• Category : Tech Tips

 
 

Working with certificates

Introduction and motivation Encryption protocols like HTTPS use certificates to authenticate the remote server (sometimes also the client) as there are no other means to verify to which device you are currently talking. If the server (in our case the switch providing management access via an HTTP based REST API) is located in our own network, it is usually acceptable to work with so-called self-signed certificates. A self-signed certificate is not signed by a certification authority (CA), which would confirm that the CA (an institution you trust) has verified the identity of the certificate holder. By default, Arista EOS based...
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Basic troubleshooting steps for some CVP and telemetry issues

Objective The aim of this document is to convey a set of troubleshooting steps that can be carried out when running into issues with CVP and telemetry. General issues covered Issue 1- The CVP web-explorer is not reachable Issue 2- A configlet/image bundle push task to the switch failed Issue 3- Device not getting added to telemetry The CVP web-explorer is not reachable Follow the below sequential steps in order to isolate the issue: 1. Check if the CVP node is reachable from the local machine. 2. Login to the CVP node as a CVP user and check if the...
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CVP AAA TACACS+ authorization with Cisco ISE

CVP AAA TACACS+ authorization with Cisco ISE Introduction We saw last time how to correctly integrate Aruba ClearPass CPPM with CVP so TACACS+ users can authenticate with the correct network role. The purpose of this document is to show the same for Cisco ISE (successor of ACS) TACACS+. Our goal is to make Cisco ISE send us the cvp-roles=network-admin attribute in the Authorization reply packet.   NOTE If you are running CVP versions 2018.2.0 and 2018.2.1 you might hit BUG 345723 due to which in tacacs-provider authorization we are not checking for TAC_PLUS_AUTHOR_STATUS_PASS_ADD flag. We can provide a binary patch...
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CVP TIP – Encrypt local username passwords with Configlet Builder

Introduction   Arista CloudVision Portal (CVP) uses configlets to create configuration snippets for individual or groups of switches based on user selection. These configlets can be either static or dynamic. Static configlets include static EOS CLI configuration statements as if they were right on the switch configuration file. These configlets are used to create the full configuration for the network switches. An example of a static configlet in Arista CloudVision Portal: Below example is a static Arista EOS CLI configuration. These small pieces of configuration snippets can be applied as configlets in Network Provisioning view to selected device or devices....
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vEOS Router ECMP HA Deployment Guide in GCP

vEOS Router ECMP HA Deployment Guide in GCP Introduction In this document we demonstrate deployment of Arista vEOS Router in Google Cloud Platform  (GCP). Currently, vEOS Router on GCP doesn’t support Cloud HA. We will use GCP routes and priorities to support HA and ECMP. A vEOS Router can be used to create a virtual machine instance that can be used to implement various Azure deployments such as edge routers and transit routers. This document provides a guide to deploy a hub-spoke topology in GCP. Overview Arista vEOS Router is a new platform release of EOS that is supported on Google...
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How to source Splunk Forwarder traffic from a Loopback Interface

The diagram below describes the use case: SWITCH1 has a Splunk Forwarder that needs to send traffic to SPLUNK at 10.0.0.10.  SWITCH2 is originating a default route via BGP. SWITCH1 is only advertising its Loopback0 interface into BGP.  The Splunk Forwarder CLI configuration does not currently support specifying a source interface, and in this scenario this is a problem because SWITCH3 has no route to reach 192.168.255.0, which would be the source IP for any traffic that SWITCH1 sends to SPLUNK.  SWITCH3 does however have a route to SWITCH1’s Loopback0 interface. We verify this by pinging SPLUNK from SWITCH1 and...
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Using CloudVision Portal to Manage Arista AnyCloud

Introduction There are many advantages to using Arista’s vEOS Router and CloudVision Portal (CVP) in hybrid cloud environments. Among those advantages are: Arista EOS is a proven and stable network operating system used in some of the largest networks in the world. The same EOS that runs on our physical switches also runs in the public cloud. CloudVision Portal provides a common management model for network devices whether running in a customer’s private data center or in public cloud environments. CloudVision Portal provides turn-key automation and real-time telemetry across private and public cloud environments. One of the primary challenges to...
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Data rate, FEC and auto-neg features of Arista’s 7020R series

Data rate, FEC and auto-neg features of Arista’s 7020R series The Arista 7020R Series, including the 7020SR, 7020TR and 7020TRA, are high performance 1RU fixed systems built for high density data center deployments.  The 7020SR provides SFP+ and QSFP100 ports, while the 7020TR / TRA provide 100M/1G RJ45 ports and SFP+ ports. The RJ45, SFP+ and QSFP100 ports on the 7020R series are capable of supporting a wide range of data rates, from 100M to 100G. Different FEC and auto-negotiation options are supported on the various ports. The range of port capabilities of the 7020R series are summarized in the...
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Enterprise Internet Routing

Overview The objective of this document is to cover the most common Enterprise Internet Routing use case. The information provided here is based on two Arista switches peering with two ISP’s (Internet Service Providers) for redundancy. There are many other valid deployment models that are not covered in this document. Terminology BGP – Border Gateway Protocol ISP – Internet Service Provider BGP Peering – a session between two BGP routers that allows exchange of routes Full Internet Routing Table – all public routes on the Internet AS – Autonomous System – defines domain boundaries IGP – Interior Gateway Protocol EGP...
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ClearPass TACACS+ Authorization with CVP

ClearPass TACACS+ Authorization with CVP Introduction The purpose of this article is to learn how to correctly set up the TACACS+ service in Aruba ClearPass in order to successfully authenticate on the CVP GUI as a network admin. Our goal is to configure ClearPass Policy Manager [CPPM] to send us the cvp-roles=network-admin attribute in the TACACS+ Authorization reply packet. By default this does not happen, because cvp-roles is a custom attribute that has to be added to the TACACS+ dictionary on any type of TACACS+ implementation. Without this, the default role of network-operator will be allocated to the user, that...
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Layer 2 Data Center Interconnect – Reference Designs

