Category Archives: Networking

vCloud Air: OnDemand IaaS by VMware


Cloud computing is currently a highly discussed topic in many IT strategy meetings. The ability to spin workloads in third party cloud and pay only for what you actually use certainly make sense from financial point of view. There are many great use cases for that.

Imagine you have a big event, something like Super Bowl and your current infrastructure would likely struggle to handle such load for the duration of the event. You have two options how to prepare for it, you can buy new assets – compute, storage and network spending a lot of dollars or you can build your application stacks in third party cloud and leave it running for certain period of time and then tear down when the event is over. The second option also gives you virtually unlimited resources if you need to use them. How cool is that?

There are many Infrastructure as a Service offerings in the market, one of the most popular include Amazon AWS, Microsoft Azure or Google Cloud Compute. It was only matter of time that other vendors would start offer the same thing to address the competition.

One of such vendors is VMware. Initially, the popular hypervisor vendor offered two flavors of their public cloud offering named vCloud Air. First was a Dedicated Cloud, targeted on customers who wanted to essentially lease the entire servers for better physical isolation and security. The second was a Virtual Private Cloud, which is cheaper, but the hypervisor would run other companies’ VMs as well and provide logical isolation.

In either case, both of the offering were targeted on larger customers and you and me did not have an easy option to just spin couple of VMs for testing without committing to some long term payment plant.

With the new OnDemand access flavor that model changes and you now have a true option to pay as you go. This flavor allows any individual from flesh and bone (with credit card) to spin a workload in VMware’s data center and pay only for what he uses.


vCloud Air Common Use Cases

To support this idea, they even get you a nice started pack of $300 dollars worth of resources. It is like with gas provider, where they would get you certain number of gas for free to try their service out. Good move to attrack people like me to poke around and spin some workloads.

I think that many enterprise companies will consider this option, as their infrastructure teams are familiar with vSphere and this cloud is built upon the same foundations as their data centers, making migration and interoperability a little bit easier for both sides.

How does it feel to spin a couple of VMs in this environment? Lets have a look.

Signing Up

First, you need to go to super secret URL only know by 5 individuals in the world. I like my audience so I am going to share that URL with you and it is at

The landing pages gives you couple of information what vCloud is, couple of testimonial and general information. Click on Service Offering/Virtual Private Cloud OnDemand to get started.

Lets take advantage of that $300 voucher shall we? For that we need a VMware Account First. You you have one log in now, otherwise make the clickie-clickie action and create one.

During the registration you need to enter a valid credit card and billing information.


Creating a new account for vCloud Air

At this point you will have an options to select the Support Level Plan. I’ll go with the basic one OnDemand Online Support. Make sure that the promo code ondemand2015 has been applied. As so many people are trying to get the hands on, you likely end up in the queue with Sing up request pending. So wait for it.

Ok, it took around 5 minutes to get the confirmation email with the login page URL and initial links to set the password.


You need to reset your temporary password

Entering to the vCloud

Now that you we have set the credentials, lets go back to to main login page at If you would like to use VMware Remote Console, install it & enable the plugin in your browser.


The Login Screen looks nice and clean, thumbs up for that.

Building our first vPC

After login you are presented by main dashboard, that includes Services, Subscriptions and Tools. After Clicking the Virtual Private Cloud Ondemand, you have an option to select in which physical location you want to build your vPC. Since I am located in UK I’ll go with UK Slough 1 6 option. Slough is small town in Berkshire.


After couple of seconds a new vPC instance will be build. After the gears stop spinning you will receive the following handy infrastructure to play with.

Default vPC topology

Default vPC topology

The infrastructure is composed of one Gateway, that provides access to your private cell. This gateway is connected to public segment which is according Ripe a chunk of larger pool that VMware allocated for this particular cloud.

The second network, is a private segment where would build your VM. We will get to that later. I want to show you around the interface.

The first tab you find under vPC is the Resource Usage which shows you how much you resources you consume and how much for last hour/day or month. You also have option to view detailed report. Give that your financial department to sponsor your vCloud adventures.


Creating new virtual machine

Next, looking at Virtual Machines tab, you have an option to spin your first workload or migrate it from your private data center. Lets keep things simple for now and select the first option.

Creating the first workload

Creating the first workload

As any good cloud offering, you will be presented by a catalog of virtual machines that you can select from. Most of the Linux flavors are free, and you pay same extra fees for Windows VMs for licensing. You also have an option to create an empty machine, called shell VM from scratch. I’ll go with CentOS 6.4 32 Bit for now.

Selecting a VM from catalog

Selecting a VM from catalog

In customization page, you have the options to name your VM and specifie resource it will consume. You also get a nice cost calculation to get an idea how much your new puppy it will cost you. In production workload size should meet the application demand that this VM will run. I am testing the functionality so I have selected the minimums, send me some bitcoins and next we will go crazy with 16vCPUs and 120GB RAM.

