PANTHEON.tech @ TechXLR8 in London

In mid-June, the TechXLR8 multi-genre tech festival took place in London. Although being part of the London Tech Week 2017, it comprised of further eight ‘smaller’ events: 5G World, IoT World Europe, Cloud & DevOps World, Apps World Evolution, VR & AR World, AI & Machine Learning World, Connected Cars & Autonomous Vehicles Europe and Project Kairos.

Poster for the TechXLR8 in London, attended by PANTHEON.tech

Since it was, from a global perspective, one of the key industry meetings, PANTHEON.tech could not have missed it. We’ve participated in TechXLR8 Cloud & DevOps World section where we showcased our SDN, ODL and networking skills and know-how: we’ve seen a lot of great things, we’ve managed to acquire interesting contacts with international companies active in telco, content delivery and SDN segments. Products from our portfolio such as SysRepo, ODL, HoneyComb, VPP, FD.io turned out to be really great topics for discussion.

Which keywords did the participants respond to best? Linux Foundation, OpenStack, Docker, Kubernetes, BigData. The demand for Pantheon’s business cards was so high that it caught us by surprise. We even had to ration them on the last day, such was the appetite for PANTHEON.tech!

Juraj Veverka

PANTHEON.tech @ GeeCon 2017 in Krakow

Every year, Krakow welcomes some of the biggest industry names to talk about Java and everything related. This time, PANTHEON.tech couldn’t miss it.

First day in Krakow

The proverbial long and winding road does exist. It sits between Žilina in northern Slovakia and Polish Krakow. After a couple of hours of tiresome driving, we’ve safely arrived in the city. It was a lonesome journey with only radio Pogoda keeping us company by talking gibberish and playing some traditional Polish songs (also in gibberish). The city of Wypadki is surely a magical place. A place where trucks have voting rights and bikers outnumber pigeons 3 to 1. Unfortunately, there was no time to explore further. We checked-in and prepared a schedule of talks to visit.

 

Second day survival

GeeCon took place in a well-equipped multiplex near the city centre. As it turned out, the venue was not built for this type of events. The corridors‘ bottleneck started to fill with attendees blocking the passage to talk rooms, and you could have spent the whole breaks standing in line in front of a bathroom.

However, the 2017 GeeCon brought out the big guns right at the beginning. David Moore from Sabre showed us the true meaning of “experience.” Although his talk had a rather bland title “Platform and Product Evolution at Sabre”. He touched a broad spectrum of topics – from organizational structures and their need to reflect the software architecture to his hatred towards “layered-cake” architecture designs.

Next on the schedule were some sub-par talks about Java 9 in general, mixed with some never-ending Docker hype, CUDA computing, and introductory profiling. And then we got the juicy stuff. Milen Dyankov from Liferay was not afraid to speak openly about the state and purpose of Jigsaw, the need for the OSGi, and where it all fits together. Great talk for an audience of all levels of familiarity with modular concepts in Java. And of all genders, of course.

We were really pumped up for Monica Beckwith’s talk boldly called “Java Performance Engineers Survival guide”. The abstract was attractive and her CV was quite impressive: JavaOne rock star, previously working in AMD as performance engineer, then Sun, later at Oracle working on GC. Suffice to say, the expectations were really high. However, this was probably the biggest disappointment of the entire event.

We ended the day with a dry sauna back at the hotel and went to sleep.

Third day with Java and Avast

After such an exhausting first day, we started with a well-prepared soft-skills talk promising to improve our client presentations, only to continue with the trend of microservices and reactive programming. Right before lunch, Jarosław Pałka showed us the magic of bytecode. It stood up to the high anticipations and made us want to –javaagent something.

Avast people demonstrated how to utilize Docker in production and Marcin Grzejszczak explained the idea behind consumer-driven contracts of APIs. This certainly got our attention and we will consider it for future projects.

After Steve Poole’s light talk about Java vulnerabilities, we headed back to the hotel to get ready for the biggest IT party of the year. A large club located inside an old fort hosted geeks the entire night and they seriously did show their mad dancing skills, as you can see in the photo.

Fourth day, after the party

The morning after the party, waking up was a bit more painful. We ate the breakfast quickly and checked out.


Even though the party was hard, the audience listened carefully at the first presentation about interrupted exception. We decided to fork us and take a part at different presentations. To the roots of JVM – Java native runtime and another hype – Akka (full auditorium with no spare room left). Later on, we continued with some general JavaScript and JPA lectures.

We joined together at the presentation called “Distributed systems explained (with NodeJS)”, given by Bruno Bossola. Our long-standing question on how to do testing properly was answered by Anton Arhipov – TestContainers.

There was a great presentation about code generation and the reasons why we should generate configurations instead of code at the very end of the conference. Here we felt as if the future was already here. Rod Johnson presented Atomist – a bot for Slack.

Thank you to PANTHEON.tech and to the organizers of GeeCon for this amazing experience.

