To configure VM Virtlet is using cloud-init. As always you can check Virtlet documentation to see exactly how Virtlet uses it.
Cloud-init data is passed to the VM using Pod's annotations.
The most common use case is to pass SSH public key to the VM:
VirtletSSHKeys: |
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCaJEcFDXEK2ZbX0ZLS1EIYFZRbDAcRfuVjpstSc0De8+sV1aiu+dePxdkuDRwqFtCyk6dEZkssjOkBXtri00MECLkir6FcH3kKOJtbJ6vy3uaJc9w1ERo+wyl6SkAh/+JTJkp7QRXj8oylW5E20LsbnA/dIwWzAF51PPwF7A7FtNg9DnwPqMkxFo1Th/buOMKbP5ZA1mmNNtmzbMpMfJATvVyiv3ccsSJKOiyQr6UG+j7sc/7jMVz5Xk34Vd0l8GwcB0334MchHckmqDB142h/NCWTr8oLakDNvkfC1YneAfAO41hDkUbxPtVBG5M/o7P4fxoqiHEX+ZLfRxDtHB53 me@localhost
or it can be pulled from Secret:
VirtletSSHKeySource: secret/mysecret
It's also possible to create a new user by defining user data:
VirtletCloudInitUserData: |
ssh_pwauth: True
users:
- name: testuser
gecos: User
primary-group: testuser
groups: users
lock_passwd: false
shell: /bin/bash
# the password is "testuser"
passwd: "$6$rounds=4096$wPs4Hz4tfs$a8ssMnlvH.3GX88yxXKF2cKMlVULsnydoOKgkuStTErTq2dzKZiIx9R/pPWWh5JLxzoZEx7lsSX5T2jW5WISi1"
sudo: ALL=(ALL) NOPASSWD:ALL
ssh-authorized-keys:
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCaJEcFDXEK2ZbX0ZLS1EIYFZRbDAcRfuVjpstSc0De8+sV1aiu+dePxdkuDRwqFtCyk6dEZkssjOkBXtri00MECLkir6FcH3kKOJtbJ6vy3uaJc9w1ERo+wyl6SkAh/+JTJkp7QRXj8oylW5E20LsbnA/dIwWzAF51PPwF7A7FtNg9DnwPqMkxFo1Th/buOMKbP5ZA1mmNNtmzbMpMfJATvVyiv3ccsSJKOiyQr6UG+j7sc/7jMVz5Xk34Vd0l8GwcB0334MchHckmqDB142h/NCWTr8oLakDNvkfC1YneAfAO41hDkUbxPtVBG5M/o7P4fxoqiHEX+ZLfRxDtHB53 me@localhost
It's also possible to use ConfigMap as a source for user data:
VirtletCloudInitUserDataSource: configmap/vm-user-data
When you are passing Environment variables to a Pod then Virtlet uses cloud-init to pass it to a Vm and store in a /etc/cloud/environment
file.
When you are using ConfigMap or Secret in a Pod then they are passed to a VM using cloud-init by creating new files there. Pod's volumes are also converted to mounts
and mounted in VM using cloud-init.
See virtlet/examples/k8s.yaml
where VirtletCloudInitUserData
is used to do some advanced scripting there.