0.10.2 (19.12.2016)
This release introduces a crucial warming-up phase when starting Hermes Frontend.
Features
(591) Frontend graceful startup
Frontend tries to load and cache all Avro schemas and Kafka topic metadata before accepting any traffic.
Before this change large clusters were throwing 5xx and had very big latencies during warmup phase.
Currently startup moment is barely noticable for clients (and in metrics).
(667) Declare max message size on topic
With this change users are asked to specify the maximum size of message on a topic during topic creation.
This size is then used to calculate the size of Kafka buffers in Hermes Consumers. Prior to this change
Consumer Kafka buffers were set to the same size for every topic (default: 10Mb per partition), which could
cause crashes when starting Consumers with large number of subscriptions with lags.
By default message size is a soft limit, warn log is emitted when message larger than declared size is received.
frontend.force.topic.max.message.size flag can be switched to make it a hard limit (Frontend will return
http 413 Payload Too Large status).
Also calculation based on message size os disabled by default (will be enabled by default in next versions). To use this
feature set consumer.use.topic.message.size flag.
(666) Options to configure Consumer HTTP client SSL Context
New options to configure Consumers HTTP client:
consumer.http.client.validate.certsconsumer.http.client.validate.peer.certsconsumer.http.client.enable.crldp