Martin Dindoffer

Milan Frátrik

Sponsoring the Automotive Linux Summit in Tokyo

PANTHEON.tech is proud to announce that we’ve become a Silver Sponsor of the Automotive Linux Summit, which will be taking place at Tokyo Conference Center Ariake from May 31 till June 2, 2017. In practice, this means more visibility for our brand plus a lot of networking potential. Which equals great potential for meeting new customers.

The Automotive Linux Summit is a one-of-a-kind event where automotive innovators meet with Linux ninjas, research & development managers and business executives. The result? Connecting developers with their peers and vendors, driving innovation towards the automotive future.

With PANTHEON.tech’s background, skills and global plans, this is a place where we naturally belong.

And we’re not going to miss the chance.

Martin Firák

PANTHEON.tech @ PyCon 2017 in Bratislava

The PyConSK 2017 conference took place at Slovak University of Technology’s Faculty of Informatics and Information Technologies in Bratislava over the weekend from March 10th to 12th.

First day & its challenges

The first day, the Slovak Day took place. The presentations in the large auditorium were focused not only on Python, but also on Robot Framework, artificial intelligence, Open Data, e-government and many other topics. Presentations in the Small auditorium discussed education, elaborating on best practices in teaching Python at high schools.

The presentation “Alternative Methods of Running Tests and Evaluation of their Results” gave a good insight into using test suites and their interpretation. Another interesting presentation was “Custom Python Libraries for Robot Framework,” which was an inviting introduction to Robot framework for beginners. Another two presentations caught our attention: the first one, by Exponea’s Jožo Kováč, was rather more serious.

In “How can Artificial Intelligence in Python Help a Company Grow?” he gave examples of AI’s benefits for e-commerce. The second one, and also the last presentation of the first day, was the funniest of the whole conference. Speaker Michal Kaukič shone out from others by his excellent sense of humor on the topic, which was otherwise boring – “Graphics in Jupyter Notebooks.” He did not give us much opportunities to fall asleep, as twenty per cent of the time the whole auditorium was laughing.

Second day & Django Girls

Saturday’s presentations were mostly in English. The first one was given by Pavel Serbajlo: “What Makes Silicon Valley Software Developers Special?” Since he spent over 4 years in the USA, he knew what he was talking about. It was interesting for all of us to hear what the values in Silicon Valley are, how people work, communicate, commute and how they live.

Other two presentations, “Making Monitoring Boring” and “Building Data Pipelines with Python” were presentations which I definitely wanted to hear due to personal interest in data mining and Linux administration.

The lunch break was a perfect time to establish new contacts, or simply talk to each other while enjoying a great meal. There were several sponsors booths representing RedHat, Fedora, Mozilla, Exponea, Kiwi, Eset, Kistler and others.

After the lunch break, I attended an interesting presentation, “From Code to Community,” which was focused on a community and its ability to organize not only smaller meet-ups, but also bigger conferences like PyCon.DE. The last speaker that day, Adrian Holovaty, co-BDFL of the Django web framework, had a humanely-focused speech about the community aspects of open source.

On the event’s third day, Sunday, I briefly visited the Django Girls workshop and shortly after that I went to Code Analysis with Coala sprint. I did not know much about Coala, so I really appreciate that I could learn something new about this great open source project helping developers improving their code quality.

Two presentations in the large auditorium were interesting for me as well. In “Object Calisthenics,” Pawel Lewtak discussed nine steps leading to a better code. He showed us how to use nine rules called Object Calisthenics in order to write the code shorter, more precise, easier to read and easy to test. At “Automating Network Equipment with Python,” by Elisa Jasinska, we could learn about automated access to devices by Cisco, Juniper, Arista and others.

I can recommend such a great conference, as PyCon surely is, to all Python enthusiasts. Videos from the event can be found on YouTube.

Ján Hradil

Software Developer

We believe in women in IT

The biggest Python conference in Slovakia, Pycon 2017, is being held during the weekend of March 10 – 12, 2017. We have decided to grant sponsorship to a one-day workshop called Django Girls. The project believes in women’s potential in IT and since the co-owner of Pantheon Technologies, Janka Švorcová, is a woman, we considered our support as a matter of course.

The workshop is focused on website development and thanks to sponsor contributions is completely free of charge. Also, a grant programme covering the travel and accommodation costs for the participants was set up. The application was open to all girls who speak Slovak or English and own a computer. The participants do not need any previous skills or knowledge in this field, since the programming curriculum covers even the very basics.
The whole project and workshop take place as a part of Django Girls, an international initiative and NGO aiming at making IT more attractive to women. Django Girls’ learning tools are being used by volunteers to teach programming skills all around the world.

