Cisco UCS – “Unable to Communicate With UCSM Controller”
When upgrading UCS firmware, it’s important to periodically check the state of the HA clustering service running between the two Fabric Interconnects. The infrastructure portions of UCS are generally redundant due to these two FIs but only if the clustering service has converged - so it’s important to use the “show cluster state” command to verify this is the case. During a firmware upgrade to 2.2(1b), I checked this: 6296FAB-A# connect local-mgmt 6296FAB-A(local-mgmt)# show cluster state Cluster Id: 8048cd6e-5d54-11e3-b36c-002a6a499d04 Unable to communicate with UCSM controller The error message - “unable to communicate with UCSM controller” worried me, and it was given when I ran the “show cluster state” command as well as the “cluster lead” command - the latter of which is necessary to switch an FI’s role in the cluster from subordinate to primary.Cisco UCS – “Unable to Communicate With UCSM Controller”
When upgrading UCS firmware, it’s important to periodically check the state of the HA clustering service running between the two Fabric Interconnects. The infrastructure portions of UCS are generally redundant due to these two FIs but only if the clustering service has converged - so it’s important to use the “show cluster state” command to verify this is the case. During a firmware upgrade to 2.2(1b), I checked this: 6296FAB-A# connect local-mgmt 6296FAB-A(local-mgmt)# show cluster state Cluster Id: 8048cd6e-5d54-11e3-b36c-002a6a499d04 Unable to communicate with UCSM controller The error message - “unable to communicate with UCSM controller” worried me, and it was given when I ran the “show cluster state” command as well as the “cluster lead” command - the latter of which is necessary to switch an FI’s role in the cluster from subordinate to primary.Cisco UCS – “Unable to Communicate With UCSM Controller”
When upgrading UCS firmware, it’s important to periodically check the state of the HA clustering service running between the two Fabric Interconnects. The infrastructure portions of UCS are generally redundant due to these two FIs but only if the clustering service has converged - so it’s important to use the “show cluster state” command to verify this is the case. During a firmware upgrade to 2.2(1b), I checked this: 6296FAB-A# connect local-mgmt 6296FAB-A(local-mgmt)# show cluster state Cluster Id: 8048cd6e-5d54-11e3-b36c-002a6a499d04 Unable to communicate with UCSM controller The error message - “unable to communicate with UCSM controller” worried me, and it was given when I ran the “show cluster state” command as well as the “cluster lead” command - the latter of which is necessary to switch an FI’s role in the cluster from subordinate to primary.Farewell to Networking
Almost twenty years ago, I began my career in networking. HP hubs and routers, no VLANs, one router PHY port per subnet. From there I installed an ATM backbone using LANE in the venerable Catalyst 5500 platform, then moved on to GigE in 3750 stacks and finally to 10G Nexuses (Nexa, Nexi?). I’ve seen WiFi […]
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The post Farewell to Networking appeared first on Packet Pushers Podcast and was written by Matthew Mengel.
Cisco UCS Error – “Process Failed”
One of the (sadly numerous) issues I’ve run into while upgrading to Cisco UCSM version 2.2(1b) is this little error message indicating that a service failed to start: This gives us an error code of F0867 and it’s letting us know that the UCSM process httpd_cimc.sh failed on one of our Fabric Interconnects. For those that don’t know, you can get a list of processes within UCSM by connecting to local management and running “show pmon state”.Cisco UCS Error – “Process Failed”
One of the (sadly numerous) issues I’ve run into while upgrading to Cisco UCSM version 2.2(1b) is this little error message indicating that a service failed to start: This gives us an error code of F0867 and it’s letting us know that the UCSM process httpd_cimc.sh failed on one of our Fabric Interconnects. For those that don’t know, you can get a list of processes within UCSM by connecting to local management and running “show pmon state”.Cisco UCS Error – “Process Failed”
One of the (sadly numerous) issues I’ve run into while upgrading to Cisco UCSM version 2.2(1b) is this little error message indicating that a service failed to start: This gives us an error code of F0867 and it’s letting us know that the UCSM process httpd_cimc.sh failed on one of our Fabric Interconnects. For those that don’t know, you can get a list of processes within UCSM by connecting to local management and running “show pmon state”.Quick Thoughts on Learning Python
I was scheduled to be a guest on an upcoming episode of the Packet Pushers podcast, on the topic of Python for network engineers. Unfortunately due to bad luck I'm not going to be able to make the recording. Here are some quick thoughts on learning Python. If you're already an expert programmer you already know how to learn languages, so this post isn't for you.Scenario 1: You've coded in another language, but you're not an expert.
