【261期】面试官：说出几个你熟悉的 Zookeeper 命令
目录
客户端、服务器命令 节点属性 help命令 新增、查询节点 修改节点 删除节点 查看子节点列表 查看节点状态 监听器 权限控制
首先说明一下环境，溪源使用zookeeper版本为3.5.10；由于版本不同，命令语法略有差异，提前说明一下，但是基本原理一致，大家可以通过help命令查看自己当前版本的命令语法。
客户端、服务器命令
切换至zookeeper安装目录下的bin目录输入以下命令启动服务器或者客户端
启动ZK服务: ./zkServer.sh start 查看ZK服务状态: ./zkServer.sh status 停止ZK服务: ./zkServer.sh stop 重启ZK服务: ./zkServer.sh restart 连接内部客户端: ./zkCli.sh或者./zkCli.sh -server 127.0.0.1(指定连接服务器IP):2181
节点属性
学习zookeeper常用命令之前先介绍一下节点属性的含义。
-cZxid：当前数据结点创建时的事务ID——针对于zookeeper数据结点的管理：我们对结点数据的一些写操作都会导致zookeeper自动地为我们去开启一个事务，并且自动地去为每一个事务维护一个事务ID
ctime：当前数据结点创建时的时间mZxid：当前数据结点最后一次更新时的事务IDmtime：当前数据结点最后一次更新时的时间pZxid：当前数据节点最后一次修改其子节点**更改的zxid。修改指(增加子节点、删除子节点)，并不指其子节点的数据发生改变；cversion：当前数据节点对应子结点的更改次数dataVersion：当前结点数据的发生更改的次数aclVersion：当前结点的ACL更改次数——类似linux的权限列表，维护的是当前结点的权限列表被修改的次数ephemeralOwner：如果结点是临时结点，则表示创建该结点的会话的SessionID；如果是持久结点，该属性值为0dataLength：当前节点的数据内容长度numChildren：当前数据结点的子结点个数
help命令
zookeeper基本常用命令通过help查看，遇到错误命令可以直接查询语法。
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
Command not found: Command not found help
新增、查询节点
新增命令：create [-s] [-e] path data
其中 -s 为有序结点，-e 临时结点（默认是持久结点）
查询命令：get [-s] [-w] path
-s查看节点所有信息:数据信息+节点属性值-w查看节点数据信息
实战
//创建持久化节点node1
[zk: localhost:2181(CONNECTED) 0] create /node1 "123"
Created /node1
//查看node1节点属性
[zk: localhost:2181(CONNECTED) 1] get -s /node1
123
cZxid = 0x43
ctime = Wed Jul 29 21:27:31 CST 2020
mZxid = 0x43
mtime = Wed Jul 29 21:27:31 CST 2020
pZxid = 0x43
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 3
numChildren = 0
//创建有序持久化节点
[zk: localhost:2181(CONNECTED) 2] create -s /seqNode1 "seq1"
Created /seqNode10000000011
//查看有序持久化节点信息
[zk: localhost:2181(CONNECTED) 3] get -s /seqNode10000000011
seq1
cZxid = 0x44
ctime = Wed Jul 29 21:28:25 CST 2020
mZxid = 0x44
mtime = Wed Jul 29 21:28:25 CST 2020
pZxid = 0x44
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 4
numChildren = 0
//创建临时节点
[zk: localhost:2181(CONNECTED) 4] create -s -e /tmpNode1 "tmp"
Created /tmpNode10000000012
[zk: localhost:2181(CONNECTED) 5] get -s /tmpNode10000000012
tmp
cZxid = 0x45
ctime = Wed Jul 29 21:35:28 CST 2020
mZxid = 0x45
mtime = Wed Jul 29 21:35:28 CST 2020
pZxid = 0x45
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x10029ab39130008
dataLength = 3
numChildren = 0
修改节点
命令：set [-s] [-v version] path data
可以直接进行修改;也可以选择使用版本号
-v + 版本号，类似乐观锁原理；
[zk: localhost:2181(CONNECTED) 13] set /node1 "456"
[zk: localhost:2181(CONNECTED) 14] get -w /node1
456
[zk: localhost:2181(CONNECTED) 15] set -v 0 /node1 "234"
WATCHER::
WatchedEvent state:SyncConnected type:NodeDataChanged path:/node1
[zk: localhost:2181(CONNECTED) 16] get -w /node1
234
删除节点
命令：delete [-v version] path:可以直接删除，也可以指定版本号删除，此命令只能删除单个节点，如果存在子节点，则需要依次删除子节点
deleteall path：直接删除指定的所有节点
[zk: localhost:2181(CONNECTED) 0] delete /node1
[zk: localhost:2181(CONNECTED) 1] get -s /node1
org.apache.zookeeper.KeeperException$NoNodeException: KeeperErrorCode = NoNode for /node1
[zk: localhost:2181(CONNECTED) 4] create /node1 "node1"
Created /node1
[zk: localhost:2181(CONNECTED) 5] create /node1/node11 "node11"
Created /node1/node11
//使用delete删除存在子节点的节点，删除失败
[zk: localhost:2181(CONNECTED) 6] delete /node1
Node not empty: /node1
[zk: localhost:2181(CONNECTED) 7] get -s /node1
node1
cZxid = 0x4f
ctime = Wed Jul 29 21:53:37 CST 2020
mZxid = 0x4f
mtime = Wed Jul 29 21:53:37 CST 2020
pZxid = 0x50
cversion = 1
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 5
numChildren = 1
[zk: localhost:2181(CONNECTED) 8] deleteall /node1
[zk: localhost:2181(CONNECTED) 9] get /node1
org.apache.zookeeper.KeeperException$NoNodeException: KeeperErrorCode = NoNode for /node1
注意：删除存在子节点时，命令不要再使用rmr，此命令已经无效。
推荐：250期面试题汇总
[zk: localhost:2181(CONNECTED) 17] rmr /node1
The command 'rmr' has been deprecated. Please use 'deleteall' instead.
