VirtuallyNil

Logging in ESXi March 3, 2010

After listening to the VMware Communities Roundtable podcast of last week I thought I would create a short post on ESXi logging. It was episode #83 which focused on ESXi and was very interesting, it was geared towards administrators who are familiar with ESX and the pros and cons of moving to ESXi.

One thing that was mentioned by the main guest VMware’s Charu, which I haven’t tried before, was to setup persistent logging for an ESXi host. As he mentioned, although there is logging in ESXi which gets stored in the /var/log/ directory it is all in memory so if the host crashes, all logs are lost. While I already had the remote syslog setup it seems this local logging is a different log file.

On one of our test servers I went into Configuration->Advanced Settings (Software) -> Syslog -> Local and entered a directory and filename on a VMFS datastore and it started logging immediately to the specified file.

I then tried to see if it was a copy of a log that was already being created somewhere on the host and while it looks similar to the /var/log/vmware/hostd.log file it seems to be more verbose.

The other logs that I am aware of that are useful are:
/var/log/messages
/var/log/vmware/hostd.log
/var/log/vmware/vpx/vpxa.log

These are available via the browser interface (http://hostname/host). The messages file is what is sent via to the remote syslog if configured. There are also logs in /var/log/vmware/aam/that relate to the HA agent on the host and if there problems with a host enabling the agent it is sometimes fruitful to look in here at the latest files.

I would say that setting up both local persistent and remote syslog logging as a very good recommendation in configuring ESXi hosts especially in a production environment.