• Author : Manas Moothedath

 
 

Password Recovery

This article describes how to gain access to an Arista 7130 device if you lose the password. There are two solutions: Password recovery using grub from the serial console. Factory restore via USB. Password recovery using grub: This approach requires access via the serial console: Enter “reload” on the device command line to reboot C16-B1-10381-3#reload Are you sure you want to reload? yes or [no] yes INIT: Sending processes the TERM signal Reloading... When grub appears press ‘del’ to enter interactive boot mode GNU GRUB version 2.00 +--------------------------------------------------------------------------+ |lvm/vg1-mos_0.13.9 | |lvm/vg1-mos_0.13.3 | | | | | | | | |...
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Interface Status

The “show interfaces status” commands show the link status of the receive (Rx) and transmit (Tx). Besides “up” and “down”, the command gives addition information of the status of the port. This includes: Link status: shutdown – the port has been shutdown through the management platform. (Tx only) no source – the interface is not sourcing signal from anywhere. (Rx only) no signal – there is no signal received. (Rx only) no link – a signal is detected on the line side but there is not a valid link coming into device from upstream. Flags returned from the underlying driver...
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How do I get “tech-support” info from a 7130 device?

Arista 7130 devices have the ability to generate a zip archive of useful information which may be used to troubleshoot and diagnose issues. The archive contains information about the device configuration, state and relevant log files. Creating a tech-support archive To create a tech support archive use the “show tech-support” command: tad6#show tech-support Files zipped to A32-A4-52963-3_20170228_121510.zip To obtain the zip please use scp or a similar tool. Example cli command: bash scp A32-A4-52963-3_20170228_121510.zip <user>@<host>:<path> Number of errors encountered: 0 Transferring the archive from the Arista 7130 device There are a few options to transfer the file from the device:...
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How to update your Arista 7130 device

Arista 7130 devices run MOS. You can find the latest version of MOS at the Software Release Portal page. Broadly, there are two ways of updating the software on your device: a complete re-install, or the addition of the new image. The most commonly used method is the latter – a new software image is uploaded, the configuration is retained, and the device is reloaded to the new software. A complete re-image of the device would be required in order to restore the device to a factory-fresh state. That includes all configuration, including SSH keys, log files, startup configuration files,...
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How to set up MetaMux for a typical exchange

Introduction This is an example configuration of MetaMux on an Arista 7130 being used with a typical exchange connection. Configuration overview: 3 servers will be used to connect to each exchange connection receiving market data Market data and order responses from the Exchange feed will be delivered to each server on NIC 1. The Layer 3 process will be handled by an existing existing switch, however the Arista 7130 device could be set up to do BGP/PIM. This example shows three servers but may easily be modified for additional servers. All links are 10G. This config assumes management features etc....
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How to setup BGP for Exchange Connectivity

This is an example configuration of MetaMux on an Arista 7130 device being used with a typical exchange connection. BGP / PIM peering is done via internal routing daemons. Overview: This example shows 2 servers connected to one exchange gateway but may easily be modified for additional servers Market data and order responses from the Exchange feed will be delivered to the server on NIC 1 The Layer 3 processes (such as BGP / PIM peering) is done via internal routing daemons which receive a copy of the packets via internal 10G interfaces (ma5 & ma6) ma5/ma6 interfaces are only...
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How to install an application

Applications may be installed on your Arista 7130 device. Application installs will persist across reboots. Applications are installed in /opt/apps when using the install process. Presently, MOS ships with the latest stable version of each of the relevant applications, however if there’s a need to install a specific version of an application, instructions are below. Installing an application from the CLI Download the desired software application image as an RPM from the Software Download page. The file will be named something like “application-version.x86_64.rpm” i.e. metamux-0.14.3-1967.x86_64.rpm Copy the file to your Arista 7130 device. This can be done in a number...
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Automating MOS upgrade

Ways to mass-deploy MOS updates. Background While upgrading MOS is generally fairly straightforward via the web UI or using the CLI, it can be time-consuming for mass-deployment. Below is a automation script that network administrators can use to bulk-upgrade Arista 7130 devices. The script is written in Python using the pexpect module. It requires the ssh and scp executable on your host. You can download the script from the Arista releases page. Usage python mos-upgrade-ssh.py <options>. Where options are: -u admin, --user admin -p PASSWORD, --password PASSWORD you will be prompted if none is supplied. Enter anything if password is...
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How to remove MOS image with older releases

Step-by-step guide Check what you have installed. For example: C16-B1-10381-3 login: admin C16-B1-10381-3>enable C16-B1-10381-3#show boot system mos_0.7.0 mos_0.7.1 mos_0.7.2 mos_0.8.0 [BOOT] Remove the one(s) you no longer need. Note you cannot remove currently active volumes (marked as [BOOT]). Also note that you can nuke multiple volumes at once with wildcards – for example: C16-B1-10381-3#bash sudo lvremove /dev/vg1/mos_0.7* Do you really want to remove active logical volume mos_0.7.2? [y/n]: y Logical volume "mos_0.7.2" successfully removed Do you really want to remove active logical volume mos_0.7.1? [y/n]: y Logical volume "mos_0.7.1" successfully removed Do you really want to remove active logical volume...
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What is MOS core?

