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How to create a custom ESXi VIB to execute a script once?

07.16.2015 by William Lam // 16 Comments

Earlier this week I received a question from a customer who was interested in creating a custom ESXi VIB that could execute a specific script within the payload as part of the installation and only running it once. This was a fairly common request that I have seen in the past and as far as I knew, this type of behavior was not possible. What was unique about this particular custom inquiry was that they mentioned they found some references on this being possible. Being the curious person I am, I decided to take another look and reach out to a few folks in Engineering.

After speaking with one of the Engineers familiar with our VIB specification, to my surprise I learned that this type of behavior was actually indeed possible but was not very well documented externally. The typical use case for this is usually to apply certain configurations which are not exposed through the traditional ESXi interfaces like the vSphere API/CLI which includes Host Profiles. One example that comes to mind is being able to deploy a VIB across several hundred ESXi hosts that could configure a specific ESXi Advanced Setting which might be marked hidden. Another example would be updating a configuration file like /etc/vmware/config or running a series of ESXi Shell commands which can not available in the vSphere API and require the use of SSH and the ESXi Shell. There are many other examples, but this should give you an idea of some of the common use cases that I have heard from customers.

Here is what is required to execute a specific script as part of the VIB installation:

  • Created an "init" script which needs to be stored under /etc/init.d as part of your VIB payload (e.g. /etc/init.d/lamw-special-vib)
  • You must ensure that the "live-install-allowed" param is set to true in your VIB's descriptor.xml file (this assumes the changes can be applied without requiring reboot to take affect)
  • The init script will need to parse special keywords passed as command-line arguments

Here is a table showing the pair of special keywords that are passed to the init script as command-line arguments during a VIB install, upgrade or remove:

Arg1 Arg2 VIB Operation
start install VIB install
start upgrade VIB upgrade
stop remove VIB removal

It is up to creator of the init script to handle the different VIB operations by parsing the command-line arguments which would then determine the operations that would get executed within the script. This not only allows you to control the commands that are executed during an installation of a VIB but it also allows you specify the commands to run upon the removal of a VIB which is quite handy for properly cleaning up an uninstall. In addition, since these special keywords are not passed as part of the ESXi boot up process, the commands within the script will not execute and ensures it only runs once during the install.

Here is very simple shell script (you could also do this in Python as well) which demonstrates how to handle the three different types of VIB operations and then uses the "logger" utility to write some output to syslog:

#!/bin/sh

ARG1=$1
ARG2=$2

if [[ "${ARG1}" == "start" ]] && [[ "${ARG2}" == "install" ]]; then
 # commands to run go here #
 /bin/logger "William's custom script ran on start-install"
elif [[ "${ARG1}" == "start" ]] && [[ "${ARG2}" == "upgrade" ]]; then
 /bin/logger "William's custom script ran on start-upgrade"
 # commands to run go here #
elif [[ "${ARG1}" == "stop" ]] && [[ "${ARG2}" == "remove" ]]; then
 /bin/logger "William's custom script ran on stop-remove"
 # commands to run go here #
fi

As you can see, this allows you to perform a variety of tasks through the use of a custom ESXi VIB which is a great way to be able to roll out a set of changes that may not be possible using either the vSphere API or Host Profiles for example. Best of all, this solution does not require the use of SSH which is great since many customers already disable this by default.

For more information on creating a custom VIB, be sure to check out my blog post here and you can even use this Docker image I created for building custom ESXi VIBs.

Categories // Automation, ESXi Tags // ESXi, host profile, vib, vib author

ghettoVCB VIB & offline bundle for ESXi

05.28.2015 by William Lam // 63 Comments

It is still amazing to see that the number of contributions and suggestions from the community continues to grow for my free and simple VM backup solution called ghettoVCB. I created ghettoVCB almost 8 years ago which now has over 1.2 million views, pretty insane if you ask me! Although I am quite busy these days which includes a new born, I still try to find time to update the script as time permits. A couple of weeks back I received an email from one of my readers who came across ghettoVCB and was quite happy with the free solution. He also had some feedback asking why I did not provide an installable VIB for ghettoVCB?

