Zookeeper笔记

本文涉及的产品
数据可视化DataV,5个大屏 1个月
日志服务 SLS,月写入数据量 50GB 1个月
注册配置 MSE Nacos/ZooKeeper,118元/月
简介: Zookeeper笔记

Zookeeper



服务器


腾讯服务器


安装目录结构


github地址

ProcessOn地址:https://www.processon.com/mindmap/61b04da95653bb4f1e5ec85e


安装


解压文件:

[root@VM-0-9-centos zookeeper]# tar -zxvf apache-zookeeper-3.5.8-bin.tar.gz 

信息:

[root@VM-0-9-centos ~]# echo 太难了吧
太难了吧
[root@VM-0-9-centos ~]# cd usr/local
-bash: cd: usr/local: 没有那个文件或目录
[root@VM-0-9-centos ~]# cd /usr/local
[root@VM-0-9-centos local]# mkdir zookeeper
[root@VM-0-9-centos local]# cd zookeeper/
[root@VM-0-9-centos zookeeper]# ll
总用量 0

删除文件:

[root@VM-0-9-centos zookeeper]# rm -rf apache-zookeeper-3.5.8-bin.tar.gz 
[root@VM-0-9-centos zookeeper]# ll
总用量 4
drwxr-xr-x 6 root root 4096 12月  7 11:05 apache-zookeeper-3.5.8-bin

展示文件夹目录:

[root@VM-0-9-centos apache-zookeeper-3.5.8-bin]# ll
总用量 40
drwxr-xr-x 2 root root  4096 5月   4 2020 bin
drwxr-xr-x 2 root root  4096 5月   4 2020 conf
drwxr-xr-x 5 root root  4096 5月   4 2020 docs
drwxr-xr-x 2 root root  4096 12月  7 11:05 lib
-rw-r--r-- 1 root root 11358 5月   4 2020 LICENSE.txt
-rw-r--r-- 1 root root   432 5月   4 2020 NOTICE.txt
-rw-r--r-- 1 root root  1560 5月   4 2020 README.md
-rw-r--r-- 1 root root  1347 5月   4 2020 README_packaging.txt
[root@VM-0-9-centos apache-zookeeper-3.5.8-bin]# cd bin
[root@VM-0-9-centos bin]# ls
README.txt    zkCli.cmd  zkEnv.cmd  zkServer.cmd            zkServer.sh          zkTxnLogToolkit.sh
zkCleanup.sh  zkCli.sh   zkEnv.sh   zkServer-initialize.sh  zkTxnLogToolkit.cmd

查看文件内容(读写方式)


vim + 文件名


按Esc ,后输入:


:w 保存但不退出


:wq 保存并退出


:q 退出


:q! 强制退出,不保存


:e! 放弃所有修改,从上次保存文件开始再编辑命令历史


#zookeper 数据存储目录及日志保存目录(如果没有指明dataLogDir,则日志也保存在这个文件中)

dataDir=/tmp/zookeeper


改为:

#zookeper 数据存储目录及日志保存目录(如果没有指明dataLogDir,则日志也保存在这个文件中)

dataDir=/usr/local/zookeeper/zkdata


重命名:

[root@VM-0-9-centos conf]# mv zoo_sample.cfg zoo.cfg
[root@VM-0-9-centos conf]# ll
总用量 12
-rw-r--r-- 1 root root  535 5月   4 2020 configuration.xsl
-rw-r--r-- 1 root root 2712 5月   4 2020 log4j.properties
-rw-r--r-- 1 root root  935 12月  7 12:59 zoo.cfg

启动ZK服务器: bin路径下# ./zkServer.sh start …/conf/zoo.cfg

[root@VM-0-9-centos bin]# ./zkServer.sh
/usr/bin/java
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper/apache-zookeeper-3.5.8-bin/bin/../conf/zoo.cfg
Usage: ./zkServer.sh [--config <conf-dir>] {start|start-foreground|stop|restart|status|print-cmd}
[root@VM-0-9-centos bin]# ./zkServer.sh start ../conf/zoo.cfg
/usr/bin/java
ZooKeeper JMX enabled by default
Using config: ../conf/zoo.cfg
Starting zookeeper ... STARTED

