[release] add release notes for 2.5.0 release (apache#5837)

*Motivation*

Add the release notes for 2.5.0 release

site2/website/release-notes.md

@@ -1,5 +1,140 @@
 
-## Apache
+## Apache Pulsar Release Notes
+
+### 2.5.0 &mdash; 2019-12-06 <a id="2.5.0"></a>
+
+#### PIPs
+
+- [PIP-41] Introduce Protocol Handler API [#5130](https://github.com/apache/pulsar/pull/5130) [#5743](https://github.com/apache/pulsar/pull/5473) 
+- [PIP-45] Pluggable metadata interface [#5330](https://github.com/apache/pulsar/pull/5330) 
+- [PIP-44] Separate schema compatibility checker for producer and consumer [#5227](https://github.com/apache/pulsar/pull/5227)
+- [PIP-43] Producer send messages with different schema [#5141](https://github.com/apache/pulsar/issues/5141) [#5517](https://github.com/apache/pulsar/pull/5517) 
+- [PIP-51] Introduce sticky consumer [#5388](https://github.com/apache/pulsar/pull/5388)
+- [PIP-38] Support batch receive in java client. [#4621](https://github.com/apache/pulsar/pull/4621)
+- [PIP-52] PIP-52: [pulsar-sever] Add support of dispatch throttling relative to publish-rate [#5797](https://github.com/apache/pulsar/pull/5797)
+
+#### Fixes
+
+- [Broker] Avoid retrying deleting namespace when topic is already deleted/fenced [#4665](https://github.com/apache/pulsar/pull/4665)
+- [Broker] Fix expiry monitor to continue on non-recoverable error [#4818](https://github.com/apache/pulsar/pull/4818) 
+- [Broker] fix ns-isolation api to fetch policy for specific broker [#5314](https://github.com/apache/pulsar/pull/5314)
+- [Broker] external protocols not set to local broker data [#5749](https://github.com/apache/pulsar/pull/5479)
+- [Broker] Add handle exception KeeperException.BadVersionException  [#5563](https://github.com/apache/pulsar/pull/5563)
+- [Broker] Fix message deduplicate issue while using external sequence id with batch produce [#5491](https://github.com/apache/pulsar/pull/5491)
+- [Broker] Remove cursor while remove non-durable subscription [#5719](https://github.com/apache/pulsar/pull/5719) 
+- [Broker] Fix potential read 0 entries cause dispatcher stop dispatch [#5894](https://github.com/apache/pulsar/pull/5894)
+- [Proxy] Proxy doesn't use the right ca certicate to connect to brokers [#5971](https://github.com/apache/pulsar/pull/5971)
+- [Client] Add SentConnectFrame state check when running `handleError` [#5913](https://github.com/apache/pulsar/pull/5913)
+
+#### Enhancements
+
+- [Zookeeper] Bump zookeeper to version 3.5.6 [#5043](https://github.com/apache/pulsar/pull/5043)
+- [BookKeeper] Upgrade bk version to 4.10.0 [#5607](https://github.com/apache/pulsar/pull/5607)
+- [Broker] Process requests asynchronously on some REST APIs [4765](https://github.com/apache/pulsar/pull/4765) [4778](https://github.com/apache/pulsar/pull/4778) [4795](https://github.com/apache/pulsar/pull/4795) 
+- [Broker] Fixes not owned bundles got selected when broker overloading [#5002](https://github.com/apache/pulsar/pull/5002)
+- [Broker] Support update partition for global topic  [#5306](https://github.com/apache/pulsar/pull/5306)
+- [Broker] Ensure the handling of PartitionMetadataRequest is async end-to-end [#5307](https://github.com/apache/pulsar/pull/5307)
+- [Broker] Allow to automatically assign TCP ports when starting a broker  [#3555](https://github.com/apache/pulsar/pull/3555) 
+- [Broker] Introduce publish rate-limiting on topic [#3986](https://github.com/apache/pulsar/pull/3986)
+- [Broker] Add publish rate limit for each broker to avoid OOM [#5710](https://github.com/apache/pulsar/pull/5710)
+- [Broker] Allow for namespace default of offload threshold [#5872](https://github.com/apache/pulsar/pull/5872)
+- [Broker] Avoid unsafe split when validate hostname which might be ipv6 address [#5713](https://github.com/apache/pulsar/pull/5713)
+- [Broker] Support batch authorization of partitioned topic [#5767](https://github.com/apache/pulsar/pull/5767)
+- [Client][Java] Introduce `batchingMaxBytes` setting in pulsar producer [#5045](https://github.com/apache/pulsar/pull/5045)
+- [Client][Java] Add epoch for connection handler to handle create producer timeout [#5571](https://github.com/apache/pulsar/pull/5571)
+- [Performance] Reduce char[] creation on jvm heap [#5055](https://github.com/apache/pulsar/pull/5055)
+- [CLI] Add a broker tool for operations of a specific broker [#5768](https://github.com/apache/pulsar/pull/5768)
+- [CLI] Validate topic name before creating partition/non partition topic via admin cli [#5148](https://github.com/apache/pulsar/pull/5148)
+- [CLI] Make PulsarClusterMetadataSetup idempotent [#5879](https://github.com/apache/pulsar/pull/5879)
+
+#### Stats & Monitoring 
+
+- [Broker] Added delayed messages in Prometheus when using namespace-level metrics aggregation [#4691](https://github.com/apache/pulsar/pull/4691)
+- [Dashboard] Increasing Dashboard consumerName field to 256 varchar [4716](https://github.com/apache/pulsar/pull/4716)
+- [Dashboard] integrate peek into messages page [#4966](https://github.com/apache/pulsar/pull/4966)