A totally valid question and the answer was quite simple. When I had first created ghettoVCB back in the classic ESX 3.x days, the concept of a VIB had not existed yet. With the release of ESXi 5.0, the idea of the VIB was introduced but it was only recently in 2012 did VMware publish a method for customers to create custom VIBs for ESXi using the VIB Author Fling. I do have to admit at one point I did think about providing a VIB for ghettoVCB, but I guess I never went through with it for whatever reason. Looking back now, this was a no-brainer to provide a simplified user experience and not to mention the benefit of having ghettoVCB installed as a VIB is that it will automatically persist on ESXi after reboots which was a challenge for new users to ESXI.

So without further ado, here is ghettoVCB provided in either a VIB or offline bundle form:

  • vghetto-ghettoVCB.vib
  • vghetto-ghettoVCB-offline-bundle.zip

To install the ghettoVCB VIB, you just need to download the VIB and run the following ESXCLI command and specifying the full path to the VIB:

esxcli software vib install -v /vghetto-ghettoVCB.vib -f

Once installed, you will find all ghettoVCB configuration files located in:

/etc/ghettovcb/ghettoVCB.conf
/etc/ghettovcb/ghettoVCB-restore_vm_restore_configuration_template
/etc/ghettovcb/ghettoVCB-vm_backup_configuration_template

Both ghettoVCB and ghettoVCB-restore scripts are located in:

/opt/ghettovcb/bin/ghettoVCB.sh
/opt/ghettovcb/bin/ghettoVCB-restore.sh

One additional thing I would like to point out is that you can also quickly tell which version of ghettoVCB is running by inspecting the installed VIB by using the following ESXCLI command:

esxcli software vib get -n ghettoVCB

If you look at the screenshot above, I have highlighted two important pieces of information in green. The first is the "Description" property which includes the Github commit hash of the particular revision of ghettoVCB and the "Creation Date" property which contains the date of that commit. This can be handy if you want to compare it to the latest ghettoVCB repository found on Github here. Thanks again Markus for the suggestion!

For those of you who are interested in the details for creating your own ghettoVCB VIB, the next section is specifically for you. Earlier this week I blogged about a Docker Container that I have created to help build custom ESXi VIBs and as you can see now, that was the basis for us to be able to quickly create ghettoVCB VIB based on the latest revision of the script.

Step 1 - Create a new Docker Machine following the steps outlined here.

Step 2 - Login to the Docker Machine and create a new Dockerfile which contains the following:

FROM lamw/vibauthor

# Due to https://stackoverflow.com/a/49026601
RUN rpm --rebuilddb
RUN yum clean all
RUN yum update -y nss curl libcurl;yum clean all

# Download ghettoVCB VIB build script
RUN curl -O https://raw.githubusercontent.com/lamw/vghetto-scripts/master/shell/create_ghettoVCB_vib.sh && chmod +x create_ghettoVCB_vib.sh

# Run ghettoVCB VIB build script
RUN /root/create_ghettoVCB_vib.sh

CMD ["/bin/bash"]

Step 3 -  Next we need to build our new Docker Container which will use the VIB Author Container by running the following command:

docker build -t lamw/ghettovcb .

Screen Shot 2015-05-26 at 2.14.52 PMThe output will be quite verbose, but what you will be looking for is text highlighted in green as shown in the screenshot above. You should see the successful build of both the VIB and offline bundle as well as Docker Container showing a successful build.

Step 4 - After a successful build of our Docker Container, we can now launch the container by running the following command:

docker run --rm -it lamw/ghettovcb

Screen Shot 2015-05-26 at 2.16.58 PM
Once logged into the Docker Container, you will see the generated VIB and the offline bundle for ghettoVCB as shown in the screenshot above.