检查状态:

[root@VM-0-9-centos bin]# ./zkServer.sh status
/usr/bin/java
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper/apache-zookeeper-3.5.8-bin/bin/../conf/zoo.cfg
Client port found: 2181. Client address: localhost.
Mode: standalone  

Mode: standalone --表示单节点

停止命令:

[root@VM-0-9-centos bin]# ./zkServer.sh stop ../conf/zoo.cfg
/usr/bin/java
ZooKeeper JMX enabled by default
Using config: ../conf/zoo.cfg
Stopping zookeeper ... STOPPED

启动客户端zkCli (需先启动zk服务)

[root@VM-0-9-centos bin]# ./zkServer.sh start ../conf/zoo.cfg 
/usr/bin/java
ZooKeeper JMX enabled by default
Using config: ../conf/zoo.cfg
Starting zookeeper ... STARTED
[root@VM-0-9-centos bin]# ./zkCli.sh
/usr/bin/java
Connecting to localhost:2181
....

内部命令:

ZooKeeper -server host:port cmd args
        addauth scheme auth
        close 
        config [-c] [-w] [-s]
        connect host:port
        create [-s] [-e] [-c] [-t ttl] path [data] [acl]
        delete [-v version] path
        deleteall path
        delquota [-n|-b] path
        get [-s] [-w] path
        getAcl [-s] path
        history 
        listquota path
        ls [-s] [-w] [-R] path
        ls2 path [watch]
        printwatches on|off
        quit 
        reconfig [-s] [-v version] [[-file path] | [-members serverID=host:port1:port2;port3[,...]*]] | [-add serverId=host:port1:port2;port3[,...]]* [-remove serverId[,...]*]
        redo cmdno
        removewatches path [-c|-d|-a] [-l]
        rmr path
        set [-s] [-v version] path data
        setAcl [-s] [-v version] [-R] path acl
        setquota -n|-b val path
        stat [-w] path
        sync path

ZK内部以节点(树)的方式保存数据

创建节点与查看节点:

[zk: localhost:2181(CONNECTED) 3] create /test1
Created /test1
[zk: localhost:2181(CONNECTED) 4] ls /
[test1, zookeeper]
[zk: localhost:2181(CONNECTED) 5] create /test1/sub1
Created /test1/sub1
[zk: localhost:2181(CONNECTED) 6] ls /
[test1, zookeeper]
[zk: localhost:2181(CONNECTED) 7] ls /test1
[sub1]

路径必须以根路径斜杠"/"开头


zk中的znode是什么样的结构

zk中的znode,包含了四个部分:

data:保存数据

acl:权限,定义了什么样的用户能够操作这个节点,且能够进行怎样的操作

c:create 创建权限,允许在该节点下创建子节点

w:write 更新权限,允许更新该节点的数据

r: read 读取权限,允许读取该节点的内容以及子节点的列表信息

d: delete 删除权限,允许删除该节点的子节点

a:admin管理者权限,允许对该节点进行acl权限设置

stat: 描述当前znode的元数据

child :当前节点的子节点


创建带数据的节点 , 查看节点下数据及其详细信息

[zk: localhost:2181(CONNECTED) 12] create /test2 abc
Created /test2
[zk: localhost:2181(CONNECTED) 13] get /test2
abc
[zk: localhost:2181(CONNECTED) 14] get -s /test2
abc
cZxid = 0x4
ctime = Tue Dec 07 13:41:10 CST 2021
mZxid = 0x4
mtime = Tue Dec 07 13:41:10 CST 2021
pZxid = 0x4
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 3
numChildren = 0

解释:


[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-IC3AfyvW-1640140815389)(D:\python\笔记\img\image-20211207134322088.png)]


创建持久序号节点: (防止并发) 特点:单调递增

[zk: localhost:2181(CONNECTED) 15] ls /
[test1, test2, zookeeper]
[zk: localhost:2181(CONNECTED) 16] create /test3
Created /test3
[zk: localhost:2181(CONNECTED) 17] create /test3
Node already exists: /test3
[zk: localhost:2181(CONNECTED) 18] create -s /test3
Created /test30000000003
[zk: localhost:2181(CONNECTED) 19] create -s /test3
Created /test30000000004
[zk: localhost:2181(CONNECTED) 20] create -s /test3
Created /test30000000005
[zk: localhost:2181(CONNECTED) 21] ls /
[test1, test2, test3, test30000000003, test30000000004, test30000000005, zookeeper]