+- [Dashboard] Support parse batch entry [#4992](https://github.com/apache/pulsar/pull/4992)
+
+#### Security
+
+- [Broker] Add broker-bookie mTLS support [#5042](https://github.com/apache/pulsar/pull/5042)
+
+#### Tiered Storage
+
+- HDFS Offloader [#4403](https://github.com/apache/pulsar/pull/4403)
+- Fix the problem of repeated storage of offload driver metadata [#5834](https://github.com/apache/pulsar/pull/5834)
+
+#### Pulsar Schema
+
+- [Broker] Pulsar schema api should respect to namespace level compatibility [#4821](https://github.com/apache/pulsar/issues/4821)
+- [Client][Java] NPE is thrown when a consumer consumes a partitioned topic with struct schema
+ [#4960](https://github.com/apache/pulsar/pull/4960)
+- [Broker] Add compatibility check for primitive schema types [#5051](https://github.com/apache/pulsar/pull/5051)
+- [Broker] Support uploading key/value schema using Pulsar admin [#5000](https://github.com/apache/pulsar/pull/5000)
+- [Client][Java] Schema support encoding & encoding ByteBuf [#5123](https://github.com/apache/pulsar/pull/5123)
+
+#### Pulsar IO
+
+- [Broker] Support reload Source and Sink for Pulsar IO [5008](https://github.com/apache/pulsar/pull/5008)
+- [Connector] Added Kinesis Source Connector [#3784](https://github.com/apache/pulsar/pull/3784)
+- [Connector] Add a source connector for MongoDB [#5316](https://github.com/apache/pulsar/pull/5316)
+- [Connector] Support CDC Connector for MongoDB [#5590](https://github.com/apache/pulsar/pull/5590)
+- [Connector] Improve hbase sink performance [#5705](https://github.com/apache/pulsar/pull/5705)
+
+#### Pulsar Functions
+
+- [Function Worker] Allow resource overcommitting when running functions in Kubernetes [4829](https://github.com/apache/pulsar/pull/4829)
+- [Function Worker] Make Function Authentication Provider pluggable [#5404](https://github.com/apache/pulsar/pull/5404)
+- [Function Worker] Added deletion of state for Functions [#5469](https://github.com/apache/pulsar/pull/5469) 
+- [Function Worker] Distribute the CA for KubernetesSecretsTokenAuthProvider [#5398](https://github.com/apache/pulsar/pull/5398)
+- [Function Runtime] Function runtime pluggable [#5463](https://github.com/apache/pulsar/pull/5463)
+- [Function Runtime] Allow functions to pass runtime specific options [#5400](https://github.com/apache/pulsar/pull/5400)
+
+#### Pulsar SQL
+
+- Support for other schema name separators in pulsar SQL [4732](https://github.com/apache/pulsar/issues/4732)
+- Reuse ManagedLedgerFactory instances across SQL queries [4813](https://github.com/apache/pulsar/pull/4813) 
+- Using pulsar SQL query messages will appear `NoSuchLedger` when zk root directory changed [#5001](https://github.com/apache/pulsar/pull/5001)
+
+#### Java client
+
+- Not allow use acknowledgeCumulative on Key_shared subscription [#5339](https://github.com/apache/pulsar/pull/5339)
+- Fix bug that beforeConsume() of interceptor is not called when receiver queue size is 0 [#5777](https://github.com/apache/pulsar/pull/5777)
+
+#### Go client
+
+- Use buffered channels to avoid blocking on callback  [#5336](https://github.com/apache/pulsar/pull/5336)
+
+#### C++ client
+
+- Change state_ to closed when resultOk is returned [#5446](https://github.com/apache/pulsar/pull/5446)
+- Expose redelivery count [#5677](https://github.com/apache/pulsar/pull/5677)
+
+#### Adaptors
+
+- Add support of pulsar-kafka-adapter for kafka-0.9 API [#4886](https://github.com/apache/pulsar/pull/4886)
+- Add support of pulsar-kafka-adapter for kafka-0.8 API [#4797](https://github.com/apache/pulsar/pull/4797) 
+- Make client keepalive interval configurable on pulsar-client-kafka [#5131](https://github.com/apache/pulsar/pull/5131)
+
+#### Transaction
+
+> The development of Pulsar Transaction is still ongoing
+
+- [Buffer] Add new marker to show which message belongs to transaction [#4776](https://github.com/apache/pulsar/pull/4776)
+- [Buffer] Add data ledger position in txn commit marker [#4826](https://github.com/apache/pulsar/pull/4826)
+- [Buffer] Add basic operation of transaction [#4738](https://github.com/apache/pulsar/pull/4738)
+- [Buffer] Add new commands for the transaction [#4866](https://github.com/apache/pulsar/pull/4866)
+- [Protocol] Add default handler to handle transaction related commands [#4891](https://github.com/apache/pulsar/pull/4891)
+- [Client] Introduce Transaction Client API [#4952](https://github.com/apache/pulsar/pull/4952)
+- [Client] Add transaction coordinator client [#4953](https://github.com/apache/pulsar/pull/4953)
+- [Broker] Ownership change listeners [#5457](https://github.com/apache/pulsar/pull/5457)
+- [Coordinator] Bootstrap pulsar system namespace and create TC assign topic [#5515](https://github.com/apache/pulsar/pull/5515)
+- [Coordinator] Add transaction metadata store service [#5504](https://github.com/apache/pulsar/pull/5504) 
+
+For a complete list of issues fixed, see
+
+https://github.com/apache/pulsar/milestone/22?closed=1
+
+https://github.com/apache/pulsar/releases/tag/v2.5.0 
 
 ### 2.4.2 &mdash; 2019-12-04 <a id="2.4.2"></a>