I would start with the basic Python class at Google Code. It's targeted specifically at people who know basic programming skills in some other language. It was perfect for me; I went through the exercises and was able to quickly start writing simple, useful Python scripts.
Scenario 2: You don't know how to write code at all.
Start with the Udacity CS101 class if you like guided learning, or Learn Python the Hard Way if you prefer books. Be prepared to spend a lot of time on either. It's not easy the first time around.
After you've gotten through one of those two scenarios, do the following:
- Spend time browsing the documentation for the Python Standard Library. Python is a large language, Continue reading
Quick Thoughts on Learning Python
I was scheduled to be a guest on an upcoming episode of the Packet Pushers podcast, on the topic of Python for network engineers. Unfortunately due to bad luck I'm not going to be able to make the recording. Here are some quick thoughts on learning Python. If you're already an expert programmer you already know how to learn languages, so this post isn't for you.Scenario 1: You've coded in another language, but you're not an expert.
I would start with the basic Python class at Google Code. It's targeted specifically at people who know basic programming skills in some other language. It was perfect for me; I went through the exercises and was able to quickly start writing simple, useful Python scripts.
Scenario 2: You don't know how to write code at all.
Start with the Udacity CS101 class if you like guided learning, or Learn Python the Hard Way if you prefer books. Be prepared to spend a lot of time on either. It's not easy the first time around.
After you've gotten through one of those two scenarios, do the following:
- Spend time browsing the documentation for the Python Standard Library. Python is a large language, Continue reading
Healthy Paranoia Show 21: Windows Forensics with Andrew Case
That’s right, it’s time for another surveillance-free, EFF-approved episode of Healthy Paranoia! Where the passwords are salted and the packets are always encrypted. This episode is hosted by the infamous Mrs. Y, queen of metadata and official privacy advocate for Healthy Paranoia, and recorded in the NSA-proofed SCIF with Grecs, of Novainfosec.com and Shmoocon Firetalks. […]
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The post Healthy Paranoia Show 21: Windows Forensics with Andrew Case appeared first on Packet Pushers Podcast and was written by Mrs. Y.
[Storage Flow Control] Part 1- Introduction
When making the leap to adopting FCoE as a storage medium, there are a few things to consider in order to be successful. Many of these concepts are foreign to the storage administrator who has been operating a native Fibre Channel SAN for the better part of the last decade or more - this is because while Fibre Channel networks are costly, they are purpose-built. There is no concept of a loop in Fibre Channel - with Ethernet we deal with these all the time.[Storage Flow Control] Part 1- Introduction
When making the leap to adopting FCoE as a storage medium, there are a few things to consider in order to be successful. Many of these concepts are foreign to the storage administrator who has been operating a native Fibre Channel SAN for the better part of the last decade or more - this is because while Fibre Channel networks are costly, they are purpose-built. There is no concept of a loop in Fibre Channel - with Ethernet we deal with these all the time.[Storage Flow Control] Part 1- Introduction
When making the leap to adopting FCoE as a storage medium, there are a few things to consider in order to be successful. Many of these concepts are foreign to the storage administrator who has been operating a native Fibre Channel SAN for the better part of the last decade or more - this is because while Fibre Channel networks are costly, they are purpose-built. There is no concept of a loop in Fibre Channel - with Ethernet we deal with these all the time.Using the latest Open vSwitch with Devstack and OpenDaylight
While setting up my OpenDaylight OVSDB and Devstack following the awesome instructions from Kyle Mestery, I thought it would be fun to run the latest OVS from source on my compute nodes...
