MPLS bottom-of-stack bit confused one of my readers. In particular, he had a problem with the part where the egress MPLS Label Switch Router (LSR) should go from labeled (MPLS) to unlabeled (IPv4, IPv6) packets and has to figure out what’s in the packet.
Read more ...I had the opportunity to attend last week’s OpenStack summit. With 4500 attendees, it clearly demonstrates that OpenStack is the clear mindshare leader for organizations interested in building cloud infrastructure. It is also significant to note that approximately half of the participants came from Europe which demonstrates that the “Old World” is not far behind the “New” when it comes to the desire to adopt cloud technology.
Parallel to the summit, the OpenContrail community organized both a user group meeting as well as an Advisory Board meeting. Both of these events ended up focusing the discussion in operations. While the user group presentations typically started with a description of the goals of the project most of the discussion in the room focused on topics such as automating and documenting deployment, provisioning, software upgrades and troubleshooting.
As a software developer, one often tends to focus on expanding the feature set. In both of these events there was a clear message that the user community takes reliability, scale and performance as the main reasons they adopted OpenContrail but is grappling with operational aspects. This means in one hand that testing, specifically unit testing of each component, is absolutly key is maintaining users Continue reading
I’m currently reading and enjoying “The Practice of Cloud System Administration.” It doesn’t go into great depth in any one area, but it covers a range of design patterns and implementation considerations for large-scale systems. It works for two audiences: A primer for junior engineers who need a broad overview, or as a reference for more experienced engineers. It doesn’t cover all the implementation specifics, nor should it: it would date very quickly if it tried.
I’ve long disliked the term “non-functional requirements,” so I enjoyed this passage:
Rather than the term “operational requirements,” some organizations use the term “non-functional requirements.” We consider this term misleading. While these features are not directly responsible for the function of the application or service, the term “non-functional” implies that these features do not have a function. A service cannot exist without the support of these features; they are essential.
It is all the fashion today to separate requirements into ‘functional’ and ‘non-functional,’ but the authors are right to point out that this can be misleading. Perhaps it’s the old Operations Engineer in me, but if a product doesn’t have things like Backup & Restore, or Configuration Management, then it’s a Continue reading
This week we walk through the news of the week (there wasn't much).
The post Network Break 20 appeared first on Packet Pushers Podcast and was written by Greg Ferro.
Periodically, I get a message from someone asking for troubleshooting help. The most recent of these went something like the following (paraphrasing)–
I have the following routers, R1 through R5, and I cannot ping R5 from R1. Please tell me what the problem is.
In these cases, I could review the configuration or import them into my lab. Inevitably, that might solve the problem for the individual. However, it doesn’t really help the individual solve problems in the future. I prefer to try to help others think through the problem and reach the solution on their own.
Given the symptom of R1 not being able to ping R5, what could that mean? My initial thoughts are–
The first step in troubleshooting this is to understand that there should be two flows being produced. The first flow is a series of echo requests from R1 to R5 and the other flow is a Continue reading
Taking a little side-step from the normal networking-based Sunday hero worship, today’s Secret Sunday is a pointer to Microsoft’s Raymond Chen, sometimes referred to as “Microsoft’s Chuck Norris“. But John, you say, it’s Microsoft; why would you do that to … Continue reading
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Everything is so gloomy these days isn’t it? SDN is going to put us out of a job so you have to learn Python or go make burgers (been there done that). The CCIE is now irrelevant so why would anyone pursue it? While there are some good arguments for its demise there are also […]
The post How the CCIE changed my life appeared first on Packet Pushers Podcast and was written by Keith Humphreys.
We all know that IT changes rapidly, but we still don’t always accept what that means. Companies and technologies change over time, and good engineers recognise this. Poor engineers cling to past beliefs, refusing to accept change. Try to keep an open mind, and periodically re-evaluate your opinions.
Consider the Linux vs Microsoft debate. I’ve been an Open Source fan for a long time, and have plenty of experience running Linux on servers and desktops. Today I use OS X as my primary desktop. I’ve cursed at Microsoft many times over the years, usually when dealing with some crash, security issue, or odd design choice.
But it annoys the hell out of me when I hear engineers spouting tired old lines about Microsoft products crashing, or having poor security. This is usually accompanied by some smug look “Hur hur hur…Microsoft crash…Blue Screen of Death…hur hur hur”
I get frustrated because these people aren’t paying attention to what Microsoft has been doing. They have come a very long way since the 2002 Bill Gates email setting security as the top priority. It’s a big ship to turn, and it took time. Their overall security model and practices are far better than they were, Continue reading
I’m a long way from being the first person to comment that some of the icons we use in our software are somewhat anachronistic. The example we hear most often is that of the Save icon in most software: It … Continue reading
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Last week Midokura decided to follow Juniper’s lead and make MidoNet an open-source product (after all, a similar move worked really well for Contrail, right?).
