Hi, Here are some upgrade options: - Standard rolling upgrade: node by node - Fast rolling upgrade: rack by rack. If clients use CL=LOCAL_ONE then it's OK as long as one rack is UP. For higher CL it's possible assuming you have no more than one replica per rack e.g. CL=LOCAL_QUORUM with RF=3 and 2 racks is a *BAD* setup. But RF=3 with 3 rack is OK. - Double write in another cluster: easy for short TTL data (e.g. TTL of few days) When possible, this option is not only the safest but also allows major change (e.g. Partitioner for legacy clusters). And of course it's a good opportunity to use new cloud instance type, change number of vnodes, etc. As Sean said, it's not possible for C* servers to stream data with other versions when Streaming versions are different. There is no workaround.You can check that here https://github.com/apache/cassandra/blob/cassandra-3.11/src/java/org/apache/cassandra/streaming/messages/StreamMessage.java#L35The community plans to work on this limitation to make streaming possible between different major versions starting from C*4.x Last but not least, don't forget to take snapshots (+ backup) and to prepare a rollback script.System keyspace will be automatically snapshotted by Cassandra when the new version will start: the rollback script should be based on that snapshot for the system part.New data (both commitlog and sstables flushed in 3.11 format) will be lost even with such a script but it's useful to test it and to have it ready for the D day.(See also snapshot_before_compaction setting but it might be useless depending on your procedure.) Romain
Le vendredi 26 juillet 2019 à 23:51:52 UTC+2, Jai Bheemsen Rao Dhanwada <jaibheem...@gmail.com> a écrit : yes correct, it doesn't work for the servers. trying to see if any had any workaround for this issue? (may be changing the protocol version during the upgrade time?) On Fri, Jul 26, 2019 at 1:11 PM Durity, Sean R <sean_r_dur...@homedepot.com> wrote: This would handle client protocol, but not streaming protocol between nodes. Sean Durity – Staff Systems Engineer, Cassandra From: Alok Dwivedi <alok.dwiv...@instaclustr.com> Sent: Friday, July 26, 2019 3:21 PM To: user@cassandra.apache.org Subject: Re: [EXTERNAL] Apache Cassandra upgrade path Hi Sean The recommended practice for upgrade is to explicitly control protocol version in your application during upgrade process. Basically the protocol version is negotiated on first connection and based on chance it can talk to an already upgraded node first which means it will negotiate a higher version that will not be compatible with those nodes which are still one lower Cassandra version. So initially you set it a lower version that is like lower common denominator for mixed mode cluster and then remove the call to explicit setting once upgrade has completed. Clustercluster= Cluster.builder() .addContactPoint("127.0.0.1") .withProtocolVersion(ProtocolVersion.V2) .build(); Refer here for more information if using Java driver https://docs.datastax.com/en/developer/java-driver/3.7/manual/native_protocol/#protocol-version-with-mixed-clusters Same thing applies to drivers in other languages. Thanks Alok Dwivedi Senior Consultant https://www.instaclustr.com/ On Fri, 26 Jul 2019 at 20:03, Jai Bheemsen Rao Dhanwada <jaibheem...@gmail.com> wrote: Thanks Sean, In my use case all my clusters are multi DC, and I am trying my best effort to upgrade ASAP, however there is a chance since all machines are VMs. Also my key spaces are not uniform across DCs. some are replicated to all DCs and some of them are just one DC, so I am worried there. Is there a way to override the protocol version until the upgrade is done and then change it back once the upgrade is completed? On Fri, Jul 26, 2019 at 11:42 AM Durity, Sean R <sean_r_dur...@homedepot.com> wrote: What you have seen is totally expected. You can’t stream between different major versions of Cassandra. Get the upgrade done, then worry about any down hardware. If you are using DCs, upgrade one DC at a time, so that there is an available environment in case of any disasters. My advice, though, is to get through the rolling upgrade process as quickly as possible. Don’t stay in a mixed state very long. The cluster will function fine in a mixed state – except for those streaming operations. No repairs, no bootstraps. Sean Durity – Staff Systems Engineer, Cassandra From: Jai Bheemsen Rao Dhanwada <jaibheem...@gmail.com> Sent: Friday, July 26, 2019 2:24 PM To: user@cassandra.apache.org Subject: [EXTERNAL] Apache Cassandra upgrade path Hello, I am trying to upgrade Apache Cassandra from 2.1.16 to 3.11.3, the regular rolling upgrade process works fine without any issues. However, I am running into an issue where if there is a node with older version dies (hardware failure) and a new node comes up and tries to bootstrap, it's failing. I tried two combinations: 1. Joining replacement node with 2.1.16 version of cassandra In this case nodes with 2.1.16 version are able to stream data to the new node, but the nodes with 3.11.3 version are failing with the below error. ERROR [STREAM-INIT-/10.x.x.x:40296] 2019-07-26 17:45:17,775 IncomingStreamingConnection.java:80 - Error while reading from socket from /10.y.y.y:40296. java.io.IOException: Received stream using protocol version 2 (my version 4). Terminating connection 2. Joining replacement node with 3.11.3 version of cassandra In this case the nodes with 3.11.3 version of cassandra are able to stream the data but it's not able to stream data from the 2.1.16 nodes and failing with the below error. ERROR [STREAM-IN-/10.z.z.z:7000] 2019-07-26 18:08:10,380 StreamSession.java:593 - [Stream #538c6900-afd0-11e9-a649-ab2e045ee53b] Streaming error occurred on session with peer 10.z.z.z java.io.IOException: Connection reset by peer at sun.nio.ch.FileDispatcherImpl.read0(Native Method) ~[na:1.8.0_151] at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:39) ~[na:1.8.0_151] at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223) ~[na:1.8.0_151] at sun.nio.ch.IOUtil.read(IOUtil.java:197) ~[na:1.8.0_151] at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:380) ~[na:1.8.0_151] at sun.nio.ch.SocketAdaptor$SocketInputStream.read(SocketAdaptor.java:206) ~[na:1.8.0_151] at sun.nio.ch.ChannelInputStream.read(ChannelInputStream.java:103) ~[na:1.8.0_151] at java.nio.channels.Channels$ReadableByteChannelImpl.read(Channels.java:385) ~[na:1.8.0_151] at org.apache.cassandra.streaming.messages.StreamMessage.deserialize(StreamMessage.java:56) ~[apache-cassandra-3.11.3.jar:3.11.3] at org.apache.cassandra.streaming.ConnectionHandler$IncomingMessageHandler.run(ConnectionHandler.java:311) ~[apache-cassandra-3.11.3.jar:3.11.3] at java.lang.Thread.run(Thread.java:748) [na:1.8.0_151] Note: In both cases I am using replace_address to replace dead node, as I am running into some issues with "nodetool removenode" . I use ephemeral disk, so replacement node always comes up with empty data dir and bootstrap. Any other work around to mitigate this problem? I am worried about any nodes going down while we are in the process of upgrade, as it could take several hours to upgrade depending on the cluster size. The information in this Internet Email is confidential and may be legally privileged. It is intended solely for the addressee. Access to this Email by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution or any action taken or omitted to be taken in reliance on it, is prohibited and may be unlawful. When addressed to our clients any opinions or advice contained in this Email are subject to the terms and conditions expressed in any applicable governing The Home Depot terms of business or client engagement letter. 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