chia7712 commented on code in PR #17445:
URL: https://github.com/apache/kafka/pull/17445#discussion_r1795062840
##########
docs/upgrade.html:
##########
@@ -141,6 +141,67 @@ <h5><a id="upgrade_400_notable"
href="#upgrade_400_notable">Notable changes in 4
</ul>
<h4><a id="upgrade_3_9_0" href="#upgrade_3_9_0">Upgrading to 3.9.0 from any
version 0.8.x through 3.8.x</a></h4>
+
+ <h5><a id="upgrade_390_zk" href="#upgrade_390_zk">Upgrading
ZooKeeper-based clusters</a></h5>
+ <p><b>If you are upgrading from a version prior to 2.1.x, please see the
note in step 5 below about the change to the schema used to store consumer
offsets.
+ Once you have changed the inter.broker.protocol.version to the latest
version, it will not be possible to downgrade to a version prior to 2.1.</b></p>
+
+ <p><b>For a rolling upgrade:</b></p>
+
+ <ol>
+ <li>Update server.properties on all brokers and add the following
properties. CURRENT_KAFKA_VERSION refers to the version you
+ are upgrading from. CURRENT_MESSAGE_FORMAT_VERSION refers to the
message format version currently in use. If you have previously
+ overridden the message format version, you should keep its current
value. Alternatively, if you are upgrading from a version prior
+ to 0.11.0.x, then CURRENT_MESSAGE_FORMAT_VERSION should be set to
match CURRENT_KAFKA_VERSION.
+ <ul>
+ <li>inter.broker.protocol.version=CURRENT_KAFKA_VERSION (e.g.
<code>3.8</code>, <code>3.7</code>, etc.)</li>
+ <li>log.message.format.version=CURRENT_MESSAGE_FORMAT_VERSION
(See <a href="#upgrade_10_performance_impact">potential performance impact
+ following the upgrade</a> for the details on what this
configuration does.)</li>
+ </ul>
+ If you are upgrading from version 0.11.0.x or above, and you have
not overridden the message format, then you only need to override
+ the inter-broker protocol version.
+ <ul>
+ <li>inter.broker.protocol.version=CURRENT_KAFKA_VERSION (e.g.
<code>3.8</code>, <code>3.7</code>, etc.)</li>
+ </ul>
+ </li>
+ <li>Upgrade the brokers one at a time: shut down the broker, update
the code, and restart it. Once you have done so, the
+ brokers will be running the latest version and you can verify that
the cluster's behavior and performance meets expectations.
+ It is still possible to downgrade at this point if there are any
problems.
+ </li>
+ <li>Once the cluster's behavior and performance has been verified,
bump the protocol version by editing
+ <code>inter.broker.protocol.version</code> and setting it to
<code>3.9</code>.
+ </li>
+ <li>Restart the brokers one by one for the new protocol version to
take effect. Once the brokers begin using the latest
+ protocol version, it will no longer be possible to downgrade the
cluster to an older version.
+ </li>
+ <li>If you have overridden the message format version as instructed
above, then you need to do one more rolling restart to
+ upgrade it to its latest version. Once all (or most) consumers
have been upgraded to 0.11.0 or later,
+ change log.message.format.version to 3.8 on each broker and
restart them one by one. Note that the older Scala clients,
+ which are no longer maintained, do not support the message format
introduced in 0.11, so to avoid conversion costs
+ (or to take advantage of <a
href="#upgrade_11_exactly_once_semantics">exactly once semantics</a>),
+ the newer Java clients must be used.
+ </li>
+ </ol>
+
+ <h5><a id="upgrade_390_kraft" href="#upgrade_390_kraft">Upgrading
KRaft-based clusters</a></h5>
+ <p><b>If you are upgrading from a version prior to 3.3.0, please see the
note in step 3 below. Once you have changed the metadata.version to the latest
version, it will not be possible to downgrade to a version prior to
3.3-IV0.</b></p>
+
+ <p><b>For a rolling upgrade:</b></p>
+
+ <ol>
+ <li>Upgrade the brokers one at a time: shut down the broker, update
the code, and restart it. Once you have done so, the
+ brokers will be running the latest version and you can verify that
the cluster's behavior and performance meets expectations.
+ </li>
+ <li>Once the cluster's behavior and performance has been verified,
bump the metadata.version by running
+ <code>
+ bin/kafka-features.sh upgrade --metadata 3.9
+ </code>
+ </li>
+ <li>Note that cluster metadata downgrade is not supported in this
version since it has metadata changes.
+ Every <a
href="https://github.com/apache/kafka/blob/trunk/server-common/src/main/java/org/apache/kafka/server/common/MetadataVersion.java";>MetadataVersion</a>
+ after 3.2.x has a boolean parameter that indicates if there are
metadata changes (i.e. <code>IBP_3_3_IV3(7, "3.3", "IV3", true)</code> means
this version has metadata changes).
+ Given your current and target versions, a downgrade is only
possible if there are no metadata changes in the versions between.</li>
+ </ol>
Review Comment:
nit: could you please add a new line?
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
