how to use "activemq-admin" to view the list of queues; number of messages in the queue;
I read through the tutorial : http://activemq.apache.org/activemq-command-line-tools-reference.html
didn't find a working solution...
and my web console on the slave machine does not work... the web console seems always go with the master machine (in the master/slave structure)
I just want to test that if I send messages into queues on master, slave could update.
so I am trying to use activemq-admin.
The way it works is that Slave is waiting to get a lock to the DB (Kahadb by default) , you will not be able to check the slave , bring down the master and now the slave will become the master broker and you should be able to see all the queues and messages dropped in them (assuming you are using persistence)
You can use JMX, web console or programatically, as you can find here. The easiest solution, I think, is to use web console like here.
I can't understand why isn't accessible the web console. Check for ActiveMQ config xml.
Also you can connect via JMX like:
service:jmx:rmi:///jndi/rmi://localhost:1099/jmxrmi
Go here for more information.
Related
We have a couple of crusty AWS hosts running a RabbitMQ implementation in a cluster. We need to upgrade the hardware, and therefore we developed a Chef cookbook to spawn replacement servers.
One thing that we would rather not recreate by hand is the admin users, the queues, etc.
What is the best method to get that stuff from the old hosts to the new ones? I believe it's everything that lives in the /var/lib/rabbitmq/mnesia directory.
Is it wise to copy the files from one host to another?
Is there a programmatic means to do this?
Can it be coded into our Chef cookbook?
You can definitely export and import configuration via command line: https://www.rabbitmq.com/management-cli.html
I'm not sure about admin user, though.
If you create new rabbitmq nodes on your new hardware, you will get all the users in that new node. This is easy to try:
run docker container with image of rabbitmq (with management plugin)
and create a user
run another container and add that node to the
cluster of the first one
kill rabbitmq on the first one, or delete
the docker container and you will see that you still have the newly
created user on the 2nd (but now master) node
I wrote docker since it's faster to create a cluster this way, but if you already have a cluster you could use it for testing if you prefer.
For the queues and exchanges, I don't want to quote almost everything found in the rabbitmq doc page for the high availability, but I will just say that you have to pay attention to the following:
exclusive queues because they are gone once the client connection is gone
queue mirroring (if you have any set up, if not it would be wise to consider it, if not even necessary)
I would do the migration gradually, waiting for the queues to get emptied and then kill of the nodes on the old hardware. It maybe doable in a big-bang fashion, but seems riskier. If you have a running system, than set up queue mirroring and try to find appropriate moment to do manual sync - but careful, this has a huge impact on the broker performance.
Additionally there is this shovel plugin (I have to point out that I did not use it or even explore it) but that may be another way to go since (quoting form the link):
In essence, a shovel is a simple pump. Each shovel:
connects to the source broker and the destination broker, consumes
messages from the queue, re-publishes each message to the destination
broker (using, by default, the original exchange name and
routing_key).
I have a live application that for some reason stopped processing messages. Now after reboot there are 3 millions messages piled up. Looks like it will take about 60 hours to process. I'd like to just purge all of the messages. How safe or dangerous is it to simply run a "DELETE FROM ACTIVEMQ_MSGS" type command to get rid of the messages?
It's not correct to delete something from a persistant storage directly. Try using API exposed via JMX instead.
Connect with jconsole or a similar tool to your broker management port (if not enabled - see the link below). Switch to the MBean tab, then: org.apache.activemq → your_instance_name → Queue. Afterwards, clean target queue(s) with "Purge" operation.
JMX must be enabled in the broker for use:
http://activemq.apache.org/jmx.html
I have a two activeMQ(5.6.0) brokers. They use a shared kaha database so only one can be 'running' at once.
I have a (asp.net) webservice that puts a message on a queue, locally if I start and stop the brokers the webservice fails over correctly
when I test with the brokers on seperate machines it sometimes works but often I get "socketException: Connection reset" errors and the message is lost.
The connection string I am using is below. Note that I am aware NMS does not understand the priority backup command but I have left it there for the future.
failover:(tcp://MACHINE1:61616,tcp://MACHINE2:62616)?transport.initialReconnectDelay=1000&transport.timeout=10000&randomize=false&priorityBackup=true
How can I make my fail over between brokers fool proof?
The shared Kaha database was on a simple share. Currently activeMQ (or windows) cannot reliably get or release the lock in this configuration. The shared database must sit on a 'real' SAN so that both instances of the queue software see the database as being on a local filestore not a network location.
See this page for more info http://activemq.apache.org/shared-file-system-master-slave.html
I need help with the Embedded ActiveMq and Spring Framework.
Problem is :-
I am using Embedded ActiveMQ with Spring framework JMS Support.
As part of development I have a component which publish messages to Virtual Topic. And i have another componet which subscribes messages from the topic.
Now problem here is the application which is subscribing messages is running in cluster environment i.e one master instance and one slave instance. Events which i have published are going to either master instance or slave instance. But i want messages to be subscribed by only master instance. Is there any way i can block slave instance not to subscribe events?
We have a system property set to differentiate master and slave instance.I have tried add condition by overriding createConnection method of ActiveMqConnectionFactory class.
if(master) {
ActiveMqConnectionFactory.createConnection}
else
return null.
in this case, DefaultMessageListener of Spring framework which we configured to listen events always trying to refresh connection, since i am returning null for slave, it is failing to create connection. the thread is going to infinite loop with 5000MS interval..
Is there any way i can say MessageListener to stop refreshing connection..
Please kindly help me to resolve this issue..
if the cluster is master/slave...then only one should be active at a given time...sounds like you have dual masters from an AMQ client perspective...
regardless, you can always use ActiveMQ security to control access to a given topic/queue based on connection credentials (see http://activemq.apache.org/security.html)
I read in ActiveMQ page, using JMX we can monitor queues in activemq. How can we get notified if a queue has messages (depth high) or service interval is high in ActiveMQ. Without using any shell scripts in unix environment. Is it possible through Java program? If yes, give me some ideas to get this done.
For a JMX-free approach, you can also use the XML feed served by the activemq console page. The XML feed is hosted at http://ip:port/admin/xml/queues.jsp
This will have tags similar to this for each queue:
<queue name="your queue">
<stats size="0" consumerCount="1" enqueueCount="0" dequeueCount="0"/>
....
</queue>
Just parse this XML in your code and you are good to go.
you can use Java via JMX APIs to periodically poll for queue stats (see this guide)
for the notification approach, you'd need to use advisory messages to monitor messages delivered to a queue (see this guide)
Yes it is possible in Java.
Starting from version 5.8 of ActiveMQ jolokia agent comes embedded. So it is possible for you to get all stats that JMX can pull using HTTP request which will retuen you stats as JSON and then you can check current values and raise Email alert using SMTP if values go beyond threshold you have decided.
Lets say you want to pull Broker stats using Jolokia hit below URL in your browser enter AMQ console username and password which is admin by default
http://servername.com:8161/api/jolokia/read/org.apache.activemq:type=Broker,brokerName=localhost
Or if you dont want to go through all this trouble , You can use ready made Python script which I have created to Monitor AMQ Heap, Queue params and Broker availability.You can take a look , it may help you in developing your custiom script or program
AMQMonitor and Alerting script