I’ll attach the VM to the default-routed-network.

Workload customization and estimated cost

Workload customization and estimated cost

The creation of this small VM took roughly 3 minutes. And the status is shown under main Virtual Machine tab.

New VM is up and running

New VM is up and running

If you got your hands dirty with Amazon AWS, you know that after creating a workload it will receive an elastic IP address that is publicly routable, and using an RSA key pair you can log in though SSH.

The vCloud Air, by default works a little bit differently, are you recalling some mumbling earlier in this post about Remote Console Plugin? That is exactly what we are going to use to access the VM. At least initially. While selecting the VM, open Actions menu and select Open In Console.

Accessing the console through Remote Console Plugin

Accessing the console through Remote Console Plugin

Allow pop-ups and vuala, you are at the VM console. It is that easy.

Sitting at the console

Sitting at the console

I was not able to figured out that the default credentials looking at my magic ball that I have on my table, but I know where to look for it.

For that we need to look further at the VM details.

Discovering the auto generated password

Discovering the auto generated password

Go back to Remote Console and login. To confirm that we indeed ended in the default routed network, lets look at NIC settings and try to reach default gateway.


Tip: You are stuck in Remote Console, press CTRL+ALT to escape the window.

The default Edge configuration will not respond to ping, but you can verify layer 2 by examining the VM ARP table.

Connecting VM to Internet

Our VM is very lonely at the moment, it can only speak to the Edge Gateway in some sort of way. Wouldn’t be great if it could speak to everyone on the Internet? For that to happen, we need to perform some additional configuration on Edge Gateway.

First, we enable the communication from the VM to the internet by configuring Dynamic NAT Translation. On the main page navigate to Gateways tab and select the existing gateway.

Default vPC Gateway

Default vPC Gateway

You will be presented by Gateway specific options, such as NAT Rules, Firewall Rules, Networks, and Public IPs. Before you can add a NAT Translation, you need to add new Public IP address. So start by requesting one.

In the background a new job will be initiated in vCloud Director, which is doing the heavy lifting under this light web UI.

Note: I had some problems assigning a public IP address in my first VDC1, where the job would never finish and I could not do anything with the gateway anymore, therefore I have opened a ticket with vCloud support and they were able to fix the issue with public IP assignments

After the task finishes you are actually assigned the same public address that your edge gateway currently uses.

Public IP successfully assigned

Public IP has been successfully assigned

Lets revisit theĀ  NAT Rules tab and create our first entry that will dynamically translate our internal VM to the public IP address above.

Adding Source NAT entry

Adding Source NAT entry

Simple as that, click Next and Finish.

Although the dynamic NAT rule is in place we are still unable to reach any external resource. We need to modify the default edge firewall policy to allow this communication.

Go to Firewall Rules tab and Add a new entry called Internal-to-Internet.

Allowing default internal network to talk to anything on the Internet

Click Next and Finish. With all per-requisites in place the VM can finally reach the internet.

VM is happy happy now

The default vDC private network automatically assigns an address from a pool to newly create virtual machines. These pools are configured in vCloud Director under each Organization VDC Networks respectively. But by default they not include DNS server configuration. For now I will cheat a little bit and edit the list of servers manually in VM at /etc/resolv.conf. You are now fully equip to install additional packages.

Coping and Pasting to virtual console sucks, wouldn’t be great if we could SSH to our box? For that we need three things in place. OpenSSH installed and configured on the box, static NAT entry and a Firewall Policy. There are bunch of great tutorials out there showing how to setup the first part.

For the second part, we are going to create a DNAT entry for VM that will map an external IP address and its port 22 to VM internal address. The second entry will show in the list.


Newly added destination NAT for our SSH traffic.

Finally, add a new firewall rule to allow communication from outside on port TCP/22. For added security define only a single or a range of public addresses that you are connecting from.


Newly added firewall rule to allow SSH inbound.

Lets connect to our VM via SSH and install Apache web server shall we?


Installing and starting apache

As with any new service, we need to add SNAT entry and Firewall rule to permit communication from the Internet.

You also need to modify the host firewall, iptables in this case to allow communication from outside to httpd service.

After repeating the same steps as above you have a web server running in vCloud Air. How cool is that?

Your first vSphere VM running in cloud.

Your first vSphere VM running in cloud.

Lets stop for a moment and imagine the possibilities, if you can build VM you can build an entire application stack. If you can build an entire application stack, you can build an entire virtual data center. And that is the way to go my friends.

This concludes the basics how to build inside this third party cloud. In next article I am going to focus on scaling and creating more complex network topologies as well as exploring some additional features and parameters available exclusively through the vCloud Director interface.

