305-300 VM Deployment And Provisioning Practice Test 2 — 15 Questions

Question 1

You are using Packer to build an AWS AMI. The build uses the 'amazon-ebs' builder and a 'file' provisioner to upload a configuration file to '/etc/myapp/config.yml'. The provisioner runs successfully, but the file is missing in the resulting AMI. What is the most likely reason?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

The file was uploaded after the AMI snapshot was taken.. In Packer, provisioners run in the order they are defined, and the AMI snapshot is taken after all provisioners complete. If the file is missing, it suggests the provisioner did not run before the snapshot, perhaps due to misplacement in the build configuration or an error that was not surfaced. The 'file' provisioner uploads directly to the destination, so if it ran successfully, the file should be present. The most plausible cause is that the snapshot occurred before the provisioner, which can happen if the provisioner is defined in a separate build block or if the build is customized.

Answer

The 'file' provisioner requires the 'destination' directory to exist; it does not create it.

Answer

The file was uploaded to a temporary location and not moved to the final destination.

Answer

The 'file' provisioner does not support uploading to absolute paths.

Question 2

You are using cloud-init to provision a fleet of Ubuntu VMs. You need to ensure that the instance is configured with a static IP address on the primary interface and that the hostname is set to a value derived from the instance's metadata. Which two cloud-init modules or configuration sections should you use? (Choose two.)

Accepted Answer

The network configuration in the 'network' section of the cloud-init configuration, using the 'config' key to define a static IP.. To set a static IP, the network section with the config key is the correct cloud-init mechanism. For hostname derived from metadata, the top-level hostname key supports templating from instance metadata. These two together satisfy the requirements. Other options either use non-existent modules, indirect methods, or modules not designed for this purpose.

Answer

The 'set_hostname' module, which reads the hostname from instance metadata and applies it.

Answer

The 'runcmd' module, with a command that reads metadata and runs hostnamectl set-hostname.

Answer

The 'write_files' module, using a file that contains the desired hostname and a script to apply it.

Question 3

You are writing a Packer template that uses the amazon-ebs builder. You need to ensure that the temporary instance launched during the build is terminated even if provisioning fails. Which Packer configuration option should you set?

Accepted Answer

Set "skip_cleanup": false and ensure the build is not interrupted by a signal that prevents cleanup.. The amazon-ebs builder automatically terminates the temporary instance after the build, including on provisioning failure, unless skip_cleanup is set to true. To ensure termination, set skip_cleanup to false (the default). Additionally, be aware that external interruptions can bypass cleanup, so proper signal handling is important. Other options either do not exist or control different aspects like AMI deregistration.

Answer

Set "force_deregister": true in the builder configuration.

Answer

Set "terminate_instance": true in the builder configuration.

Answer

Set "skip_cleanup": false in the builder configuration.

Question 4

In a Packer build process for OpenStack, which 'post-processor' type is typically used to upload the resulting image to the Glance image service?

Accepted Answer

openstack. Packer's `openstack` post-processor takes the artifact produced by the builder (typically a qcow2 or raw image) and uploads it to the OpenStack Glance image service, registering it as a bootable image. It handles authentication against Keystone and can set image metadata such as name, visibility, and tags. This makes it the standard way to publish a Packer-built image into an OpenStack cloud.

Answer

manifest

Answer

shell-local

Answer

compress

Question 5

When using Vagrant to manage a libvirt-based provider, which command verifies that the virtual machine is currently running and identifies the provider in use?

Accepted Answer

vagrant status. The vagrant status command reports the current state of each machine defined in the Vagrantfile (running, poweroff, not created, etc.) and shows the provider in use (e.g., libvirt, virtualbox). It is the canonical way to verify that a VM is up and which provider is backing it.

Answer

vagrant up

Answer

vagrant validate

Answer

vagrant box list

Question 6

You are configuring cloud-init to inject an SSH key into a new VM. Which directive in the configuration metadata ensures the key is added to the correct user's authorized_keys file?

Accepted Answer

ssh_authorized_keys. In cloud-init user-data, the ssh_authorized_keys directive is a per-user key that specifies which SSH public keys should be written to that user's ~/.ssh/authorized_keys file. It is nested under the users list entry for the target user, ensuring the key lands in the correct account's authorized_keys rather than being applied globally.

Answer

users.ssh_key

Answer

ssh_keys

Answer

authorized_keys_file

Question 7

Which file in a Vagrant project directory is processed by default to define the virtual environment configuration?

