蜜雪冰城网络营销案例分析,浙江网站seo,做电力产品的外贸网站,南充房产信息查询系统全新集群选举 zookeeper 全新集群选举机制网上资料很多说法很模糊#xff0c;仔细思考了一下#xff0c;应该是这样 得到票数最多的机器机器总数半数 具体启动过程中的哪个节点成为 leader 与 zoo.cfg 中配置的节点数有关#xff0c;下面以3个举例 选举过程如下
server…
全新集群选举 zookeeper 全新集群选举机制网上资料很多说法很模糊仔细思考了一下应该是这样 得到票数最多的机器机器总数半数 具体启动过程中的哪个节点成为 leader 与 zoo.cfg 中配置的节点数有关下面以3个举例 选举过程如下
server1 启动给自己投票然后群发投票信息由于其他 server 没有启动所有收不到任何反馈信息状态处于 LOOKINGserver2 启动给自己投票由于myid文件内容比server1的大自己得票两票机器总数半数是1.5符合上面的规则所以胜出server2 成为 leaderserver1 成为 followerserver3 启动给自己投票由于myid文件内容比server2的大自己得票三票机器总数半数是1.5符合上面的规则但是 leader 已经有了所以只能成为 follower有点委屈有点类似于国内结婚每个男人只有一个老婆哈哈哈 机器总数对应在 zoo.cfg 中配置如下形式配置节点信息 server.myid文件中的id节点ip:2888:3888 集群节点数量计算公式 y2x1x为正整数y为节点数 为什么是奇数之前写过一篇文章
redis集群最少使用三个主节点和使用16384个槽以及主节点数量不超过1000的原因_zlpzlpzyd的博客-CSDN博客 很多说法是按照5个节点来讲的按照公式来讲三个应该可以。 下面就来试一下
在自己的机器上安装 zookeeper 三个节点
分别为 master、node1、node2 zoo.cfg
sudo tee conf/zoo.cfg -EOF
tickTime2000
initLimit10
syncLimit5
dataDir/opt/zookeeper
clientPort2181
server.1master:2888:3888
server.2node1:2888:3888
server.3node2:2888:3888
EOF
各个节点的 zoo.cfg 文件内容一致。 master
echo 1 /opt/zookeeper/myid
node1
echo 2 /opt/zookeeper/myid
node2
echo 3 /opt/zookeeper/myid 启动 zookeeper
先启动两个节点看看情况
[rootmaster apache-zookeeper-3.9.0-bin]# ./bin/zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /opt/apache-zookeeper-3.9.0-bin/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[rootnode1 apache-zookeeper-3.9.0-bin]# ./bin/zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /opt/apache-zookeeper-3.9.0-bin/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED 节点状态
[rootmaster apache-zookeeper-3.9.0-bin]# ./bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /opt/apache-zookeeper-3.9.0-bin/bin/../conf/zoo.cfg
Client port found: 2181. Client address: localhost. Client SSL: false.
Mode: follower
[rootnode1 apache-zookeeper-3.9.0-bin]# ./bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /opt/apache-zookeeper-3.9.0-bin/bin/../conf/zoo.cfg
Client port found: 2181. Client address: localhost. Client SSL: false.
Mode: leader
配置了三个节点只启动了两个节点的情况下正常选举符合想法。说明3个节点中有两个节点启动就可以完成选举流程。 下面再启动 node2
[rootnode2 apache-zookeeper-3.9.0-bin]# ./bin/zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /opt/apache-zookeeper-3.9.0-bin/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[rootnode2 apache-zookeeper-3.9.0-bin]# ./bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /opt/apache-zookeeper-3.9.0-bin/bin/../conf/zoo.cfg
Client port found: 2181. Client address: localhost. Client SSL: false.
Mode: follower
符合上面的推测 突发奇想两个节点会是什么情况
个人猜测跟上面两个节点启动一致。 两个节点
分别为 master、node1 zoo.cfg
sudo tee conf/zoo.cfg -EOF
tickTime2000
initLimit10
syncLimit5
dataDir/opt/zookeeper
clientPort2181
server.1master:2888:3888
server.2node1:2888:3888
server.3node2:2888:3888
EOF
各个节点的 zoo.cfg 文件内容一致。 启动 zookeeper
[rootmaster apache-zookeeper-3.9.0-bin]# ./bin/zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /opt/apache-zookeeper-3.9.0-bin/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[rootnode1 apache-zookeeper-3.9.0-bin]# ./bin/zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /opt/apache-zookeeper-3.9.0-bin/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
节点状态
[rootmaster apache-zookeeper-3.9.0-bin]# ./bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /opt/apache-zookeeper-3.9.0-bin/bin/../conf/zoo.cfg
Client port found: 2181. Client address: localhost. Client SSL: false.
Mode: follower
[rootnode1 apache-zookeeper-3.9.0-bin]# ./bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /opt/apache-zookeeper-3.9.0-bin/bin/../conf/zoo.cfg
Client port found: 2181. Client address: localhost. Client SSL: false.
Mode: leader
最终结果如上面猜测。 为什么最少三个节点
去看一下官方文档 ZooKeeper: Because Coordinating Distributed Systems is a Zoo For replicated mode, a minimum of three servers are required, and it is strongly recommended that you have an odd number of servers. If you only have two servers, then you are in a situation where if one of them fails, there are not enough machines to form a majority quorum. Two servers are inherently less stable than a single server, because there are two single points of failure. 对于集群节点最少的 server 数量是三个 强烈建议是奇数。如果是两个 server当其中一个节点有故障没有足够的机器进行优先级处理。
符合上面的最少三个节点的理论。 非全新集群选举