临时节点: 随着会话的结束,自动删除(大约10秒延迟)

[zk: localhost:2181(CONNECTED) 22] create -e /test4
Created /test4
[zk: localhost:2181(CONNECTED) 23] ls /
[test1, test2, test3, test30000000003, test30000000004, test30000000005, test4, zookeeper]
[zk: localhost:2181(CONNECTED) 1] ls /
[test1, test2, test3, test30000000003, test30000000004, test30000000005, test4, zookeeper]
[zk: localhost:2181(CONNECTED) 2] ls /
[test1, test2, test3, test30000000003, test30000000004, test30000000005, zookeeper]

临时序号节点:

[zk: localhost:2181(CONNECTED) 3] create -e -s /test6
Created /test60000000007
[zk: localhost:2181(CONNECTED) 4] get -s /test60000000007
null
cZxid = 0xd
ctime = Tue Dec 07 14:49:20 CST 2021
mZxid = 0xd
mtime = Tue Dec 07 14:49:20 CST 2021
pZxid = 0xd
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x10000858b9f0001
dataLength = 0
numChildren = 0

ephemeralOwner = 0x10000858b9f0001 持久节点值为0,临时节点为其sessionid

创建容器节点: -c 特点:无子节点后会被定期(60s)删除

删除节点

[zk: localhost:2181(CONNECTED) 5] create -c /Mycontainer
Created /Mycontainer
[zk: localhost:2181(CONNECTED) 6] ls /
[Mycontainer, test1, test2, test3, test30000000003, test30000000004, test30000000005, test60000000007, zookeeper]
[zk: localhost:2181(CONNECTED) 7] create -c /Mycontainer/sub1
Created /Mycontainer/sub1
[zk: localhost:2181(CONNECTED) 8] create -c /Mycontainer/sub2
Created /Mycontainer/sub2
[zk: localhost:2181(CONNECTED) 9] ls /Mycontainer
[sub1, sub2]
[zk: localhost:2181(CONNECTED) 10] delete /Mycontainer/sub1
[zk: localhost:2181(CONNECTED) 11] ls /Mycontainer
[sub2]
[zk: localhost:2181(CONNECTED) 12] delete /Mycontainer/sub2
[zk: localhost:2181(CONNECTED) 13] ls /Mycontainer
[]
[zk: localhost:2181(CONNECTED) 14] ls /
[test1, test2, test3, test30000000003, test30000000004, test30000000005, test60000000007, zookeeper]

TTL节点,指定到期时间,到期自动销毁

日志与快照

[root@VM-0-9-centos local]# cd zookeeper
[root@VM-0-9-centos zookeeper]# ll
总用量 8
drwxr-xr-x 7 root root 4096 12月  7 13:02 apache-zookeeper-3.5.8-bin
drwxr-xr-x 3 root root 4096 12月  7 13:18 zkdata
[root@VM-0-9-centos zookeeper]# cd zkdada
-bash: cd: zkdada: 没有那个文件或目录
[root@VM-0-9-centos zookeeper]# cd zkdata/
[root@VM-0-9-centos zkdata]# ll
总用量 8
drwxr-xr-x 2 root root 4096 12月  7 13:18 version-2
-rw-r--r-- 1 root root    4 12月  7 13:18 zookeeper_server.pid
[root@VM-0-9-centos zkdata]# cd version-2/
[root@VM-0-9-centos version-2]# ll
总用量 12
-rw-r--r-- 1 root root 67108880 12月  7 14:56 log.1   (日志)
-rw-r--r-- 1 root root      424 12月  7 13:18 snapshot.0  (快照)

zk通过

在恢复时先恢复快

度更快

递归查询 : 查询下所有子节点

[zk: localhost:2181(CONNECTED) 2] ls -R /test1
/test1
/test1/sub1

删除所有节点

删除单节点

对节点赋值

[zk: localhost:2181(CONNECTED) 3] deleteall /test1
[zk: localhost:2181(CONNECTED) 4] ls /
[test2, test3, test30000000003, test30000000004, test30000000005, zookeeper]
[zk: localhost:2181(CONNECTED) 6] delete /test2
[zk: localhost:2181(CONNECTED) 7] ls /
[test3, test30000000003, test30000000004, test30000000005, zookeeper]
[zk: localhost:2181(CONNECTED) 8] get /test3
null
[zk: localhost:2181(CONNECTED) 9] set /test3 Hello
[zk: localhost:2181(CONNECTED) 10] get /test3
Hello