Accepted Answer

Vagrantfile. Vagrant automatically reads a file named 'Vagrantfile' in the project directory to determine the configuration of the virtual environment, including the box to use, network settings, provisioning scripts, and provider configuration. This file is written in Ruby DSL syntax and is the single source of truth for a Vagrant project. Without a Vagrantfile, the 'vagrant up' command cannot determine what VM to create.

Answer

settings.json

Answer

provision.sh

Answer

config.yml

Question 8

When defining a Vagrant network configuration for a libvirt provider, which mode allows the VM to receive an IP address directly from the physical network's DHCP server?

Accepted Answer

public_network. In Vagrant with the libvirt provider, the 'public_network' mode bridges the VM's network interface to a physical network, allowing it to obtain an IP address from the physical network's DHCP server. This makes the VM appear as a separate device on the LAN.

Answer

nat

Answer

forwarded_port

Answer

private_network

Question 9

A cloud-init configuration file is failing to apply the 'write_files' module. Which log file on the target instance should you examine to diagnose the parsing error?

Accepted Answer

/var/log/cloud-init.log. The /var/log/cloud-init.log file is the primary log for cloud-init and records all stages of the cloud-init process, including the parsing and execution of modules like write_files. When a configuration file fails to apply, cloud-init logs detailed error messages, such as syntax errors or invalid YAML, in this file. Therefore, examining /var/log/cloud-init.log is the correct way to diagnose parsing errors.

Answer

/var/log/syslog

Answer

/var/log/messages

Answer

/var/log/auth.log

Question 10

What is the primary function of the cloud-init 'runcmd' module?

Accepted Answer

Running arbitrary shell commands. The cloud-init `runcmd` module executes arbitrary shell commands on the instance during the final stage of boot, after other configuration modules have run. It is commonly used to run scripts, start services, or perform custom setup that is not covered by declarative modules. Because it runs late in the boot sequence, it can rely on packages and files configured by earlier modules.

Answer

Setting the system locale

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Configuring users

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Installing software packages

Question 11

When provisioning with Vagrant, which command is best used to apply changes to a configuration (like adding a new shell script) without destroying the existing virtual machine?

Accepted Answer

vagrant provision. The `vagrant provision` command is specifically designed to run provisioners (such as shell scripts, Ansible, Puppet, etc.) on a running Vagrant-managed VM without destroying or recreating it. When you modify a provisioning script or add a new one, `vagrant provision` applies those changes to the existing machine, ensuring the VM's state is updated according to the new configuration. This is the correct approach because it preserves the VM's current state while enforcing the updated provisioning logic.

Answer

vagrant halt

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vagrant reload

Answer

vagrant up

Question 12

You need to ensure that a specific package is installed during the first boot of a cloud instance. Which cloud-init key should be added to the configuration?

Accepted Answer

packages. The cloud-init configuration key `packages` is the standard directive for specifying a list of packages to install during instance initialization. It is processed by the `package-update-upgrade-install` module, which runs early in the boot sequence, ensuring the packages are present before other configuration steps. This key works across distributions by using the native package manager (apt, yum, dnf, etc.) to install the listed packages.

Answer

yum_install

Answer

software

Answer

install_packages

Question 13

Which Packer builder is most appropriate for creating an image specifically for Amazon Web Services (AWS)?

Accepted Answer

amazon-ebs. The amazon-ebs builder is Packer's native AWS builder that launches a temporary EC2 instance, provisions it, creates an EBS-backed AMI, and terminates the instance. It is the standard and most appropriate choice for producing AWS AMIs directly. The other builders target different platforms or artifact formats.

Answer

virtualbox-iso

Answer

qemu

Answer

docker

Question 14

In a Vagrantfile, which method is used to pass environment variables into the guest virtual machine during the provisioning phase?

Accepted Answer

config.vm.provision "shell", env: { "VAR" => "value" }. In a Vagrantfile, environment variables are passed to a shell provisioner using the `env` option on the provisioner block: `config.vm.provision "shell", env: { "VAR" => "value" }`. This injects the variables into the environment of the provisioning script running inside the guest. It is the documented, supported way to make host-side values available to guest provisioning.

Answer

config.env.set

Answer

config.vm.env

Answer

vagrant.env.set

Question 15

In cloud-init, which syntax is required at the very beginning of the configuration file to ensure it is recognized as a cloud-config script?

Accepted Answer

#cloud-config. Cloud-init identifies a cloud-config file by the literal header #cloud-config on the very first line. Without this exact shebang-style marker, cloud-init treats the payload as a different user-data format (e.g., shell script or MIME multipart) and will not process the YAML directives.

Answer

#!/bin/bash

Answer

#cloud-init

Answer

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