Train Series Release Notes¶

18.0.0.0b1-102¶

The option rabbitmq_erlang_version_spec has been added allowing deployers to set the version of erlang used on a given installation.

The override rabbitmq_memory_high_watermark can be used to set the maximum size of the erlang Virtual Machine before the garbage collection is triggered. The default is lowered to 0.2, from 0.4 as the garbage collection can require 2x of allocated amount during its operation. This can result in a equivalent use of 0.4, resulting in 40% of memory usage, visible to the rabbitMQ container. The original default setting of 0.4 can lead to 80% memory allocation of rabbitMQ, potentially leading to a scenario where the underlying Linux kernel is killing the process due to shortage of virtual memory.

The rabbitMQ high watermark is set to 0.2 rather than 0.4 to prevent possible OOM situations, which limits the maximum memory usage by rabbitMQ to 40% rather than 80% of the memory visible to the rabbitMQ container. The override rabbitmq_memory_high_watermark can be used to alter the limit.

The data structure for rabbitmq_gpg_keys has been changed to be a dict passed directly to the applicable apt_key/rpm_key module. As such any overrides would need to be reviewed to ensure that they do not pass any key/value pairs which would cause the module to fail.

The default values for rabbitmq_gpg_keys have been changed for all supported platforms will use vendored keys. This means that the task execution will no longer reach out to the internet to add the keys, making offline or proxy-based installations easier and more reliable.

The default queue policy has changed to ^(?!(amq\.)|(.*_fanout_)|(reply_)).* instead of ^(?!amq\.).* for efficiency. The new HA policy excludes reply queues (these queues have a single consumer and TTL policy), fanout queues (they have the TTL policy) and amq queues (they are auto-delete queues, with a single consumer).

The default Mnesia dump_log_write_threshold value has changed to 300 instead of 100 for efficiency. dump_log_write_threshold specifies the maximum number of writes allowed to the transaction log before a new dump of the log is performed. Increasing this value can increase the performances during the queues/exchanges/bindings creation/destroying. The values should be between 100 and 1000. More detail [1].

[1] http://erlang.org/doc/man/mnesia.html#dump_log_write_threshold

The option rabbitmq_disable_non_tls_listeners has been removed in favor of setting the bind address and port configuration directly using a new option rabbitmq_port_bindings. This new option is a hash allowing for multiple bind addresses and port configurations.

The use of the apt_package_pinning role as a meta dependency has been removed from the rabbitmq_server role. While the package pinning role is still used, it will now only be executed when the apt task file is executed.

Default source of rabbitmq and erlang packages has been switched to cloudsmith.io