zookeeper學習筆記2

zookeeper的實用場景有統一配置，統一命名服務,集羣管理,分佈式鎖，分佈式隊列。

今天，個人實驗場景是集羣管理的ha功能.

實驗架構以下:

Server[A/B]代碼:

此處，咱們須要第3方的模塊
zkclient.py（https://github.com/phunt/zk-smoketest/blob/master/zkclient.py）

須要作些稍微的修改，由於我這裏的ACL採用的是digest，而不是world

導入些模塊:

import base64
import hashlib

定義些變量

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}

再將代碼處的ZOO_OPEN_ACL_UNSAFE修改成ZOO_DIGEST_ACL_SAFE

最後就是認證了,咱們須要在ZKClient類中的__init__最後一行添加zookeeper.add_auth(self.handle,"digest",auth , None)

這樣，咱們鏈接的句柄就是通過認證的了.

注意Server[A/B]代碼不一樣之處是service函數處，所輸出的ip內容是不同的。

#!/usr/bin/env python
import logging
from os.path import basename, join ,dirname
from zkclient import ZKClient, zookeeper
from SimpleXMLRPCServer import SimpleXMLRPCServer

DEBUG=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 = logging

class TCZookeeper(object):

    ZK_HOST = "192.168.x.5:2181"
    ROOT = "/tc"
    WORKERS_PATH = join(ROOT, "nodes")
    MASTERS_NUM = 1
    TIMEOUT = 1000

    def __init__(self, verbose = True):
        self.VERBOSE = verbose
        self.masters = []
        self.path = None

        self.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:
                    pass

    def register(self):
        self.path = self.zk.create(self.WORKERS_PATH + "/node", "192.168.x.4", flags=zookeeper.EPHEMERAL | zookeeper.SEQUENCE)
        self.paths=self.path
        self.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()

啓動Server[A|B]輸出以下:

A機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機192.168.x.5(zookeeper也在這臺機器噢):
[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...

咱們再來看看Agent代碼:

#!/usr/bin/env python
import xmlrpclib
import logging
from os.path import basename, join ,dirname
from zkclient import ZKClient, watchmethod
from SimpleXMLRPCServer import SimpleXMLRPCServer

DEBUG=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 = logging

class TCZookeeper(object):
    ZK_HOST = "192.168.x.5:2181"
    ROOT = "/tc"
    NODES_PATH = join(ROOT, "nodes")
    MASTERS_NUM = 1
    TIMEOUT = 1000

    def __init__(self, verbose = True):
        self.VERBOSE = verbose
        self.masters = []
        self.path = None

        self.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
        """
        @watchmethod
        def 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:
            pass
    
    def 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()

啓動agent輸出以下:

[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...

最後，咱們看下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:
        pass
    time.sleep(1)

輸出結果:

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

此時，咱們將其192.168.x.4服務關掉.

很快打印的內容就變成

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

再看agent輸出有，

[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

看到沒，原先MasterIP：192.168.x.4,如今192.168.x.5

呵呵，HA的功能試驗完成了.

參考文檔:

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

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