We recently had serious issues with the ActiveMQ redelivery plugin. Under high load messages would not be redelivered at all (according to the application logs), they went straight to the DLQ. In isolated tests redelivery worked, but not as intended. We would get six redeliveries in a few milliseconds and then nothing. Why?
It turned out to be a conflict between client-side redelivery and broker redelivery. The client side redelivery kicked in and quickly failed six times. Then when the broker got a chance the maximum redelivery count had already been reached, so the message was moved to the DLQ. See this post.
Following the advice in the post we added
jms.redeliveryPolicy.maximumRedeliveries=0 to the broker url, and voila! It worked.
Hawtio is bundled in several applications as a management console. In one project we are using it with JBoss EAP 6. However, when the application server starts hawtio attempts to update itself from Github:
Performing a pull in git repository .hawtio/config on remote URL: https://github.com/hawtio/hawtio-config.git. Subsequent pull attempts will use debug logging Failed to pull from the remote git repo with credentials null due: https://github.com/hawtio/hawtio-config.git: 407 Proxy Authentication Required. This exception is ignored.
I certainly don’t want applications in production to update themselves dynamically with unforseen effects and neither do I want them to phone home. What to do? Fortunately it is possible to control this, see the documentation. Simply add the following Java options:
-Dhawtio.offline=true -Dhawtio.config.cloneOnStartup=false -Dhawtio.config.pullOnStartup=false