乐观锁删除:

只有当 dataVersion = 1 与参数 -v 1 对应才会删除成功

[zk: localhost:2181(CONNECTED) 11] get -s /test3
Hello
cZxid = 0x5
ctime = Tue Dec 07 13:52:37 CST 2021
mZxid = 0x19
mtime = Tue Dec 07 15:25:58 CST 2021
pZxid = 0x5
cversion = 0
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 5
numChildren = 0
[zk: localhost:2181(CONNECTED) 12] delete -v 0 /test3
version No is not valid : /test3
[zk: localhost:2181(CONNECTED) 13] delete -v 1 /test3
[zk: localhost:2181(CONNECTED) 14] ls /
[test30000000003, test30000000004, test30000000005, zookeeper]

权限管理:

会话1

[zk: localhost:2181(CONNECTED) 15] addauth digest Tiam:123:cdrwa
[zk: localhost:2181(CONNECTED) 16] create /test-node
Created /test-node
[zk: localhost:2181(CONNECTED) 17] set /test-node Hello
[zk: localhost:2181(CONNECTED) 18] get /test-node
Hello
[zk: localhost:2181(CONNECTED) 19] create /test-auth hahaha auth:Tiam:123:cdrwa
Created /test-auth
[zk: localhost:2181(CONNECTED) 20] get /test-auth
hahaha

会话2: 无权限查看

WatchedEvent state:SyncConnected type:None path:null
[zk: localhost:2181(CONNECTED) 0] ls /
[test-node, test30000000003, test30000000004, test30000000005, zookeeper]
[zk: localhost:2181(CONNECTED) 1] get /test-node
Hello
[zk: localhost:2181(CONNECTED) 2] ls /
[test-auth, test-node, test30000000003, test30000000004, test30000000005, zookeeper]
[zk: localhost:2181(CONNECTED) 3] get /test-auth
org.apache.zookeeper.KeeperException$NoAuthException: KeeperErrorCode = NoAuth for /test-auth


Zookeeper客户端


Zookeeper官方

shell命令 客户端

cd /usr/local/zookeeper/apache-zookeeper-3.5.8-bin/bin

./zkCli.sh

Curator客户端 是对zookeeper支持最好的一款客户端工具

watch 监听机制

**会话1:**监听内容,监听目录 (只监听子文件夹)

[zk: localhost:2181(CONNECTED) 2] get -w /test-node
Hello
[zk: localhost:2181(CONNECTED) 3] ls -w /test-node
[]

**会话2:**一但其他会话改变值

[zk: localhost:2181(CONNECTED) 0] set /test-node centos
[zk: localhost:2181(CONNECTED) 1] create /test-node/watch-node
Created /test-node/watch-node

**会话1:**会话监听提示值改变

[zk: localhost:2181(CONNECTED) 4] 
WATCHER::

WatchedEvent state:SyncConnected type:NodeDataChanged path:/test-node

WATCHER::

WatchedEvent state:SyncConnected type:NodeChildrenChanged path:/test-node

监听目录下所有文件:

[zk: localhost:2181(CONNECTED) 5] ls -R -w /test-node
/test-node
/test-node/sub1
/test-node/watch-node
/test-node/sub1/ss1
[zk: localhost:2181(CONNECTED) 6] 
WATCHER::

WatchedEvent state:SyncConnected type:NodeChildrenChanged path:/test-node/sub1


关闭,开启,防火墙

# 查看状态 ==> active (running)  运行中
[root@VM-0-9-centos ~]# sudo systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
   Active: active (running) since 二 2021-12-07 10:52:33 CST; 1 day 1h ago
     Docs: man:firewalld(1)
 Main PID: 576 (firewalld)
   CGroup: /system.slice/firewalld.service
           └─576 /usr/bin/python2 -Es /usr/sbin/firewalld --nofork --nopid

