perfSONAR User Q&A and Other Discussion

["Garnizov, Ivan (RRZE)" <>]

Hello Murilo,

 

Thank you for sharing. Unfortunately the information you share is much in the specifics of the implementation you are devising for RNP. I was looking to get a more high level evaluation from your side on the functionality and technology used in the RNP project.  Certainly it will be difficult for me to give exact implementation solution from where I stand.

 

Still I admit my email predisposes your reply.

 

IMO you have to think on the reasons you need to apply Linux Namespaces on communication with directly connected clients. You have to be aware Linux Namespaces do lead to a lot of complications in operation, unless you really have the need to measure in overlapping address spaces, where routing is also involved. The decision and the implementation I will leave up to you though.

 

I hope the shared links to the documentation will be of great help and we’ll be looking for your feedback on the usage of pScheduler context switching.

 

Best regards,

Ivan

 

Jubiläumsjahr 2018 - IT in Bewegung

Das RRZE - der IT-Dienstleister der FAU

www.50-jahre.rrze.fau.de

 

From: Murilo Vetter [mailto:]
Sent: Donnerstag, 7. Juni 2018 15:54
To: Garnizov, Ivan (RRZE) <>
Cc: perfsonar-user <>
Subject: Re: [perfsonar-user] Re: Running pscheduler inside a linux namespace

 

Hi Ivan,

 

I attached 2 figures that explains better what we are trying to do with perfSONAR tools (iperf3 and ping).

 

The idea is to homologate symmetric and assymetric links from costumer network.

 

Today, what we already implemented in MonIPÊ is an interface in the PoP that manages the homologation tests, generating reports.

It is implemented within a host that performs both type-approval tests (homologation tests) and regular tests.

It is already implemented using monipe toolset (iperf2 TCP and UDP, and ping), running in 2 namespaces with 2 network interfaces inside linux machine.

These 2 network interfaces are mapped to 1 physical interface using VMXNet3 Driver.

 

For symmetric links we call iperf directly inside the namespaces of the host.

For assymmetric links we call bwctl directly inside the namespaces of the host.

In this case, we have another host in the client that have 2 bwctl instance, one for upstream and another for downstream.

 

Homologation tests runs inside namespace in parallel to regular tests, that run outside namespace.

 

As we want to migrate MonIPÊ solution to use perfSONAR toolset, specially pscheduler to run regular tests, we are trying to put all these (regular tests and homologation tests) inside one host as we already did with MonIPÊ.

The only differance now is that we are going to control homologation tests centrally.

 

Previous tests demonstrate that it is possible to run regular tests and homologation tests in parallel using perfSONAR.

 

Now we are evaluating to use pscheduler to schedule tests, so we could develope a central interface to control homogation tests.

As I could see until now, pscheduler would not fit in these scenario. Now, the idea is to develope an API that controls it and a central management interface to talk with this API.

If it would fit, we would like to use it to make our schedules and control this kind of tests.

 

I also attached one report that show a 24 hour test (iperf UDP) that shows that the link is homologated.

 

I hope it's being clear what we're trying to do.

 

 

Regards,

--

Murilo Vetter
Analista REMEP-FLN/PoP-SC
PoP-SC - Ponto de Presença da RNP em Santa Catarina
REMEP-FLN - Rede Metropolitana de Educação e Pesquisa da Região de Florianópolis
RNP - Rede Nacional de Ensino e Pesquisa
UFSC - Universidade Federal de Santa Catarina
SETIC - Superintendência de Governança Eletrônica e Tecnologia da Informação e Comunicação
Fundações de Apoio FEESC e FEPESE
--/--

www.pop-sc.rnp.br
remep.pop-sc.rnp.br
CHAMADOS:
+55(48)3721-3000
INOC: 11242*100

 

---

De: "Garnizov, Ivan (RRZE)" <>
Para: "Murilo Vetter" <>
Cc: "perfsonar-user" <>
Enviadas: Quinta-feira, 7 de junho de 2018 9:26:04
Assunto: RE: [perfsonar-user] Re: Running pscheduler inside a linux namespace

 

Hello Murilo,

 

Would it be possible for you also to give some more light on the idea of RNP to use the context switching?

