How many times have you locked yourself out of your device? In my professional career, this happened to me several times when I was either configuring AAA or making any routing related changes. Usually, the reason for this is the human error associated with invalid configuration. Some vendors offer a commit model that allows you to apply the configuration and then save it to the system by committing the change. As we know not all vendors offer the commit model approach and when a change is introduced in the system, such a change is pushed immediately. This approach means that sometimes, as a result of an erroneous change, we may lose access to the device, create loops, shutdown the interface we didn’t want, etc. In such a situation, we often have to use the console to gain access back to the device, if we have one, in the worst case, if the configuration has not been saved to the device, we can ask someone who has physical access to the device to reboot the device.
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Useful Arista commands
In this post I would like to show you some useful commands available on the Arista switches that you can use in your daily work.
The first command that is very useful is the watch command, which repeats the given command at a specified interval and can additionally display the differences between individual performances.
For example, if we want to monitor CRC errors on a given interface, instead of repeating the show int x / x several times, we can use the watch command, which will run the above mentioned command automatically every 2s and display information as shown below.
Continue readingCloudVision Portal – Part 1
In this blog I will show you how to install Arista CloudVision Partal (CVP) and discuss the basic functions that can be performed through the portal. CloudVision is a solution for network management and work automation. The CloudVision portal can be managed via the interactive interface EOS CLI, eAPI or directly from the GUI. This tool allows you to build hierarchical configurations, monitor various system parameters in real time, change software versions and much more. The CVP works on ESX or KVM hypervisors and can be configured as a single server or cluster. Due to the scalability and redundancy, it is recommended to implement the cluster.
In this post I intend to demonstrate the implementation with one node due to the lack of computing resources on my home server. Arista’s official documentation says ESX and KVM are the recommended hypervisors for CVP. Due to the fact that I do not have ESX and KVM on my computer, I intend to run CVP on a VMWare workstation. Before I show you how to install CPV, I must first possess the right CVP image. CVP can be downloaded from the official Arista website, but only with a valid technical support contract.
In this example I will use OVA cvp-2019.1.2.ova template. I will first import the OVA template and then show you the basic steps required during the first installation.
Continue readingArista – BGP EVPN virtual L4-L7 service insertion.
In this blog I am going to show you how to provide L4-L7 service insertion within BGP EVPN fabric especially using eBGP between appliance and leaf pair switches. The challenge with L4-L7 service insertion is that such appliance can be deployed as virtual machine and could be easily migrated (vMotion) at any point across different ESX hosts connected to different leaf switches. That’s often seen in multi tenant environments where end customers are not big enough and they don’t need powerful physical appliance to provide L4-L7 service. If this is a case and there is a business requirement to engaged dynamic routing protocol between fabric and appliance, you must be sure that after migration of the appliance it can re-establish adjacency fast enough to minimize business impact.
Below is a network diagram which I am going to use to show configuration steps and some design consideration to achieve end-to-end connectivity for such design requirements.
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