Chapter 29. Troubleshooting
There are some pretty useful diagnostic tools on Arista switches, some of which we’ve already covered, such as tcpdump. Sometimes, we need to know more detail about what the switch is doing, and that’s where performance monitoring comes into play.
In Linux, you can follow live updates to a log file by using the
tail -f filename command. You can do something similar when viewing your system log in EOS with the command-line interface (CLI) command
show logging follow. Syslog messages are stored in Linux where any Linux person would expect to see them, namely, in /var/log/:
[admin@Arista ~]$ ls /var/log EosInit error.log messages NorCalInit eventMon.db nginx-access.log Post fneserver nginx-error.log agents inotifyrun-local.log ntpstats btmp inotifyrun-secure.log ppp cli inotifyrun-sys.log qt cron kernel.debug secure eos lastlog spooler eos-console libvirt startup-config-output eos-console-sync logrot.log tallylog eos-monitor maillog wtmp eos-monitor-sync mcelog yum.log
/var/log/messages contains all of the syslog messages that you would see on the console. Note that you need
sudo to view this file:
[admin@Arista ~]$ cd /var/log [admin@Arista log]$ tail messages tail: cannot open 'messages' for reading: Permission denied [admin@Arista log]$ sudo tail messages Nov 29 02:07:34 Arista Stp: %SPANTREE-6-STABLE_CHANGE: Stp state is now stable Nov 29 02:07:56 Arista Cli: %SYS-5-CONFIG_I: Configured from console by admin on vty3 (10.0.0.100) Nov 29 02:08:01 ...