Reduce RabbitMQ Overhead

hrosenbe commented 4 years ago

This pull request contains changes to reduce the overhead of RabbitMQ. These are:

Change the Liveness and Readiness probes to use curl to the management API rather than using rabbitmqctl status. There is a known issue with rabbitmqctl causing high CPU usage when used in Kubernetes probes.
Limit the number of erlang scheduler threads used by RabbitMQ to 1. Otherwise RabbitMQ will launch as many scheduler threads as there are CPUs on the Kubernetes node. This adds overhead, particularly on a heavily loaded system.

These changes have been tested using Micro instances on 20 x 4vCPU worker nodes. At lower numbers of instances there was no impact on peak WvUsers. At higher numbers of instances I saw an improvement of 3 to 5%.

vmwclabot commented 4 years ago

@hrosenbe, you must sign every commit in this pull request acknowledging our Developer Certificate of Origin before your changes are merged. This can be done by adding Signed-off-by: John Doe <john.doe@email.org> to the last line of each Git commit message. The e-mail address used to sign must match the e-mail address of the Git author. Click here to view the Developer Certificate of Origin agreement.

Commit ae6a4d7de3ae54f8dc7fed4148df4f78187d33d2 must be signed by hrosenbe@vmware.com
Commit 2ca81bb473ff3ec674ef93aad61c9783f1bb9c62 must be signed by hrosenbe@vmware.com

hrosenbe commented 4 years ago

This pull request accidentally includes the changes from #150. I am closing it and will recreate.

vmware / weathervane

Reduce RabbitMQ Overhead #149