MOS core is a regular MOS which includes all the features without the weight of any bundled FPGA Apps. Ideal for customers using 7130 Connect devices (7130-16, 7130-48, 7130-96), as well as custom application developers. MOS core installations are ideal for devices that are getting “insufficient free space” error while doing an upgrade. testing:~$ sudo mos-install mos-0.16.0.iso Volume group "vg1" has insufficient free space (160 extents): 164 required. Volume group "vg1" has insufficient free space (11 extents): 125 required. % Command 'sudo /usr/sbin/mos-install mos-0.14.1.iso' returned non-zero exit status 5 test(config)#boot system file:mos-0.14.1.iso Volume group "vg1" has insufficient free space (99...
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What to do when you are getting a “meltdown”, “powerdown” or “system powered down” message

This is step-by-step guide on what actions to take if you are getting messages similar to below. Jan 17 02:08:34 C16-B1-10381-3 daemon.emerg /usr/bin/meltdownd: Temperature 35000 for /sys/class/hwmon/hwmon3/temp1_input is over critical value of 70000. or 17 02:08:34 C16-B1-10381-3 daemon.emerg /usr/bin/meltdownd: over temperature, system powerdown or Jan 17 02:08:50 C16-B1-10381-3 daemon.emerg /usr/bin/meltdownd: system powered down Step-by-step guide Upgrade to MOS-0.16.0 or later version. This can be downloaded from our releases page. Please refer to our FAQ page on how to update your Arista 7130 device. For details about the fix refer to MOSH-1223 within the MOS-0.16.0 release notes. Power cycle the device....
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Troubleshooting a suspected defective fan

Problem: The “show environment cooling” command shows a fan as “NOT WORKING”. Example: M32-A2-06308-5>show env cooling System Cooling Status: OK Ambient temperature: 41C Airflow: BACK-TO-FRONT (REV) Fan Status Speed ---- ------------------------ -------- 1 OK 51% 2 OK 51% 3 NOT WORKING 0% 4 OK 50% Solution: A 7130 device uses two field replaceable fan modules with two fans each providing a total of four fans. The fans are numbered 1-4 from left to right as you look at the rear of the device. The fans should fit snuggly so that they snap into place. Fans are removed by pinching the...
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How to fix high CPU usage caused by the logrotate process

There have been reports of devices experiencing high cpu usage due to the logrotate process consuming CPU resources on Arista 7130 devices. This can be confirmed by dropping down to bash and running the “top” command as shown on the following images. The primary cause of the problem was a logrotate bug introduced in MOS-0.16.0 (fixed in MOS-0.16.7). An incorrect regex pattern lead to the compressed quagga log files being rotated infinitely along with the normal log files leading to chains like this: /mnt/flash/log/quagga/quagga.log-20180513.gz-20180520.gz-20180527.gz-20180603.gz-20180610.gz-20180617.gz-20180624.gz-20180701.gz-20180708.gz-20180715.gz-20180722.gz This leads to the device eventually either running out of disk space or inodes or both....
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Blinking green/amber lights on ports

Below is a short description of what the blinking lights on the SFP ports of an Arista 7130 mean. Green – an SFP is plugged in and is not reporting loss of signal from the SFP. Red – possible link detection and flickers with traffic flow. Amber – link has been detected but there is no traffic.  

At what point-of-time does MetaWatch timestamp?

The term packet capture is used widely to refer to capturing network traffic. It is however, worth understanding precisely what the term packet refers to. The IEEE sets the standards for Ethernet and define an Ethernet packet at the physical layer as a unit of data wrapping a MAC frame at the data link layer (IEEE Std 802.3-2015 Chapter 3.1.1). An Ethernet packet is therefore an Ethernet frame, prefixed by preamble and start frame delimiter (SFD) bytes and optionally suffixed by an extension field (only used for half-duplex GbE networks). Moving up to the network layer, the IETF set the...
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Why do interface statistics differ between the CLI and SNMP

As of MOS release 0.8.0 support for all interfaces has been added to SNMP, reporting interface status (up or down), carrier status (RX link state), interface alias (CLI interface description, as of 0.8.1), and statistics. However, SNMP statistics reported are those provided by the standard Net-SNMP implementation and differ from those reported via the CLI in two important ways: SNMP statistics reported by the interface and if-mib MIBs are a subset of those reported by the CLI. SNMP unicast frames reported by the interface MIB are actually total frame counts. These differences will be resolved in later releases as we...
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What happened to the CLI “phy” commands?

The ‘phy’ command has been deprecated and split into two commands to separately change the ports speed and signalling mode. Speed is set and reported as an integer in Mb/sec. While the ‘phy’ commands will continue to work their use should be replaced with the newer commands, particularly in saved configs. For example setting a port to 1G is now done via the following: hostname>enable hostname#configure hostname(config)#interface et1 hostname(config-if-et1)#speed 1000 To show the speed of a group of ports the ‘show speed’ command should now be used: hostname>enable hostname#configure hostname(config)#interface et5-8 hostname(config-if-et5-8)#show speed Port Speed ---- ------ et5 1000 et6...
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How to install Xilinx or Altera development tools on an Arista 7130

In order to perform development work on an Arista 7130 device with an FPGA, it’s necessary to install the tools from Xilinx on that device. This allows remote access to the FPGA via the network. Step-by-step guide for Xilinx tools Download the Vivado WebInstall for Linux 64 package from the Xilinx web site – http://www.xilinx.com/support/download.html Run the installer to install the tools on an x86_64 linux machine. We regularly use CentOS for this purpose. [root@dory ~]# chmod a+x /tmp/Xilinx_Vivado_SDK_2014.4_1119_1_Lin64.bin [root@dory ~]# /tmp/Xilinx_Vivado_SDK_2014.4_1119_1_Lin64.bin Use the graphical interface to install the “Hardware Server (Standalone)” package. The installation location is not important. Copy...
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