 

Gabriel Žifčák

Marketing officer at Pantheon

Sources:

https://djangogirls.org/

https://www.pycon.sk/2017/

 

Your Time is Now

  • 12,000 registered visitors at place –
  • 14,000 connected devices –
  • 25,000 registered online visitors –
  • 29,374,360 words presented in sessions –
  • 67,000 meals packed for Rise Against Hunger (17,000 more than planned!) –
  • 2,713 customer and partner meetings in the Meeting Village –
  • 31,000,000 people have seen the CLEUR (Cisco Live Europe) content –

This year’s Cisco Live (CL) Berlin 2017 rocked the Messe Berlin. From a Cisco Data Center standpoint ACI, Tetration and ASAP continued to grab the headlines. In particular, Cisco ACI has established itself as the dominant SDN technology with over 2,700 customers and a growing eco-system of 65 partners in just two and a half years.

cisco live 2017

 

Keynotes

Future-Proof your Business – fantastic and catchy opening keynotes were delivered by Cisco Vice President of Growth Initiatives (and Chief of Staff to CEO Chuck Robbins) Ruba Borno, who shared Cisco’s vision that the only future-proofed solution for digital transformation would be the next-generation secure network.

Cisco’s intelligence unit consists of more than 250 leading security experts, data scientists and hackers. These are the guys who are hacking the hackers. This is an organization that has the back of every Cisco partner’s customer. Cisco’s products teams then take all this intelligence and add automation, add machine learning, and provide Cisco’s partners and customers with integrated security architecture. All of this in order to protect their partners, protect their employees, their assets and their intellectual property.

By the way, did you know that Cisco has the best breach detection time in the market? They are able of detecting over 90% security incidents within three minutes and since Cisco put the web everywhere, it’s now time to abandon the legacy point product security behavior and adopt an integrated and dynamic self-learning holistic approach. So, that you not only have less complexity, but also feel more secure.

With Cisco, we know that we have the best networking hardware with the most advanced software. Yet you shouldn’t be satisfied with the best software of today. What you should go for is the best software for tomorrow. And it not only needs to be advanced, it also needs to be advanceable.

Tetration, according to Ruba Borno, is one of the coolest platforms Cisco has. It understands your entire data center in the context of the application environment. It can automatically map your application landscape, it can automatically map your dependences across applications, it can also determine which security policy to apply. And it can also enforce it and it, doing so at scale.

The closing guest keynote was delivered by Virgin Galactic’s Commercial Director Stephen Attenborough, who, at one point, was also the company’s first employee. He was the one who had established Virgin Galactic’s commercial foundations including a community of 700 future astronauts, and is now also responsible for work streams investigating additional applications and markets for space vehicles. This also includes the now very actively pursued small satellite launch program.

 

ACI Solutions Partners

CL Berlin’s platinum sponsor was Citrix who’ve had a significant presence in the partner area this year. At booth P2, you could engage their experts on how to securely deliver apps and data over any network with Citrix XenDesktop, XenApp and NetScaler on Cisco UCS/HyperFlex virtualization infrastructure in order to increase your business’s productivity, agility and differentiation.

 

DevNet Zone

DevNet is Cisco’s new developer program which provides their partners with tools to produce Cisco-enabled applications. These can then be sold to Cisco’s customers and (or) use the company’s API to enhance or manage your existing Cisco network. Or, to put it more simply, DevNet is where applications meet the infrastructure. DevNet is often considered an old tool, but did you know it’s only been around for three years, launched in December 2013?

DevNet is teaching researchers and engineers how to use new tools and resources as well as helping them in their daily work and careers to impact their companies. DevNet is about helping people innovate. And what specific role did DevNet play at this year’s Cisco Live? According to Cisco’s Senior Director Rick Tywoniak, one of DevNet’s contributions to CL Berlin week was working with 13 innovation centers around the world, helping the CL visitors in cooperation with the engineers working out there, and highlighting some of the cool apps that were developed using Cisco’s APIs. One of such examples can be found in the retail space: MishiPay is a company whose software allows integrating self-checkouts via wi-fi. In case you decide to leave the store without checking out all your items, the MishiPay application learns of your misbehavior and sets the alarm off!

 

Data Center Innovation: Speaker one

Liz Centoni (Senior Vice President & General Manager, Computing Systems Product Group at Cisco)

The world of Data Centers and the Cloud happens to be very dynamic. The amount of network changes that we see in modern data centers is much bigger than probably in any other segment in the IT space. The real challenge is managing all of these. The user community is evolving – this is something known and traditional. Applications that can be anywhere from bare metal to virtualization to containers, and can sit anywhere – multiple clouds and on the premises as well. In order to address all of these, let’s have a look at the overall holistic approach that is based on four elements (four design principles), that build an integrated architecture: Analyze – Simplify – Automate – Protect.

 

 

What Liz Centoni sees as a well working customer driven product can be described by three keywords: one architecture – standardized operations – simplicity. An example of this is Cisco integrated system for Microsoft Azure Stack. Its advantages comprise of unified infrastructure management, Cisco generation 4 VIC card, optimized fabric design, and proven policy driven architecture.

