Latency: the Killer of Spread-Out Application Stack Ideas

A few months ago I described how bandwidth limitations shatter the dreams of spread-out application stacks with elements residing (or being dynamically migrated) between data centers. Today let’s focus on bandwidth’s ugly cousin: latency.

TL&DR Summary: Spreading the server components of an application across multiple locations (multiple data centers or hybrid cloud deployments) can easily result in dismal performance even when there’s plenty of bandwidth available.

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Ansible Tower 2.1 Released

Tower2.1_BlogHeader

Today we're excited to release Ansible Tower 2.1, the next version of the UI, Server, and REST endpoint for Ansible Tower. This release adds several major new features:

Surveys may now be created with our easy form builder and can be attached to any job template in Ansible Tower.  When launching a job with an attached survey, the system will prompt the user to answer any number of questions - multiple choice, numeric, text, etc. The results of these questions will then be available as variables in Ansible Tower jobs.  Surveys are graphically constructed from within the interface with no programming required.

job-launch-with-credentials-and-survey.png

Portal Mode is a simplified view into Ansible Tower. If you have users who are not Ansible experts that need to run Ansible jobs, Portal Mode presents a simple two column view. On one side, there's a list of all the job templates they can launch. On the other side, there's a list of all the completed or in-progress jobs they can view, to know how their job is running.

portal-mode.png

Combined, these two features provide solid options for users that want to provide self-service features to others. For instance, admins can let developers or QA departments provision Continue reading

Bare Metal For the Rest of Us

Bare metal switching technology fueled the world’s big cloud data centers, with a simplified supply chain as the economic driver. Now the technology and economics are hitting the mainstream in open networking solutions for the rest of us.

Bare metal servers changed the world of compute. The same thing is happening in networking: bare metal switches are the foundation for an inevitable shift in data center networking. The movement is called “open networking” but at it’s core, it’s really just about great physical networks with the additional benefits of a rich ecosystem, broad support for automation and monitoring tools, and improved economics.

The big players in bare metal switching – including Accton and Quanta – leverage best-in-class components to deliver high performance switches, and they do it fast. Add an OS (more on that later) and you’ve got a disaggregated model that enables networking that fulfills the vision of the software-defined data center. If SDDC doesn’t matter so much to you, then think of this: bare metal may fulfill your vision of a more affordable, manageable network that gives you the time and funding for more projects that really help your business.

(For comparisons on pricing and shipping speed versus Continue reading

SDN, data center predictions for 2015

The predictions for data center and SDN in 2015 are still rolling in. Technology Business Research says software will pervade the data center while start-up Plexxi believes policy and disaggregation will be front and center.Here’s the link to TBR’s 2015 Data Center Predictions. Some of the more interesting prognostications in it are the acceleration of SDN in the enterprise and the ability of hyperconvergence to converge.To read this article in full or to leave a comment, please click here

Why SDN all-stars are heading to Brocade

Why is it that a who’s who of SDN developers is landing at Brocade? Over the past two years, the company has lured a handful of industry All-Stars to work on software enabling its networking portfolio, including Fibre Channel storage-area network switches, and Ethernet switches and routers. The most recent hire is Michael Bushong, who jumped from start-up Plexxi to Brocade late last year to run product management.To read this article in full or to leave a comment, please click here

How Does MPLS-TE Interact with QoS

MPLS Traffic Engineer is sometimes promoted as a QoS solution (it seems bandwidth calendaring is a permanent obsession of some networking engineers, and OpenFlow is no more a solution than MPLS-TE was ;), but in reality it’s pretty hard to make the two work together seamlessly (just ask anyone who had to implement auto-bandwidth MPLS-TE in a large network).

Not surprisingly, we addressed the topic during our MPLS Tech Talk.

