Hi John,

I'll be working on this with engineering in the morning; thanks for
the details thus far.

This is puzzling: Metrons do not route traffic to dopplers outside
their zone today. If all your app instances are spread evenly, and all are
serving an equal amount of requests, then I would expect no
major variability in Doppler load either.

For completeness, what version of CF are you running? I assume your
configurations for all dopplers are roughly the same? All app instances per
AZ are serving an equal number of requests?

Thanks,
Erik Jasiak

On Monday, May 25, 2015, john mcteague <john.mcteague(a)gmail.com> wrote:

Correct, thanks.

On Mon, May 25, 2015 at 12:01 AM, James Bayer <jbayer(a)pivotal.io> wrote:

ok thanks for the extra detail.

to confirm, during the load test, the http traffic is being routed
through zones 4 and 5 app instances on DEAs in a balanced way. however the
dopplers associated with zone 4 / 5 are getting a very small amount of load
sent their way. is that right?


On Sun, May 24, 2015 at 3:45 PM, john mcteague <john.mcteague(a)gmail.com>
wrote:

I am seeing logs from zone 4 and 5 when tailing the logs (*cf logs
hello-world | grep App | awk '{ print $2 }'*), I see a relatively even
balance between all app instances, yet doppler on zones 1-3 consume far
greater cpu resources (15x in some cases) than zones 4 and 5. Generally
zones 4 and 5 barely get above 1% utilization.

Running *cf curl /v2/apps/guid/stats | grep host | sort *shows 30
instances, 6 in each zone, a perfect balance.

Each loggregator is running with 8GB RAM and 4vcpus.


John

On Sat, May 23, 2015 at 11:56 PM, James Bayer <jbayer(a)pivotal.io>
wrote:

john,

can you say more about "receiving no load at all"? for example, if
you restart one of the app instances in zone 4 or zone 5 do you see logs
with "cf logs"? you can target a single app instance index to get restarted
with using a "cf curl" command for terminating an app index [1]. you can
find the details with json output from "cf stats" that should show you the
private IPs for the DEAs hosting your app, which should help you figure out
which zone each app index is in.
http://apidocs.cloudfoundry.org/209/apps/terminate_the_running_app_instance_at_the_given_index.html

if you are seeing logs from zone 4 and zone 5, then what might be
happening is that for some reason DEAs in zone 4 or zone 5 are not routable
somewhere along the path. reasons for that could be:
* DEAs in Zone 4 / Zone 5 not getting apps that are hosted there
listed in the routing table
* The routing table may be correct, but for some reason the routers
cannot reach DEAs in zone 4 or zone 5 with outbound traffic and routers
fails over to instances in DEAs 1-3 that it can reach
* some other mystery

On Fri, May 22, 2015 at 2:06 PM, john mcteague <
john.mcteague(a)gmail.com> wrote:

We map our dea's , dopplers and traffic controllers in 5 logical
zones using the various zone properties of doppler, metron_agent and
traffic_controller. This aligns to our physical failure domains in
openstack.

During a recent load test we discovered that zones 4 and 5 were
receiving no load at all, all traffic went to zones 1-3.

What would cause this unbalanced distribution? I have a single app
running 30 instances and have verified it is evenly balanced across all 5
zones (6 instances in each). I have additionally verified that each logical
zone in the bosh yml contains 1 dea, doppler server and traffic controller.

Thanks,
John

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Thank you,

James Bayer

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Thank you,

James Bayer