Custom Ubuntu OVAs

Customizing Imported Ubuntu OVAs

There may be a need to make specific configuration changes on the imported ova template before using it to create/update EKS-A clusters.

Set up SSH Access for Imported OVA

SSH user and key need to be configured in order to allow SSH login to the VM template

Clone template to VM

Create an environment variable to hold the name of modified VM/template

export VM=<vm-name>

Clone the imported OVA template to create VM

govc vm.clone -on=false -vm=<full-path-to-imported-template> - folder=<full-path-to-folder-that-will-contain-the-VM> -ds=<datastore> $VM

Configure VM with cloud-init and the VMX GuestInfo datasource

Create a metadata.yaml file

instance-id: cloud-vm
local-hostname: cloud-vm
  version: 2
        name: ens*
      dhcp4: yes

Create a userdata.yaml file


  - default
  - name: <username>
    primary_group: <username>
    groups: sudo, wheel
    ssh_import_id: None
    lock_passwd: true
    - <user's ssh public key>

Export environment variable containing the cloud-init metadata and userdata

export METADATA=$(gzip -c9 <metadata.yaml | { base64 -w0 2>/dev/null || base64; }) \
       USERDATA=$(gzip -c9 <userdata.yaml | { base64 -w0 2>/dev/null || base64; })

Assign metadata and userdata to VM’s guestinfo

govc vm.change -vm "${VM}" \
  -e guestinfo.metadata="${METADATA}" \
  -e guestinfo.metadata.encoding="gzip+base64" \
  -e guestinfo.userdata="${USERDATA}" \
  -e guestinfo.userdata.encoding="gzip+base64"

Power the VM on

govc vm.power -on “$VM”

Customize the VM

Once the VM is powered on and fetches an IP address, ssh into the VM using your private key corresponding to the public key specified in userdata.yaml

ssh -i <private-key-file> username@<VM-IP>

At this point, you can make the desired configuration changes on the VM. The following sections describe some of the things you may want to do:

Add a Certificate Authority

Copy your CA certificate under /usr/local/share/ca-certificates and run sudo update-ca-certificates which will place the certificate under the /etc/ssl/certs directory.

Add Authentication Credentials for a Private Registry

If /etc/containerd/config.toml is not present initially, the default configuration can be generated by running the containerd config default > /etc/containerd/config.toml command. To configure a credential for a specific registry, create/modify the /etc/containerd/config.toml as follows:

# explicitly use v2 config format
version = 2

# The registry host has to be a domain name or IP. Port number is also
# needed if the default HTTPS or HTTP port is not used.
  username = ""
  password = ""
  auth = ""
  identitytoken = ""
 # The registry host has to be a domain name or IP. Port number is also
 # needed if the default HTTPS or HTTP port is not used.
  username = ""
  password = ""
  auth = ""
  identitytoken = ""

Restart containerd service with the sudo systemctl restart containerd command.

Convert VM to a Template

After you have customized the VM, you need to convert it to a template.

Cleanup the machine and power off the VM

This step is needed because of a known issue in Ubuntu which results in the clone VMs getting the same DHCP IP

sudo su
echo -n > /etc/machine-id
rm /var/lib/dbus/machine-id
ln -s /etc/machine-id /var/lib/dbus/machine-id
cloud-init clean -l --machine-id

Delete the hostname from file


Delete the networking config file

rm -rf /etc/netplan/50-cloud-init.yaml

Edit the cloud init config to turn preserve_hostname to false

vi /etc/cloud/cloud.cfg

Power the VM down

govc vm.power -off "$VM"

Take a snapshot of the VM

It is recommended to take a snapshot of the VM as it reduces the provisioning time for the machines and makes cluster creation faster.

If you do snapshot the VM, you will not be able to customize the disk size of your cluster VMs. If you prefer not to take a snapshot, skip this step.

govc snapshot.create -vm "$VM" root

Convert VM to template

govc vm.markastemplate $VM

Tag the template appropriately as described here

Use this customized template to create/upgrade EKS Anywhere clusters