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03_Flume多节点Failover实践

时间:2017-12-02 11:11:03      阅读:152      评论:0      收藏:0      [点我收藏+]

标签:技术分享   tran   分享   process   spec   select   lin   ber   故障恢复   

1、实践场景

模拟上游Flume Agent在发送event时的故障切换 (failover)

1)初始:上游Agent向active的下游节点Collector1传递event

2)Collector1故障: kill该进程的方式来模拟, event此时发送给Collector2,完成故障切换

3)Collector1恢复:重新运行该进程,经过最大惩罚时间后,event将恢复发送给Collector1

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2、配置文件

Agent配置文件

# flume-failover-client
# agent name: a1
# source: exec with given command, monitor output of the command, each line will be generated as an event
# channel: memory
# sink: k1 k2, each set to avro type to link to next-level collector

# 01 define source,channel,sink name
a1.sources = r1
a1.channels = c1
a1.sinks = k1 k2

# 02 define source
a1.sources.r1.type = exec
a1.sources.r1.command = tail -f /root/flume_test/server.log

# 03 define sink,each connect to next-level collector via hostname and port
a1.sinks.k1.type = avro
a1.sinks.k1.hostname = slave1   # sink bind to remote host, RPC(上游Agent avro sink绑定到下游主机)
a1.sinks.k1.port = 4444

a1.sinks.k2.type = avro
a1.sinks.k2.hostname = slave2   # sink band to remote host, PRC(上游Agent avro sink绑定到下游主机)
a1.sinks.k2.port = 4444

# 04 define sinkgroups,only 1 sink will be selected as active based on priority and online status
a1.sinkgroups = g1
a1.sinkgroups.g1.sinks = k1 k2
a1.sinkgroups.g1.processor.type = failover

# k1 will be selected as active to send event if k1 is online, otherwise k2 is selected
a1.sinkgroups.g1.processor.priority.k1 = 10   # 基于优先级进行选择,优先级高的被选中active; 优先级相同则根据k1,k2出现的先后顺序进行选择
a1.sinkgroups.g1.processor.priority.k2 = 1

# failover time,milliseconds
# if k1 is down and up again, k1 will be selected as active after 1 seconds
a1.sinkgroups.g1.processor.priority.maxpenality = 1000  # 回切时间


# 05 define channel
a1.channels.c1.type = memory
# number of events in memory queue 
a1.channels.c1.capacity = 1000  
# number of events for 1 commit(commit events to memory queue)
a1.channels.c1.transactioncapacity = 100

# 06 bind source,sink to channel
a1.sources.r1.channels = c1
a1.sinks.k1.channel = c1

a1.sinks.k2.channel = c1

Collector1配置文件

# 01 specify agent,source,sink,channel
a1.sources = r1
a1.sinks = k1
a1.channels = c1

# 02 avro source,connect to local port 4444
a1.sources.r1.type = avro        # 下游avro source绑定到本机,端口号要和上游Agent指定值保持一致
a1.sources.r1.bind = slave1
a1.sources.r1.port = 4444

# 03 logger sink
a1.sinks.k1.type = logger 

# 04 channel,memory
a1.channels.c1.type = memory
a1.channels.c1.capacity = 1000
a1.channels.c1.transactionCapacity = 100

# 05 bind source,sink to channel
a1.sources.r1.channels = c1
a1.sinks.k1.channel = c1

Collector2配置文件

# 01 specify agent,source,sink,channel
a1.sources = r1
a1.sinks = k1
a1.channels = c1

# 02 avro source,connect to local port 4444
a1.sources.r1.type = avro      # 下游avro source绑定到本机,端口号要和上游Agent指定值保持一致
a1.sources.r1.bind = slave2
a1.sources.r1.port = 4444

# 03 logger sink
a1.sinks.k1.type = logger 

# 04 channel,memory
a1.channels.c1.type = memory
a1.channels.c1.capacity = 1000
a1.channels.c1.transactionCapacity = 100

# 05 bind source,sink to channel
a1.sources.r1.channels = c1
a1.sinks.k1.channel = c1

 

3、启动Collector1,2 以及Agent

启动Collector1

# ./bin/flume-ng agent --conf conf --conf-file ./conf/flume-failover-server.properties --name a1 -Dflume.root.logger=INFO,console

 解读:根据当前目录下的conf目录中的flume-failvoer-server.properties配置文件启动flume agent; agent名称为a1;

            flume向终端打印INFO级别及以上的日志信息

 

启动Collector2

 # ./bin/flume-ng agent --conf conf --conf-file ./conf/flume-failover-server.properties --name a1 -Dflume.root.logger=INFO,console

 启动Agent

# ./bin/flume-ng agent --conf conf --conf-file ./conf/flume-failover-client.properties --name a1 -Dflume.root.logger=INFO,console

 

注意:

1)要先启动下游Collector,再去启动Agent;  否则Agent启动后就会进行下游有效站点的选择,此时Collector如果还没有启动,则会出现报错

技术分享图片

 

2)3个Agent正常启动后, Agent会建立和所有下游站点的连接: 经历 open -> bound -> connected 三个阶段

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4、故障模拟及恢复

1) 故障发生前: 首先向log文件,管道方式添加数据,查看event是否在Collector1的终端被打印

技术分享图片

Collector1所在的Slave1节点收到并向终端打印event

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 2) 故障模拟: kill collector1进程

 3)再次尝试发送数据

 技术分享图片

 Collector2所在的Slave2节点收到并向终端打印event

 技术分享图片

 与此同时,Agent将一直尝试重新建立和Collector1的连接

 技术分享图片

 

4)重新启动Collector1进程,模拟故障恢复

# ./bin/flume-ng agent --conf conf --conf-file ./conf/flume-failover-server.properties --name a1 -Dflume.root.logger=INFO,console

 

 

5)向log中再次追加数据,查看event是否重新被发送给collector1, 并被打印到终端

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此时Collecot1收到并打印事件 (回切时间在Agent的配置中设置为1秒)

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 6) 考虑所有下游节点全部down掉,之后下游节点恢复的情况,数据最终给谁?

 由于Flume有基于event的事务机制,当下游节点全部down掉时,Flume会将event保留在channel中

 当下游节点重新恢复,Agent会再次进行active节点选择,然后将evnet再次发送

 当下游节点收到event后,Agent才将event从channel中移除

 如果是Collecotr2先恢复, 则event会发送给Collector2;  并且Collecot1之后并不会收到发给Collector2的数据,因此event此时已经从Agent的channel中被移除

 

03_Flume多节点Failover实践

标签:技术分享   tran   分享   process   spec   select   lin   ber   故障恢复   

原文地址:http://www.cnblogs.com/shay-zhangjin/p/7946282.html

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