 

Data Center Innovation: Speaker two

Ishmael Limkakeng (Vice President, Product Marketing at Cisco)

“Combination of Cisco’s portfolio in a Data Center right now is the best it has ever been. We use Tetration to understand how an application works. We use ACI to automate how an application gets installed. We use Data Center to deploy that, wherever the right workload for the right environment. And then we come back again to Analytics to understand what we did, to make sure, we did, what we intended. That’s how we see this all coming together.”

 

 

Demos and Theater Presentations at World of Solutions

At this year’s World of Solutions this year, SDN/ACI, Tetration Analytics, UCS and Cloud took center stage in the Data Center category. There were multiple demos showcasing ACI and Tetration innovations.

Generally speaking, as Cisco’s recent ground-breaking innovation, Tetration was a hot topic during the whole CL. At the Tetration demo area, customers learned the details about end-to-end application visibility and automated white-list policies for granular segmentation. It was a unique occasion to meet Cisco’s experts and discuss with them recent innovations such as automatic policy enforcement, Tetration Apps, flexible form-factor based deployment options. Following the Tetration launch on February 1, 2017, its innovations have attracted endorsements from customers, partners and media. Check out ecosystem partner quotes here.

Social Networking

Last but not least, as a Cisco Live attendee, you benefited from the opportunity to interact with your peers, Cisco staff and partner technical experts in both structured and informal settings. And this is what counts the most!

Andrej Vanko, MSc.

IT Project Manager at Pantheon Technologies, s.r.o.

 

Sources:

blogs.cisco.com

www.ciscolive.com

youtube channel: Cisco Live Europe

PANTHEON.tech @ OPNFV Fast Data Stack – FOSDEM 2017

On February 5th, we were present at the OPNFV Fast Data Stack on FOSDEM conference that is hosted every year at Brussels’ Université libre de Bruxelles. It was a great gathering of software developers who presented their work in the form of 30-minute presentation. People came not just from Europe, but also oversees and other parts of world.  Lectures took place in more than 30 rooms and more than 600 speakers were presenting their projects.

There was a number of interesting lectures not only in the field of networking, but also robotics, neural networks, microprocessors, algorithms and data modeling. Some presenters were members of large teams, some were presenting their own projects. The scope was very wide including almost every programing language one had ever heard about. Visitors could see everything from startups up to trending projects such as Kubernetes, OpenDaylight or OpenStack. Every lecture was recorded and videos can be found on the FOSDEM website. Our presentation was scheduled in the NFV (Network Function Virtualization) section.

About virtualization and networking

Virtualization became very popular over the last years. Virtual machines curb the need for physical resources and make data centers more flexible and accessible. Today’s servers are really powerful and therefore able of hosting many VMs. This shed a new point of view on networking and, as a response, it got virtualized too in the form of virtual forwarders – processes capable of forwarding traffic within a hosting machine. OVS and VPP are the popular technologies these days and both support a very powerful set of data plane libraries and network interface controller drivers for fast packet processing, called DPDK. You may think of VPP and OVS as virtual forwarders between physical NICs and the virtual machines.

What is OPNFV Fast Data Stack?

OPNFV FDS makes it easier to maintain complicated data center environments. It’s a complex multilayer suite that includes software components designed for creating virtual machines and forwarding traffic. All the components are built with Apex installer on given set of host machines that need to match demanding performance needs and have a basic connectivity as well. As a result, a complex stack is created, providing a rich user-interface to network operators. The input exposes abstract set of tools for managing the life cycle of network, virtual machines and policies across given nodes.

Under the hood

Let’s have a look on key components of the OPNFV FDS suite. As mentioned above, multiple components operate at different layers of the stack. Each component participates in transforming defined abstraction to an actual configuration for underlying infrastructure.  On top of the stack resides OpenStack. This software is known for its scalability, loads of plugins and vast community. FDS uses OpenStack for managing VMs and for defining forwarding topology and policy rules. Forwarding inputs can be characterized by elements such as networks, subnets, routers or ports. Policy inputs by security groups and security group rules. One layer bellow is the OpenDaylight controller, also popular for its community, and plugins.

In the OPNFV FDS setup, it is used as a controller unit that consumes OpenStack’s abstractions and applies it to an underlying infrastructure using OpenDaylight’s Group Based Policy plugin. When the plugin detects that a policy can be resolved for at least two endpoints, configuration is generated and flushed to forwarders. OPNFV FDS setup, presented on FOSDEM, is using VPP in the hypervisor to forward packets between physical NICs and the VMs.

VPP, Vector Packet Processing, is a virtual switching/routing technology operating at a very impressive rate. It is impressively fast thanks to the DPDK library and CPU cache optimizing techniques. The beauty of Vector Packet Processing is that instead of handling packets one by one, VPP will perform one micro-operation after another to a group of packets which performs better with heavy load and results in increased throughput. VPP exposes C APIs and CLI for configuration. However, it’s not yet possible to use C API remotely because VPP does not run any management client.  Therefore, Honeycomb is used in the setup to provide NETCONF interface for the VPP forwarder. OpenDaylight uses NETCONF to talk to a HC Agent.

