Jens, "After fetching a FlowFile-stream file and unpacked it back into NiFi I calculate a sha256. 1 minutes later I recalculate the sha256 on the exact same file. And got a new hash. That is what worry’s me. The fact that the same file can be recalculated and produce two different hashes, is very strange, but it happens. "
Ok so to confirm you are saying that in each case this happens you see it first compute the wrong hash, but then if you retry the same flowfile it then provides the correct hash? Can you please also show/share the lineage history for such a flow file then? It should have events for the initial hash, second hash, the unpacking, trace to the original stream, etc... Thanks On Wed, Oct 20, 2021 at 11:00 AM Jens M. Kofoed <jmkofoed....@gmail.com> wrote: > > Dear Mark and Joe > > I know my setup isn’t normal for many people. But if we only looks at my > receive side, which the last mails is about. Every thing is happening at the > same NIFI instance. It is the same 3 node NIFI cluster. > After fetching a FlowFile-stream file and unpacked it back into NiFi I > calculate a sha256. 1 minutes later I recalculate the sha256 on the exact > same file. And got a new hash. That is what worry’s me. > The fact that the same file can be recalculated and produce two different > hashes, is very strange, but it happens. Over the last 5 months it have only > happen 35-40 times. > > I can understand if the file is not completely loaded and saved into the > content repository before the hashing starts. But I believe that the unpack > process don’t forward the flow file to the next process before it is 100% > finish unpacking and saving the new content to the repository. > > I have a test flow, where a GenerateFlowfile has created 6x 1GB files (2 > files per node) and next process was a hashcontent before it run into a test > loop. Where files are uploaded via PutSFTP to a test server, and downloaded > again and recalculated the hash. I have had one issue after 3 days of running. > Now the test flow is running without the Put/Fetch sftp processors. > > Another problem is that I can’t find any correlation to other events. Not > within NIFI, nor the server itself or VMWare. If I just could find any other > event which happens at the same time, I might be able to force some kind of > event to trigger the issue. > I have tried to force VMware to migrate a NiFi node to another host. Forcing > it to do a snapshot and deleting snapshots, but nothing can trigger and error. > > I know it will be very very difficult to reproduce. But I will setup multiple > NiFi instances running different test flows to see if I can find any reason > why it behaves as it does. > > Kind Regards > Jens M. Kofoed > > Den 20. okt. 2021 kl. 16.39 skrev Mark Payne <marka...@hotmail.com>: > > Jens, > > Thanks for sharing the images. > > I tried to setup a test to reproduce the issue. I’ve had it running for quite > some time. Running through millions of iterations. > > I’ve used 5 KB files, 50 KB files, 50 MB files, and larger (to the tune of > hundreds of MB). I’ve been unable to reproduce an issue after millions of > iterations. > > So far I cannot replicate. And since you’re pulling the data via SFTP and > then unpacking, which preserves all original attributes from a different > system, this can easily become confusing. > > Recommend trying to reproduce with SFTP-related processors out of the > picture, as Joe is mentioning. Either using GetFile/FetchFile or > GenerateFlowFile. Then immediately use CryptographicHashContent to generate > an ‘initial hash’, copy that value to another attribute, and then loop, > generating the hash and comparing against the original one. I’ll attach a > flow that does this, but not sure if the email server will strip out the > attachment or not. > > This way we remove any possibility of actual corruption between the two nifi > instances. If we can still see corruption / different hashes within a single > nifi instance, then it certainly warrants further investigation but i can’t > see any issues so far. > > Thanks > -Mark > > > > > > On Oct 20, 2021, at 10:21 AM, Joe Witt <joe.w...@gmail.com> wrote: > > Jens > > Actually is this current loop test contained within a single nifi and there > you see corruption happen? > > Joe > > On Wed, Oct 20, 2021 at 7:14 AM Joe Witt <joe.w...@gmail.com> wrote: > > Jens, > > You have a very involved setup including other systems (non NiFi). Have you > removed those systems from the equation so you have more evidence to support > your expectation that NiFi is doing something other than you expect? > > Joe > > On Wed, Oct 20, 2021 at 7:10 AM Jens M. Kofoed <jmkofoed....@gmail.com> wrote: > > Hi > > Today I have another file which have been running through the retry loop one > time. To test the processors and the algorithm I added the HashContent > processor and also added hashing by SHA-1. > I file have been going through the system, and both the SHA-1 and SHA-256 are > both different than expected. with a 1 minutes delay the file is going back > into the hashing content flow and this time it calculates both hashes fine. > > I don't believe that the hashing is buggy, but something is very very > strange. What can influence the processors/algorithm to calculate a different > hash??? > All the input/output claim information is exactly the same. It is the same > flow/content file going in a loop. It happens on all 3 nodes. > > Any suggestions for where to dig ? > > Regards > Jens M. Kofoed > > > > Den ons. 20. okt. 2021 kl. 06.34 skrev Jens M. Kofoed > <jmkofoed....