I may be too skeptical (again), but I fail to see how this could possibly work.
Read more ...CORE Services is a feature of the CORE Network Emulator — an open-source network simulator — that configures and starts processes on each node running in a network simulation. Examples of processes supported by CORE Services are: quagga, dhcpd, or radvd.
Because the CORE Network Emulator implements its virtual nodes using a lightweight virtualization technology called Linux namespaces, we cannot use the normal init or upstart scripts to start networking daemons on these nodes. We must use CORE Services.
A benefit of using CORE Services is that they allow us to set up and manage processes running on each node by using the CORE GUI. This may reduce the time required to configure nodes used in a simulation scenario, especially if a large number of nodes require similar configuration procedures. Also, network scenarios that require customized configurations can be saved and used again if those configurations are implemented by customizing CORE Services.
To run complex network simulation scenarios, we must understand how to use CORE Services. In this post we will provide an overview of CORE Services.
CORE Services are used to start processes on the virtual nodes in a CORE network simulation. For the processes Continue reading
Ethan Banks (@ecbanks) initiated an interesting Twitter conversation last weekend by claiming that the constant “technique churn” within organizations that utilize SDN and NetOps is doing the networking industry a disservice. Banks feels that ever-changing frameworks make it nearly impossible to thoroughly understand new technologies. Our own Mike Bushong (@mbushong) took a deep dive into the subject on the Plexxi blog this week in response to those claims. Be sure to check it out before you head out for the day.
In this week’s PlexxiTube video of the week, Dan Backman explains how Plexxi’s Big Data fabric solution can run both L2 and L3 simultaneously.
SDN Users’ Wish Lists Sounds a Lot Like White Box Switching
In an article this week for SDN Central, Craig Matsumoto looks at users that are growing increasingly tired of vendor lock-in and therefore turn to white box switching to provide additional interoperability. In my opinion, the interoperability provided is interesting as it is not a property of vendor intentions. When we accelerate the pace of innovation, there are going to be new capabilities that get added to gear. At the time of first-add, no one else supports the feature. At Continue reading
I am in the Bay Area this week, working on some network automation stuff, and I was fortunate to be able to stop by and say hello to the Storage Field Day 6 folks over drinks.
I was told by several impressed delegates about a talk by Andy Warfield of Coho Data, where he described how they used OpenFlow to steer storage traffic intelligently to and from various nodes in a distributed storage array.
For the majority of the discussion, he talks at length about how NICs have long been able to push more data than a single CPU core is able to process, and as a result, they have to be intelligent about the distribution of packet processing onto the cores within a multicore system.
In summary, a big problem with file-based storage systems is dealing with load sharing. NFS clients have to point to an IP address where the exports are located, and if this IP address was available only on a single NIC on a storage array, this pretty severely limits your options – that port becomes a big bottleneck. I’ve seen some customers assign IP addresses to several ports on an array, and use them in rotations Continue reading
Sometimes we confuse effort with outcome. We think that hours spent are more important than outcomes achieved. Or we unintentionally create a system where effort is rewarded, rather than outcomes.
Consider a situation where you work for a consulting firm, doing capped Time & Materials jobs. The client gets charged for the amount of time actually worked. Any amount of time up to the cap will be accepted. If more time is needed to complete a task, you’ll need to go back to the client to negotiate for more time/money. Occasionally you’ll need to do that, but usually the job will be completed under the cap.
As a consultant, you’re normally measured on your utilisation, and the amount you bill. So what’s the optimum amount of work to do for each job? Funnily enough, it is very close to the amount estimated – no matter what the estimate was. Maximise revenue & utilisation, while still doing the work under budget. There’s no incentive to do the job quicker.
Look at it from the perspective of two different consultants, Alice & Bob:
Note: We had an audio problem and Network Break 19 is now fixed.
The post Network Break 19 – Fixed appeared first on Packet Pushers Podcast and was written by Greg Ferro.
Welcome to Technology Short Take #46. That’s right, it’s time for yet another collection of links and articles from around the Internet on various data center-related technologies, products, projects, and efforts. As always, there is no rhyme or reason to my collection; this is just a glimpse into what I’ve seen over the past few weeks. I hope you are able to glean something useful.