查看子节点列表
命令：
ls [-s] [-w] [-R] path:
ls2 path [watch]
[zk: localhost:2181(CONNECTED) 19] ls /
[a0000000001, b0000000002, c, hadoop, seqNode10000000011, zookeeper]
[zk: localhost:2181(CONNECTED) 20] ls -s /
[a0000000001, b0000000002, c, hadoop, seqNode10000000011, zookeeper]cZxid = 0x0
ctime = Thu Jan 01 08:00:00 CST 1970
mZxid = 0x0
mtime = Thu Jan 01 08:00:00 CST 1970
pZxid = 0x53
cversion = 22
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 0
numChildren = 6
[zk: localhost:2181(CONNECTED) 21] create /node1 "node1"
Created /node1
//当前节点下没有子节点，返回空数组
[zk: localhost:2181(CONNECTED) 22] ls /node1
[]
[zk: localhost:2181(CONNECTED) 23] create /node1/node11 "node11"
Created /node1/node11
[zk: localhost:2181(CONNECTED) 24] ls /node1
[node11]
查看节点状态
使用stat命令查看节点状态，与get命令的区别是此命令不返回数据信息；
[zk: localhost:2181(CONNECTED) 25] stat /node1
cZxid = 0x55
ctime = Wed Jul 29 22:05:16 CST 2020
mZxid = 0x55
mtime = Wed Jul 29 22:05:16 CST 2020
pZxid = 0x56
cversion = 1
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 5
numChildren = 1
监听器
特殊说明get path [watch]命令已被废弃：
[zk: localhost:2181(CONNECTED) 27] get /node1 watch
'get path [watch]' has been deprecated. Please use 'get [-s] [-w] path' instead.
node1
使用 get [-s] [-w] path注册的监听器能够在结点内容发生改变的时候，向客户端发出通知。需要注意的是zookeeper的触发器是一次性的(One-time trigger)，即触发一次后就会立即失效。
//一个窗口监听，新打开一个窗口修改节点数据
[zk: localhost:2181(CONNECTED) 29] get -w /node1
node1
//收到修改信息
[zk: localhost:2181(CONNECTED) 30]
WATCHER::
WatchedEvent state:SyncConnected type:NodeDataChanged path:/node1
//另一个窗口修改节点：
[zk: localhost:2181(CONNECTED) 0] set /node1 "set node1"
权限控制
zookeeper类似文件系统，client可以创建结点、更新结点、删除结点，那么如何做到结点的权限控制呢？
zookeeper的 access control list 访问控制列表可以做到这一点。
acl权限控制，使用scheme：id：permission来标识，主要涵盖3个方面：
权限模式(scheme)：授权的策略 授权对象(id)：授权的对象 权限(permission)：授予的权限
权限模式
授权对象
给谁授予权限 授权对象ID是指，权限赋予的实体，例如：IP地址或用户
权限
create、delete、read、writer、admin也就是 增、删、查、改、管理权限，这5种权限简写为 c d r w a，注意：这五种权限中，有的权限并不是对结点自身操作的例如：delete是指对子结点的删除权限。
可以试图删除父结点，但是子结点必须删除干净，所以delete的权限也是很有用的
授权的相关命令
world模式:
[zk: localhost:2181(CONNECTED) 31] getAcl /node1
'world,'anyone
: cdrwa
[zk: localhost:2181(CONNECTED) 32] setAcl /node1 world:anyone:drwa
[zk: localhost:2181(CONNECTED) 33] create /node1/node2 "node2"
Authentication is not valid : /node1/node2
[zk: localhost:2181(CONNECTED) 34] setAcl /node1 world:anyone:cdrwa
[zk: localhost:2181(CONNECTED) 35] create /node1/node2 "node2"
Created /node1/node2
IP模式：
需要两台虚拟机一起授权的话需要用逗号将授权列表隔开：setAcl /ipNode ip:192.168.103.133:cdrwa,ip:192.168.103.132:cdrwa
[zk: localhost:2181(CONNECTED) 8] create /ipNode "ipNode"
Created /ipNode
[zk: localhost:2181(CONNECTED) 9] get -s /ipNode
ipNode
cZxid = 0x65
ctime = Wed Jul 29 23:22:23 CST 2020
mZxid = 0x65
mtime = Wed Jul 29 23:22:23 CST 2020
pZxid = 0x65
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 6
numChildren = 0
