13. Cloud and Virtualization
Linux Bridge Modes
A Linux bridge can operate is several modes
Multi-homed
A computer or virtual machine that has more than one NIC and more than one IP address.
Container
A consistent runtime environment that houses software applications.
13.3.3 Virtual Networking Facts
A hypervisor presents a virtual hardware environment that's used by a virtual machine. Part of that environment is a virtual network. This lesson covers the following topics: Virtual switches Linux bridge modes Multi-homed considerations Overlay networks
Virtual switch
A logical network switch built into a hypervisor.
Non-persistent disk volume
A method for discarding changes to a VM disk volume so that it reverts to a known state when a VM shuts down.
Persistent disk volume
A method for preserving the changes to a VM disk volume between VM reboots.
Container template
A set of files that make up a container that can be copied to create a new container.
Virtual machine (VM) template
A set of files that make up a virtual machine that can be copied to create a new virtual machine.
There are two types of hypervisors, Type 1 and Type 2. Which of the following describes those two types? (Choose TWO.) A type 1 hypervisor runs on bare metal hardware and is referred to as a native hypervisor. A type 1 hypervisor is a software application that runs on top of a conventional operating system. A type 2 hypervisor is an operating system that runs the hypervisor as a dedicated system. A type 2 hypervisor runs on an operating system.
A type 1 hypervisor runs on bare metal hardware and is referred to as a native hypervisor. A type 2 hypervisor runs on an operating system. A Type 1 hypervisor runs on bare metal hardware and is referred to as a native hypervisor. Microsoft Hyper-V and VMware ESX are examples of a Type 1 hypervisor. A Type 2 hypervisor runs on an operating system such as Windows, MacOS, or Linux. VMware Workstation, Oracle VM VirtualBox, Parallels Desktop for Mac, and open source QEMU are examples of Type 2 hypervisors.
Full virtualizaiton
A type of virtualization that presents a full set of virtualized hardware.
Paravirtualization
A type of virtualization where the guest operating system communicates directly with the host's physical hardware.
Hardware-assisted virtualization
A type of virtualization where the hosts hardware handles some of the virtualization that the hypervisor normally performs.
Overlay network
A virtual network built on top of an existing network.
Linux bridge
A virtual switch in a Linux hypervisor.
Lynda, a network administrator, has been tasked with connecting the VMs on multiple virtual machine hosts in a way that doesn't expose the VMs to the external network. Which of the following should you implement? A virtual network switch A Linux bridge Multi-homed virtual NICs An overlay network
An overlay network Overlay networks can be used to connect VMs on different host machines in a way that doesn't expose them to the external network. A Linux bridge is a virtual switch. It behaves like a network switch. It offers additional features, such as NAT. A virtual network switch works just like a physical network switch. Virtual machines can also be configured as a multi-homed system with multiple virtual NICs.
Anaconda and Kickstart
Anaconda is an installation program that's used by Fedora, Red Hat Enterprise Linux, and other distributions. > Anaconda identifies the computer's hardware, creates a file system, and provides a user interface that guides the installation process. > Anaconda installations can be scripted with kickstart for unattended installations. Using kickstart, a Linux administrator creates a single file containing the answers to all the questions that would be asked during a typical installation. This file can be kept on a server and read by individual computers during the Linux installation.
13.1.4 Linux Cloud and Virtualization Facts
As a Linux administrator, you should be able to describe cloud and virtualization concepts and compare different cloud and virtualization technologies. This lesson covers the following topics: Virtualization and hypervisors Types of virtualization Container virtualization Comparison of containers and virtual machines Cloud service categories
13.1 Cloud and Virtualization Overview
As you study this section, answer the following questions: In IT, what is a cloud? What are clouds made of? What is virtualization? What is a hypervisor? What is the difference between Type 1 and Type 2 hypervisors? What are the three types of virtualization? What is a virtual machine? What is a container? What services are available in the cloud? What is the difference between block and blob storage? In this lesson, you will learn to: Install a hypervisor. Key terms for this section include the following:
13.2 Virtual Machines
As you study this section, answer the following questions: What is a virtual machine template? What types of templates are used for virtual machine? What is bootstrapping? How is Cloud-init used in bootstrapping? How are Anaconda and Kickstart used in bootstrapping? What is the difference between thick and thin virtual disk provisioning? In this lesson, you will learn to: Create a virtual machine. Key terms for this section include the following:
13.3 Virtual Networking
As you study this section, answer the following questions: What is a virtual switch? What is a Linux bridge? What modes are available on a Linux bridge? What is a multi-homed virtual machine? What is an overlay network? In this lesson, you will learn to: Configure networking on a virtual machine. Key terms for this section include the following:
Which of the following types of cloud storage is managed from a dashboard or webpage? Libraries Container Blob Block
Blob Blob is short for binary large object. Blobs can be any type of data, like documents, video, audio, or backup data. You don't store and retrieve blob data the same way you would on a network drive. Instead, blob storage is managed from a dashboard or webpage. As you upload files, each file or blob is given a URL that's used to access or download the blob. This is especially useful because that URL can be used as a link in other websites. Block storage is like traditional drive space. Container and libraries are not cloud storage types.