Watch the video

HTIRW: IETF Organizational Structure

So far, we’ve looked at the naming system, routing, and policy in our travel through “internet land.” Last time, we took a quick look at some of the various organizations that create the standards that make the internet work. This time I’m going to start looking in more depth at one specific standard body, or […]

Author information

Russ White

Principal Engineer at Ericsson

Russ White is a Network Architect who's scribbled a basket of books, penned a plethora of patents, written a raft of RFCs, taught a trencher of classes, and done a lot of other stuff you either already know about — or don't really care about. You can find Russ at 'net Work, the Internet Protocol Journal, and his author page on Amazon.
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The post HTIRW: IETF Organizational Structure appeared first on Packet Pushers Podcast and was written by Russ White.

Parsing Junos XML with Python

I’ll admit it – I’ve drunk the “Network Engineers should learn programming” Kool-Aid. In so doing, I’m gearing up for Kirk Byers upcoming “Python for Network Engineers” course by hacking a bit of Python most every evening. Kirk has recently released a Python “wrapper” module for the popular Python SSH module “Paramiko” that simplifies connections […]

Author information

Will Dennis

Will Dennis

Will Dennis has been a systems and network administrator since 1989, and is currently the Network Administrator for NEC Laboratories America, located in Princeton NJ. He enjoys the constant learning it takes to keep up with the field of network and systems administration, and is currently pursuing the Cisco CCNP-R/S certification. He can be found on the Twitters as @willarddennis, and on Google Plus.

The post Parsing Junos XML with Python appeared first on Packet Pushers Podcast and was written by Will Dennis.

My 2015 goals

I’ve always sort of set goals for myself, but I never really write any of them down.  This year, after talking to a friend about it, I decided to write down some actual goals for 2015.  What really struck me about the conversation was a single sentence he said.  I believe the exact words he used were “Write them down and you’ll be amazed at how motivated you can be”.  Since it certainly sounded like he was speaking from experience, here’s my list.  Some are more subjective which will make them harder to ‘check off’ than others.  Some are related to my work/career, some are personal, and some are just sort of for fun. 

Run a marathon – Some of you know I made a serious attempt at this 2 years ago.  It started with others offering tips and training schedules, continued with me disregarding the training plan, and ended with me doing it wrong and messing up my knee.  So this year, I’m going to make a serious attempt at following a training schedule and try and get this done.  I’ll aim for the Twin Cities marathon which happens Continue reading

Remove Duplicates from Pocket List

One problem I’ve noticed with my Pocket list is that my reading list contains quite a few duplicate entires. Sometimes I forget I saved an article and I save it multiple times, or maybe I save it across-sources (like Twitter or Facebook, or just browsing.

It looks like Pocket has some protective capabilities around this. If I endlessly spam the button provided to me by my Pocket chromecast extension, Pocket only saves the one copy and all is good.

However, take the following example. Many of the articles we read and put into our Pocket list use some kind of URL options for tracking purposes:

?utm_source=social&utm_medium=twitter&utm_campaign=1215

If you arrive to an article from different sources, but save both to Pocket, Pocket will treat these as different URLs. This means that if you’re bad about staying caught up with your Pocket list (like I am), it can be very easy to save duplicate articles, making the situation even worse.

Fortunately I have a solution. I wrote this python script to automate the removal of duplicates of entries in your pocket list.

Currently this script works by removing ALL text after a question mark (?) or a hash mark (#) in each Continue reading

Remove Duplicates from Pocket List

One problem I’ve noticed with my Pocket list is that my reading list contains quite a few duplicate entires. Sometimes I forget I saved an article and I save it multiple times, or maybe I save it across-sources (like Twitter or Facebook, or just browsing. It looks like Pocket has some protective capabilities around this. If I endlessly spam the button provided to me by my Pocket chromecast extension, Pocket only saves the one copy and all is good.

Remove Duplicates from Pocket List

One problem I’ve noticed with my Pocket list is that my reading list contains quite a few duplicate entires. Sometimes I forget I saved an article and I save it multiple times, or maybe I save it across-sources (like Twitter or Facebook, or just browsing. It looks like Pocket has some protective capabilities around this. If I endlessly spam the button provided to me by my Pocket chromecast extension, Pocket only saves the one copy and all is good.

Technology Short Take #47

Welcome to Technology Short Take #47! This is the first Technology Short Take for 2015 and the first to be published on the new blog platform. I have quite a bit of information to share this time around, so buckle up and let’s get started!

