Tag Archives: esxi

Citrix NetScaler – Fatal trap 9: general protection fault while in kernel mode

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The other day one of our NetScaler appliances was unable to boot up after a power down. It was getting stuck during the FreeBSD bootup phase (before the NetScaler software actually loads) with the error:

Fatal trap 9: general protection fault while in kernel mode

The only information I could find on this specific issue was here: https://support.citrix.com/article/CTX238252, but this was not relevant to us. I could not find anything else online talking about receiving this error on a NetScaler appliance. Restoring to previous snapshots of the appliance didn’t resolve the issue. After some digging I found that this VM was set to the highest VM compatibility level. At some point someone had set the comparability level of the VM to be upgraded to version 15, but this didn’t take effect until the VM was actually powered down (it had been rebooted many times since without issues).

To remediate this issue I did the following:

  • Removed the VM from inventory
  • Manually edited the vmx file ‘virtualHW.version‘ line to say virtualHW.version = “4”. I chose a lower version, so that I could use the GUI to upgrade the version later. This can be done using WinSCP or something similar to download/edit the file
  • Added VM back to inventory
  • Upgraded VM compatibility to version 7 in vCenter to let the system actually run through the VMX and check settings

After doing all of the above I was able to successfully boot up the NetScaler appliance. The main takeaway here is that the ‘fatal trap’ error was directly related to the VM compatibility setting in ESXi in this particular case.

Deploying Home Assistant Hass.io to ESXi 6.5

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I recently did a complete overhaul of my home ESXi home lab environment. With the new capacity/reliability came the desire to move as much onto it as possible. One of these items was my Home Assistant Hass.io instance which was running on a Raspberry Pi 3 (and originally a Raspberry Pi 1 B). Running it on the Pi has always come with painfully slow reboot and update times. With VM real estate available I see no reason to rely on mini computers to run various workloads around my home. I can re-purpose these boards for other projects. ESXi will also bring the ability to do machine-level snapshots which will be more complete and easier to revert to than the snapshot mechanism within Hass.io.

The main issue I ran into was with the VMDK. The way the VMDK was created it split into multiple files and I couldn’t consolidate or delete snapshots. The VMDK was also getting locked preventing vMotions. To get around this I cloned the VMDK in shell using vmkfstools. I also had to use the proper storage controller, network adapter, and firmware settings. I’ve listed all steps below:

  • Create a new VM with the following parameters:
    • Guest OS – CentOS 7 (64-bit) (The VM will adjust this automatically later)
    • 1 vCPU
    • 2GB RAM
    • 1x E1000 NIC (NIC will not be usable as VMXNET 3)
    • Remove any other devices like CD-ROM, hard disk, SCSI controller, etc.
  • Download the latest stable HassOS VMDK from https://github.com/home-assistant/hassos/releases
  • Copy this VMDK up to the VM directory in ESXi/vSphere
  • Open an SSH session to the ESXi host and change directory to the location of the VMDK you just copied (ex. cd /vmfs/volumes/datastore1/HASSOSVM)
  • Clone the VMDK using the following command: vmkfstools -i “hassos_ova-2.8.vmdk” “hassos_ova-2.8_new.vmdk” (This creates a thick copy of the disk and avoids locking/snapshot issues with the virtual disk)
  • Delete the original VMDK from the datastore as it is no longer needed
  • Edit the VM and add an existing hard drive selecting the VMDK you just cloned
  • Change the controller for the disk from “New SCSI controller” to “IDE 0”
  • Remove the newly added SCSI controller as it is not needed for the IDE virtual disk
  • Go to “VM Options” and change the Firmware from “BIOS” to “EFI”
image

After all this has been completed you just need to power on the VM. Assuming DHCP is configured properly on the network Hass.io is using it will pick up an IP and start configuring. With Hass.io running on an older Xeon-powered host I have never seen the VM get over 50-60 percent CPU utilization and even then I’ve only seen those spikes when running an update. Updates of HassOS and Hass.io take a minute or two when they would sometimes take up to 10-15 minutes when running on a Pi.

Storage vMotion operations timing out

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I recently ran across an issue during a ESXi cluster/SAN migration where we were down to a handful of VMs that were failing when trying to move them to the new cluster/SAN (using simultaneous compute/storage vMotion operations). I’d like to note that this was on vCenter 6.7 and ESXi 6.5.

The errors were:

  • Timed out waiting for migration data. The source detected that the destination failed to resume.
  • Operation timed out.
  • Timed out waiting for migration data. vMotion migration {#######################} failed to read stream keepalive: connection closed by remote host, possibly due to timeout.

I looked at all the standard issues (storage issues, vMotion connectivity issues, etc.) When looking at the VMs the only thing that made them different compared others in the cluster was the number of virtual disks attached to them. All four of the VMs were SQL Server Availability Group members and had a larger number of disks (5+). When looking into timeouts related to the number of disks I came across this VMware article: Using Storage vMotion to migrate a virtual machine with many disks timeout (1010045). The errors in the article were not the same, but it it aligned with my suspicion about the number of disks. I couldn’t look at the kernel vpxd logs because they had already rolled over, but I decided to give it a shot. I shutdown the problem VMs, set the fsr.maxSwitchoverSeconds configuration parameter to 900 for each one, powered them on, and retried the compute/storage vMotion operations. All vMotion operations completed successfully after this change.

I would like to note that there is a separate configuration parameter called vmotion.maxSwitchoverSeconds which controls the compute side of things. You can try adjusting this as well when having vMotion timeout issues.

OVA deployment issues in vCenter 6.5+

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A team member was recently tasked with deploying a number of OVA templates provided by a vendor. There was difficulty with the OVA deployment failing after sitting on “Validating” for a long time. This would usually happen after selecting a compute resource in vCenter. The vendor stated they have seen this numerous times with vCenter 6.5 clients. They advised to remove a host from the cluster and deploy directly to that host. Being a person that cannot accept hacky workarounds I decided to dive into it. We are currently on vCenter 6.7 U1 with 6.5 ESXi U3 hosts. I extracted the OVA and started looking into the OVF XML. Everything looked to be formatted correctly, but I still felt vCenter wasn’t liking something in the XML. I began troubleshooting by commenting out entire <ProductSections> elements of the XML. Commenting out the first set of options did not work, but the second did. Looking closer at the second showed a very long ‘ValueMap’ string for the time zone selector in the ovf:qualifiers attribute. The most likely scenario was this this causing the issue with its length and complexity. I decided to clear out the entire ovf:qualifiers attribute (empty quotes) and hard code the value to be ‘America/New_York’. I then saved the OVF, initiated a new deployment (selecting all VMDKs, the OVF, but excluding the MF file as that would cause a checksum error), and hitting next… VOILA! I was able to successfully deploy this OVF without any errors. I also performed the same action for all of the other vendor templates.

Original time zone property:

Modified time zone property:

I didn’t dig further, but I imagine the vendor’s standalone host hack worked because the web GUI on the host has different code (maybe missing a bug) than vCenter. I’d also like to note that this could be accomplished by using the Import-VApp PowerCLI PowerShell cmdlet (without modifying any files), but you’d also have to create a OvfConfiguration hashtable object to pass as a parameter which may be more work than it is worth.