每日日报2021 10/20
今天我要学习的是Zookeeper
Zookeeper 服务的启动命令是 zkServer.sh start
zkServer.sh
#!/usr/bin/env bash
# use POSTIX interface, symlink is followed automatically
ZOOBIN="${BASH_SOURCE-$0}"
ZOOBIN="$(dirname "${ZOOBIN}")"
ZOOBINDIR="$(cd "${ZOOBIN}"; pwd)"
if [ -e "$ZOOBIN/../libexec/zkEnv.sh" ]; then
. "$ZOOBINDIR"/../libexec/zkEnv.sh
else
. "$ZOOBINDIR"/zkEnv.sh //相当于获取 zkEnv.sh 中的环境变量（ZOOCFG="zoo.cfg"）
fi
# See the following page for extensive details on setting
# up the JVM to accept JMX remote management:
# http://java.sun.com/javase/6/docs/technotes/guides/management/agent.html
# by default we allow local JMX connections
if [ "x$JMXLOCALONLY" = "x" ] 尚硅谷技术之 Zookeeper（源码分析）
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then
JMXLOCALONLY=false
fi
if [ "x$JMXDISABLE" = "x" ] || [ "$JMXDISABLE" = 'false' ]
then
echo "ZooKeeper JMX enabled by default" >&2
if [ "x$JMXPORT" = "x" ]
then
# for some reason these two options are necessary on jdk6 on Ubuntu
# accord to the docs they are not necessary, but otw jconsole cannot
# do a local attach
ZOOMAIN="-Dcom.sun.management.jmxremote
-
Dcom.sun.management.jmxremote.local.only=$JMXLOCALONLY
org.apache.zookeeper.server.quorum.QuorumPeerMain"
else
if [ "x$JMXAUTH" = "x" ]
then
JMXAUTH=false
fi
if [ "x$JMXSSL" = "x" ]
then
JMXSSL=false
fi
if [ "x$JMXLOG4J" = "x" ]
then
JMXLOG4J=true
fi
echo "ZooKeeper remote JMX Port set to $JMXPORT" >&2
echo "ZooKeeper remote JMX authenticate set to $JMXAUTH" >&2
echo "ZooKeeper remote JMX ssl set to $JMXSSL" >&2
echo "ZooKeeper remote JMX log4j set to $JMXLOG4J" >&2
ZOOMAIN="-Dcom.sun.management.jmxremote
-
Dcom.sun.management.jmxremote.port=$JMXPORT
-
Dcom.sun.management.jmxremote.authenticate=$JMXAUTH
-
Dcom.sun.management.jmxremote.ssl=$JMXSSL
-
Dzookeeper.jmx.log4j.disable=$JMXLOG4J
org.apache.zookeeper.server.quorum.QuorumPeerMain"
fi
else
echo "JMX disabled by user request" >&2
ZOOMAIN="org.apache.zookeeper.server.quorum.QuorumPeerMain"
fi
if [ "x$SERVER_JVMFLAGS" != "x" ]
then
JVMFLAGS="$SERVER_JVMFLAGS $JVMFLAGS"
fi
… …
case $1 in
start)
echo -n "Starting zookeeper ... "
if [ -f "$ZOOPIDFILE" ]; then
if kill -0 `cat "$ZOOPIDFILE"` > /dev/null 2>&1; then
echo $command already running as process `cat "$ZOOPIDFILE"`.