Which of the following cloud storage types is accessed through network drives or as a cloud computing resource? Block Blob Full virtualization Paravirtualization
Block Cloud providers offer two types of cloud storage, block storage and blob storage. Block storage is like traditional drive space. It might be offered like a network drive or as a drive that's accessed by a cloud computing resource. Block storage stores files in directories in the same fashion as any other local file system. Full virtualization presents a virtual hardware environment, which emulates a physical hardware environment. Paravirtualization improves performance by allowing the guest operating system to communicate directly with some of the host's physical hardware. Blob is short for binary large object. Blobs can be any type of data, like documents, video, audio, or backup data. You don't store and retrieve blob data the same way you would on a network drive. Instead, blob storage is managed from a dashboard or webpage. As you upload files, each file or blob is given a URL that's used to access or download the blob. This is especially useful because that URL can be used as a link in other websites.
13.1.5 Practice Questions
CIST 2431
13.2.5 Practice Questions
CIST 2431
13.3.4 Practice Questions
CIST 2431
Cloud Service Categories
Cloud services are services that are obtained from a location that is not local, that is, in the cloud. The cloud can be defined as the hardware, networks, storage devices, and interfaces that deliver computing as a service. You can divide cloud services into categories.
Cloud-init
Cloud-init is implemented by: > Installing the cloud-init application on a Linux template > Customizing the /etc/cloud/cloud.cfg file. > Clone the template to create a new VM. > Supply metadata (hostname, default locale, SSH host keys, etc.) by mounting a cloud-init optical drive or through a cloud-init interface. Cloud-init is also used by many cloud providers that provide a cloud-init dashboard to create custom Linux machines.
Which of the following is a function of a virtual network switch? Connects the VMs virtual NIC and the host's physical NIC. Reduces local virtual network traffic. Replaces the need for a physical network switch. Provides proxy and packet filtering.
Connects the VMs virtual NIC and the host's physical NIC. A virtual network switch works just like a physical network switch. A software connection is made between the virtual switch and the host's physical NIC. A software connection is made between the virtual switch and the virtual machine's virtual NIC.
Which of the following templates, which use the JSON file format, can be copied and used to create multiple containers, that run the same applications? OVF YAML OVA Container image
Container image A container image can also be saved as a template, which can be copied and used to create multiple containers that run the same applications. The Open Container Initiative, or OCI, has published standards for container images. A popular container engine, Docker, has also published a standard. Both the OCI and Docker standards rely on the JSON file format. OVF and OVA are not used for this purpose. YAML is a superset of JSON, but in this scenario, the template is using the JSON file format.
Comparison of containers and virtual machines
Containers and virtual machines have benefits and shortcomings.
Container Virtualization
Containers are defined as consistent runtime environments. You create containers using special software called a container engine. Each container: - Includes: > Applications > Libraries > Other binaries > Configuration files - Is isolated from other applications running in other containers. - Can be saved and easily ported to other container environments.
Persistent
Disk volumes in persistent mode behave like conventional disk drives. All data that's written to the virtual disk is permanent so that it's available when the virtual machine starts again.
When implementing a network gateway, implementing a firewall, or increasing performance, multiple NICs can be added to a computer. Which of the following can be implemented on VMs to provide this capability? A bridged network Dual-homed NICs An overlay network An switch in isolated mode
Dual-homed NICs Physical computers can have multiple NICs connected to multiple subnets to increase performance, use the computer as a network gateway, or use the computer as a network firewall. Virtual machines can also be configured as a multi-homed system with multiple virtual NICs. Depending on your requirements, you can connect each NIC to a separate virtual switch or connect multiple NICs to a single virtual switch. You can link each physical NIC on the host machine to a different virtual switch, or you could link several physical NICs to one virtual switch.
