Hi, Gwen, Thanks for writing up the wiki. Some comments below.
1. To make it more general, should we support a binding and an advertised host for each protocol (e.g. plaintext, ssl, etc)? We will also need to figure out how to specify the wildcard binding host. 2. Broker format change in ZK The broker registration in ZK needs to store the host/port for all protocols. We will need to bump up the version of the broker registration data. Since this is an intra-cluster protocol change, we need an extra config for rolling upgrades. So, in the first step, each broker is upgraded and is ready to parse brokers registered in the new format, but not registering using the new format yet. In the second step, when that new config is enabled, the broker will register using the new format. 3. Wire protocol changes. Currently, the broker info is used in the following requests/responses: TopicMetadataResponse , ConsumerMetadataResponse, LeaderAndIsrRequest and UpdateMetadataRequest. 3.1 TopicMetadataResponse and ConsumerMetadataResponse: These two are used between the clients and the broker. I am not sure that we need to make a wire protocol change for them. Currently, the protocol includes a single host/port pair in those responses. Based on the type of the port on which the request is sent, it seems that we can just pick the corresponding host and port to include in the response. 3.2 UpdateMetadataRequest: This is used between the controller and the broker. Since each broker needs to cache the host/port of all protocols, we need to make a wire protocol change. We also need to change the broker format in MetadataCache accordingly. This is also an intra-cluster protocol change. So the upgrade path will need to follow that in item 2. 3.3 LeaderAndIsrRequest: This is also used between the controller and the broker. The receiving broker uses the host/port of the leader replica to send the fetch request. I am not sure if we need a wire protocol change in this case. I was imagining that we will just add a new broker config, sth like replication.socket.protocol. Base on this config, the controller will pick the right host/port to include in the request. 4. Should we plan to support security just on the new java clients? Supporting security in both the old and the new clients adds more work and gives people less incentive to migrate off the old clients. Thanks, Jun On Tue, Nov 25, 2014 at 11:13 AM, Gwen Shapira <gshap...@cloudera.com> wrote: > Hi Everyone, > > One of the pre-requisites we have for supporting multiple security > protocols (SSL, Kerberos) is to support them on separate ports. > > This is done in KAFKA-1684 (The SSL Patch), but that patch addresses > several different issues - Multiple ports, enriching the channels, SSL > implementation - which makes it more challenging to review and to test. > > I'd like to split this into 3 separate patches: multi-port brokers, > enriching SocketChannel, and the actual security implementations. > > Since even just adding support for multiple listeners per broker is > somewhat involved and touches multiple components, I wrote a short design > document that covers the necessary changes and the upgrade process: > > > https://cwiki.apache.org/confluence/display/KAFKA/Multiple+Listeners+for+Kafka+Brokers > > Comments are more than welcome :) > > If this is acceptable, hope to have a patch ready in few days. > > Gwen Shapira >
