William Lam

Custom Attributes != vSphere Tags

01.13.2015 by William Lam // 21 Comments

A common question that I see frequently asked by customers is whether Custom Attributes in vCenter Server can be completely replaced by vSphere Tags? Both Custom Attributes and vSphere Tags provide metadata capabilities, but there are some underlying differences between the two and depending on how you use Custom Attributes today, you may or may not be able to completely migrate over to using vSphere Tags, at least in the short term.

UPDATE (11/16/16): vSphere 6.5 now allows you to fully view and manage Custom Attributes directly from the vSphere Web Client.

Custom Attributes allows you to specify custom "keys" associated with either a Virtual Machine or an ESXi host object using the vSphere C# Client. ~~which are the only supported objects~~ When using the vSphere API, you can apply Custom Attributes it across variety of vSphere Objects and for more details, please have a look at this post here. Once enabled for either a VM or an ESXi host, you will be able to assign an object-specific metadata "value" to these objects. An example would be a Custom Attribute called "Application Owner" and for VM1 I have a value of "Duncan Epping" and for VM2 I have a value of "Alan Renouf".

vSphere Tags also provides a metadata capability, but it goes beyond just VMs and ESXi host. vSphere Tags can be applied to all objects within the vSphere Inventory. A major distinction between Custom Attributes and vSphere Tags which will help answer our initial question is that vSphere Tags can not be used to store object-specific metadata, it is used for categorizing or logically organizing various objects together. An example would be a Tag called "Production" which can then be assigned to VM1 and VM2 for organizational purposes but you would not be able to assign a specific value for each of the VMs.

This distinction of not being able to assign object-specific metadata is the key difference between vSphere Tags and Custom Attributes. If you currently rely on this capability of Custom Attributes, you will not be able to completely migrate over to using vSphere Tags. A good way to think about vSphere Tags today is that they are similar to vSphere Folders but much more dynamic and search across all vSphere Objects. The lack of object-specific metadata for vSphere Tags is something that VMware Engineering is aware of today and hopefully they will be able to enhance in the future to support the Custom Attributes use case, so that vSphere Tags can be used exclusively.

In fact, I also hope to see vSphere Tags get enhanced so that permissions can also be applied onto Tags which would then propagate to the underlying associated vSphere Objects. I know this is another common request from customers that have looked at using vSphere Tags. I would like to also see a proper API exposed for Tags so that they can be managed and accessed programmatically, which can be quite handy for CMDB or provisioning systems. Today, there are no vSphere APIs for Tags, but you can manage them using PowerCLI Tagging cmdlet. Searchability is also another area that vSphere Tags can get further enhancements on. Today you can only search on objects by Tag name, but in the future I hope to see support for more complex queries which include searching through the values of the Tags assigned.

In summary, Custom Attributes are not going away anytime soon, at least until their capabilities are on-par with vSphere Tags. You will be able to continue accessing Custom Attributes which is available today in the vSphere C# Client or using the vSphere API. Custom Attributes are currently not visible in the vSphere Web Client, but you can use this custom vSphere Web Client plugin which makes the Custom Attributes available in the vSphere Web Client. Going forward, the future will be vSphere Tags, but in the mean time you may want to use both sets of metadata capabilities depending on your use case.

Quick Tip - Automate JVM Heap configurations after increasing VCSA memory

01.12.2015 by William Lam // 1 Comment

If you are using the VCSA (vCenter Server Appliance) and you wish to increase the VM memory settings to one of the three supported memory configurations: 8-16GB, 24GB & 32GB, there is on additional configuration change before the new memory configuration can take effect. This change is adjusting the JVM Heap memory settings for the following vCenter Server Services: vSphere Web Client, Inventory Service and SPS (vSphere Profile-Driven Storage). If you would like to do this from the UI, you can access the VCSA's VAMI interface and under vCenter Server->Services tab, there is a "Inventory Size" toggle that you will need to set based on your VCSA's configured memory. Once you have save the settings, you will need to restart the vCenter Server for the changes to take effect.

Note: The text in the VAMI states that the appliance requires at least 16GB of RAM for a Medium configuration which is actually incorrect, it should actually say 24GB for Medium configuration. The correct supported VCSA memory configuration maximum can be found here.

The UI is great but what if you wish to automate this change? This is especially handy if you have already automated the memory increase for the VCSA itself. Luckily, we can turn to our handy vpxd_servicefg command which supports modifying the JVM Memory based on the three supported vSphere Inventory Sizes. Below is the chart with the respective Inventory Size and command to issue within the VCSA. The parameters reflect the JVM Heap configurations for the vSphere Web Client, Inventory Service and SPS (vSphere Profile-Driven Storage).

Inventory Size	VCSA Memory	Command
Small	8-16GB	/usr/sbin/vpxd_servicecfg 'jvm-max-heap' 'write' '512' '3072' '1024'
Medium	24GB	/usr/sbin/vpxd_servicecfg 'jvm-max-heap' 'write' '512' '6144' '2048'
Large	32GB	/usr/sbin/vpxd_servicecfg 'jvm-max-heap' 'write' '1024' '12288' '4096'

Once the command has successfully completed, you can refresh the VCSA VAMI interface and you should see the appropriate size has been configured. For the changes to take effect, you will need to restart the vCenter Service by issuing one of the following commands:

/usr/sbin/vpxd_servicecfg service restart

/etc/init.d/vmware-vpxd restart

CoreOS is now available as OVA in Alpha channel

01.08.2015 by William Lam // 11 Comments

It looks like the folks over at CoreOS have now also produced an OVA image which can be easily imported into a vSphere or even vCloud Air environment. Previously, it took a few addition steps to convert the "hosted" disk image originally meant for VMware Fusion/Workstation to properly work in a vSphere/vCloud Air based environment. The CoreOS OVA is currently only available in the CoreOS Alpha channel for the "Production" image which also includes VMware's open-vm-tools and the latest release as of today is CoreOS 554.0.0.

You can using either the vSphere C# or vSphere Web Client to import the OVA or you can automate this simply by using command-line via ovftool. Here's an example snippet that you can run directly against an ESXi host:

/Applications/VMware\ OVF\ Tool/ovftool \
        --name=CoreOS \
        "--net:VM Network=VM Network" \
        --datastore=mini-local-datastore-2 \
        --diskMode=thin \
        'http://alpha.release.core-os.net/amd64-usr/554.0.0/coreos_production_vmware_ova.ova' \
        'vi://root:*protected email*'

You can also import the CoreOS OVA into vCloud Air's but you will need to connect into the vCloud Director interface to upload or you can also use ovftool. For more details on how to import using ovftool, check out their documentation here.

Here's a screenshot of deploying CoreOS from a vCloud Air Catalog:

The "Production" CoreOS image does not contain insecure SSH keys as the "insecure" image and so you will still need to create a Cloud Config ISO if you wish to further customize the image including login credentials. You can take a look at the script I had created for deploying CoreOS from the Stable channel and for more details check out the Cloud Config documentation as well.