Introduction VxLAN is a popular choice for extending Layer 2 both intra and inter DC using overlays. Arista offers multiple control plane choices for VxLAN: Static HER, CVX and EVPN. In this article, two approaches to designing a L2 DCI over a L3 underlay are discussed. High-level technical details of each design approach is described first, followed by a comparison of the two options along with their typical use cases. Design 1: Multi-domain Overlay In this design, two overlay domains are identified: DC Fabric domain: This is the VxLAN domain within the DC Layer 3 Leaf-Spine Fabric with Leafs acting...
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Enabling eAPI on Multiple Devices using Netmiko

Preface In standard Arista deployments, one of the most powerful and common tools that will be used is the EOS API (eAPI). It is good practice to enable this on every initial deployment. One of the best ways to do this is via Zero Touch Provisioning (ZTP), but in some cases, ZTP is not an option. When this becomes the case, it can be easy to enable eAPI on all of your devices quickly through the use of the Python programming language and SSH (which is enabled by default on all Arista Switches). Throughout this document, we will go over...
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Applying Hot Patches to EOS Software with CloudVision Portal

Maintaining a secure posture within any enterprise is a difficult task. This task can be particularly difficult on the network infrastructure due to a variety of reasons including software quality and network downtime availability. Arista’s unique software architecture has often enabled most security patches to be delivered as hot patches that can be applied to a live running system with low to no impact to the network dataplane eliminating some of the most difficult challenges with maintaining a secure software posture. The only challenge that remains is the effort required to distribute these software patches. In this article, we are...
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IPv4 & IPv6 MPLS VPN Configuration Guide

IPv4 and IPv6 VPN Overview   RFC 4364 allows for Service Providers and Enterprises to use their backbone infrastructure to provide the services to multiple such customers, or internal departments, while: Maintaining privacy Allowing for IP address overlap amongst customers Constrained route distribution – so that only the service provider routers which need the routes have them.   This is achieved through the usage of VRFs, Route Distinguishers and Route-Targets   The IPv4/IPv6 VPN Standard RFC 4364 does the following: Specifics an BGP IPv4 VPN control plane with a MPLS data plane BGP control plane, new address family to advertise...
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Writing your own webhook relay – sending event alerts to Discord

Writing your own webhook relay – sending event alerts to Discord   Introduction Starting from version 2018.2.0, CVP supports configuring event alerts, where receivers can be email, Slack, PagerDuty, webhooks and others. The purpose of this article is to demonstrate how easy it is to write your own webhook relay app that will forward alerts to your favorite webhook endpoint, in my case, a Discord channel. Discord is getting more and more popular, not only amongst gamers, but also lots of companies started to use it. I’ve been using it for a couple of years now, and it made sense...
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BGP Peering – Configuration Best Practices – Security and Manageability

      BGP Peering – Configuration Best Practices – – – – – – – – – – – – – – – – Security and Manageability       1) Introduction This article provides suggestions of BGP peering configuration, with general best practices and some particular considerations for manageability and security.     2) Arista EOS Security – General   It is recommended to approach security not only specifically for BGP but to englobe other aspects of security for Arista EOS. More global security topics are covered in other articles, listed below. The present article focuses solely on...
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Traffic Generator on Arista

The following tools can be used to generate traffic on Arista switches for testing purposes :– Iperf – Ethxmit Both Iperf and Ethxmit tools are pre-installed on Arista switches and no additional configuration is required to use them.                                                                                                                              ...
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Traffic Engineering with Segment Routing and sFlow

Introduction Segment Routing (SR) solves a number of issues the existing MPLS IP networks face. Among the many benefits of Segment Routing, Traffic Engineering is a key one. Based on live telemetry events, traffic can be steered intelligently across a network using MPLS label paths a.k.a segment lists. The example discussed in this article shows how you can leverage BGP SR policy to alter traffic paths based on sFlow telemetry data. An SR Policy, discussed in detail here, is identified using a 2-tuple of Endpoint and color. Endpoint here refers to a destination prefix while color is a 32-bit BGP extended...
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Monitoring some agent’s memory utilisation

  Monitoring some agent’s memory utilisation   This article develops further https://eos.arista.com/introduction-to-managing-eos-devices-memory-utilisation/ authored by Colin MacGiollaEain to bring the context to a specific agent’s memory utilisation and how to remediate.   1) Introduction Monitoring the memory usage of specific EOS processes maybe useful to detect which features consume the control-plane resources, as a first step to clarify whether it is a normal behaviour or not. In abnormal circumstances the overall system may be running low on memory, in which case some culprit agent may be restarted, or some other agent may suffer a restart too (collateral damage) by the process scheduler. Examples...
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IP static route with health check

Introduction The purpose is to simplify ip static route with health check does_it_live.py script, it’s easy to enable this feature quickly without complicated programming. This feature leverages the Reachability Health Checks document ( https://eos.arista.com/reachability-health-checks/ ) and does_it_live.py  ( https://github.com/alexisdacquay/does_it_live ) which was made by Alexis Dacquay. Due to Reachability Health Checks(does_it_live.py) support rich parameters, there are mode(icmp/dns), interval, timeout, dampening, source. We just take it and use it. Configuration The following configuration commands have been added as part of this feature support: 1. Create ping check script on-boot: t3 – timeout 3 seconds, i3 – interval 3 seconds, 1.1.1.1 – ping check ip.   configuration:==============event-handler...
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