If you wish to copy the VIB and offline bundle out of the Docker Container into the Docker Host, you can use Docker Volumes. I found this useful thread over on Stack overflow which I have modified to include the copying of the ghettoVCB VIB and offline bundle out to Docker Host by running the following command:

docker run -i -v ${PWD}/artifacts:/artifacts lamw/ghettovcb sh << COMMANDS
cp vghetto-ghettoVCB* /artifacts
COMMANDS

Finally, to copy the ghettoVCB VIB from the Docker Host to your desktop, we first need to identify the IP Address given to our Docker Machine by running the following command:

docker-machine ip osxdock

Currently, Docker Machine does not include a simple "scp" command so we will need to use regular scp command and specify the private SSH keys which you can find by running "docker-machine inspect [NAME-OF-DOCKER-HOST]" and connecting to our Docker Host to copy the ghettoVCB VIB by running the following command:

scp -i /Users/lamw/.docker/machine/machines/osxdock/id_rsa [email protected]:artifacts/vghetto-ghettoVCB.vib .

Categories // Automation, Docker, ESXi, Fusion Tags // container, Docker, docker-machine, ESXi, ghettoVCB, ghettovcb-restore, vib, vib author

A Docker Container for building custom ESXi VIBs

05.26.2015 by William Lam // 16 Comments

I recently had a need to create a custom ESXi VIB using the VIB Author Fling for a project that I was working on. As part of the project's deliverables, I wanted to also provide an ESXi VIB which would need to be built against any new updates for the project. Given this would be an infrequent operation, I thought why not use a Docker Container for this operation? I could just spin up a Docker Container on-demand and not have to worry about managing a local VM for just running this particular task.

With that I have created a VIB Author Docker Container which can be used to author custom ESXi VIBs. I have also made this container available on the Docker Registry for others to use which you can find more details here: https://registry.hub.docker.com/u/lamw/vibauthor/

If you already have a Docker host running, you can pull down the VIB Author Docker Container by jumping to Step 5 in the instructions below. If you do not and you are running Mac OS X like I am, you can follow the instructions below using Docker Machine and VMware Fusion to try out my VIB Author Docker Container.

Step 1 - Install the Docker client by running the following command:

brew install docker

Step 2 - Download and install Docker Machine by running the following commands:

curl -L https://github.com/docker/machine/releases/download/v0.2.0/docker-machine_darwin-amd64 > /usr/local/bin/docker-machine
chmod +x /usr/local/bin/docker-machine

Step 3 - Create Docker Machine using the VMware Fusion driver by running the following command:

docker-machine create --driver vmwarefusion osxdock --vmwarefusion-memory-size 1024
eval "$(docker-machine env osxdock)"

docker-container-vib-author-esxi-vib-0
Note: Thanks to Omer Kushmaro for his blog post here on how to quickly get started with Docker Machine with VMware Fusion

Step 4 - Once the Docker Machine is booted up, we can now connect to it using SSH by running the following command:

docker-machine ssh osxdock

docker-container-vib-author-esxi-vib-3
At this point, we are now logged into our Docker Machine which has both the Docker client/server running and we are now ready to pull down the VIB Author container from the Docker registry.

Step 5 - To pull down the VIB Author Docker Container that I have built, run the following command within the Docker Machine:

docker pull lamw/vibauthor

docker-container-vib-author-esxi-vib-1
Step 6 - Once the Docker Container has been successfully downloaded, you can now run the VIB Author Container by running the following command:

docker run --rm -it lamw/vibauthor

docker-container-vib-author-esxi-vib-2
Once logged into the VIB Author Container, you confirm that the VIB Author Fling has been installed by running the "vibauthor" command as shown in the screenshot above. In the next blog post, I will go through an example of building a custom ESXi VIB using the VIB Author Container as well as transferring the outputted files from the Docker host back onto your desktop. Stay tuned!

Categories // Apple, Docker, ESXi, Fusion Tags // container, Docker, docker-machine, ESXi, vib, vib author

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William is Distinguished Platform Engineering Architect in the VMware Cloud Foundation (VCF) Division at Broadcom. His primary focus is helping customers and partners build, run and operate a modern Private Cloud using the VMware Cloud Foundation (VCF) platform.

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