I also struggled with esxtop zenpack. I was experiencing the buffer too small error. This appears to be a problem with how subprocess is being used in python.
I was able to get the zenpack somewhat working by editing the resxtop function as follows:
[code]
def resxtop(self, command):
import os
"""
Run the resxtop command and return the output into a cache file,
or die and print the error message.
"""
password = self.options.password
env = dict(VI_PASSWORD=password)
# proc = subprocess.call(command, stderr=PIPE, shell=True)
# proc.check
os.system(command)
[/code]
Unfortunately, while the VMs are listed under the guest section of the device page, so is a bunch of other junk.
FYI, the SSL bug in vSphere CLI was corrected a couple of days ago, so be sure to download CLI 5.1 update 1 if you're trying to use this or other zenpacks that utilize CLI tools.