i > "${MY_ID_FILE}" + echo "server.${i}=${peer}:2888:3888:observer;2181" >> "${CFG_BAK}" + else + echo "server.${i}=${peer}:2888:3888:participant;2181" >> "${CFG_BAK}" + fi +done + +# Once the dynamic config file is written it shouldn't be modified, so the final +# reconfigure needs to happen through the "reconfig" command. +cp ${CFG_BAK} ${CFG} + +# TODO: zkServer-initialize is the safe way to handle changes to datadir +# because simply starting will create a new datadir, BUT if the user changed +# pod template they might end up with 2 datadirs and brief split brain. +/opt/zookeeper/bin/zkServer.sh start + +# TODO: We shouldn't need to specify the address of the master as long as +# there's quorum. According to the docs the new server is just not allowed to +# vote, it's still allowed to propose config changes, and it knows the +# existing members of the ensemble from *its* config. This works as expected, +# but we should correlate with more satisfying empirical evidence. +/opt/zookeeper/bin/zkCli.sh reconfig -add "server.$MY_ID=$MY_NAME:2888:3888:participant;2181" +/opt/zookeeper/bin/zkServer.sh stop |