Is there any good way to integrate OpenLDAP or ApacheDS servers (or maybe another open-source LDAP server) with JMS to propagate LDAP database modification to another service?
Basically I need to have LDAP server cluster (several instances with master to master replication) and another standalone Java application, connected via a JMS server (e.g. ActiveMQ), so that:
All changes to LDAP data structure are sent to the Java app.
The Java app. can send messages to the LDAP database via JMS server to update LDAP data
I found out that there is a way to set up JMS replication for ApacheDS (https://cwiki.apache.org/DIRxSRVx11/replication-requirements.html#ReplicationRequirements-GeneralRequirements), but I am in doubt whether it will work in case we have a cluster of several ApacheDS masters + one JMS replication node to send all modifications to the cluster.
UPDATE: The page describing JMS replication for ApacheDS turned out to be 5 ears old, so currently the only way of replication in ApacheDS, I know about, is LDAP protocol based replication.
There IDM products that will perform what you are asking about.
I know NetIQs IDM products works well with JMS.
OpenLDAP and ApacheDS have a changeLog that you could use to determine the changes made.
You could then write some code to send the changes to JMS Queue.
I can't speak for ApacheDS, but OpenLDAP already contains a full-blown replication system, with about six different ways to configure it; in other words, you can do it perfectly well, and much more efficiently, without Java and JMS.
Related
I have an instance of ActiveMQ 5.16.4 running that is using MySQL as a persistent data storage. Recently the MySQL server had some issues, and ActiveMQ lost its connection to MySQL. That caused multiple Spring microservices to throw errors because ActiveMQ wasn't working.
Is it possible to have master/slave ActiveMQ running where master and slave uses separate persistence storage?
I have done some research and found "pure master slave", but it says that it is deprecated and not recommend to use and will be removed in 5.8. It says to use shared storage which I am trying to avoid (cause my problem is what if storage itself is down).
What are my options to keep running ActiveMQ if it loses connection to database?
If you're using ActiveMQ "Classic" (i.e. 5.x) then your only option is to use shared storage between the master and the slave. This could be a shared file system or a relational database. This, of course, is a single point of failure.
However, there are both file system and database technologies that can mitigate this risk. For example you could use a replicated file system (e.g. Ceph or GlusterFS) or a replicated database (e.g. MySQL).
You might also consider using ActiveMQ Artemis (i.e. the next-generation broker from ActiveMQ) which supports replication natively.
I feel like I am missing something very fundamental here.
I can bring up a RabbitMQ cluster with three nodes (rabbit1, rabbit2 and rabbit3) without an issue. Then when I start writing my microservices it seems like each client connects to only one rabbit instance. So let's say I have all my services connect to rabbit1.
If rabbit1 then goes down will my entire infrastructure blow up? Do the services have a way of switching to another rabbit node? It seems like they cannot, in which case, what is the point of having a cluster?
In case someone else runs into this and has trouble (like myself) finding this in the documentation, RabbitMQ does not manage client connection auto-recovery. From the docs:
Some client libraries provide a mechanism for automatic recovery from
network connection failures... Other clients may consider network
failure recovery to be a responsibility of the application.
So first check if you library offers auto-recovery, if not you'll have to implement it yourself.
I am trying to setup a distributed system based on current spring-cloud release (meaning mostly Netflix OSS) using the following components
1 or more cloud config servers
1 or more Eureka servers
1 or more services using Eureka and Config Server clients
The setup above is easy enough to get going however once you start looking into setting up so that configuration changes in the cloud Config servers automatically trigger changes in the values of the actual clients, things start getting more complicated.
It is my understanding that for such a feature to work one should introduce spring-cloud-bus clients to the services which in turn will use, currently the only supported implementation, rabbitmq servers (the actual rabbitmq binaries and not some spring-boot app like eureka or Config servers) to allow change events in the Config server to be propagated to the clients automatically.
It sounds counterintuitive to setup such a system and have to hardcode addresses to rabbitmq servers in the clients (even if one will be keeping the amount of rabbitmq servers more or less static).
How is one supposed to register rabbitmq server instances in the Eureka service discovery server(s) to allow for clients to find them without having to have any knowledge about their location prior to startup?
I cannot seem to find any documentation on how this is done given that rabbitmq is not a spring-cloud component. In fact very little documentation seems to exist regarding on how the rabbitmq + eureka + spring-cloud-bus should be setup together.