Supported scenarios

The FDS Demo presented on FOSEDEM showed the L2 scenario, meaning that L2 traffic is passed via VXLAN tunnels between the nodes. Traffic is routed on centralized node and routing is not performed by VPP itself, but by the OpenStack Qrouter service that is interconnected into every L2 domain in VPP via tap ports. NAT and routing towards external networks is also done by Qrouter.

Moving forward, FDS project is also looking at the L3 scenarios, where routing could be either distributed or centralized and will be done by VPP process together with NAT. All this efforts need attention on every layer of the stack including Apex installer.

Conclusion

We were pleased to present the FDS project at the FOSDEM conference. We believe that OPNFV FDS is a key component in network virtualization with a very bright future. For more information about the setup, and project itself, please visit this page.

Tomáš Čechvala, Michal Čmarada

Software Engineers

OpenDaylight RPC & implementation

What Could Possibly Go Wrong With Adding This One Cool Feature

OpenDaylight uses YANG as its Interface Definition Language. This is an architecture decision we have made way back in 2013 and it works reasonably well for the most part.

One of YANG concepts, used rather heavily, is the use of RPC. For YANG and its intended use in NETCONF’s client/server model it works perfectly fine, but trouble starts brewing when you borrow concepts and try to make them fit your use case.

OpenDaylight uses YANG RPCs to not only define its northbound model, but also model interactions between its individual plugins. It does this in an environment, which is a single process, but rather a cluster of nodes, each having a mesh of plugins, some activated some not.

From architecture’s view, which looks at things from an elevation of 10,000 feet, the problem of making RPCs work in this sort of environment is quite simple: all you need are registries and request routers. From implementation perspective, though, things can easily go wrong… implementations have bugs, quirks and limitations which are not immediately apparent. They just surface when you try and push the system closer to its architectural limits.

The Trouble with Names

RFC 6020 defines only the basic RPC concept and assumes there is a single implementation servicing any request for that RPC. This is okay as long as you are targeting singleton actions — like ‘ping IP’, ‘clear system log’ and similar. In a complex system, though, requests are typically associated with a particular resource — like ‘create a flow on this switch’. Since YANG did not give us this tool, we have decided to create an OpenDaylight extension to allow an RPC to be bound to a context. This gave rise to two unfortunate names: ‘Global RPCs‘ and ‘Routed RPCs‘, the first being normal RPCs and the second being bound to a context. Plus, a third name, ‘RPCs‘, to refer to either one of those concepts. Are you confused yet?

The initial implementation of these concepts was done back in 2013, when there was no clustering in sight, by a team who have spent days upon days discussing the difference. When clustering came into the implementation picture, in 2014, the implementation team attached their own meaning to the word ‘Routed’ and we ended up with an implementation, where Routed RPCs are routed between cluster nodes, but the default ones are not. That is the subject matter behind BUG-3128. It did not matter much as long as all cluster-enabled applications used Routed RPCs, but that changed with emergence of Cluster Singleton Service and its wide-spread adoption among plugins.

These days we have YANG 1.1, defined in RFC 7950, which has the same underlying concept with much less confusing names. ‘Global RPCs’ are ‘RPCs‘. ‘Routed RPCs’ are ‘actions‘. Since those terms make the conversation about semantics a reasonable affair, this is the last you hear about Global and Routed RPCs from me.

Fun with Concepts, Contexts and Contracts

In order to support both RPCs and actions, OpenDaylight’s MD-SAL infrastructure has to define a concept to identify them both. Since the two are utterly similar in what they do, DOMRpcIdentifier was born. It is used to identify either an action or an RPC. To do that is is an abstract class with two concrete, private final implementations: DOMRpcIdentifier$Global and DOMRpcIdentifier$Local. Why those names? I do not remember the details, but I could wager a guess about what I was thinking back then. At any rate, the two implementations differ only in their implementation of DOMRpcIdentifier.getContextReference(). DOMRpcIdentifier$Global’s is always empty and DOMRpcIdentifier$Local’s is always non-empty.

This is consistent with how RPCs (without a context reference) and actions (with a context reference) are invoked and it makes the API involved in the context of RPC/action invocation clean and simple. API contract. In the context of registering an RPC or action implementation, things are slightly less straightforward. It is a separate interface, with a rather terse Javadoc. In both cases there is a hint of ‘a conceptual dynamic router’, but not much in terms of details.

Unless you were very curious as to the details of the API contracts involved, after reading the documentation available, with some OpenDaylight tutorials under your belt, you would feel this is a dead-simple matter and just use the interfaces provided. Run a few test cases and everything works just fine. No trouble in sight.