To do this, execute the following commands on one of your compute nodes
before running stack.sh
sudo apt-get -y --force-yes install build-essential devscripts
gcc dkms make automake autoconf debhelper libssl-dev
pkg-config python-all python-qt4 python-zopeinterface
python-twisted-conch gdebi-core dh-autoreconf hardening-wrapper
libtool graphviz ipsec-tools module-assistant python-twisted-web
racoon git
git clone git://git.openvswitch.org/openvswitch
cd openvswitch
./boot.sh
dpkg-buildpackage -b -us -uc -nc
cd ..
Once you’ve built the .deb’s you can copy these to your other compute
nodes using scp:
scp *.deb ubuntu@devstack-compute2:
Replace ubuntu with your username and devstack-compute2 with the
name or IP address of your other compute nodes.
Finally we can install the packages as follows:
sudo dpkg -i *.deb
At the time of writing this will build Open vSwitch 2.1.90. You can check the version as follows:
sudo ovs-vsctl --version
Which will give the following output
ovs-vsctl (Open vSwitch) 2.1.90
Compiled Jan 16 2014 15:18:45
Huge thanks to @FlorianOtel for his help with Devstack!
@dave_tucker
Using the latest Open vSwitch with Devstack and OpenDaylight
While setting up my OpenDaylight OVSDB and Devstack following the awesome instructions from Kyle Mestery, I thought it would be fun to run the latest OVS from source on my compute nodes...
A brief departure from talking IPv6
There is a lot of news surrounding Net Neutrality, and potential repercussions of decisions made by courts, and some players out there that want to grab as much cash as they can, and claim it is in the best interest of their customers.
Netflix is just an example people love citing because it is bandwidth intensive, yet is not the entire story itself. Take a moment and understand how the Internet is pieced together. The Internet is a mass of interconnections between networks. These interconnections happen basically 1 of 3 ways:
transit: network A pays network B to reach every other network that isn’t A or B. Good networks usually get multiple transits for failover, and/or alternate paths to those other networks. You can buy multiple ports for bonding to increase capacity, etc. Average transit price without a Service Level Agreement (SLA, guaranteed connectivity or you can yell at us a lot and we credit you) is around $1-2/mbit, and with a SLA can hit upwards of $10/mbit. These are current avg. prices when buying 10G at a time of connectivity/capacity right now.
peering (settlement free, or “free”): Network A spends a bunch of money to get into popular Continue reading
Large flow marking using hybrid OpenFlow
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| Figure 1: Marking large flows |
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| Figure 2: Large flow marking controller results |
ping -f 10.0.0.238 -s 1400Figure 2 shows the results, the left half of the chart shows traffic when the controller is disabled and the right half shows traffic when the controller is enabled. The blue line trends the largest unmarked flow seen in the network and the gold line shows the largest marked flow. When controller is disabled, none of the traffic is marked. When the controller is enabled, sFlow-RT detects the large flow Continue reading
Using the latest Open vSwitch with Devstack and OpenDaylight
While setting up my OpenDaylight OVSDB and Devstack following the awesome instructions from Kyle Mestery, I thought it would be fun to run the latest OVS from source on my compute nodes...
Cisco ACI – Speculation of its Inner Workings
Last week I was at a Cisco users group meeting where some sales engineers were giving a presentation on the new Application Centric Infrastructure (ACI) architecture and Nexus 9000 products. It was a very high-level overview, but it was interesting. I had assumed when Cisco made the ACI announcement that it would be based on […]
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The post Cisco ACI – Speculation of its Inner Workings appeared first on Packet Pushers Podcast and was written by Eric Flores.
Why We Need to Learn During Weekend
We are group of design architects/consultants who do network design in daily basis. We are spread in different countries across Asia, Europe and Middle East. We happen to have CCDE certification too. And all of us have the same dream to build the community filled up with real design experts, those who actually do design work to solve real world's network design problems. And we want to teach real design skills based on our experiences. To help those who want to become the next design architects/consultants, or to pass CCDE exam. To achieve this, we conduct design expert workshop in various locations, during the weekend.Wait. What?
Why do we need to learn during the weekend?
It might be a good workshop. It might be an opportunity to hear real world's network design examples. It might be a good chance to meet another design professionals.
But come on, attending technical workshop during the weekend?
I hear you. I know how it feels.
After long hours of work during weekday, we deserve our weekend. When we need to learn something related to work, we should do it during workday. When we need to learn design, we can ask the company to Continue reading