IMO the context switching you are trying to configure relies on IP routing inside the network contexts. The question here is, if layer2 measurements would have been sufficient to accomplish the goals of your project. An example of this would be a tool, which would allow you to perform L2 measurements in any L2 segment (virtual interface). The tool does not have limits and support multiple L2 segmentation technologies and it is a matter of a parameter switch to switch the segments.

Here is a link to the tool: https://github.com/jwbensley/Etherate ( there is also EtherateMT )

 

Please note: AFAIK there is still no commitment for this tool to be added to the pS supported tools, but your feedback will be valued.

 

 

Best regards,

Ivan

 

Jubiläumsjahr 2018 - IT in Bewegung

Das RRZE - der IT-Dienstleister der FAU

www.50-jahre.rrze.fau.de

 

From: Murilo Vetter []
Sent: Donnerstag, 7. Juni 2018 13:40
To: Mark Feit <>
Cc: Garnizov, Ivan (RRZE) <>; perfsonar-user <>
Subject: Re: [perfsonar-user] Re: Running pscheduler inside a linux namespace

 

Thanks Mark for the clarification.

 

Bests,

--

 

Murilo Vetter
Analista REMEP-FLN/PoP-SC
PoP-SC - Ponto de Presença da RNP em Santa Catarina
REMEP-FLN - Rede Metropolitana de Educação e Pesquisa da Região de Florianópolis
RNP - Rede Nacional de Ensino e Pesquisa
UFSC - Universidade Federal de Santa Catarina
SETIC - Superintendência de Governança Eletrônica e Tecnologia da Informação e Comunicação
Fundações de Apoio FEESC e FEPESE
--/--

www.pop-sc.rnp.br
remep.pop-sc.rnp.br
CHAMADOS:
+55(48)3721-3000
INOC: 11242*100

 

---

De: "Mark Feit" <>
Para: "Murilo Vetter" <>, "Garnizov, Ivan (RRZE)" <>
Cc: "perfsonar-user" <>
Enviadas: Quarta-feira, 6 de junho de 2018 14:07:59
Assunto: Re: [perfsonar-user] Re: Running pscheduler inside a linux namespace

 

Murilo Vetter writes:

 

# pscheduler task --context '{ "schema": 1, "contexts": [ [ { "context": "linuxnns", "data": { "namespace": "ns-ens224" } } ], [ { "context": "linuxnns", "data": { "namespace": "ns-ens256" } } ] ] }' throughput --source 192.168.0.39 --dest 192.168.0.45 --source-node 192.168.0.43 --dest-node 192.168.0.43
Submitting task...
Unable to post task: Error while tasking 192.168.0.43: Unable to post task to 192.168.0.43: ERRO: Task already exists. All participants must be on separate systems.

 

Would it have a way to overcome this error, forcing to do the test? Maybe in a future implementation? Or it is not suppose to?

I tried with 2 different IP on the same host with no namespace configured and it showed the same problem.

 

pScheduler does not allow running of multi-participant tests (throughput and simplestream) where the same server acts as more than one of the participants.  Part of it has to do with the way the API’s resource model is organized and part of it has to do with avoiding running resource-intensive tests on the same server at the same time and getting distorted results.  Any of the single-participant tests (rtt, trace, latency) will work because there’s no second pScheduler involved and they do everything necessary to exercise the namespace changes.  For those, you’d specify a source, a source node and a destination.

 

I do my testing of this on pairs of VMs with a private segment between them.  There’s a utility script in the sources that does the alternate namespace setup and can be customized for your environment:  https://github.com/perfsonar/pscheduler/blob/master/scripts/create-netns

 

--Mark