About That Router Thing…

The Simultaneous Release name of OpenDaylight for the release currently in development is Carbon, meaning we have shipped 5 major releases, so this ‘dynamic router’ thing vaguely referenced actually exists somewhere and it does something to fulfill the API contracts imposed on it, otherwise the applications would not be able to work at all. The entry point into the implementation is DOMRpcRouter. Glancing over that, it contains some ugliness, but it gets the general outline of the two sides of the contract done.

Digging a bit deeper into the invocation path, you get into the fork at AbstractDOMRpcRoutingTableEntry.invokeRpc(). The RPC invocation path is rather straightforward, but the invocation path for actions is far from simple. Out of two code paths (actions and RPCs) we suddenly have 4, as an action can be invoked without a context reference as if it were an RPC and there is a brief mention of remote rpc connector registering action implementations with an empty context reference … wait … WHAT???!!!

Okay, we seem to have two implementations integrated based on implementation details, without that being supported by a single line in the API contract. The connector referenced is actually sal-remoterpc-connector and is something that is meaningful in clusters. To make some sense of this, we have to go back to 2013 again.

A Tale of Three Routers

From the get go, the MD-SAL architecture was split into two distinct worlds: Binding-Independent (BI, DOM) and Binding-Aware (BA, Binding). This split comes from two competing requirements: type-safety provided by Java for application developers who interact with specific data models and infrastructure services which are independent of data models. The former is supported by interfaces and classes generated from YANG models and generally feels like any code where you deal with DTOs. The latter is supported by an object model similar to XML DOM, where you deal with hierarchical ‘document’ trees and all you have to go by are QNames. For obvious reasons most developers interacting with OpenDaylight have never touched the BI world, even though it underpins pretty much every single feature available in the platform.

A very dated picture of how the system is organized can be found here. It is obvious that the two worlds need to seamlessly interoperate — for example RPCs invoked by one world must be able to be serviced by the other and the caller should be none the wiser. Since RPCs are the equivalent of a method call, this process needs to be as fast as possible, too. That lead to a design, where each world has its own Broker and the two brokers are connected. Invocations within the world would be handled by that world’s broker, foregoing any translation. A very old picture of how an inter-world call would look like can be seen in this diagram.

For RPCs this meant that there were two independent routing tables with re-exports being done from each of them. The idea of an RPC router was generalized in the (now long-forgotten) RpcRouter interface. Within a single node, the Binding and DOM routers would be interconnected. For clustered scenarios, a connector would be used to connect the DOM routers across all nodes. So an inter-node BA RPC request from node A to node B would go through: BA-A -> BI-A -> Connector-A -> Connector-B -> BI-B -> BA-B (and back again). Both the BI and connector speak the same language, hence can communicate without data translation.

The design was simple and effective, but has not quite survived the test of time, most notably the transition to dynamic loading of models in the Karaf container. Model loading impacts data translation services needed to cross the BA/BI barrier, leading to situations where an RPC implementation was available in BA world, but could not yet be exported to the BI world — leading to RPC routing loops, and in case of data store services missing data and deadlocks.

To solve these issues, we have decided to remove the BA/BI split from the implementation and turn the Binding-Aware world into an overlay on top of the Binding-Independent world. This means that all infrastructure services always go through BI, and the Binding RPC Broker was gradually taken behind the barn, there was a muffled sound in 2015, and these days we only have two routers, one hiding behind a connector name.

Blueprint for a New Feature

Probably the most significant pain point identified by new people coming to OpenDaylight is that the technology stack is a snowflake, providing few familiar components, with implementation and documentation being borderline hostile to newcomers. One of such pieces is the Configuration Subsystem (CSS). Driven by invalid YANG and magic XMLs, it is a model-driven service activation, dependency injection and configuration framework built on top of JMX. While it offers the ability to re-wire a running instance in a way which does not break anything half-way through reconfiguration, it is a major pain to get right.

It pre-dates MD-SAL (which offers nicer configuration change interactions) and is utterly slow (because the JMX implementation is horrible). It was also designed to safeguard against operator errors and this is quite contrary to what Karaf’s feature service provides — if you hit feature:uninstall, those services are going down without any safeties whatsoever.

To fix this particular sore spot, one of the decisions from the Beryllium design summit was to extend Blueprint with a few capabilities and start the long journey to OpenDaylight without CSS, where internal wiring would be done in Blueprint and user-visible configuration would be stored in MD-SAL configuration data store. The crash-course page is a very easy read.

You will note that there is support for injecting and publishing RPC implementations — which is a nice feature for developers. Rather than having to deal with registries, I can declare a dependency on an RPC service and have Blueprint activate me when it becomes available like this:

<odl:rpc-service id="fooRpcService" interface="org.opendaylight.app.FooRpcService"/>

I can also publish my bean as an implementation, just with a single declaration, like this:

<bean id="fooRpcService" class="org.opendaylight.app.FooRpcServiceImpl">   
<!-- constructor args --> </bean> <odl:rpc-implementation ref="fooRpcService"/>

This is beyond neat, this is awesome.

