activemq热备与消息丢失

1. 解压 tar -zxvf apache-activemq-5.12.0-bin.tar.gz
2. 改名 mv apache-activemq-5.12.0 activemq
3. cd activemq/bin
4. 启动 ./activemq start
5. 访问 ip:8161/admin

/* 楼主本地的虚拟机这么安装没问题，可是远程的服务器安装却启动失败
 * 如果启动报错的话，可以通过 ./activemq console查看启动信息
 * 我启动失败是应为主机名不合法， 通过 hostname 命令可以查看当前主机名
 * hostnamectl set-hostname newname设置新的主机名
 * hostnamectl –static set-hostname newname设置静态名字
 * 使用 reboot 重启之后， 就是新的名字了  (名字最好是简短的纯英文)
 */

消息丢失：如果在.5机器发送了2条消息，然后用.6机器去消费1条；这个时候对于.5机器来说.6就是一个客户端，它拿走了2条消息消费了一条还剩一条待消费。而此时剩下的一条只能通过.6机器消费，无法通过.5拿到消息。这样就达不到高性能的目的，我们可以通过消息回流来解决。

activemq热备配置(可以是n台，我以2台为例，灰色部分都是默认配置文件)：vim  activemq/conf/activemq.xml

<!-- START SNIPPET: example -->
<beans
  xmlns="http://www.springframework.org/schema/beans"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
  http://activemq.apache.org/schema/core http://activemq.apache.org/schema/core/activemq-core.xsd">
    <!-- Allows us to use system properties as variables in this configuration file -->
    <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="locations">
            <value>file:${activemq.conf}/credentials.properties</value>
        </property>
    </bean>
   <!-- Allows accessing the server log -->
    <bean id="logQuery" class="io.fabric8.insight.log.log4j.Log4jLogQuery"
          lazy-init="false" scope="singleton"
          init-method="start" destroy-method="stop">
    </bean>
    <broker xmlns="http://activemq.apache.org/schema/core" brokerName="localhost" dataDirectory="${activemq.data}">
        <destinationPolicy>
            <policyMap>
              <policyEntries>
                <policyEntry topic=">" >
                    <!-- The constantPendingMessageLimitStrategy is used to prevent
                         slow topic consumers to block producers and affect other consumers
                         by limiting the number of messages that are retained
                         For more information, see:
                         http://activemq.apache.org/slow-consumer-handling.html
                    -->
                  <pendingMessageLimitStrategy>
                    <constantPendingMessageLimitStrategy limit="1000"/>
                  </pendingMessageLimitStrategy>
                </policyEntry>
                <!-- 消息回流：加这段配置就不会出现消息丢失的情况(有中文会启动失败)  这段注释要删掉 -->
                <policyEntry queue=">" enableAudit="false">
                    <networkBridgeFilterFactory>
                        <conditionalNetworkBridgeFilterFactory replayWhenNoConsumers="true" />
                    </networkBridgeFilterFactory>
                </policyEntry>
              </policyEntries>
            </policyMap>
        </destinationPolicy>
        <!--
            The managementContext is used to configure how ActiveMQ is exposed in
            JMX. By default, ActiveMQ uses the MBean server that is started by
            the JVM. For more information, see:
            http://activemq.apache.org/jmx.html
        -->
        <managementContext>
            <managementContext createConnector="false"/>
        </managementContext>
        <!--
            Configure message persistence for the broker. The default persistence
            mechanism is the KahaDB store (identified by the kahaDB tag).
            For more information, see:
            http://activemq.apache.org/persistence.html
        -->
        <persistenceAdapter>
            <kahaDB directory="${activemq.data}/kahadb"/>
        </persistenceAdapter>
        <!-- 热备配置：只需要在这里指定服务器地址就好了(有中文会启动失败)  这段注释要删掉 -->
        <networkConnectors>
            <networkConnector uri="static://(tcp://192.168.5.5:61616,tcp://192.168.5.6:61616)" />
        </networkConnectors>
          <!--
            The systemUsage controls the maximum amount of space the broker will
            use before disabling caching and/or slowing down producers. For more information, see:
            http://activemq.apache.org/producer-flow-control.html
          -->
          <systemUsage>
            <systemUsage>
                <memoryUsage>
                    <memoryUsage percentOfJvmHeap="70" />
                </memoryUsage>
                <storeUsage>
                    <storeUsage limit="100 gb"/>
                </storeUsage>
                <tempUsage>
                    <tempUsage limit="50 gb"/>
                </tempUsage>
            </systemUsage>
        </systemUsage>
        <!--
            The transport connectors expose ActiveMQ over a given protocol to
            clients and other brokers. For more information, see:
            http://activemq.apache.org/configuring-transports.html
        -->
        <transportConnectors>
            <!-- DOS protection, limit concurrent connections to 1000 and frame size to 100MB -->
            <transportConnector name="openwire" uri="tcp://0.0.0.0:61616?maximumConnections=1000&amp;wireFormat.maxFrameSize=104857600"/>
            <transportConnector name="amqp" uri="amqp://0.0.0.0:5672?maximumConnections=1000&amp;wireFormat.maxFrameSize=104857600"/>
            <transportConnector name="stomp" uri="stomp://0.0.0.0:61613?maximumConnections=1000&amp;wireFormat.maxFrameSize=104857600"/>
            <transportConnector name="mqtt" uri="mqtt://0.0.0.0:1883?maximumConnections=1000&amp;wireFormat.maxFrameSize=104857600"/>
            <transportConnector name="ws" uri="ws://0.0.0.0:61614?maximumConnections=1000&amp;wireFormat.maxFrameSize=104857600"/>
        </transportConnectors>
        <!-- destroy the spring context on shutdown to stop jetty -->
        <shutdownHooks>
            <bean xmlns="http://www.springframework.org/schema/beans" class="org.apache.activemq.hooks.SpringContextHook" />
        </shutdownHooks>
    </broker>
    <!--
        Enable web consoles, REST and Ajax APIs and demos
        The web consoles requires by default login, you can disable this in the jetty.xml file
        Take a look at ${ACTIVEMQ_HOME}/conf/jetty.xml for more details
    -->
    <import resource="jetty.xml"/>
</beans>
<!-- END SNIPPET: example -->

测试：