What you can learn from Networking for VMware Admins


It was not so long ago when I was searching for good resource that would uncover what is happening at the hypervisor level from network point of view and how it all clicks together to provider connectivity to ever increasing number of virtual machines. I am happy to say that I have found that resource. It is called Networking for VMware Administrators by Chris Wahl and Steve Pantol.

Networking-for-VMware-Administrators 1

The book starts by discussing the very foundation of networking, what networks is and what benefits it provides. Continuing with with common models and protocol stacks like ISO OSI and TCP/IP and the concepts of layering.

Comparing ISO OSI to TCP/IP

Comparing ISO OSI to TCP/IP

Diving more deeply into the individual layers authors start with physical layer. Ethernet technology is explained in great detail as well as common physical connectivity options like copper or fiber. You will also gain some knowledge about most used network connectors such as RJ-45 and modules like older GBIC or SFP.

10Gbps Twinax Cable used for short interconnections

10Gbps Twinax Cable used for short connections

The chapters build on top of each other and after the foundation and physical network properties next chapter covers data-link operations in great detail. You learn about switching and common network challenges like preventing network loops with spanning tree or increasing network through put by utilizing link aggregation technologies.

Another layer that could not be forgotten is Layer 3 or Network layer. In this chapter IP addressing and routing is explained in detail. Other common services such as automatic address configuration thought DHCP or name resolution with DNS are well touched giving you as a reader better overall perspective.

With the foundation lied down in first 5 chapters the book continues to touch popular converged network infrastructures. Concept of stateless computing from Cisco is explained – the Unified Computing System as well as the HP’s Blade Chassis C7000. Both are compared to give you better insight on one over the other.

Cisco Unified Computing System

Cisco Unified Computing System

The true discussion on virtual networking begins with Chapter 7: How Virtual Switching Differs from Physical Switching. This is an excellent entry point chapter, which describes similarities and differences between both. It touches on common virtual vSwitch terms such as virtual machines’s NIC cards (vNIC), Port-Group, physical uplinks (pNIC), VM kernel ports (vmk) and generally how does the virtual architecture fits with physical.

vSwitch Architecture

vSwitch Architecture


vSwitch Forwarding Logic

Better yet, this chapter outlines various configuration options on vSwitch like number of uplinks, MTU and Security Settings. Last but not least trunking and VLAN tagging options are explained.

Chapter 9 focus on vSphere Distributed Switch which is commonly found in enterprise environments. It explains how it differs from Standard vSwitch in control and data plane operations. And elaborates on many extra features it provides. You can expect to gain knowledge on link discovery protocols CDP and LLDP, exporting traffic flows with NetFlow, monitoring traffic in virtual environment using Port Mirroring, segmenting traffic using VLANs and Private VLANs and finally Load Based teaming and Network IO Control for intelligent traffic management.

After you gain this strong foundation, you are free to enter to realm of third party virtual switch. Cisco Nexus 1000V is the topic of next chapter. Authors explain the reasons why you might consider using this third party switch from Cisco in your environment. It touches on core architecture concepts like Virtual Supervisor Module (VSM) and Virtual Ethernet Module (VEM) and various modes of deployment options.

Nexus 1000V deployment options

Nexus 1000V deployment options

If you are more practical type of person, you will definitely like the lab scenarios that authors put together. A step by stem approach is outlined how to build a basic vSphere environment using Cisco UCS as main computing platform. In later chapters you will also discover how to migrate workloads from standard virtual switch to distributed virtual switch without causing downtime.

After discussing general networking technologies with relevant examples, Chapter 14 moves our direction toward IP based storage, starting with iSCSI. General uses cases are explained as well the idea of initiators and targets. Best practices for setting up iSCSI storage adapters are also well explained giving you good confidence when planning in production environment.

The storage topics are then closed by discussing NFS based storage and its uses cases. I especially like the right depth of topics around storage. Practical demonstration at the end of the chapter is also a huge benefit to better put things together.

The next to last chapter deals with additional vSwitch design options, showing many different scenarios with or without IP based storage in place and using 1 Gbps or 10 Gbps network adapters.

One of many vSwitch design options

One of many vSwitch design options

Finally, the last chapter discusses additional design options when dealing with heavy load vMotion migrations. You will learn how to design multiple VM kernel adapters for moving workloads around in case you need to. Network IO Control is also revisited in relation of egress traffic shaping and protecting v host from traffic overload, in case of multiple hosts decide to migrate loads onto same destination hypervisor.

Although I am primarily a network guy I must admin I enjoyed this well written book from the first page to last. It gave exactly what I was looking for, a good foundation of vSphere networking which is the base for advanced technologies like virtual overlays with VXLAN.