[
https://issues.apache.org/jira/browse/CURATOR-394?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15950417#comment-15950417
]
ASF GitHub Bot commented on CURATOR-394:
----------------------------------------
Github user lvfangmin commented on the issue:
https://github.com/apache/curator/pull/208
One concern is that this diff changed the default behavior to not passing
'enable', which will break the users who are already using service discovery
server and client with the enable field.
If I understand correctly, there are 4 cases:
1. discovery server: w enable, client: w enable
2. discovery server: w/o enable, client: w/o enable
3. discovery server: w/o enable, client: w enable
4. discovery server: w enable, client: w/o enable
The first 2 cases we don't need to worry about, the 3rd one will fail
because the server cannot recognize the new enable field, the 4th will fail
because the client cannot recognize the new field, sounds like we only need to
change the code to be able to ignore unknown field, what's the reason of having
OldServiceInstance?
> UnrecognizedPropertyException: "enabled" incompatibility
> --------------------------------------------------------
>
> Key: CURATOR-394
> URL: https://issues.apache.org/jira/browse/CURATOR-394
> Project: Apache Curator
> Issue Type: Bug
> Components: Recipes
> Affects Versions: 2.12.0
> Reporter: Gian Merlino
>
> When doing a rolling upgrade of our services from Curator 2.10.0 to Curator
> 2.12.0 we noticed some of the non-upgraded services started throwing this
> error. The cause seems to the combination of a new field added to
> ServiceInstance in CURATOR-275, and the lack of an "ignore unknown
> properties" setting on the ObjectMapper used by Curator 2.10.0.
> This makes it so clients need to be upgraded before services. But if you have
> a cluster where some services are also clients of other services (or of a
> service they are a part of) then I don't see a way to do a rolling upgrade
> with the way things currently are. Whatever instance you upgrade first will
> start announcing itself in a way that breaks instances running the previous
> version of the code. This doesn't seem to be configurable either, so the new
> "enabled" field can't be omitted from the serialized form.
> One possible solution is to revert CURATOR-275, add an "ignore unknown
> properties" to the ObjectMapper, and then re-introduce CURATOR-275 in a
> future release. That'd create a "you must go through release X first to
> upgrade to release Y" situation, but it would at least make it possible to do
> rolling updates.
> Another possible solution is to accept that clients always need to be
> upgraded before services, and accept that if you can't do this, it's
> impossible to update without downtime. This seems like something that'd be
> good to avoid though.
> {code}
> 2017-03-23 16:22:35,652
> [DruidTaskResolver[com.metamx.tranquility.druid.IndexService@37a0ec3c]] WARN
> c.m.t.finagle.DruidTaskResolver - Poll failed, trying again
> at[2017-03-23T16:23:10.899Z].
> org.codehaus.jackson.map.exc.UnrecognizedPropertyException: Unrecognized
> field "enabled" (Class org.apache.curator.x.discovery.ServiceInstance), not
> marked as ignorable
> at [Source: [B@e9cde06; line: 1, column: 226] (through reference chain:
> org.apache.curator.x.discovery.ServiceInstance["enabled"])
> at
> org.codehaus.jackson.map.exc.UnrecognizedPropertyException.from(UnrecognizedPropertyException.java:53)
> ~[org.codehaus.jackson.jackson-mapper-asl-1.9.13.jar:1.9.13]
> at
> org.codehaus.jackson.map.deser.StdDeserializationContext.unknownFieldException(StdDeserializationContext.java:267)
> ~[org.codehaus.jackson.jackson-mapper-asl-1.9.13.jar:1.9.13]
> at
> org.codehaus.jackson.map.deser.std.StdDeserializer.reportUnknownProperty(StdDeserializer.java:673)
> ~[org.codehaus.jackson.jackson-mapper-asl-1.9.13.jar:1.9.13]
> at
> org.codehaus.jackson.map.deser.std.StdDeserializer.handleUnknownProperty(StdDeserializer.java:659)
> ~[org.codehaus.jackson.jackson-mapper-asl-1.9.13.jar:1.9.13]
> at
> org.codehaus.jackson.map.deser.BeanDeserializer.handleUnknownProperty(BeanDeserializer.java:1365)
> ~[org.codehaus.jackson.jackson-mapper-asl-1.9.13.jar:1.9.13]
> at
> org.codehaus.jackson.map.deser.BeanDeserializer._handleUnknown(BeanDeserializer.java:725)
> ~[org.codehaus.jackson.jackson-mapper-asl-1.9.13.jar:1.9.13]
> at
> org.codehaus.jackson.map.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:703)
> ~[org.codehaus.jackson.jackson-mapper-asl-1.9.13.jar:1.9.13]
> at
> org.codehaus.jackson.map.deser.BeanDeserializer.deserialize(BeanDeserializer.java:580)
> ~[org.codehaus.jackson.jackson-mapper-asl-1.9.13.jar:1.9.13]
> at
> org.codehaus.jackson.map.ObjectMapper._readMapAndClose(ObjectMapper.java:2732)
> ~[org.codehaus.jackson.jackson-mapper-asl-1.9.13.jar:1.9.13]
> at
> org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1973)
> ~[org.codehaus.jackson.jackson-mapper-asl-1.9.13.jar:1.9.13]
> at
> org.apache.curator.x.discovery.details.JsonInstanceSerializer.deserialize(JsonInstanceSerializer.java:50)
> ~[org.apache.curator.curator-x-discovery-2.10.0.jar:na]
> at
> org.apache.curator.x.discovery.details.ServiceCacheImpl.addInstance(ServiceCacheImpl.java:193)
> ~[org.apache.curator.curator-x-discovery-2.10.0.jar:na]
> at
> org.apache.curator.x.discovery.details.ServiceCacheImpl.start(ServiceCacheImpl.java:96)
> ~[org.apache.curator.curator-x-discovery-2.10.0.jar:na]
> {code}
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
