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Posted to users@tomcat.apache.org by Thorsten Schöning <ts...@am-soft.de> on 2019/10/17 09:34:45 UTC
Experiences with Tomcat in some IoT-project?
Hi all,
TL;DR:
Is someone hosting web interfaces, web services etc. in IoT-related
projects using Tomcat? If so, under which hardware requirements,
especially CPU and RAM and using which frameworks/... for the
interface etc.? Did you do so in the past and might have failed
terribly, for what reasons?
The background:
I'm working on some IoT-project creating some device(s) with currently
only very few and vague requirements. Some of those requirements are
providing a web interface and web services, but another one is that
some variant of the device should be used in some battery-powered
context as well. If that should provide a web interface/web services
as well and how complex etc. still needs to be discussed.
Additionally, there's some cloud-based software with its own frontend
interacting with the predecessor of the newly created device. That
whole stack is implemented using Apache Tomcat, Wicket and Axis 2 and
because we are a pretty small company and stuff I would like to reuse
as much of that stack as possible and somewhat reasonable.
What we currently test is some Avenger96-Board with 1 GiB of RAM
running some Yocto-Linux, but it already seems that this doesn't fit
to a battery-powered mode. So some far less powerful hardware with
e.g. only 128 MiB of RAM gets considered as well.
https://www.96boards.org/product/avenger96/
The AV96 with 1 GiB of RAM runs my tested server-software pretty fine,
but fails with 128 MiB. With some easy steps the image could be
changed to make ~60 MiB of RAM free for my usage, but that simply
wasn't enough to start my web-app at all. Tomcat itself ran fine even
with only 15 MiB of RAM free, though, unless used with my app. :-)
What I would like to get a feeling for is if that approach is even
worth following or not. So thanks for everything you share!
Mit freundlichen Grüßen,
Thorsten Schöning
--
Thorsten Schöning E-Mail: Thorsten.Schoening@AM-SoFT.de
AM-SoFT IT-Systeme http://www.AM-SoFT.de/
Telefon...........05151- 9468- 55
Fax...............05151- 9468- 88
Mobil..............0178-8 9468- 04
AM-SoFT GmbH IT-Systeme, Brandenburger Str. 7c, 31789 Hameln
AG Hannover HRB 207 694 - Geschäftsführer: Andreas Muchow
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Re: Experiences with Tomcat in some IoT-project?
Posted by Thorsten Schöning <ts...@am-soft.de>.
Guten Tag Christopher Schultz,
am Donnerstag, 17. Oktober 2019 um 18:48 schrieben Sie:
> When you say that your desired 1GiB board doesn't "fit into
> battery-operated mode", what do you mean?[...]
Thanks for your valuable input, it's pretty in line with what I saw in
my tests already. Regarding the battery-mode, customers want to
operate the whole device only powered by some rechargeable battery in
some use cases and a colleague calculated that power consumption of
the AV96 is simply too high for that purpose. The CPU itself,
refreshing RAM even with hibernate and stuff like that. Some different
discussed board/CPU with far less power consumption only provides 128
MiB of RAM, hence the tests.
Mit freundlichen Grüßen,
Thorsten Schöning
--
Thorsten Schöning E-Mail: Thorsten.Schoening@AM-SoFT.de
AM-SoFT IT-Systeme http://www.AM-SoFT.de/
Telefon...........05151- 9468- 55
Fax...............05151- 9468- 88
Mobil..............0178-8 9468- 04
AM-SoFT GmbH IT-Systeme, Brandenburger Str. 7c, 31789 Hameln
AG Hannover HRB 207 694 - Geschäftsführer: Andreas Muchow
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Re: Experiences with Tomcat in some IoT-project?
Posted by Christopher Schultz <ch...@christopherschultz.net>.
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Thorsten,
On 10/17/19 05:34, Thorsten Schöning wrote:
> Hi all,
>
> TL;DR:
>
> Is someone hosting web interfaces, web services etc. in
> IoT-related projects using Tomcat? If so, under which hardware
> requirements, especially CPU and RAM and using which frameworks/...
> for the interface etc.? Did you do so in the past and might have
> failed terribly, for what reasons?
Without having ever tried to do anything like this, I have a few data
points for you.
First, Tomcat itself can fit into a very small heap space. Usually,
the JVM plus Tomcat can run in about 12-16 MiB the last time I
checked. The application itself is usually the memory hog. So watch
out for frameworks who eat a lot of RAM. Also be aware that XML
processing (e.g. Axis) is a memory hog, just because XML is verbose.
You might want to consider NOT using SOAP at all for performance
reasons. Also, nobody uses SOAP anymore :) I've had *great* success
with the "Noggit" event-based JSON parser. It's the JSON parser that
Solr uses when you upload a multi-gigabyte JSON document for indexing.
I have an application that served hundreds of simultaneous users on a
single node with a 64MiB heap. We only had to adjust the heap because
(a) our cached data started growing and (b) our user's sessions
started growing as well (mostly due to more users). (We have fixed the
caching settings and we are now able to run thousands of users with a
512MiB heap).
Second, I wouldn't want to run a JVM on anything which had as little
as 128MiB of RAM. Linux itself can happily run in ~16 - 32 MiB of RAM,
but everything adds a little. The JVM is pretty hefty and don't forget
about caches: if the OS has to eliminate caches, your performance will
drop like a rock. If you start to swap, memory-constrained Linux can
really thrash and get no work done.[1]
When you say that your desired 1GiB board doesn't "fit into
battery-operated mode", what do you mean? How about something like
RPi? Even the Pi Zero has 512MiB of RAM and all the wireless stuff
you'll likely want. It's not exactly a powerhouse, but it should be
able to run simple web services. I don't know about battery options,
though.
Hope that helps,
- -chris
> The background:
>
> I'm working on some IoT-project creating some device(s) with
> currently only very few and vague requirements. Some of those
> requirements are providing a web interface and web services, but
> another one is that some variant of the device should be used in
> some battery-powered context as well. If that should provide a web
> interface/web services as well and how complex etc. still needs to
> be discussed.
>
> Additionally, there's some cloud-based software with its own
> frontend interacting with the predecessor of the newly created
> device. That whole stack is implemented using Apache Tomcat, Wicket
> and Axis 2 and because we are a pretty small company and stuff I
> would like to reuse as much of that stack as possible and somewhat
> reasonable.
>
> What we currently test is some Avenger96-Board with 1 GiB of RAM
> running some Yocto-Linux, but it already seems that this doesn't
> fit to a battery-powered mode. So some far less powerful hardware
> with e.g. only 128 MiB of RAM gets considered as well.
>
> https://www.96boards.org/product/avenger96/
>
> The AV96 with 1 GiB of RAM runs my tested server-software pretty
> fine, but fails with 128 MiB. With some easy steps the image could
> be changed to make ~60 MiB of RAM free for my usage, but that
> simply wasn't enough to start my web-app at all. Tomcat itself ran
> fine even with only 15 MiB of RAM free, though, unless used with my
> app. :-)
>
> What I would like to get a feeling for is if that approach is even
> worth following or not. So thanks for everything you share!
>
> Mit freundlichen Grüßen,
>
> Thorsten Schöning
>
[1]
https://www.phoronix.com/scan.php?page=news_item&px=Linux-Does-Bad-Low-R
AM
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