[
https://issues.apache.org/jira/browse/HADOOP-16579?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Mate Szalay-Beko updated HADOOP-16579:
--------------------------------------
Description:
*Update:* the original idea was to only update Curator but keep the old
ZooKeeper version in Hadoop. However, we encountered some run-time
backward-incompatibility during unit tests with Curator 4.2.0 and ZooKeeper
3.5.5. We haven't really investigated deeply these issues, but upgraded to
ZooKeeper 3.5.5 (and later to 3.5.6). We had to do some minor fixes in the unit
tests (and also had to change some deprecated Curator API calls), but [the
latest PR|https://github.com/apache/hadoop/pull/1656] seems to be stable.
ZooKeeper 3.5.6 just got released during our work. (I think the official
announcement will get out maybe tomorrow, but it is already available in maven
central or on the [Apache ZooKeeper ftp
site|https://www-eu.apache.org/dist/zookeeper/]). It is considered to be a
stable version, contains some minor fixes and improvements, plus some CVE
fixes. See the [release
notes|https://github.com/apache/zookeeper/blob/branch-3.5.6/zookeeper-docs/src/main/resources/markdown/releasenotes.md].
----
Currently in Hadoop we are using [ZooKeeper version
3.4.13|https://github.com/apache/hadoop/blob/7f9073132dcc9db157a6792635d2ed099f2ef0d2/hadoop-project/pom.xml#L90].
ZooKeeper 3.5.5 is the latest stable Apache ZooKeeper release. It contains
many new features (including SSL related improvements which can be very
important for production use; see [the release
notes|https://zookeeper.apache.org/doc/r3.5.5/releasenotes.html]).
Apache Curator is a high level ZooKeeper client library, that makes it easier
to use the low level ZooKeeper API. Currently [in Hadoop we are using Curator
2.13.0|https://github.com/apache/hadoop/blob/7f9073132dcc9db157a6792635d2ed099f2ef0d2/hadoop-project/pom.xml#L91]
and [in Ozone we use Curator
2.12.0|https://github.com/apache/hadoop/blob/7f9073132dcc9db157a6792635d2ed099f2ef0d2/pom.ozone.xml#L146].
Curator 2.x is supporting only the ZooKeeper 3.4.x releases, while Curator 3.x
is compatible only with the new ZooKeeper 3.5.x releases. Fortunately, the
latest Curator 4.x versions are compatible with both ZooKeeper 3.4.x and 3.5.x.
(see [the relevant Curator
page|https://curator.apache.org/zk-compatibility.html]). Many Apache projects
have already migrated to Curator 4 (like HBase, Phoenix, Druid, etc.), other
components are doing it right now (e.g. Hive).
*The aims of this task are* to:
- change Curator version in Hadoop to the latest stable 4.x version (currently
4.2.0)
- also make sure we don't have multiple ZooKeeper versions in the classpath to
avoid runtime problems (it is
[recommended|https://curator.apache.org/zk-compatibility.html] to exclude the
ZooKeeper which come with Curator, so that there will be only a single
ZooKeeper version used runtime in Hadoop)
In this ticket we still don't want to change the default ZooKeeper version in
Hadoop, we only want to make it possible for the community to be able to build
/ use Hadoop with the new ZooKeeper (e.g. if they need to secure the ZooKeeper
communication with SSL, what is only supported in the new ZooKeeper version).
Upgrading to Curator 4.x should keep Hadoop to be compatible with both
ZooKeeper 3.4 and 3.5.
was:
*Update:* the original idea was to only update Curator but keep the old
ZooKeeper version in Hadoop. However, we encountered some run-time
backward-incompatibility during unit tests with Curator 4.2.0 and ZooKeeper
3.5.5. We haven't really investigated these issues, but upgraded to ZooKeeper
3.5.5 (and later to 3.5.6). We had to do some minor fixes in the unit tests
(and also had to change some deprecated Curator API calls), but the latest PR
seems to be stable.
ZooKeeper 3.5.6 just got released during our work. (I think the official
announcement will get out maybe tomorrow, but it is already available in maven
central or on the [apache zookeeper ftp
site|[https://www-eu.apache.org/dist/zookeeper/]]). It is considered to be a
stable version, contains some minor fixes and improvements, plus some CVE
fixes. See the release notes:
[https://github.com/apache/zookeeper/blob/branch-3.5.6/zookeeper-docs/src/main/resources/markdown/releasenotes.md]
----
Currently in Hadoop we are using [ZooKeeper version
3.4.13|https://github.com/apache/hadoop/blob/7f9073132dcc9db157a6792635d2ed099f2ef0d2/hadoop-project/pom.xml#L90].
ZooKeeper 3.5.5 is the latest stable Apache ZooKeeper release. It contains
many new features (including SSL related improvements which can be very
important for production use; see [the release
notes|https://zookeeper.apache.org/doc/r3.5.5/releasenotes.html]).
Apache Curator is a high level ZooKeeper client library, that makes it easier
to use the low level ZooKeeper API. Currently [in Hadoop we are using Curator
2.13.0|https://github.com/apache/hadoop/blob/7f9073132dcc9db157a6792635d2ed099f2ef0d2/hadoop-project/pom.xml#L91]
and [in Ozone we use Curator
2.12.0|https://github.com/apache/hadoop/blob/7f9073132dcc9db157a6792635d2ed099f2ef0d2/pom.ozone.xml#L146].
