问题
I have 4 ActiveMQ Artemis 2.10.1 instances running in a cluster. A client (A) connects to one of the nodes and publishes MQTT message with QoS=0 and retain=true. When a new MQTT client (B) connects to another node in the cluster and subscribes for the topic, the previously sent message is not received. When than client A publishes a next message, client B gets the message.
Is it a bug in Artemis that retained message sent by A is not received by a client B when it connects to another node in the cluster or I'm missing something?
If I connect client A and client B to the same node in the cluster, client B gets the message after it is connected and subscribed for the topic.
broker.xml - I use poc.# for the testing:
<configuration xmlns="urn:activemq"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xi="http://www.w3.org/2001/XInclude"
xsi:schemaLocation="urn:activemq /schema/artemis-configuration.xsd">
<core xmlns="urn:activemq:core" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="urn:activemq:core ">
<name>Broker 01</name> <!-- changed on every node -->
<persistence-enabled>true</persistence-enabled>
<journal-type>NIO</journal-type>
<paging-directory>data/paging</paging-directory>
<bindings-directory>data/bindings</bindings-directory>
<journal-directory>data/journal</journal-directory>
<large-messages-directory>data/large-messages</large-messages-directory>
<journal-datasync>true</journal-datasync>
<journal-min-files>2</journal-min-files>
<journal-pool-files>10</journal-pool-files>
<journal-device-block-size>4096</journal-device-block-size>
<journal-file-size>10M</journal-file-size>
<journal-buffer-timeout>1328000</journal-buffer-timeout>
<journal-max-io>1</journal-max-io>
<disk-scan-period>5000</disk-scan-period>
<max-disk-usage>90</max-disk-usage>
<critical-analyzer>true</critical-analyzer>
<critical-analyzer-timeout>120000</critical-analyzer-timeout>
<critical-analyzer-check-period>60000</critical-analyzer-check-period>
<critical-analyzer-policy>HALT</critical-analyzer-policy>
<acceptors>
<acceptor name="artemis">tcp://0.0.0.0:61616</acceptor>
<acceptor name="mqtt">tcp://0.0.0.0:1883?protocols=MQTT</acceptor>
</acceptors>
<connectors>
<connector name="netty-connector">tcp://10.0.0.2:61616</connector> <!-- changed on every node -->
</connectors>
<broadcast-groups>
<broadcast-group name="my-broadcast-group">
<group-address>231.7.7.7</group-address>
<group-port>9876</group-port>
<broadcast-period>2000</broadcast-period>
<connector-ref>netty-connector</connector-ref>
</broadcast-group>
</broadcast-groups>
<discovery-groups>
<discovery-group name="my-discovery-group">
<group-address>231.7.7.7</group-address>
<group-port>9876</group-port>
<refresh-timeout>10000</refresh-timeout>
</discovery-group>
</discovery-groups>
<cluster-connections>
<cluster-connection name="artemis-cluster">
<address></address>
<connector-ref>netty-connector</connector-ref>
<retry-interval>1000</retry-interval>
<use-duplicate-detection>true</use-duplicate-detection>
<message-load-balancing>ON_DEMAND</message-load-balancing>
<max-hops>1</max-hops>
<discovery-group-ref discovery-group-name="my-discovery-group"/>
</cluster-connection>
</cluster-connections>
<security-settings>
<security-setting match="#">
<permission type="createNonDurableQueue" roles="amq"/>
<permission type="deleteNonDurableQueue" roles="amq"/>
<permission type="createDurableQueue" roles="amq"/>
<permission type="deleteDurableQueue" roles="amq"/>
<permission type="createAddress" roles="amq"/>
<permission type="deleteAddress" roles="amq"/>
<permission type="consume" roles="amq"/>
<permission type="browse" roles="amq"/>
<permission type="send" roles="amq"/>
<!-- we need this otherwise ./artemis data imp wouldn't work -->
<permission type="manage" roles="amq"/>
</security-setting>
<!-- Security setting for testing. -->
<security-setting match="poc.#">
<permission type="createNonDurableQueue" roles="read-write"/>
<permission type="deleteNonDurableQueue" roles="read-write"/>
<permission type="createDurableQueue" roles="read-write"/>
<permission type="deleteDurableQueue" roles="read-write"/>
<permission type="createAddress" roles="read-write"/>
<permission type="deleteAddress" roles="write"/>
<permission type="consume" roles="read-write"/>
<permission type="browse" roles="read-write"/>
<permission type="send" roles="write"/>
</security-setting>
</security-settings>
<address-settings>
<address-setting match="activemq.management#">
<dead-letter-address>DLQ</dead-letter-address>
<expiry-address>ExpiryQueue</expiry-address>
<redelivery-delay>0</redelivery-delay>
<max-size-bytes>-1</max-size-bytes>
<message-counter-history-day-limit>10</message-counter-history-day-limit>
<address-full-policy>PAGE</address-full-policy>
<auto-create-queues>true</auto-create-queues>
<auto-create-addresses>true</auto-create-addresses>
<auto-create-jms-queues>true</auto-create-jms-queues>
<auto-create-jms-topics>true</auto-create-jms-topics>
</address-setting>
<address-setting match="#">
<dead-letter-address>DLQ</dead-letter-address>
<expiry-address>ExpiryQueue</expiry-address>
<redelivery-delay>0</redelivery-delay>
<max-size-bytes>-1</max-size-bytes>
<message-counter-history-day-limit>10</message-counter-history-day-limit>
<address-full-policy>PAGE</address-full-policy>
<auto-create-queues>true</auto-create-queues>
<auto-create-addresses>true</auto-create-addresses>
<auto-create-jms-queues>true</auto-create-jms-queues>
<auto-create-jms-topics>true</auto-create-jms-topics>
</address-setting>
<!-- Address setting for testing -->
<address-setting match="poc.#">
<dead-letter-address>DLQ</dead-letter-address>
<expiry-address>ExpiryQueue</expiry-address>
<redelivery-delay>0</redelivery-delay>
<max-size-bytes>-1</max-size-bytes>
<message-counter-history-day-limit>10</message-counter-history-day-limit>
<address-full-policy>PAGE</address-full-policy>
<auto-create-queues>true</auto-create-queues>
<auto-delete-queues>true</auto-delete-queues>
<auto-create-addresses>true</auto-create-addresses>
<auto-delete-addresses>true</auto-delete-addresses>
<default-address-routing-type>MULTICAST</default-address-routing-type>
</address-setting>
</address-settings>
<addresses>
<address name="DLQ">
<anycast>
<queue name="DLQ" />
</anycast>
</address>
<address name="ExpiryQueue">
<anycast>
<queue name="ExpiryQueue" />
</anycast>
</address>
</addresses>
</core>
</configuration>
回答1:
You need to set this <address-setting> for the address you're concerned with:
<redistribution-delay>0</redistribution-delay>
See the "Message Redistribution" section of the ActiveMQ Artemis documentation for more details on this.
来源：https://stackoverflow.com/questions/58744799/apache-mq-artemis-mqtt-retained-message-not-available-for-a-client-that-connec