Networking

  • Michael Webster isn’t a name that normally pops up here in the Networking section of my Technology Short Takes, but he recently wrote an article on installing Cumulus Linux from a MacBook Pro that I thought might be handy. I’m particularly jealous that Michael was able to get his hands on a Cumulus-supported switch while here I am—with a full NSX installation just ready to integrate with Cumulus—not making any progress on that front.
  • Speaking of Cumulus Linux, here’s a write-up on using Cumulus Linux on Dell Networking switches; in particular, this article describes how to install Cumulus Linux on a Dell S6000-ON. I spoke to some folks at Dell a while ago about getting my hands on a Cumulus-compatible switch, but never heard back. Sure would be nice…(hint, hint).
  • The folks over at Weave (who are building a lightweight overlay networking solution for Docker containers) recently posted some thoughts on life and Continue reading

DDoS Packet Forensics: Take me to the hex!

A few days ago, my colleague Marek sent an email about a DDoS attack against one of our DNS servers that we'd been blocking with our BPF rules. He noticed that there seemed to be a strange correlation between the TTL field in the IP header and the IPv4 source address.

CC BY 2.0 image by Jeremy Keith

The source address was being spoofed, as usual, and apparently chosen randomly, but something else was going on. He offered a bottle of Scotch to the first person to come up with a satisfactory solution.

Here's what some of the packets looked like: 

$ tcpdump -ni eth0 -c 10 "ip[8]=40 and udp and port 53"
1.181.207.7.46337 > x.x.x.x.53: 65098+  
1.178.97.141.45569 > x.x.x.x.53: 65101+  
1.248.136.142.63489 > x.x.x.x.53: 65031+  
1.207.241.195.52993 > x.x.x.x.53: 65072+

$ tcpdump -ni eth0 -c 10 "ip[8]=41 and udp and port 53"
2.10.30.2.2562 > x.x.x.x.53: 65013+  
2.4.9.36.1026 > x.x.x.x.53: 65019+  
2.98. Continue reading

Open vSwitch performance monitoring

Credit: Accelerating Open vSwitch to “Ludicrous Speed”
Accelerating Open vSwitch to "Ludicrous Speed" describes the architecture of Open vSwitch. When a packet arrives, the OVS Kernel Module checks its cache to see if there is an entry that matches the packet. If there is a match then the packet is forwarded within the kernel. Otherwise, the packet is sent to the user space ovs-vswitchd process to determine the forwarding decision based on the set of OpenFlow rules that have been installed or, if no rules are found, by passing the packet to an OpenFlow controller. Once a forwarding decision has been made, the packet and the forwarding actions are passed back to the OVS Kernel Module which caches the decision and forwards the packet. Subsequent packets in the flow will then be matched by the cache and forwarded within the kernel.

The recent Open vSwitch 2014 Fall Conference included the talk, Managing Open vSwitch across a large heterogeneous fleet by Chad Norgan, describing Rackspace's experience with running a large scale OpenStack deployment using Open vSwitch for network virtualization. The talk describes the key metrics that Rackspace collects to monitor the performance of the large pools of Open vSwitch instances.

Continue reading

Time For A Data Diet?

I’m running out of drive space. Not just on my laptop SSD or my desktop HDD. But everywhere. The amount of data that I’m storing now is climbing at an alarming rate. What’s worse is that I often forget I have some of it until I go spelunking back through my drive to figure out what’s taking up all that room. And it’s a problem that the industry is facing too.

The Data Junkyard

Data is accumulating. You can’t deny that. Two factors have lead to this. The first is that we now log more data from things than ever before. In this recent post from Chris Evans (@ChrisMEvans), he mentions that Virgin Atlantic 787s are generating 500GB of data per flight. I’m sure that includes telemetry, aircraft performance, and other debugging information that someone at some point deemed crucial. In another recent article from Jacques Mattheij (@JMattheij), he mentions that app developers left the debug logging turned on, generating enormous data files as the system was in operation.

Years ago we didn’t have the space to store that much data. We had to be very specific about what needed to be Continue reading

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