Curator 2.x is supporting only the ZooKeeper 3.4.x releases, while Curator 3.x
is compatible only with the new ZooKeeper 3.5.x releases. Fortunately, the
latest Curator 4.x versions are compatible with both ZooKeeper 3.4.x and 3.5.x.
(see [the relevant Curator
page|https://curator.apache.org/zk-compatibility.html]). Many Apache projects
have already migrated to Curator 4 (like HBase, Phoenix, Druid, etc.), other
components are doing it right now (e.g. Hive).
*The aims of this task are* to:
- change Curator version in Hadoop to the latest stable 4.x version (currently
4.2.0)
- also make sure we don't have multiple ZooKeeper versions in the classpath to
avoid runtime problems (it is
[recommended|https://curator.apache.org/zk-compatibility.html] to exclude the
ZooKeeper which come with Curator, so that there will be only a single
ZooKeeper version used runtime in Hadoop)
In this ticket we still don't want to change the default ZooKeeper version in
Hadoop, we only want to make it possible for the community to be able to build
/ use Hadoop with the new ZooKeeper (e.g. if they need to secure the ZooKeeper
communication with SSL, what is only supported in the new ZooKeeper version).
Upgrading to Curator 4.x should keep Hadoop to be compatible with both
ZooKeeper 3.4 and 3.5.
> Upgrade to Apache Curator 4.2.0 and ZooKeeper 3.5.6 in Hadoop
> -------------------------------------------------------------
>
> Key: HADOOP-16579
> URL: https://issues.apache.org/jira/browse/HADOOP-16579
> Project: Hadoop Common
> Issue Type: Improvement
> Reporter: Mate Szalay-Beko
> Assignee: Norbert Kalmár
> Priority: Major
>
> *Update:* the original idea was to only update Curator but keep the old
> ZooKeeper version in Hadoop. However, we encountered some run-time
> backward-incompatibility during unit tests with Curator 4.2.0 and ZooKeeper
> 3.5.5. We haven't really investigated deeply these issues, but upgraded to
> ZooKeeper 3.5.5 (and later to 3.5.6). We had to do some minor fixes in the
> unit tests (and also had to change some deprecated Curator API calls), but
> [the latest PR|https://github.com/apache/hadoop/pull/1656] seems to be stable.
> ZooKeeper 3.5.6 just got released during our work. (I think the official
> announcement will get out maybe tomorrow, but it is already available in
> maven central or on the [Apache ZooKeeper ftp
> site|https://www-eu.apache.org/dist/zookeeper/]). It is considered to be a
> stable version, contains some minor fixes and improvements, plus some CVE
> fixes. See the [release
> notes|https://github.com/apache/zookeeper/blob/branch-3.5.6/zookeeper-docs/src/main/resources/markdown/releasenotes.md].
>
> ----
> Currently in Hadoop we are using [ZooKeeper version
> 3.4.13|https://github.com/apache/hadoop/blob/7f9073132dcc9db157a6792635d2ed099f2ef0d2/hadoop-project/pom.xml#L90].
> ZooKeeper 3.5.5 is the latest stable Apache ZooKeeper release. It contains
> many new features (including SSL related improvements which can be very
> important for production use; see [the release
> notes|https://zookeeper.apache.org/doc/r3.5.5/releasenotes.html]).
> Apache Curator is a high level ZooKeeper client library, that makes it easier
> to use the low level ZooKeeper API. Currently [in Hadoop we are using Curator
> 2.13.0|https://github.com/apache/hadoop/blob/7f9073132dcc9db157a6792635d2ed099f2ef0d2/hadoop-project/pom.xml#L91]
> and [in Ozone we use Curator
> 2.12.0|https://github.com/apache/hadoop/blob/7f9073132dcc9db157a6792635d2ed099f2ef0d2/pom.ozone.xml#L146].
> Curator 2.x is supporting only the ZooKeeper 3.4.x releases, while Curator
> 3.x is compatible only with the new ZooKeeper 3.5.x releases. Fortunately,
> the latest Curator 4.x versions are compatible with both ZooKeeper 3.4.x and
> 3.5.x. (see [the relevant Curator
> page|https://curator.apache.org/zk-compatibility.html]). Many Apache projects
> have already migrated to Curator 4 (like HBase, Phoenix, Druid, etc.), other
> components are doing it right now (e.g. Hive).
> *The aims of this task are* to:
> - change Curator version in Hadoop to the latest stable 4.x version
> (currently 4.2.0)
> - also make sure we don't have multiple ZooKeeper versions in the classpath
> to avoid runtime problems (it is
> [recommended|https://curator.apache.org/zk-compatibility.html] to exclude the
> ZooKeeper which come with Curator, so that there will be only a single
> ZooKeeper version used runtime in Hadoop)
> In this ticket we still don't want to change the default ZooKeeper version in
> Hadoop, we only want to make it possible for the community to be able to
> build / use Hadoop with the new ZooKeeper (e.g. if they need to secure the
> ZooKeeper communication with SSL, what is only supported in the new ZooKeeper
> version). Upgrading to Curator 4.x should keep Hadoop to be compatible with
> both ZooKeeper 3.4 and 3.5.
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