zookeeper的实用场景有统一配置，统一命名服务,集群管理,分布式锁，分布式队列。

今天，我的实验场景是集群管理的ha功能.

实验架构如下:

Server[A/B]代码:

此处，我们需要第3方的模块
zkclient.py（https://github.com/phunt/zk-smoketest/blob/master/zkclient.py）

需要做些稍微的修改，因为我这里的ACL采用的是digest，而不是world

导入些模块:

import base64
import hashlib

定义些变量

auth="badboy:test"
user="badboy"
user_auth = "%s:%s" % (user, base64.b64encode(hashlib.new("sha1", auth).digest()))
#ZOO_OPEN_ACL_UNSAFE = {"perms":0x1f, "scheme":"world", "id" :"anyone"}
ZOO_DIGEST_ACL_SAFE = {"perms":0x1f ,"scheme":"digest", "id" : user_auth}

再将代码处的ZOO_OPEN_ACL_UNSAFE修改为ZOO_DIGEST_ACL_SAFE

最后就是认证了,我们需要在ZKClient类中的__init__最后一行添加zookeeper.add_auth(self.handle,"digest",auth , None)

这样，我们连接的句柄就是经过认证的了.

注意Server[A/B]代码不同之处是service函数处，所输出的ip内容是不一样的。

#!/usr/bin/env python
import logging
from os.path import basename, join ,dirname
from zkclient import ZKClient, zookeeper
from SimpleXMLRPCServer import SimpleXMLRPCServerDEBUG=True
BASE_DIR=dirname(__file__)if DEBUG:logname=""file_mode=""
else:logname=join(BASE_DIR,"app.log")file_mode="a"logging.basicConfig(level = logging.DEBUG,format = "[%(asctime)s] %(levelname)-8s %(message)s",datefmt = "%Y-%m-%d %H:%M:%S",filename = logname,filemode = file_mode,
)log = loggingclass TCZookeeper(object):ZK_HOST = "192.168.x.5:2181"ROOT = "/tc"WORKERS_PATH = join(ROOT, "nodes")MASTERS_NUM = 1TIMEOUT = 1000def __init__(self, verbose = True):self.VERBOSE = verboseself.masters = []self.path = Noneself.zk = ZKClient(self.ZK_HOST, timeout = self.TIMEOUT)self.say("login ok!")self.__init_zk()self.register()self.start_service()def __init_zk(self):nodes = (self.ROOT, self.WORKERS_PATH)for node in nodes:if not self.zk.exists(node):try:self.zk.create(node, "")except:passdef register(self):self.path = self.zk.create(self.WORKERS_PATH + "/node", "192.168.x.4", flags=zookeeper.EPHEMERAL | zookeeper.SEQUENCE)self.paths=self.pathself.path = basename(self.path)self.say("register ok! I'm %s" % self.path)def service(self):'''do somethings'''return "My IP is:192.168.x.4"def start_service(self):server = SimpleXMLRPCServer(("192.168.x.4", 8000))self.say("Listening on port 8000...")server.register_function(self.service, "service") server.serve_forever()def say(self, msg):if self.VERBOSE:log.info(msg)if __name__ == "__main__":tczk=TCZookeeper()

启动Server[A|B]输出如下:

A机192.168.x.4:
[root@web02 scripts]# python server.py
[2014-12-24 14:40:37] INFO     login ok!
[2014-12-24 14:40:37] INFO     register ok! I'm node0000000034
[2014-12-24 14:40:37] INFO     Listening on port 8000...B机192.168.x.5(zookeeper也在这台机器噢):
[root@web02 scripts]# python server.py
[2014-12-24 14:40:37] INFO     login ok!
[2014-12-24 14:40:37] INFO     register ok! I'm node0000000035
[2014-12-24 14:40:37] INFO     Listening on port 8000...

我们再来看看Agent代码:

#!/usr/bin/env python
import xmlrpclib
import logging
from os.path import basename, join ,dirname
from zkclient import ZKClient, watchmethod
from SimpleXMLRPCServer import SimpleXMLRPCServerDEBUG=True
BASE_DIR=dirname(__file__)if DEBUG:logname=""file_mode=""
else:logname=join(BASE_DIR,"app.log")file_mode="a" logging.basicConfig(level = logging.DEBUG,format = "[%(asctime)s] %(levelname)-8s %(message)s",datefmt = "%Y-%m-%d %H:%M:%S",filename = logname,filemode = file_mode,
)log = loggingclass TCZookeeper(object):ZK_HOST = "192.168.x.5:2181"ROOT = "/tc"NODES_PATH = join(ROOT, "nodes")MASTERS_NUM = 1TIMEOUT = 1000def __init__(self, verbose = True):self.VERBOSE = verboseself.masters = []self.path = Noneself.zk = ZKClient(self.ZK_HOST, timeout = self.TIMEOUT)self.say("login ok!")self.get_master()def get_master(self):"""get children, and check who is the smallest child"""@watchmethoddef watcher(event):self.say("child changed, try to get master again.")self.get_master()children = self.zk.get_children(self.NODES_PATH, watcher)children.sort()self.say("%s's children: %s" % (self.NODES_PATH, children))self.masters = children[:self.MASTERS_NUM]self.path=self.NODES_PATH+"/"+self.masters[0]self.serverip=self.zk.get(self.path)self.say("MasterIP:%s" %self.serverip[0])       def rpc(self):try:proxy = xmlrpclib.ServerProxy("http://%s:8000/" %self.serverip[0]) return "content: %s" % str(proxy.service())except:passdef start_service(self):server = SimpleXMLRPCServer(("192.168.x.3", 8000))self.say("Listening on port 8000...")server.register_function(self.rpc, "rpc")server.serve_forever()def say(self, msg):if self.VERBOSE:log.info(msg)if __name__ == "__main__":tczk = TCZookeeper()tczk.start_service()

启动agent输出如下:

[root@web01 scripts]# python agent.py
[2014-12-24 14:43:29] INFO     login ok!
[2014-12-24 14:43:29] INFO     /tc/nodes's children: ['node0000000034', 'node0000000035']
[2014-12-24 14:43:29] INFO     MasterIP:192.168.x.4
[2014-12-24 14:43:29] INFO     Listening on port 8000...

最后，我们看下client

#!/usr/bin/env python
import xmlrpclib
import time
#proxy = xmlrpclib.ServerProxy("http://192.168.x.3:8000/")
while True:try:proxy = xmlrpclib.ServerProxy("http://192.168.x.3:8000/")print proxy.rpc()except:passtime.sleep(1)

输出结果:

root@saltstack:/scripts# python client.py
content: My IP is:192.168.x.4
content: My IP is:192.168.x.4
content: My IP is:192.168.x.4

此时，我们将其192.168.x.4服务关掉.

很快打印的内容就变成

content: My IP is:192.168.x.5
content: My IP is:192.168.x.5

再看agent输出有，

[2014-12-24 14:47:34] INFO     child changed, try to get master again.
[2014-12-24 14:47:34] INFO     /tc/nodes's children: ['node0000000035']
[2014-12-24 14:47:34] INFO     MasterIP:192.168.x.5

看到没，原先MasterIP：192.168.x.4,现在192.168.x.5

呵呵，HA的功能试验完成了.

参考文档:

http://blog.csdn.net/lengzijian/article/details/9233327

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