Friday, May 31, 2013

Disabling Hot Add/Remove on VMware vSphere

It has been a long time since VMware introduced the capability of Hot Add/Remove devices, like CPU and Memory, along with them we could also Hot Add/Remove network cards and SCSI controllers.

It was a huge improvement and helped a lot of System Administrators to reduce the server’s downtime when some upgrade was required, (keep in mind that the Operational System must be able to recognized the change that was made on its resources and adjusts itself accordingly.

But, with VMware Horizon View, we saw a proliferation of VDI projects, and this amazing feature also allows end users, with certain privileges, to remove the NIC of their own systems, intentionally or not, causing and immediate disconnection and a break of the VDI service. 
You probably noted an increase of calls into support.

It’s so easy to remove the NIC by accident that could happen even with the most Senior Technical guy.

The NIC is just there between your USB devices and stuff.

Don’t worry about removing the SCSI adapters, since it’s probably in use by the O.S., so it will not allow the removal of it.

Yeah, I know, on the support side you will need to prove the NIC was removed by someone and there's no problem on the environment,

You can get the prove you need at the Virtual Machine's log file, look for the following entry:

Mar 21 03:13:37.463: vmx| Powering off Ethernet0
Mar 21 03:13:37.463: vmx| Hot removal done.

You are probably wondering… ok, but, how do I prevent such thing from happening on my environment ?

Easy, disabling  Hot Add/Remove on the virtual machine.

- power off the Virtual Machine
- Edit the setting of it
- On the options tab, click General
- Then click on Configuration Parametes
- click Add Row
- Insert the following item devices.hotplug with value of false
- close and save everything
- power the VM back on

And Yes, you need to perform this procedure on each Virtual Machine.

Luckily, on a VDI environment hundreds of virtual desktops are based on a single virtual machine. So, perform this step on the parent virtual machine and recompose the pool,  every virtual desktop will inherit this configuration.

Another Yes........ you will lose the capability of Hot Add/Remove devices on this virtual desktop, but, it’s not a thing you would need to be worried about on a VDI environment.

I hope this tip helps you preventing your users from losing connection from their virtual desktops and why not reducing the calls into your support : )

Tuesday, May 21, 2013

Enabling vSphere Network Health Check

Networking configuration of a vSphere environment is challenging, right ?!
May be due the fact the majority of companies has different teams for managing the physical network and the vSphere environment, resulting with you having just half of the information.

As you might know, the physical network port on the switch must match the configurations of the vSphere Virtual Switch, VLAN tags, MTU, teaming etc…. add to the complexity, several hosts, each one having a few NICs and connections, is not unusual that eventually you will get a non working network port.

Troubleshooting this misconfigurations is hard…. well, not anymore !!!!

vSphere 5.1 introduced a new feature, Network Health Check.

When enabled it can monitor and check the following configuration.

VLAN – check all VLAN IDs of the portgroups created on the VDS against the trunk configuration on the physical network switch. 
MTU – check if the network switch can send/receive packets with the size, MTU, configured on the VDS. 
Teaming – check if the configuration is set for IP Hash, which is the required configuration when using LLDP(teaming).

Be aware that this check is just againts the port on which the host's NICs is connected to. It does not check all the way through other switches connection.

If you are not familiar with vSphere WebClient Server, this task can be tricky.
That’s it; Network Health Check can ONLY be enabled through vSphere Web Client. Get used with that, all new features will just be avaible through it.

So, lets go check how….

- Login on vSphere WebClient and click Networking

- Select the VDS that you want to enable the Network Health Check.

- Select Manage, Settings, Health Check and then click on Edit…

- enable the desired feature to check

To monitor the Network health check status.

- Select the VDS
- Click on the Monitor tab and then Health

Now you can monitor if some of the configuration does not match on each individual host and uplink.

Making our life easier, right ; )

Wednesday, May 8, 2013

vCloud Director agent

Have you had issues while preparing the host ESXi to VMware vCloud Director ?

Probably not, but if you are like me and constantly need to build vCloud Director labs over an over, rebuild a vCloud system or may be re-use your hosts on another vCloud system, you might end up with the following error:

Cannot prepare host.

Clicking on the message error for the details, you get:
The host “XXXX” is managed by another vCloud Director system “YYYY”. Unprepare the host from the older system or uninstall the agent software on the host.

What occurs is that vCloud Director installs an agent on the hosts ESXi to allow proper communication between vCloud components and the hosts.

Before you remove a host from a vCloud system, you should unprepared it first otherwise you will not be able to prepare it on the new system.

But, what if you don’t have access to the old system anymore?
You can always manually uninstall it ; )

On ESXi 5.x run:
esxcli software vib remove -n vcloud-agent

If you are still using old versions of ESXi, run:

Then, on vCloud admin page, click on Manage e Monitor, select hosts.
On the right page select the host you desire to install the agent and click on Prepare Host …

Now you should get all the hosts prepared and ready to your Journey to the Cloud !!!

Who am I

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I’m an IT specialist with over 15 years of experience, working from IT infrastructure to management products, troubleshooting and project management skills from medium to large environments. Nowadays I'm working for VMware as a Consulting Architect, helping customers to embrace the Cloud Era and make them successfully on their journey. Despite the fact I'm a VMware employee these postings reflect my own opinion and do not represents VMware's position, strategies or opinions. Reach me at @dumeirell

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