@gmail.com>: > > Hi Mark > > Thanks for replaying and the suggestion to look at the content Claim. > These 3 pictures is from the first attempt: > <image.png> <image.png> <image.png> > > Yesterday I realized that the content was still in the archive, so I could > Replay the file. > <image.png> > So here are the same pictures but for the replay and as you can see the > Identifier, offset and Size are all the same. > <image.png> <image.png> <image.png> > > In my flow if the hash does not match my original first calculated hash, it > goes into a retry loop. Here are the pictures for the 4th time the file went > through: > <image.png> <image.png> <image.png> > Here the content Claim is all the same. > > It is very rare that we see these issues <1 : 1.000.000 files and only with > large files. Only once have I seen the error with a 110MB file, the other > times the files size are above 800MB. > This time it was a Nifi-Flowstream v3 file, which has been exported from one > system and imported in another. But while the file has been imported it is > the same file inside NIFI and it stays at the same node. Going through the > same loop of processors multiple times and in the end the > CryptographicHashContent calculate a different SHA256 than it did earlier. > This should not be possible!!! And that is what concern my the most. > What can influence the same processor to calculate 2 different sha256 on the > exact same content??? > > Regards > Jens M. Kofoed > > > Den tir. 19. okt. 2021 kl. 16.51 skrev Mark Payne <marka...@hotmail.com>: > > Jens, > > In the two provenance events - one showing a hash of dd4cc… and the other > showing f6f0…. > If you go to the Content tab, do they both show the same Content Claim? I.e., > do the Input Claim / Output Claim show the same values for Container, > Section, Identifier, Offset, and Size? > > Thanks > -Mark > > On Oct 19, 2021, at 1:22 AM, Jens M. Kofoed <jmkofoed....@gmail.com> wrote: > > Dear NIFI Users > > I have posted this mail in the developers mailing list and just want to > inform all of our about a very odd behavior we are facing. > The background: > We have data going between 2 different NIFI systems which has no direct > network access to each other. Therefore we calculate a SHA256 hash value of > the content at system 1, before the flowfile and data are combined and saved > as a "flowfile-stream-v3" pkg file. The file is then transported to system 2, > where the pkg file is unpacked and the flow can continue. To be sure about > file integrity we calculate a new sha256 at system 2. But sometimes we see > that the sha256 gets another value, which might suggest the file was > corrupted. But recalculating the sha256 again gives a new hash value. > > ---- > > Tonight I had yet another file which didn't match the expected sha256 hash > value. The content is a 1.7GB file and the Event Duration was "00:00:17.539" > to calculate the hash. > I have created a Retry loop, where the file will go to a Wait process for > delaying the file 1 minute and going back to the CryptographicHashContent for > a new calculation. After 3 retries the file goes to the retries_exceeded and > goes to a disabled process just to be in a queue so I manually can look at > it. This morning I rerouted the file from my retries_exceeded queue back to > the CryptographicHashContent for a new calculation and this time it > calculated the correct hash value. > > THIS CAN'T BE TRUE :-( :-( But it is. - Something very very strange is > happening. > <image.png> > > We are running NiFi 1.13.2 in a 3 node cluster at Ubuntu 20.04.02 with > openjdk version "1.8.0_292", OpenJDK Runtime Environment (build > 1.8.0_292-8u292-b10-0ubuntu1~20.04-b10), OpenJDK 64-Bit Server VM (build > 25.292-b10, mixed mode). Each server is a VM with 4 CPU, 8GB Ram on VMware > ESXi, 7.0.2. Each NIFI node is running at different vm physical hosts. > I have inspected different logs to see if I can find any correlation what > happened at the same time as the file is going through my loop, but there are > no event/task at that exact time. > > System 1: > At 10/19/2021 00:15:11.247 CEST my file is going through a > CryptographicHashContent: SHA256 value: > dd4cc7ef8dbc8d70528e8aa788581f0ab88d297c9c9f39b6b542df68952efd20 > The file is exported as a "FlowFile Stream, v3" to System 2 > > SYSTEM 2: > At 10/19/2021 00:18:10.528 CEST the file is going through a > CryptographicHashContent: SHA256 value: > f6f0909aacae4952f10f6fa7704f3e55d0481ec211d495993550aedbb3fe0819 > <image.png> > At 10/19/2021 00:19:08.996 CEST the file is going through the same > CryptographicHashContent at system 2: SHA256 value: > f6f0909aacae4952f10f6fa7704f3e55d0481ec211d495993550aedbb3fe0819 > At 10/19/2021 00:20:04.376 CEST the file is going through the same a > CryptographicHashContent at system 2: SHA256 value: > f6f0909aacae4952f10f6fa7704f3e55d0481ec211d495993550aedbb3fe0819 > At 10/19/2021 00:21:01.711 CEST the file is going through the same a > CryptographicHashContent at system 2: SHA256 value: > f6f0909aacae4952f10f6fa7704f3e55d0481ec211d495993550aedbb3fe0819 > > At 10/19/2021 06:07:43.376 CEST the file is going through the same a > CryptographicHashContent at system 2: SHA256 value: > dd4cc7ef8dbc8d70528e8aa788581f0ab88d297c9c9f39b6b542df68952efd20 > <image.png> > > How on earth can this happen??? > > Kind Regards > Jens M. Kofoed > > > > <Repro.json>
