ActiveMQ

Introduction This article is a quick tip for ActiveMQ users, and introduces the Time Stamp Plugin. Common support queries we get with ActiveMQ are the broker running out of space, or Producer Flow Control kicking in. Often, the cause is simple: messages have been sent to the broker, and haven’t been consumed. This will be exacerbated if you have multiple destinations, and particularly if you use KahaDB for persistence (which is the default). See my post here to get a 10000 ft view on how KahaDB works under the covers, and how it can use a large amount of disk…

Apache ActiveMQ is a well known and very flexible message broker. As such, it fully embraced the AAA model (Authentication, Authorization, Accountability) with built-in plugins.  For example, by default, it comes with Simple Authentication Plugin: it handles user authentication based on the `activemq.xml` defined list of users. Or, as an alternative, you can load users from properties. This is very useful for tests or to quickly bootstrap a project but does not target real-life deployments. JAAS Authentication Plugin: JAAS stands for Java Authentication and Authorization Service and is quite well known in the Java EE space (or Jakarta EE space)….

ActiveMQ is often a critical component in Enterprise systems, and therefore High Availability (HA) is a “must have” in order to meet production Service Level Agreements (SLA). This blog aims at providing a deployment architecture based on a set of Apache ActiveMQ brokers wired up to a SQL database.  This blog targets Apache ActiveMQ “classic” as opposed to Apache ActiveMQ Artemis. Failover architecture for high availability What are we trying to achieve? A single instance of ActiveMQ can receive and deliver a very high volume of messages. It is very easy to increase performance and handle more messages by simply…

One of the common issues we run into with ActiveMQ, is the issue of kahadb log files not being cleared up, leading to the system potentially running out of disk space.  There are a few reasons why these log files are not cleaned up: It contains a pending message for a destination or durable topic subscription It contains an ACK for a message which is in an in-use data file – the ACK cannot be removed as a recovery would then mark the message for redelivery The journal references a pending transaction It is a journal file, and there may…