安装与配置
- 使用的服务器是WSL, 首先重置一下WSL
wslconfig /u - 下载安装包: java, zookeeper
- tar -xzvf 解压安装
- 在.bash_profile中配置Java环境, 并. .bash_profile ``` JAVA_HOME=/home/zink/jdk14 export JAVA_HOME
PATH=$JAVA_HOME/bin:$PATH export PATH
5. 在配置文件conf/zoo.cfg中修改zookeeper data存放位置
6. 启动: bin/zkServer.sh start
7. 检测状态: bin/zkServer.sh status
# zookeeper常用Shell命令
## 新增节点
create [-s] [-e] path data ,其中-s为有序节点, -e 临时节点 [-s] [-e] 可共存
## 更新节点
`set path val [-v version]`
## 删除节点
delete path [-v version] 只能删除叶子节点 rmr path : 递归删除
## 查看节点
`get path [-s] [-w]` : -w为watch, 监听
`stat path` : 只看属性, 不看数据
## 查看子节点
```ls [-s] path```
## 监听器
get -w ls -w stat -w
## Zookeeper权限控制
getAcl path setAcl path acl addauth scheme auth
### World 授权模式
e.g. setAcl /node1 world:anyone:rwa crwda : create, read, write, delete, admin
### IP授权模式
setAcl /node2 ip:127.0.0.1:cdrwa
### auth授权模式
//添加认证用户后即可访问(digest:摘要) addauth digest username:password setAcl /node3 auth:username:cdrwa
### 加密授权
digest:zink:QzClKsadasDKasdASjf=:cdrwa
### 多种模式授权
addauth digest zink:123456 setAcl /node5 ip:127.0.0.1:cdra,auth:zink:cdrwa,digest:zink:QzClKsadasDKasdASjf=:cdrwa
## Acl超级管理员
zookeeper的权限管理模式有一种叫super, 该模式提供超管,可以管理任何权限的节点
首先生成密码的密文
echo -n super:admin|openssl dgst -binary -sha1|openssl base64
然后打开zkServer.sh,在启动zookeeper的命令中添加如下:
-Dzookeeper.DigestAuthenticationProvider.superDigest=super:xQJmxLMiHGwaqBvst5y6rkB6HQs=
最后添加如下命令添加权限, 即可获取所有权限
addauth digest super:admin
# zookeeper javaAPI
znode是zookeeper集合的核心组件.
## 连接到ZooKeeper
ZooKeeper(String connectionString, int sessionTimeout, Watcher watcher)
try{ //计数器对象 CountDownLatch cdl = new CountDownLatch(1); /** * 1. 端口 * 2. 超时时间, 毫秒 * 3. 监视器对象 */ ZooKeeper zooKeeper = new ZooKeeper(“localhost:2181”, 2000, new Watcher() { @Override public void process(WatchedEvent event) { if (event.getState() == Event.KeeperState.SyncConnected){ System.out.println(“连接创建成功!”); cdl.countDown(); } } }); cdl.await(); System.out.println(zooKeeper.getSessionId()); zooKeeper.close(); }catch(Exception e){ e.printStackTrace(); }
## 配置中心案例
```java
public class MyConfigCenter implements Watcher {
String url ;
String user ;
String pass ;
CountDownLatch cdl = new CountDownLatch(1);
static ZooKeeper zooKeeper;
static String IP = "127.0.0.1:2181";
public MyConfigCenter() {
try {
zooKeeper = new ZooKeeper(IP, 2000, this);
cdl.await();
init();
} catch (KeeperException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
public void init() throws KeeperException, InterruptedException, IOException {
this.url = new String(zooKeeper.getData("/config/url",true,null));
this.user = new String(zooKeeper.getData("/config/user",true,null));
this.pass = new String(zooKeeper.getData("/config/pass",true,null));
System.out.println("config changed");
}
public static void main(String[] args) throws InterruptedException, KeeperException {
MyConfigCenter m = new MyConfigCenter();
for (int i = 0; i < 10; i++) {
Thread.sleep(1000);
System.out.println(m.url);
}
}
@SneakyThrows
@Override
public void process(WatchedEvent event) {
if (event.getType() == Event.EventType.None){
if (event.getState() == Event.KeeperState.SyncConnected){
System.out.println("Created");
cdl.countDown();
}
if (event.getState() == Event.KeeperState.Disconnected){
System.out.println("disconnected");
}
if (event.getState() == Event.KeeperState.Expired){
System.out.println("timeout");
}
if (event.getState() == Event.KeeperState.AuthFailed){
System.out.println("AuthFailed");
}
}else {
if (event.getType() == Event.EventType.NodeDataChanged){
init();
System.out.println("changed");
}
}
}
}
生成分布式唯一ID
- 连接zookeeper服务器
- 指定路径生成有序节点
- 其序列号即可作为分布式唯一ID
public String getUniqueId(){
String path = "";
try {
path = zooKeeper.create(defaultPath,new byte[0], ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.EPHEMERAL_SEQUENTIAL);
} catch (KeeperException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
return path.substring(9);
}