Vultr mainly offers a set of default operating systems such as CentOS, Ubuntu, etc.

But, you want a custom operating system. Is it possible?

Fortunately, there are options to build your custom operating system using Vultr custom ISO images. This helps server owners create instances of their own choice.

At Bobcares we help server owners setup Vultr instance from custom ISO as part of our Managed Cloud Services.

Today, we’ll discuss how we setup Vultr instance from the custom ISO and fix the common errors.

How to setup Vultr instance from custom ISO?

One of the Vultr features is that it provides an ISO library which includes custom ISOs of popular Linux and BSD distros. So, custom ISO users can use these available ISOs during server setup.

Server owners can access the ISO library from Servers > Deploy New server(+ symbol) > Server Type > ISO Library.

How to access Vultr ISO Library?

But, what if you need an ISO not in the ISO Library?

Don’t worry, our Support Engineers help server owners upload their custom ISO and setup new server using this custom ISO. Let’s see these steps in detail.

1) Upload custom ISO

Server owners can upload custom ISO images from their Vultr account control panel. We usually upload custom ISO images from Servers > Upload ISO > My ISOs > Give the Upload URL > Upload.

How to add custom ISO in Vultr?

However, Vultr accepts only custom ISOs that meet the below requirements. Otherwise, it fails.

• The custom ISO file should end in the .iso extension.
• For windows servers, the ISO must include VirtIO Drivers. VirtIO is a virtualization standard for network and device disk drivers.
• The size limit of the custom ISO should be 512 MB.
• The custom ISO’s download URL should be an absolute path.
• The ISO should be uploaded via Dropbox, Amazon S3, a web server running on an existing Vultr instance, Google Cloud storage(not Google drive).

2) Build the new instance using custom ISO

Now, our Support Experts build the new Vultr instance using this custom ISO. We use the below steps to deploy a new server.

• Go to Vultr account control panel.
• Click on Servers > Deploy new server > Select the Server Location.
• Go to Server Type  > Upload ISO > My ISOs.
• Make sure the custom ISO is selected.
• Now, choose the Server size, hostname etc.
• Click on Deploy now.

It takes a couple of minutes for the ISO to get mounted. Once this is done, our Support Experts access the server via Console(small computer screen) and do the rest of the server setup like user creation, privacy settings, network configuration, etc.

Vultr Console

3) Remove the custom ISO

A common mistake that can occur is that server owners forget to detach the ISO after installing the custom operating system. As a result, the system will continue to boot from the ISO with every server reboot. So after setting up the server, the ISO must be removed.

Our Support Experts remove the custom ISO from Servers > Click on the Vultr instance hostname > Settings > Custom ISO > Remove ISO.

Vultr customer ISO – Common failure points

Now, let’s see the common errors that can occur when creating a Vultr instance from custom ISO.

1) Problems with Network interface

We’ve seen instances where the new VPS Vultr instance has been successfully created from the custom ISO. But, it failed to make outgoing or incoming connections. In this case, our Support Engineers checked the server configuration and found that the server had wrongly configured the network interface after reboot.

Further, we use the ifconfig command to check the network interface. If we notice any problems, we’ll fix the network interface configuration. In addition to that, we make necessary changes in the network configuration file to automatically configure the interface.

2) Server stuck in installer boot menu during startup

Similarly, another common problem that we see is that the new Vultr instance got stuck in the installer Boot menu during startup. When our Support Engineers checked, we found that the customer forgot to detach the custom ISO after installing the operating system. As a result, the system always tries to boot from this custom ISO and create problems.

In such cases, we remove the attached custom ISO from Servers > Click on the Vultr instance hostname > Settings > Custom ISO > Remove ISO. After that, we reboot the server once again to fix the issue.

3) Unable to attach ISO image

Sometimes, users complain that when trying to attach an ISO image to the Vultr instance they get an error like ISO file is invalid. The actual error looks like this:

error: Unexpected exit code: 255

Here, the customer was providing the wrong download link when uploading the custom ISO. Vultr only accepts absolute path of the ISO download link. Also, the file name should end with .iso. This was creating problems in this case.

Our Support Experts provided the correct ISO path to fix this issue.

Conclusion

In short, it’s quite easy to setup a Vultr instance from custom ISO. Today, we’ve discussed how our Support Engineers build a new Vultr instance from custom ISO and fix the common errors that can occur during this process.