After upgrading the PCF RabbitMQ tile from 1.9.5 to 1.9.6 with the Push Push Notifications Service errand disabled, the Push Notifications service stop functioning.
In the push-API application logs, you will find something similar to
OUT [ERROR] ..... io.pivotal.push.service.queue.impl.RabbitMQAbstractQueue - [TENANT ...] - Failed to enqueue: attempted #1 with exception {}
The upgrade of the PCF RabbitMQ tile will cause the existing Push Notifications service to lose connectivity to Rabbit. Prior to PCF Push Notifications 1.9.3, once this connectivity is lost, the Push Notifications service will not automatically try to reconnect without being restarted.
There are 3 distinct ways to resolve or avoid this problem: