Retrieve VMware Virtual Machine Password from OVF properties

When you deploy a Virtual Machine from OVF/OVA you can sometimes preconfigure passwords using OVF properties. All configuration parameters set during the deployment can be viewed later in the Web Client within VM > Configure > Settings > vApp Options but when you want to retrieve the password, the actual value is hidden:
You can't access the password from the Client, MOB, or using the API. This article explains how you can retrieve vApp option passwords from the vCenter Database.

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Ping from specific VMkernel adapter in vSphere 6

When troubleshooting network problems on ESXi hosts you want to specify the outgoing VMkernel adapter. As explained here you can ping from a specific VMkernel adapter with the -I parameter. In vSphere 6.0, or with VXLAN activated, this might not work as expected and displays the following error.

[root@esx:~] ping -I vmk1
Unknown interface 'vmk1': Invalid argument

The problem is related to the multiple TCP/IP Stack features introduced in vSphere 6.0. To ping from specific VMkernel adapters that are not in the default Stack (defaultTcpipStack) you have to manually specify the NetStack with the -S parameter.

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What's Inside an ESXi vm-support Bundle?

When you open a Support Request (SR) at VMware, the Global Support Services usually requests you to collect diagnostic information. You can create this log bundle with a special command line tool (vm-support), with the vSphere (Web-)Client or with the API. No matter how you create the bundle the result is always the same: a .tgz file containing your ESXi Host name and the creation date with a size of about 30 - 300MB.

This post explains what's inside this log bundle, but instead of simply extracting the file and looking at the result, I am going to take a look on how the file is created and what's part of the process.

Why is it important to know? Because it does not only contain data that allows VMware GSS to identify your issue, but also to help yourself to enhance your troubleshooting skills. The script gathers the output of many useful commands and there is nearly no black magic involved. You do not need special tools or internal VMware knowledge to make use of this log bundle.


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ESXi Network Troubleshooting with tcpdump-uw and pktcap-uw

This post explains how you can troubleshoot network problems by capturing network traces of ESXi host by using the tcpdump-uw and pktcap-uw utility. The pktcap-uw tool is an enhanced packet capture and analysis tool that can be used in place of the legacy tcpdump-uw tool. The pktcap-uw tool is included by default in ESXi 5.5 and later. This post explains the main differences of both tools and how to use them.

tcpdump-uw vs. pktcap-uw - It's not the same!


Capabilities of tcpdump-uw and pktcap-uw

The tcpdump-uw utility captures traffic from VMkernel adapters. The pktcap-uw utility, introduced in ESXi 5.5 can capture traffic that flows through physical network adapters, VMkernel adapters, and virtual machines adapters.

But it's more complex...

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ESXi 5 Network Troubleshooting Commands

Check if a remote host is online and reachable.

~ # ping
PING ( 56 data bytes
64 bytes from icmp_seq=0 ttl=58 time=13.701 ms
64 bytes from icmp_seq=1 ttl=58 time=10.176 ms
64 bytes from icmp_seq=2 ttl=58 time=9.055 ms

--- ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 9.055/10.977/13.701 ms

Ping from a specific VMkernel adapter.

~ # ping -I vmk1
PING ( 56 data bytes
64 bytes from icmp_seq=0 ttl=58 time=9.991 ms
64 bytes from icmp_seq=1 ttl=58 time=9.270 ms

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Howto Shrink a Thin Provisioned Virtual Disk (VMDK)

Thin provisioned disks are a great feature to save capacity as you virtual machines filesystem will never use the full capacity. I do not know a single system where you do not have at least 10GB of free space for OS disks. I am not considering databases, applications or fileservers which will grow constantly. Having thin provisioned disk is usually no longer a performance problem so it is a valid design choice even in production.

A common issue with thin disks is that the size will grow when required, but never shrink. When you require the capacity only once you might want to get it back from the virtual machine. This post describes how to reclaim unused space from the virtual machine.

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