Thanks again for reply. Personally, I think the whole cluster should have a single version. What mattered most to me was how important the client version that sends the jobs to scheduler, that we should hope everything work well in small version changes! (In version changes less than major)
From: Sean Owen<mailto:sro...@gmail.com> Sent: Wednesday, November 24, 2021 10:48 PM To: Amin Borjian<mailto:borjianami...@outlook.com> Cc: user@spark.apache.org<mailto:user@spark.apache.org> Subject: Re: [Spark] Does Spark support backward and forward compatibility? I think/hope that it goes without saying you can't mix Spark versions within a cluster. Forwards compatibility is something you don't generally expect as a default from any piece of software, so not sure there is something to document explicitly. Backwards compatibility is important, and this is documented extensively where it doesn't hold in the Spark docs and release notes. On Wed, Nov 24, 2021 at 1:16 PM Amin Borjian <borjianami...@outlook.com<mailto:borjianami...@outlook.com>> wrote: Thank you very much for the reply you sent. It would be great if these items were mentioned in the Spark document (for example, the download page or something else) If I understand correctly, it means that we can compile the client (for example Java, etc.) with a newer version (for example 3.2.0) within the range of a major version against older server (for example 3.1.x) and do not see any problem in most cases. Am I right? (Because the issue of backward-compatibility can be expressed from both the server and the client view, I repeated the sentence to make sure I got it right.) But what happened if we update server to 3.2.x and our client was in version 3.1.x? Does it client can work with newer cluster version because it uses just old feature of severs? (Maybe you mean this and in fact my previous sentence was wrong and I misunderstood) From: Sean Owen<mailto:sro...@gmail.com> Sent: Wednesday, November 24, 2021 5:38 PM To: Amin Borjian<mailto:borjianami...@outlook.com> Cc: user@spark.apache.org<mailto:user@spark.apache.org> Subject: Re: [Spark] Does Spark support backward and forward compatibility? Can you mix different Spark versions on driver and executor? no. Can you compile against a different version of Spark than you run on? That typically works within a major release, though forwards compatibility may not work (you can't use a feature that doesn't exist in the version on the cluster). Compiling vs 3.2.0 and running on 3.1.x for example should work fine in 99% of cases. On Wed, Nov 24, 2021 at 8:04 AM Amin Borjian <borjianami...@outlook.com<mailto:borjianami...@outlook.com>> wrote: I have a simple question about using Spark, which although most tools usually explain this question explicitly (in important text, such as a specific format or a separate page), I did not find it anywhere. Maybe my search was not enough, but I thought it was good that I ask this question in the hope that maybe the answer will benefit other people as well. Spark binary is usually downloaded from the following link and installed and configured on the cluster: Download Apache Spark<https://spark.apache.org/downloads.html> If, for example, we use the Java language for programming (although it can be other supported languages), we need the following dependencies to communicate with Spark: <dependency> <groupId>org.apache.spark</groupId> <artifactId>spark-core_2.12</artifactId> <version>3.2.0</version> </dependency> <dependency> <groupId>org.apache.spark</groupId> <artifactId>spark-sql_2.12</artifactId> <version>3.2.0</version> </dependency> As is clear, both the Spark cluster (binary of Spark) and the dependencies used on the application side have a specific version. In my opinion, it is obvious that if the version used is the same on both the application side and the server side, everything will most likely work in its ideal state without any problems. But the question is, what if the two versions are not the same? Is it possible to have compatibility between the server and the application in specific number of conditions (such as not changing major version)? Or, for example, if the client is always ahead, is it not a problem? Or if the server is always ahead, is it not a problem? The argument is that there may be a library that I did not write and it is an old version, but I want to update my cluster (server version). Or it may not be possible for me to update the server version and all the applications version at the same time, so I want to update each one separately. As a result, the application-server version differs in a period of time. (maybe short or long period) I want to know exactly how Spark works in this situation.