Full Virtualization
Full virtualization: > Presents a virtual hardware environment, which emulates a physical hardware environment. > Provides the best isolation and security for VMs. > Requires extra time and processing power to provide virtual hardware emulation.
Hardware-Assisted Virtualization
Hardware-assisted virtualization: > Greatly improves a full virtualization environment. > Handle some of the virtualization processing the hypervisor would normally perform.
Virtual Machine Template Formats
Hypervisors from different vendors have different template formats.
You were recently hired by a small start-up company. The company is in a small office and has several remote employees. You have been asked to find a business service that would accommodate the current size of the company but would also be able to scale as the company grows. The service needs to provide adequate storage as well as additional computing power. Which cloud service model should you use? IaaS DaaS PaaS SaaS
IaaS Infrastructure as a Service (IaaS) delivers infrastructure to the client, such as processing, storage, networks, and virtualized environments. The client deploys and runs software without purchasing servers, data center space, or network equipment. Software as a Service (SaaS) delivers software applications to the client either over the internet or on a local area network. Platform as a Service (PaaS) delivers everything a developer needs to build an application onto the cloud infrastructure. The deployment comes without the cost and complexity of buying and managing the underlying hardware and software layers. Data as a Service (DaaS) stores and provides data from a centralized location without requiring local collection and storage.
Thick provisioning
If you choose thick provisioning, the complete amount of storage capacity is pre-allocated on the hypervisor's physical storage device. For example, if the disk size is to be 10 GB, the full 10 GB plus any overhead is set aside for the virtual disk right from the start. This physical disk space will be unavailable for use by any other virtual machine.
Bridged
In bridged mode, all VMs are configured with IP addresses on the same subnet as the host computer. > The virtual switch acts like a physical switch and forwards network frames accordingly. > All physical machines on the same subnet will be aware of the virtual machines.
Isolated
In isolated mode, the VMs only communicate with each other. > The VMs are disconnected from both the external network and from the host computer. > The VMs can only be accessed using the hypervisor's VM console. > Use this mode when testing the performance of a new system with no external distractions.
Routed
In routed mode, the host acts as a gateway. > Use this mode if the virtual machines are located in a firewall's DMZ. > Configure the VMs with IP addresses in a different subnet than the external network.
Cloud and Container Templates
In the same way that a single virtual machine can be used as a template, a cloud environment, including virtual machines, storage, and networking, can be modularized as a template. > A cloud provider can quickly instantiate a set of cloud resources using a template. > Many cloud providers use a JSON file or a YAML file to encapsulate these templates. A container image can also be saved as a template, which can be copied and used to create multiple containers, each running the same applications. > The Open Container Initiative, or OCI, has published standards for container images. > A popular container engine, Docker, has also published a standard. > Both the OCI and Docker standards rely on the JSON file format.
IaaS
Infrastructure as a Service (IaaS) is the delivery of traditional computer hardware as a service. It provides > Client storage - Block storage is like traditional drive space. It might be offered like a network drive or as a drive that's accessed by a cloud computing resource. Block storage stores files in directories in the same fashion as any other local file system. - Blob is short for binary large object. You don't store and retrieve blob data in the same way you would on a network drive. Instead, blob storage is managed from a dashboard or webpage. > Computing Power - You can use computing power from the cloud instead of buying a new server to do a particular job. You rent time from an IaaS cloud service provider instead of purchasing new hardware.
Mary, a system administrator, would like to deploy virtual machines, storage, and networking in a cloud environment. Which of the following file formats would allow Mary to modularized these items as a template? (Select TWO). XSL XML JSON YAML XSD
JSON YAML JSON and YAML are both used by cloud providers to encapsulate virtual machines, storage, and networking into templates. This provides a way to quickly instantiate a set of cloud resources using a template. XML, XSD, and XSL are not used to deploy templates as described.
Which of the following can be used to script Anaconda and provide unattended installations using a single file? Thin provisioning Kickstart Thick provisioning Cloud-init
Kickstart Kickstart provides a way to script an Anaconda installation using a single answer file. A kickstart file is a simple text file that contains keywords arranged in sections. Thick and thin provisioning determine how space is allocated when creating a virtual disk. Cloud-init is different bootstrapping technology that is independent of kickstart.