FooRpcService vs. DOMRpcIdentifier

We have already covered how Binding Aware layer sits on top of the Binding Independent one, but it is not a one-to-one mapping. This comes from the fact that Binding Independent layer is centered around what makes sense in YANG, whereas the Binding Aware layer is centered around what makes sense in Java, including various trade-offs and restrictions coming from them. One such difference is that RPCs do not have individual mappings, i.e. we do not generate an interface class for each RPC, but rather we generate a single interface for all RPC definitions in a particular YANG module. Hence for a model like

module foo { 
     rpc first { input { ... } output { ... } } 
     rpc second { input { ... } output { ... } } }

 

we generate a single FooService interface

public interface FooService { 
         Future<FirstOutput> first(FirstInput input); 
         Future<FirstOutput> second(SecondInput input); 
     }

The reasoning behind this is that a particular module’s RPCs (in the broad sense, including actions) will always be implemented by a single OpenDaylight plugin and hence it makes sense to bundle them together.

An unfortunate side-effect of this is that in the Binding Aware layer, both RPCs and actions are packaged in the same interface and it is up to the intermediate layers to sort out the ambiguities. This problem is being addressed in Binding V2, where each action has its own interface, but we have to have a solution which works even in this weird setup.

Fix Some, Break Some

Considering these complexities and gaps in the API contract documentation department, it is not quite surprising that the fix for BUG-3128, while making RPCs work correctly across the cluster had the unfortunate side-effect of breaking blueprint wiring in a downstream project (OpenFlow Plugin). In order to understand why that happened, we need to explore the interactions between DOMRpcRouter, blueprint and sal-remoterpc-connector.

When blueprint sees an <odl:rpc-service/> declaration, it will wire a dependency on the specified RPC (Binding Aware) interface being available in DOMRpcService (which is a facet of DOMRpcRouter). As soon as it sees a registration, it considers the dependency satisfied and proceeds to with the wiring of the component. This is true for LLDP Speaker, too. Note how it declares a dependency on an implementation of PacketProcessingService. Try as you may, you will not find a place where the corresponding <odl:rpc-implementation/> lives. The reason for this is quite simple: this service contains a single action and an implementation is registered when an OpenFlow switch connects to the OpenDaylight instance. So how is it possible this works?

Well, it does not. At least not the way it is intended to work.

What happens is that Blueprint starts listening for an implementation of PacketProcessingService becoming available with an empty context, just as with any old RPC. Except this is an action, so somebody has to register as a global provider for the action, i.e. as being capable to dynamically invoke it based on its content and not being tied to a particular context. That someone is sal-remoterpc-connector, in its current shape an form, which does precisely what is mentioned in that terse comment. It registers itself as a dynamic router for all actions and when a request comes in, it will try to find a remote node which has registered an implementation for the specified in the invocation. That means that unbeknownst to the Blueprint extension, all actions appear to have an implementation — even if there is no component actually providing it — and therefore LLDP Speaker will always activate, just as if that dependency declaration was not there.

The fix to address BUG-3128 performed a simple thing: rather than using blanket registrations, it only propagates registrations observed on other nodes — becoming really a connector rather than a dynamic router. Since no component provides the registration at startup time, blueprint will not see the LLDP Speaker dependency as satisfied, leading to a failure to activate. Unless an OpenFlow switch happens to connect while we are waiting — in that case, activation will go through.

So we are at a fork: we either have blueprint ‘working’, or we have RPC routing in cluster working. Getting both to work at the same time, and actually fixing LLDP Speaker to activate when appropriate, we will obviously have to perform some amount surgery on multiple components.

I will detail what changes are needed to close this little can of worms in my next post. Stay tuned!

Róbert Varga

CTO Pantheon Technologies

ngPoland and beyond

In late November 2016 we visited one of the world’s biggest Angular conferences – ngPoland. Just two months before, Angular2 had been released, so all the sessions were more or less discussing it.

The first session was focused at Angular CLI. Tracy Lee showed us how to make a simple application and put it into Firebase in 30 minutes. All with the help of Angular CLI – a command line tool which helps build applications faster, since it prepares your dev environment and you can start coding right away.
We’ve already tried Angular CLI in our project and it’s great. Do you want to watch functionality with live reload, do unit testing with Karma, and end-to-end testing with Protractor? It’s all there, plus much more.

Shai Reznik told us the Legend Of ngModules, a pretty funny story with lot of interesting info on how to write, yes, modules. Seems like a skilled developer should know how to structure applications, but it’s nice to be reminded those best practices every now and then. Especially, when it’s your first try with Angular 2 and TypeScript.

There were few moments when we called „It‘s (put year here), so use (put library/pattern/language here).“ Like „It’s 2005, use asynchronous calls,“ or „It‘s 2015, use promises, callbacks are baaaad“. Now we have another one: „It’s 2016, use observables!“ On this topic, Ben Lesh had a good talk about the RxJS library, which implements the Observer pattern for composing asynchronous and event-base programs.
We’ve tried RxJS, and it works pretty well. We replaced promises in our AJAX calls and events in components. It needs some time to get used to, but it gets pretty straightforward then.