[zk: localhost:2181(CONNECTED) 10] setAcl /ipNode ip:192.168.16.81:ra
[zk: localhost:2181(CONNECTED) 11] get -s /ipNode
org.apache.zookeeper.KeeperException$NoAuthException: KeeperErrorCode = NoAuth for /ipNode
auth模式：
命令：
addauth digest <user>:<password>
setAcl <path> auth:<user>:<acl>
//认证用户
[zk: localhost:2181(CONNECTED) 36] addauth digest qxy:123456
[zk: localhost:2181(CONNECTED) 37] get -s /node1
set node1
cZxid = 0x55
ctime = Wed Jul 29 22:05:16 CST 2020
mZxid = 0x58
mtime = Wed Jul 29 22:31:29 CST 2020
pZxid = 0x5c
cversion = 2
dataVersion = 1
aclVersion = 2
ephemeralOwner = 0x0
dataLength = 9
numChildren = 2
//设置认证用户
[zk: localhost:2181(CONNECTED) 38] setAcl /node1 auth:qxy:cdrwa
//退出，重新进入
[zk: localhost:2181(CONNECTED) 39] quit
WATCHER::
WatchedEvent state:Closed type:None path:null
2020-07-29 22:58:56,574 [myid:] - INFO [main:ZooKeeper@1422] - Session: 0x10029ab39130009 closed
2020-07-29 22:58:56,574 [myid:] - INFO [main-EventThread:ClientCnxn$EventThread@524] - EventThread shut down for session: 0x10029ab39130009
//未用户认证，无法获取节点信息
[zk: localhost:2181(CONNECTED) 0] get -s /node1
org.apache.zookeeper.KeeperException$NoAuthException: KeeperErrorCode = NoAuth for /node1
//认证用户，注意此处密码错误，不会提示错误，但是无法访问节点
[zk: localhost:2181(CONNECTED) 1] addauth digest qxy:123456
[zk: localhost:2181(CONNECTED) 2] get -s /node1
set node1
cZxid = 0x55
ctime = Wed Jul 29 22:05:16 CST 2020
mZxid = 0x58
mtime = Wed Jul 29 22:31:29 CST 2020
pZxid = 0x5c
cversion = 2
dataVersion = 1
aclVersion = 3
ephemeralOwner = 0x0
dataLength = 9
numChildren = 2
Digest模式：
命令：setAcl <path> digest:<user>:<password>:<acl>
密码是经过SHA1以及BASE64处理的密文，在shell 中可以通过以下命令计算：
echo -n <user>:<password> | openssl dgst -binary -sha1 | openssl base64
建立新的窗口，计算密码
[root@izbp14najjyuhkvm4qbic7z bin]# echo -n qxy:123456 | openssl dgst -binary -sha1 | openssl base64
hDF4uLZvMJqOX2ekKFa6kSz9HNo=
实战：
[zk: localhost:2181(CONNECTED) 5] create /digestNode "digestNode"
Created /digestNode
[zk: localhost:2181(CONNECTED) 2] setAcl /digestNode digest:qxy:hDF4uLZvMJqOX2ekKFa6kSz9HNo=:cdrwa
[zk: localhost:2181(CONNECTED) 3] get /digestNode
org.apache.zookeeper.KeeperException$NoAuthException: KeeperErrorCode = NoAuth for /digestNode
[zk: localhost:2181(CONNECTED) 2] setAcl /digestNode digest:qxy:hDF4uLZvMJqOX2ekKFa6kSz9HNo=:cdrwa
[zk: localhost:2181(CONNECTED) 3] get /digestNode
org.apache.zookeeper.KeeperException$NoAuthException: KeeperErrorCode = NoAuth for /digestNode
[zk: localhost:2181(CONNECTED) 4] getAcl /digestNode
Authentication is not valid : /digestNode
[zk: localhost:2181(CONNECTED) 5] addauth digest qxy:123456
[zk: localhost:2181(CONNECTED) 6] getAcl /digestNode
'digest,'qxy:hDF4uLZvMJqOX2ekKFa6kSz9HNo=
: cdrwa
[zk: localhost:2181(CONNECTED) 7] get /digestNode
digestNode
来源：blog.csdn.net/xuan_lu/article/details/107675047
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