Thanks for the reply, but I tracked the problem down to a missing M in task m=
anager.sh
# export JVM_ARGS=3D"${JVM_ARGS} -Xms${TM_HEAP_SIZE}M -Xmx${TM_HEAP_SIZE}M -=
XX:MaxDirectMemorySize=3D${TM_MAX_OFFHEAP_SIZE}"
export JVM_ARGS=3D"${JVM_ARGS} -Xms${TM_HEAP_SIZE}M -Xmx${TM_HEAP_SIZE}M"
I had to remove {TM_MAX_OFFHEAP_SIZE} which caused the Pi Java to barf, and h=
ad accidentally deleted the final M.
After that I could run with a heap set to 512m with minimal problem.
As for the Pi as a Flink client, it may not be powerful in conventional sens=
e but I can directly attach a cluster to a sensor array and process the data=
in real time from multiple streams, which is neat. I processed 3 million re=
adings in the prototype in just over an hour with a modest amount of process=
ing required, all on 5pis with a sixth acting as the job manager. My only co=
mplaint is that Flink has a habit of dropping task managers even though they=
're still running. I suspect that's because of slow Ethernet on the Pi3 whic=
h has been addressed on the Pi3+ just released. Realistically sized rack mou=
nted clusters are now possible from http://www.bitscope.com/product/blade/
<http://www.bitscope.com/product/blade/> a=
fter Los Alamos National Lab went looking for a cheap means to build prototy=
pe clusters, and settled on the Pi to build a 750+ node cluster.