There were more good talks at the Ng Poland conference, so it’s awesome that we all can watch the recordings on YouTube.

 

I would like to conclude this article with some advice: in the case you are about to start a new project and are deciding between Angular 1, which you’ve used before, and have knowledge of, together with skills and code snippets, and Angular 2, use the second one. Angular 2 is simply better.

PS: If you choose to accept my advice, be prepared for lack of documentation. But it’s getting better every day, trust me.

 

Daniel Malachovský

Technical Leader in Pantheon Technologies

Sysrepo at IETF 96 Hackathon in Berlin

Sysrepo, an open source project developed by several partners including Pantheon Technologies, participated at the IETF 96 Hackathon in Berlin, held from July 16th to July 17th, 2016.

The IETF Hackathon is all about promoting the collaborative spirit of open source development and integrating it into IETF standards. The Sysrepo project provides a framework that can be used to bring NETCONF & YANG management to any existing or new Unix/Linux application, which should help spreading these IETF standards into the wider open source community.

The hackathon was our first opportunity to introduce the Sysrepo project to the audience experienced with NETCONF & YANG standards. In front of our poster (see below), we led many constructive discussions with other participants and have gained lots of feedback.

ietf96-hackathon-posterApart from presenting the project to other participants of the IETF meeting, we spent the weekend by hacking on three sub-projects based on Sysrepo:

NETCONF/YANG management of Raspberry Pi

To demonstrate that NETCONF & YANG are also applicable in the IoT (Internet of Things) domain, as well as to demonstrate that Sysrepo can work also on systems with limited resources, we prepared a simple Sysrepo plugin that can control GPIO pins of the Raspberry Pi. We’ve demonstrated this on a relay switch and a thermal sensor connected to the GPIO of the Pi running on Raspbian Linux with Sysrepo and Netopeer2 – we were able to turn the relay on or off via NETCONF, or retrieve the current temperature gained from the sensor via NETCONF.

sysrepo-raspberry

Sysrepo plugin for the ietf-system YANG module

Another part of the team formed out of the hackathon participants focused on development of a Sysrepo plugin that implements the ietf-system YANG module on a generic Linux host. During the hackathon, they managed to write the code that allows NETCONF management of the host name, clock & timezone settings, and is capable of restarting and shutting down device via NETCONF RPCs.

NETCONF/YANG management of DHCPv6 in ISC Kea

The developers of the ISC Kea DHCP server joined our team with a clear goal: enable NETCONF/YANG management of their DHCP daemon using Sysrepo and Netopeer2. During the hackathon they wrote a Sysrepo plug-in for ISC Kea that is able to manage some part of Kea’s configuration via NETCONF. Their work hasn’t stopped after the hackathon ended – they expressed an interest to continue in this direction in the future too.

After the hacking ended, each team prepared a short presentation of their achievements. These were streamed online and are available on YouTube:

Although the biggest achievement for us was the high interest in the Sysrepo project among the IETF meeting participants, and all the feedback we gained from them, we were also selected as a winner in the „Most Importance to IETF“ category. You can read more about that in this blog post.

Rastislav Szabo

                                                                                 Software Engineer in Pantheon Technologies

More information on Sysrepo:

Project page: http://www.sysrepo.org/

GitHub: https://github.com/sysrepo/sysrepo

Mailing lists: http://lists.sysrepo.org/listinfo/

https://www.isc.org/blogs/ietf-hackathon-in-berlin-kea-and-yangnetconf/

OpenDaylight @ OpenSource Weekend 2016

Open source has a long history in Slovakia, reaching back to late nineties, when the community was organized around Slovak Linux Users Group (SK-LUG). They were quite successful in their Linux Weekends, gathering a followership of young enthusiasts, mostly college students. As this generation grew up and became engaged in everyday life, these gatherings have fizzled, with no apparent successor.

The Society for Open Information Technologies, has stepped up to fill this gap. It has started organizing an Open Source Weekend,  the latest iteration of which took place during the weekend of 9-10th April 2016.

It has marked the first time the SK-LUG and SOIT communities have come together in a cooperative fashion, broadening the topics covered.

I had the pleasure to hold a presentation on OpenDaylight, at least in broad strokes, its role in shaping the network industry even though it is an open source project, and also on how much of a difference Slovak people are making to it. You can find the presentation below.

For the first time, a panel discussion was introduced at an OSS Weekend. The idea came to us after an exchange on a social network, which has shown that there is great disconnect between what established corporations expect and what FOSS companies deliver — at least in Slovakia. I think the format of having multiple views and added interactions with the audience has resulted in better idea sharing and definitely in more fun. You can find the recording below (sorry, no subtitles in this one).

All in all, I found it refreshing to engage with the community. We have already made plans for more and better content, so stay tuned!

Róbert Varga
CTO in Pantheon Technologies