Virtual Switches
Linux-based hypervisors, such as Xen, KVM, and QEMU, provide a software-based virtual network switch. > A virtual network switch works just like a physical network switch. - A software connection is made between the virtual switch and the host's physical NIC. - A software connection is made between the virtual switch and the virtual machine's virtual NIC > A Linux bridge is a virtual switch - It behaves like a network switch. - It offers additional features, such as NAT. - To implement Linux bridging, install the bridge-utils software package.
Thin provisioning
Many administrators choose to use thin provisioning. A thin provisioned virtual disk consumes only the space that it needs initially, and then grows according to demand. The benefits of thin provisioning are that the disk is provisioned quickly and storage space is saved. However, the down side is that overprovisioning disks - assigning virtual disks more space than is physically available - causes the virtual machine to fail if the physical storage space becomes full. Fortunately, most hypervisors will inform you if a physical disk starts to fill up. *Another virtual disk setting offered by hypervisors is the disk mode that controls what happens when the virtual machine is shut down.
VM
Microsoft has a tool called System Center Virtual Machine Manager, or SCVMM, that can be used to manage Microsoft Hyper-V virtual machines. Templates saved by SCVMM are called VM templates. This can be confusing, since a virtual machine is refferred to as a VM.
Linux-based hypervisors, such as Xen, KVM, and QEMU, provide a software-based virtual network switch. Which of the following is an additional feature provided by a Linux bridge? Packet filtering Multi-homed NICs Overlay network NAT
NAT A Linux bridge is a virtual switch. It behaves like a network switch. It offers additional features, such as NAT. Virtual machines can also be configured as a multi-homed system with multiple virtual NICs. Overlay networks can be used to connect VMs on different host machines in a way that doesn't expose them to the external network. Packet filtering is a firewall feature.
Which of the following Linux bridge modes is the default? NAT Bridged Routed Isolated
NAT NAT mode is the default mode.
NAT
NAT mode is the default mode. > Use this this mode when there's no need for the external network to be aware of your VMs, but the VMs need access to the external network. > Guest VMs use the host's IP address to communicate with the external network. > Computers on the external network can't initiate communications to guest VMs because they only know the host's IP address. > When your VM sends a network packet to an address on external network, your host substitutes its own IP address for the VM's IP address and sends the packet. > When it receives a packet from the external network that's a response to a guest VM's message, it forwards it back to the initiating VM.
Virtual Machine Templates
No matter which hypervisor you use, you can create a virtual machine very quickly by defining the hardware environment and save those settings. However, the process of installing the operating system can take several minutes and requires user input. > The hypervisor uses your settings to instantiate, or create a new instance of, a hardware environment. > You boot the VM in this environment. > You install the operating system and then install the applications you need. To avoid installing the operating system and applications every time you create a new VM, you can create a template. > A template is a set of files that make up a VM that already has the operating system and applications installed. > To create a new VM, copy the template to a new location and then tell the hypervisor to run the VM from there.
Anna, a system administrator, created a new virtual machine that she would like to provision on additional hypervisors. Which of the following will provide a VM template that is open and can be used by hypervisors from different vendors? .vmdk XEN OVF .vmx
OVF OVF stands for Open Virtualization Format and provides an open standard to package virtual machine files for use on other systems as a template for creating a virtual machine. .vmx is a hypervisor file format. .vmdk is a hypervisor file that represents a disk drive. XEN is a Type 1 hypervisor.
Bootstrapping Techniques
One challenge with creating templates is that all virtual machines created using the same template will have the same settings. This problem can be solved with bootstrapping. > Bootstrapping is the automated process of provisioning a virtual machine with unique settings and configurations. > Bootstrapping customizes a virtual machine when the virtual machine first boots without requiring user input. > Two popular bootstrapping technologies that automate the provisioning of new Linux virtual machines are Cloud-init and a combination of Anaconda and Kickstart.
Linux bridge mode
One of several ways that a Linux bridge can operate including NAT mode, bridged mode, routed mode, and isolated mode.
Virtual Machine Disk Storage
One of the configurations that can be made during virtual machine creation as well as during bootstrapping is adding virtual storage. A virtual disk is a file or set of files maintained by the host hypervisor that appears as a physical disk to the guest operating system. You can choose to allocate or provision virtual disk space in one of two ways.
