In our case the stream is UDP broadcast, so available to all nodes anyway. I've been meaning to test UDP multicast but not got round to it yet.
On Wed, 5 Jun 2019, 17:03 Bryan Bende, <[email protected]> wrote: > That is probably a valid point, but how about putting a load balancer > in front to handle that? > > On Wed, Jun 5, 2019 at 11:30 AM James Srinivasan > <[email protected]> wrote: > > > > Presumably you'd want to mirror the stream to all nodes for when the > primary node changes? > > > > On Wed, 5 Jun 2019, 13:46 Bryan Bende, <[email protected]> wrote: > >> > >> The processor is started on all nodes, but onTrigger method is only > >> executed on the primary node. > >> > >> This is something we've discussed trying to improve before, but the > >> real question is why are you sending data to the other nodes if you > >> don't expect the processor to execute there? > >> > >> On Wed, Jun 5, 2019 at 7:04 AM Erik-Jan <[email protected]> wrote: > >> > > >> > I figured it out after further testing. The processor runs on all > nodes, despite the explicit "run on primary node only" option that I > selected. But only on the primary node the queue is processed. On the other > nodes the queue gets filled until the max is reached after which the error > message starts appearing. What I missed before is that the message is > coming from the other, non-primary nodes. > >> > I'm not sure if this is intended behavior or if it is a bug though! > For me it's a bug since I really want this processor to run on the primary > only. > >> > > >> > Op di 4 jun. 2019 16:34 schreef Erik-Jan <[email protected]>: > >> >> > >> >> Hi Bryan, > >> >> > >> >> Yes I have considerably increased the numbers in the controller > settings. > >> >> I don't mind getting my hands dirty, increasing the timeout is worth > a try. > >> >> > >> >> The errors seems to appear after quite a while. Usually I see these > messages the next morning so testing and experimenting with this error > takes a lot of time. > >> >> > >> >> Today I've been trying to reproduce this on a virtual machine with > the same OS, Nifi and Java versions but to no avail. The difference is that > this VM is not a cluster, has limited memory and cpu and still is able to > handle much more UDP data with the error appearing only a few times so far > after hours of running. It leads me to thinking there must be something in > the configuration of the cluster thats causing this. I will also try a > vanilla Nifi install on one of the nodes without clustering to see if my > configuration and cluster setup is somehow the cause. > >> >> > >> >> Op di 4 jun. 2019 om 16:14 schreef Bryan Bende <[email protected]>: > >> >>> > >> >>> Hi Erik, > >> >>> > >> >>> It sounds like you have tried most of the common tuning options that > >> >>> can be done. I would have expected batching + increasing concurrent > >> >>> tasks from 1 to 3-5 to be the biggest improvement. > >> >>> > >> >>> Have you increased the number of threads in your overall thread pool > >> >>> according to your hardware? (from the top right menu controller > >> >>> settings) > >> >>> > >> >>> I would be curious what happens if you did some tests increasing the > >> >>> timeout where it attempts to place the message in the queue from > 100ms > >> >>> to 200ms and then maybe 500ms if it still happens. > >> >>> > >> >>> I know this requires a code change since that timeout is hard-coded, > >> >>> but it sounds like you already went down that path with trying a > >> >>> different queue :) > >> >>> > >> >>> -Bryan > >> >>> > >> >>> On Tue, Jun 4, 2019 at 4:28 AM Erik-Jan <[email protected]> wrote: > >> >>> > > >> >>> > Hi, > >> >>> > > >> >>> > I'm experimenting with a locally installed 3 node nifi cluster. > This cluster receives UDP packets on the primary node. > >> >>> > These nodes are pretty powerful, have a good network connection, > have lots of memory and SSD disks. I gave nifi 24G of java heap (xms and > xmx). > >> >>> > > >> >>> > I have configured a ListenUDP processor that listens on a UDP > port and it receives somewhere between 20000 to 50000 packets per 5 > minutes. It's "Max size of message queue" is large enough (1M), I gave it 5 > concurrent tasks, it's running on the primary node only. > >> >>> > > >> >>> > The problem: after running for a while, I get the following > error: "internal queue at maximum capacity, could not queue event." > >> >>> > > >> >>> > I have reviewed the source code and understand when this happens. > It happens when the processor tries to store an event in a java > LinkedBlockingQueue and that queue reached its maximum capacity. The > offer() method has a 100ms timeout in which it waits for space to free up > and then it fails and the event gets dropped. In the logs I see exactly 10 > of these error messages per second (10 x 100ms is 1 second). Despite these > errors, I still get a very good rate of events that get through to the next > processors. Actually, it seems pretty much all of the other events get > through since the message rate in ListenUDP and the followup processor are > very much alike. The followup processors can easily handle the load and > there are no full queues, congestions or anything like that. > >> >>> > > >> >>> > What I have tried so far: > >> >>> > > >> >>> > Increasing the "Max Size of Message Queue" setting helps, but > only delays the errors. They eventually return. > >> >>> > > >> >>> > Increasing heap space is a suggestion I read from a past post: I > think 24G is more than enough actually? Perhaps even too much? > >> >>> > > >> >>> > Increasing parallelism: concurrent tasks set to 5 or 10 does not > help. > >> >>> > > >> >>> > I modified the code to use an ArrayBlockingQueue instead of the > LinkedBlockingQueue, thinking it was some kind of garbage collection. This > didn't help. > >> >>> > > >> >>> > I increased "Receive Buffer Size", "Max Size of Socket Buffer" > but to no avail. > >> >>> > > >> >>> > I tried batching. This helps a bit, like increasing the "Max Size > of Message Queue" it only seems to delay the eventual error messages though. > >> >>> > > >> >>> > I reproduced this on my local workstation. I installed nifi, did > no OS tuning at all, set the heap size to 4GB. I generate 1.3M UDP packets > per 5 minutes (the max I can reach with a simple python script). With "Max > Size of Message Queue" set to only 100, soon the error appears. In the > ListenUDP processor I see 1.34M events out, on the followup processor I see > 1.34M events incoming. The error is not as frequent as on the cluster > though, only a few every couple of minutes while the data rate is much > higher and the queue much smaller. I'm a bit desperate and hope anyone can > help me out. Why am I getting this error on a relatively quiet cluster with > not that much load? > >> >>> > > >> >>> > Best regards, > >> >>> > Erik-Jan van Baaren >