12月 07 10:52:31 VM-0-9-centos systemd[1]: Starting firewalld - dynamic firewa....
12月 07 10:52:33 VM-0-9-centos systemd[1]: Started firewalld - dynamic firewal....
12月 07 10:52:33 VM-0-9-centos firewalld[576]: WARNING: AllowZoneDrifting is e....
Hint: Some lines were ellipsized, use -l to show in full.
[root@VM-0-9-centos ~]# sudo systemctl stop firewalld
#  inactive (dead) ==> 防火墙已关闭
[root@VM-0-9-centos ~]# sudo systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
   Active: inactive (dead) since 三 2021-12-08 12:14:13 CST; 12s ago
     Docs: man:firewalld(1)
  Process: 576 ExecStart=/usr/sbin/firewalld --nofork --nopid $FIREWALLD_ARGS (code=exited, status=0/SUCCESS)
 Main PID: 576 (code=exited, status=0/SUCCESS)

12月 07 10:52:31 VM-0-9-centos systemd[1]: Starting firewalld - dynamic firewa....
12月 07 10:52:33 VM-0-9-centos systemd[1]: Started firewalld - dynamic firewal....
12月 07 10:52:33 VM-0-9-centos firewalld[576]: WARNING: AllowZoneDrifting is e....
12月 08 12:14:13 VM-0-9-centos systemd[1]: Stopping firewalld - dynamic firewa....
12月 08 12:14:13 VM-0-9-centos systemd[1]: Stopped firewalld - dynamic firewal....
Hint: Some lines were ellipsized, use -l to show in full.

打开:sudo systemctl start firewalld

搭建服务器节点

[root@VM-0-9-centos zookeeper]# cd zkdata/
[root@VM-0-9-centos zkdata]# ll
总用量 4
drwxr-xr-x 2 root root 4096 12月  7 13:18 version-2
[root@VM-0-9-centos zkdata]# mkdir zk1
[root@VM-0-9-centos zkdata]# ll
总用量 8
drwxr-xr-x 2 root root 4096 12月  7 13:18 version-2
drwxr-xr-x 2 root root 4096 12月  8 13:25 zk1
[root@VM-0-9-centos zkdata]# ll
总用量 8
drwxr-xr-x 2 root root 4096 12月  7 13:18 version-2
drwxr-xr-x 2 root root 4096 12月  8 13:25 zk1
[root@VM-0-9-centos zkdata]# mkdir zk2
[root@VM-0-9-centos zkdata]# mkdir zk3
[root@VM-0-9-centos zkdata]# mkdir zk4
[root@VM-0-9-centos zkdata]# ll
总用量 20
drwxr-xr-x 2 root root 4096 12月  7 13:18 version-2
drwxr-xr-x 2 root root 4096 12月  8 13:25 zk1
drwxr-xr-x 2 root root 4096 12月  8 13:25 zk2
drwxr-xr-x 2 root root 4096 12月  8 13:25 zk3
drwxr-xr-x 2 root root 4096 12月  8 13:26 zk4

对每个集群添加myid

[root@VM-0-9-centos zkdata]# echo 1 > ./zk1/myid
[root@VM-0-9-centos zkdata]# cd zk1
[root@VM-0-9-centos zk1]# ll
总用量 4
-rw-r--r-- 1 root root 2 12月  8 13:28 myid
[root@VM-0-9-centos zk1]# vim
[root@VM-0-9-centos zk1]# vi myid
[root@VM-0-9-centos zk1]# cd ..
[root@VM-0-9-centos zkdata]# echo 2 > ./zk2/myid
[root@VM-0-9-centos zkdata]# echo 3 > ./zk3/myid
[root@VM-0-9-centos zkdata]# echo 4 > ./zk4/myid
[root@VM-0-9-centos zkdata]# cd zk4
[root@VM-0-9-centos zk4]# ll
总用量 4
-rw-r--r-- 1 root root 2 12月  8 13:32 myid
[root@VM-0-9-centos zk4]# cat myid 
4

