Thanks to a conversation I had this morning with a Twitter user @BOK, I learned that CoreOS has just recently published a new CoreOS Alpha Image (v490.0.0) that now includes the Open VMware Tools package. In addition, the new image also now uses the optimized VMXNET3 network adapter. From our chat, it looks like this update is not available in the insecure or VMware Fusion image and I can only guess that these images may eventually get deprecated or removed completely in favor for the newer VMware image which can both run on ESXi as well as hosted products like VMware Fusion/Workstation.

@BOK also shared with me a modified version of my script that I initially created to automate the deployment of CoreOS onto ESXi. The original workflow had to be slightly modified as the new image is only available as bz2 (bunzip2) and ESXi does not contain the bunzip2 utility. This means there are now two steps: first is to extract the VMDK and upload to ESXi datastore which is going to be done manually and you can run the script which will automatically convert the VMDK to the proper format and register the VM in ESXi.

I was thinking about how I could simplify this process, even though it is just a couple of extra commands, I always like to see how I can make something easier to consume and reducing the complexity if possible. I of course decided to create a new script called deploy_coreos_on_esxi2.sh which now runs outside of the ESXi Shell. The script requires a UNIX/Linux system that has the bunzip2 utility and will automatically download both the VMX and VMDK file, perform the extraction and then upload it to ESXi host using an HTTP API provided through the vSphere Datastore. Lastly, it auto-generates the configuration shell script that will run over SSH to the ESXi host (SSH is still required) which will perform the same set of operations as my previous script did.

Note: You will be prompted to enter the ESXi root password when it tries to run the script remotely on the ESXi Shell, there is a timeout for 120seconds in case you step away from the console.

Prior to running the script, you will need to edit the following 7 variables:

• ESXi_HOST
• ESXI_USERNAME
• ESXI_PASSWORD
• ESXI_DATASTORE
• VM_NETWORK
• VM_NAME

Here is a screenshot of running the script from my Mac OS X desktop:

Once the CoreOS VM has fully booted, we can take a look at our vSphere Client and we should see that VMware Tools is in fact running and we can see the IP Address automatically being displayed in the UI:

The really nice thing about having VMware Tools running in the CoreOS image, is that you can use VMware's Guest Operations API to be able to perform operations within the guest which are proxied through VMware Tools and can be quite handy, especially if networking is not available or you want to go through a single management interface such as using the vSphere API.

There has been a tremendous amount of buzz lately regarding Docker, a platform that allows developers to easily build, deploy and manage Linux Containers. Docker can run on variety of Linux Distributions, one that has been quite popular lately is a new Linux Distribution called CoreOS.

CoreOS is actually a fork of Google's ChromeOS and was designed to run next generation workloads similar to those at Google and Facebook. A major benefit of CoreOS is the minimal footprint the base operating system consumes which allows for maximum resource utilization for the Container workloads.

Having heard so much about Docker and CoreOS, I figure this would be a great opportunity to explore and learn about a new technology which I always enjoy when I get the time. I know Duncan Epping has written an article on how to run CoreOS on VMware Fusion, but since I primarily work with vSphere, I wanted to run CoreOS on ESXi. The first place I went to was the CoreOS documentation and there is a section for VMware. After going through the instructions, I found the process to be quite manual and potentially requiring additional tools as a simple OVF/OVA for CoreOS did not exist.

I figured I could wrap the process in a very simple shell script that only required a couple of input parameters from the user based on their environment and the script would auto-magically handle the deployment. I created a shell script that would run on the ESXi Shell called deploy_coreos_on_esxi.sh

Note: The script assumes you can connect directly to the CoreOS website to download the zip directly onto the ESXi host.

There are three variables that you will need to edit prior to running the script:

• DATASTORE_PATH - The full path to the Datastore to deploy CoreOS onto (e.g. /vmfs/volumes/datastore)
• VM_NETWORK - The name of the vSphere Network to connect the CoreOS VM to
  
• VM_NAME - The name of the CoreOS VM

Once you have finished editing the script, you just need to scp to your ESXi host and run the script using the following command:

./deploy_coreos_on_esxi.sh

Here is screenshot of running the script:

Once the script has completed, you should see a new CoreOS VM on your ESXi host and if you have DHCP, you should also see an associated IP Address in the VM Console:

Once the CoreOS VM is booted up, you use the SSH key that was included in the zip file, by default it is also extracted into the CoreOS VM directory. You can SSH into the VM by running the following command:

ssh -i insecure_ssh_key core@IP-ADDRESS-OF-COREOS-VM

Once logged in, we can run "docker images" to see a list of Containers. As you can see that there is only one and we can connect to that Container by running the "toolbox" command which will pull down the latest and then connect to that Container as seen in the screenshot below.

I was hoping that I could also get VMware Tools installed within the CoreOS VM, but I was not able to get SSH working within the Toolbox as stated in the Install Debugging Tools documentation. I may need to tinker around a bit more with CoreOS.

If you are interested in other methods of deploying CoreOS, be sure to check out CoreOS's documentation.

Additional Resources:

• http://www.vreference.com/2014/06/09/deploy-coreos-into-your-esxi-lab/ - This was a great primer on CoreOS by Forbes Guthrie that I really enjoyed reading, highly recommend
• http://gosddc.com/articles/dock-your-container-on-vmware-with-vagrant-and-docker/ - If you use Vagrant and would like to play with Docker, be sure to check out Fabio Rapposelli Vagrant vCloud Provider