From ef9d12df24c0db76fd37a95551db7920d27d740c Mon Sep 17 00:00:00 2001 From: Jonathan Hung Date: Thu, 31 Oct 2019 20:33:59 -0700 Subject: [PATCH] Add 2.10.0 release notes for HDFS-12943 --- .../markdown/release/2.10.0/RELEASENOTES.2.10.0.md | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/hadoop-common-project/hadoop-common/src/site/markdown/release/2.10.0/RELEASENOTES.2.10.0.md b/hadoop-common-project/hadoop-common/src/site/markdown/release/2.10.0/RELEASENOTES.2.10.0.md index 199483fb7e..ebea56ba6d 100644 --- a/hadoop-common-project/hadoop-common/src/site/markdown/release/2.10.0/RELEASENOTES.2.10.0.md +++ b/hadoop-common-project/hadoop-common/src/site/markdown/release/2.10.0/RELEASENOTES.2.10.0.md @@ -30,6 +30,19 @@ The generic resource types feature allows admins to configure custom resource ty This also adds GPU as a native resource type, built on top of the generic resource types feature. It adds support for GPU resource discovery, GPU scheduling and GPU isolation. +--- + +* [HDFS-12943](https://issues.apache.org/jira/browse/HDFS-12943) | *Major* | **Consistent Reads from Standby Node** + +Observer is a new type of a NameNode in addition to Active and Standby Nodes in HA settings. An Observer Node maintains a replica of the namespace same as a Standby Node. It additionally allows execution of clients read requests. + +To ensure read-after-write consistency within a single client, a state ID is introduced in RPC headers. The Observer responds to the client request only after its own state has caught up with the client’s state ID, which it previously received from the Active NameNode. + +Clients can explicitly invoke a new client protocol call msync(), which ensures that subsequent reads by this client from an Observer are consistent. + +A new client-side ObserverReadProxyProvider is introduced to provide automatic switching between Active and Observer NameNodes for submitting respectively write and read requests. + + --- * [HDFS-13541](https://issues.apache.org/jira/browse/HDFS-13541) | *Major* | **NameNode Port based selective encryption**