I know that I am on a VERY old question, even though I think it worth a comment for people who read this in the future.
Most of the cloud services, lets take AWS as an example, have an Elastic IP solution - so you can configure IPs for RabbitMQ servers, and the IPs always belong to the RabbitMQ, no matter whether the instances change. You can re-attach the Elastic IP to different instances.
It works nearly the same with Elastic Load Balancer, which keeps its IP, so you could configure your microservices to a specific IP using Spring Cloud Config Server - and scale the RabbitMQ instances without a need to worry about configuration change.
what is the best way to monitor the Mule ESB instances. Is there a way i can get alerted when my mule instance goes down for some reason. I have 4 instances of Mule running and how will I come to know if 1 of them got down due to some reason.
Thanks!
I assume you are running community edition? (Enterprise edition provides a Management Console which allows you to define alerts). If you are using CE, then you are able to enable JMX monitoring on the instances and then use one of many ways to verify based on JMX info, whether your server is running. One way is to write your own application that retrieves JMX data programmatically and act accordingly.
HTH
If you are using Mule EE, you can use MMC to monitor all your instances as Gabriel has already suggested. My suggestion would be to install MMC inside tomcat on a separate server. This is to ensure that even if your Mule Server crashes or goes down, your MMC is still running and can send you alerts about your Mule server downtime. You can refer below link for details on how to setup server down and up alerts.
https://developer.mulesoft.com/docs/display/current/Working+With+Alerts
Additionally I would recommend to use MMC with database persistence to ensure you have ability to recover MMC workspace even if your MMC server crashes. You can refer about MMC setup with DB persistence at below link.
https://developer.mulesoft.com/docs/display/current/Configuring+MMC+for+External+Databases+-+Quick+Reference
If you don't have Mule EE, you may want to explore other tools or customer alerting applications as suggested by Gabriel.
HTH
You can set up a JMX agent by adding the following lines into your "conf/wrapper.conf" file :
wrapper.java.additional.19=-Dcom.sun.management.jmxremote
wrapper.java.additional.20=-Dcom.sun.management.jmxremote.port=10055
wrapper.java.additional.21=-Dcom.sun.management.jmxremote.authenticate=false
wrapper.java.additional.22=-Dcom.sun.management.jmxremote.ssl=false
wrapper.java.additional.23=-Djava.rmi.server.hostname=127.0.0.1
don't forget to change the values accordingly. Also you can implement SSL authentication with a few extra lines.
Now once your monitoring platform is set up you can always activate Java pollers and start the server.
I am confused about the function of Apache ActiveMQ.
I downloaded ActiveMQ from this link.
So I use it this way (environment: Windows 7): I start the bin/activemq.bat, then it works.
My question is: Does this mean I start a server on my machine? When I initialize the ActiveMQConnectionFactory, the broker URL is tcp://localhost:61616. But what if I want my machine to serve as a server and another machine to connect to my server?
Yes, you can use the primary box as a server and have consumers/subscribers running on other boxes (which will need to connect to the server - you will need to specify the server hostname & port for the connection to be established) - once in place, the messages on the server (topic or queue) can be consumed by the clients.
If you one have one producer and one consumer, you can look into using queues - if you have more than one consumer/subscriber, you can look into setting up a topic to which the consumers will subscribe to. Messages need to be inserted to the topic/queue as needed.
You can specify the server information in your code or preferably in the config file.
For reference to topologies:
http://activemq.apache.org/topologies.html
Also, you can choose to persist your messages or not based on your use case. Kaha DB is the preferred route (specially if performance is of concern).
Useful examples:
http://sujitpal.blogspot.com/2007/12/jms-patterns-with-activemq.html
http://vvratha.blogspot.com/2012/05/java-client-to-sendreceive-messages-for.html
Hope it helps.
Apache ActiveMQ ™ is the most popular and powerful open source messaging and Integration Patterns server
& it act like a third party server.
Apache ActiveMQ is fast, supports many Cross Language Clients and Protocols, comes with easy to use Enterprise Integration Patterns and many advanced features while fully supporting JMS 1.1 and J2EE 1.4. Apache ActiveMQ is released under the Apache 2.0 License.
ActiveMQ have the capabilities to send 100 MB single message framework and maintain 1000 concurrent connection simultaneously , for the further information you can check activemq.xml in your documentation.
Further Info at here about the ActiveMQ