配置文件内容:zoo1.cfg

复制文件

[root@VM-0-9-centos conf]# cp zoo.cfg zoo1.cfg
[root@VM-0-9-centos conf]# vim zoo1.cfg 
[root@VM-0-9-centos conf]# cp zoo1.cfg zoo2.cfg
[root@VM-0-9-centos conf]# cp zoo1.cfg zoo3.cfg
[root@VM-0-9-centos conf]# cp zoo1.cfg zoo4.cfg
[root@VM-0-9-centos conf]# ll
总用量 28
-rw-r--r-- 1 root root  535 5月   4 2020 configuration.xsl
-rw-r--r-- 1 root root 2712 5月   4 2020 log4j.properties
-rw-r--r-- 1 root root 1171 12月  8 13:50 zoo1.cfg
-rw-r--r-- 1 root root 1171 12月  8 13:51 zoo2.cfg
-rw-r--r-- 1 root root 1171 12月  8 13:51 zoo3.cfg
-rw-r--r-- 1 root root 1171 12月  8 13:51 zoo4.cfg
-rw-r--r-- 1 root root  935 12月  7 12:59 zoo.cfg


Zookeeper IP


10.0.0.9


集群建立失败–原因未知


SpringCloud整合视频进度:https://www.bilibili.com/video/BV18E411x7eT?p=28


Zookeeper视频进度:https://www.bilibili.com/video/BV1Ph411n7Ep?p=26&spm_id_from=pageDriver


待以后解决2021/12/08


相关实践学习
基于MSE实现微服务的全链路灰度
通过本场景的实验操作,您将了解并实现在线业务的微服务全链路灰度能力。
相关文章
|
存储 设计模式 负载均衡
大数据开发笔记(五):Zookeeper(二)
ZooKeeper 是一个开源的分布式协调服务。它是一个为分布式应用提供一致性服务的软件,分布式应用程序可以基于 Zookeeper 实现诸如数据发布/订阅、负载均衡、命名服务、分布式协调/通知、集群管理、Master 选举、分布式锁和分布式队列等功能。 ZooKeeper 的目标就是封装好复杂易出错的关键服务,将简单易用的接口和性能高效、功能稳定的系统提供给用户。
207 0
大数据开发笔记(五):Zookeeper(二)
|
存储 缓存 负载均衡
大数据开发笔记(五):Zookeeper(一)
ZooKeeper 是一个开源的分布式协调服务。它是一个为分布式应用提供一致性服务的软件,分布式应用程序可以基于 Zookeeper 实现诸如数据发布/订阅、负载均衡、命名服务、分布式协调/通知、集群管理、Master 选举、分布式锁和分布式队列等功能。 ZooKeeper 的目标就是封装好复杂易出错的关键服务,将简单易用的接口和性能高效、功能稳定的系统提供给用户。
179 0
|
算法 Java
Zookeeper笔记3——原理及其安装使用
Zookeeper到底能干什么? 1.配置管理:这个好理解。分布式系统都有好多机器,Zookeeper提供了这样的一种服务:一种集中管理配置的方法,我们在这个集中的地方修改了配置,所有对这个配置感兴趣的都可以获得变更。
1453 0
|
算法 Java 应用服务中间件
Zookeeper笔记二-各种一致性协议解释
我们知道Zookeeper的一致性是解决分布式事务的。 那么分布式事务代表的是强一致性。 强一致性解决的代表有以下协议(注意这几个协议跟zookeeper是没任何关系的,这是分布式的理论基础): 1.  2PC(二阶提交),顾名思义它分成两个阶段,先由一方进行提议(propose)并收集其他节点的反馈(vote),再根据反馈决定提交(commit)或中止(abort)事务。
1624 0
Zookeeper笔记1-CAP/BASE理论
分布式系统八大谬论: 1.网络相当可靠 2.延迟为0 3.传输带宽是无限的 4.网络相当安全。 5.拓扑结构不会改变 6.必须要有一名管理员 7.传输成本为0 8.网络同质化。   分布式最常出现的问题: 1.通信异常。
2010 0
|
消息中间件 负载均衡 监控