Yellow Bricks

by Duncan Epping

kb

vCenter tasks time-out or ESX disconnects?

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I just received an email from a fellow consultant about a customer which had vCenter tasks time-out every once in a while. At times also ESX hosts got disconnected for no apparent reason at all. He discovered the following article by Richard Blythe aka VMware Wolf: ESX disconnects randomly or when doing VI client tasks from VC, task randomly timeout after a long idle time. Richard created a list of issues/errors that might be related to this issue:

  • ESX disconnects randomly from VirtualCenter
  • ESX disconnects when performing VI Client tasks from VirtualCenter.
  • Tasks randomly timeout after a long idle time
  • “An error occurred communicating to the remote host” pops up.

The article refers to an issue with vCenter Update 3 in combination with firewalls using state-ful inspection. The problem occurs because of SOAP timeouts, and this behavior did not exist in VC 2.0.x or 2.5 GA, as they used a different mechanism to communicate with ESX. The official KB article hasn’t been released yet but a temporary workaround has been published by Richard. If you run into any of the before mentioned issues head over to Richard’s website and try out the workaround until the fix or official KB article is released.

HP’s Flex-10 and VMware ESX(i) support

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Recently a customer asked me if HP Flex-10 was fully supported for ESX(i) or not. For those that don’t know what Flex-10 is:

HP’s new Virtual Connect Flex-10 Ethernet module is the industry’s first interconnect that flexibly allocates the bandwidth of a 10 Gb Ethernet network port across four NIC connections. This eliminates the need for additional costly NICs, switches and cables while concurrently increasing bandwidth flexibility.

After checking the compatibility guide the answer was “Yes”. So what’s the point of mentioning it here? Well, although it was fully supported there is a mention in the KB about possible problems with HA and VMotion:

  • VI Client does not show NIC connnection is down when the uplink to external switch is down
  • VMware HA is not supported with ESXi 3.5 Update 3 (embedded and installable) hosts with uplinks connected to Flex-10 NICs.
  • VMotion migration of virtual machine May time out with the default migration timeout value of 20
  • ESX Server May fail to respond under the following configuration

I guess the tip of today: Always check the compatibility guide, but also check the KB cause problems like this might influence your implementation time, plan and even your design!

KB: Verify the health of ESX Server Operating System

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I was just skimming through the new KB articles and noticed this one “Verify the health of ESX Server Operating System“:

There are many ways to look at ESX host performance. This article focuses on quick assessment of the 4 main resources:

  • Disk Space
  • CPU
  • Memory
  • Network

The article refers to different KB articles for pinpointing and solving performance related problems. I suggest you add this article to your bookmarks cause it probably be updated on a regular base!

Check if autostart is enabled from the COS

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I didn’t know this was possible. But you can easily check via the COS if autostarting of VM’s in enabled or not according to this KB article:

  1. Log in as root to your ESX host with SSH.
  2. Open the /etc/vmware/hostd/vmAutoStart.xml file in text editor.
  3. Search for a line that reads:

    <enabled>true</enabled>

  4. If you find the line, the functionality is enabled. If you do not find the line, the functionality is disabled.
  5. If you want to disable autostart for all virtual machines on the host, remove the line.
  6. If you want to enable the functionality, add the line immediately after the line ending with:

    7. <dynamicProperty>

  7. Save your changes and exit.
  8. Restart the management agents on the ESX host:
    service mgmt-vmware restart

Just before 2008 ends: Patches!

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Just before 2008 ends VMware released a bunch of patches for the 3.0.X release of VMware ESX. 9 Patches, all are “General” patches:

ESX303-200812401-BG: Virtual Machines Stop Responding When Disconnected from Serial Port
ESX303-200812402-BG: Fix for vdf -P Command to Delimit the Output Values With Proper Spacing
 ESX303-200812403-BG: Qlogic iSCSI Driver Allocates Target IDs Greater than 255
ESX303-200812404-BG: Permissions on the Service Console File System Change to Read-Only During Long NetApp Cluster Failover
ESX303-200812405-BG: CHAP Authentication Failure on ESX Server
 ESX303-200812406-BG: Fix for hostd RPM
 ESX303-200812407-BG: Required Patch for IBM FAStT Storage Arrays (DS3000, DS4000, DS5000 families) to Correct an Issue with Failover; Fix for a VMFS Filesystem Issue
ESX303-200812408-BG: QLogic Driver RPMs Versions Mismatch
 ESX303-200812409-BG: Hyperthreading Status Reported Incorrectly on Non-HT Multicore Processors for ESX Server 3.0.3