New Features¶

• Adding retry strategy based on the mandatory flag. Missing exchanges andqueues are now identified separately for logging purposes.

Upgrade Notes¶

• Deprecating thedirect_mandatory_flag. It will not be possible todeactivate this functionality anymore.

New Features¶

• RPC dispatcher can have an extra endpoint named ping.This endpoint can be enabled thanks to a specific configuration parameter:[DEFAULT]rpc_ping_enabled=true # default is false

  The purpose of this new endpoint is to help operators do a RPC call (aping) toward a specific RPC callback (e.g. a nova-compute, or aneutron-agent).This is helping a lot for monitoring agents (for example, if agents aredeployed in a kubernetes pod).

Bug Fixes¶

• Add a new optionenable_cancel_on_failover for rabbitmq driverwhich when enabled, will cancel consumers when queue appearsto be down.

Upgrade Notes¶

• The blocking executor has been deprecated for removal in Rocky and supportis now dropped in Ussuri. Its usage was never recommended for applications,and it has no test coverage.Applications should choose the appropriate threading model that maps totheir usage instead.

New Features¶

• SSL support for oslo_messaging’s kafka driver

  Next configuration params was added

  • ssl_client_cert_file (default=’’)

  • ssl_client_key_file (default=’’)

  • ssl_client_key_password (default=’’)

Upgrade Notes¶

• Support for Python 2.7 has been dropped. The minimum version of Python nowsupported is Python 3.6.

Other Notes¶

• NoSuchMethod exception will not be logged for special non-existing methodswhich names end with ‘_ignore_errors’. Such methods might be usedas health probes for openstack services.

Critical Issues¶

• In combination with amqp<=2.4.0,oslo.messaging was unreliablewhen configured with TLS (as is generally recommended). Users wouldsee frequent errors such as this:

  MessagingTimeout:TimedoutwaitingforareplytomessageIDae039d1695984addbfaaef032ce4fda3

  Such issues would typically lead to downstream service timeouts,with no recourse available other than disabling TLS altogether(seebug 1800957).

  The underlying issue is fixed in amqp version 2.4.1, which is nowthe minimum version thatoslo.messaging requires.

Upgrade Notes¶

• With the change in the client library used, projects using theKafka driver should use extras oslo.messaging[kafka] to pull independencies for the driver.

Bug Fixes¶

• Threading issues with the kafka-python consumer client were identifiedand documented. The driver has been updated to integrate theconfluent-kafka python library. The confluent-kafka clientleverages the high performance librdkafka C client and is safefor multiple thread use.

Prelude¶

The ZMQ-based driver for RPC communications has been removed

Upgrade Notes¶

• Remove deprecated configuration options from multiple drivers.

  • The rpc_backend option from the [DEFAULT] section has been removed.

  • The AMQP driver has removed the configuration options of allow_insecure_clients, username and password from the [oslo_messaging_amqp] section.

  • The Kafa driver has removed the configuration options of kafka_default_host and kafka_default_port from the [oslo_messaging_kafka] section.

  • The Rabbit driver has removed the configuration options of rabbit_host, rabbit_port, rabbit_hosts, rabbit_userid, rabbit_password, rabbit_virtual_host rabbit_max_retries and rabbit_durable_queues from the [oslo_messaging_rabbit] section.

  Operators must switch to setting the transport_url directive in the [DEFAULT] section.

Deprecation Notes¶

• The driver support for the ZeroMQ messaging library is removed.Users of the oslo.messaging RPC services must use the supportedrabbit (“rabbit://…”) or amqp1 (“amqp://…” )drivers.

Prelude¶

RPCClient now supports RPC call monitoring for detecting the loss of a server during an RPC call.

New Features¶

• RPC call monitoring is a new RPCClient feature. Call monitoringcauses the RPC server to periodically send keepalive messages backto the RPCClient while the RPC call is being processed. This canbe used for early detection of a server failure without having towait for the full call timeout to expire.

Deprecation Notes¶

• ZeroMQ support has been deprecated. The ZeroMQ driverzmq:// hasbeen unmaintained for over a year and no longer functionsproperly. It is recommended to use one of the maintained backendsinstead, such as RabbitMQ or AMQP 1.0.

Prelude¶

Projects using any of the optional drivers can use extras to pull in dependencies for that driver.

Upgrade Notes¶

• Projects using the AMQP 1.0 driver may now depend onoslo.messaging[amqp1]. Projects using the Kafka driver may nowdepend on oslo.messaging[kafka]

Prelude¶

The Pika-based driver for RabbitMQ has been removed.

Upgrade Notes¶

• Users of the Pika-based driver must change the prefix of all thetransport_url configuration options from “pika://…” to“rabbit://…” to use the default kombu based RabbitMQ driver.

Other Notes¶

• On rabbitmq, in the past, acknownlegement of messages was done within theapplication callback thread/greenlet. This thread was blocked until themessage was ack. In newton, we rewrote the message acknownlegement toensure we haven’t two threads writting the socket at the same times.Now all pendings ack are done by the main thread. They are no more reasonto block the application callback thread until the message is ack. Otherdriver already release the application callback threads before the messageis acknownleged. This is also the case for rabbitmq, now.

Upgrade Notes¶

• Change the default value of RPC dispatcher access_policyto DefaultRPCAccessPolicy.

Deprecation Notes¶

• The blocking executor has been deprecated for removal in Rocky. Its usage was never recommended for applications, and it has no test coverage. Applications should choose the appropriate threading model that maps their usage instead.

Deprecation Notes¶

• The pika driver has been deprecated for removal in Rocky. This driver was developed as a replacement for the default rabbit driver. However testing has not shown any appreciable improvement over the default rabbit driver in terms of performance and stability.

New Features¶

• Add get_rpc_transport call to make the API clear for the separationof RPC and Notification messaging backends.

Deprecation Notes¶

• Deprecate get_transport and use get_rpc_transport orget_notification_transport to make the API usage clear for theseparation of RPC and Notification messaging backends.

New Features¶

• Retry support for oslo_messaging_notifications driver

  Configuration param ‘retry’ is added. Default is -1, indefinite

  • retry (default=-1)

Upgrade Notes¶

• RequestContextSerializer was deprecated since 4.6, and it isn’t used by any other project, so we can remove it safely.

New Features¶

• Idle connections in the pool will be expired and closed.

  Default ttl is 1200s. Next configuration params was added

  • conn_pool_ttl (defaul 1200)

  • conn_pool_min_size (default 2)

Deprecation Notes¶

• The rabbitmq driver optionDEFAULT/max_retries has been deprecated for removal (at a later point in the future) as it did not make logical sense for notifications and for RPC.