Overlay Networks
Overlay networks can be used to connect VMs on different host machines in a way that doesn't expose them to the external network. > Overlay networks are virtual networks that are built on top of an existing network. > Network packets are encapsulated within other packets that are assembled and dissected as they're moved over physical networks. > A virtual network can be overlayed on another virtual network, which can be overlayed on top of a physical network. > Overlay networking is especially important in scalable cloud technologies, where virtual resources like VMs and containers dedicated to one customer reside in the same datacenter as VMs and containers dedicated to other customers. > Overlay networking makes a network more complex and decreases network performance. > Overlay networks are flexible. Adding, moving, and removing virtual assets at different physical locations makes overlay networking very appealing and worth the drawbacks.
Paravirtualization
Paravirtualization: > Improves performance by allowing the guest operating system to communicate directly with some of the host's physical hardware. > Is implemented by modifying the guest operating system with special device drivers.
Multi-Homed Considerations
Physical computers can have multiple NICs connected to multiple subnets to increase performance, use the computer as a network gateway, or use the computer as a network firewall. Virtual machines can also be configured as a multi-homed system with multiple virtual NICs. Depending on your requirements, you can connect each NIC to a separate virtual switch or connect multiple NICs to a single virtual switch. You can link each physical NIC on the host machine to a different virtual switch, or you could link several physical NICs to one virtual switch.
PaaS
Platform as a Service (PaaS) offers a complete development environment that you can use to create cloud-ready business applications. PaaS provides: > A set of software to build an application. > A web hosting platform. > A development platform. > Deployment tools.
Which of the following describe an OVA (open virtual appliance or application) file? Provides a template that can be imported into a VM guest OS providing a deployed application. It is the container that holds a type-1 hypervisor. Encapsulates the entire type-1 hypervisor environment into a single file. Provides a single file that archives all the files that make up an OVF using TAR.
Provides a single file that archives all the files that make up an OVF using TAR. An OVA is a template that provides a single file that archives all the files that make up an OVF using TAR. Using an OVA makes it convenient to transfer a single file to another hypervisor, where the template can be used to create a new virtual machine. OVA templates are not imported into a VM guest. OVA templates do not encapsulate the entire type-1 hypervisor. OVA templates are not a container that holds a type-1 hypervisor.
Anaconda is an installation program that's used by Fedora, RHEL, and other distributions. Which of the following does Anaconda perform? (Select THREE.) Provides a user interface with guided installation steps. Modifies the PXE boot configuration. Identifies the computer's hardware. Provides paravirtualization host services. Deploys container images that include the entire virtual environment. Creates a file system. Creates LDAP user and group accounts.
Provides a user interface with guided installation steps. Identifies the computer's hardware. Creates a file system. Anaconda is an installation program that's used by Fedora, Red Hat Enterprise Linux, and other distributions. It identifies the computer's hardware, creates a file system, and provides a user interface that guides the installation process. Anaconda installations can be scripted with kickstart for unattended installations.
Cloud service
Services that are obtained from a location that is not local, like the internet.
SaaS
Software as a Service (SaaS) is designed for an average end user. SaaS provides applications that end users need to do their day-to-day work. Instead of installing the applications locally on their hard drive, users can run applications from the cloud, usually within a web browser.
Hypervisor
Software that implements the virtualization of computers and operating systems.
OVF and OVA
The OVF standard was formed by an industry working group comprised of over 160 companies and organizations, and it's widely accepted. > OVF stands for open virtualization format. > OVF refers to both the packaging standard and a virtual machine package stored in an OVF package. > An OVF package consists of a directory that contains virtual machine files created with the OVF format. > Virtual machine templates can be exchanged as OVF packages. > Virtual machine templates are often sent as an OVA file, which is an OVF directory saved as a tar archive file.
Bootstrapping
The automated process of provisioning a virtual machine with unique settings and configurations.
virsh
The libvirt software also provides a command line tool named virsh for controlling virtualization. The virsh tool has many arguments that are commands in and of themselves. For example: > The virtsh list command displays the virtual machines running on the hypervisor. > The virsh start command starts a virtual machine. > The virsh shutdown command cleanly shuts down a virtual machine.
libvirt
The libvirt software is an open-source application programming interface (API) that's used for creating, monitoring, migrating, starting, and stopping virtual machines. If you're a software developer, you can use the functions and routines provided by the libvirt API to interface with a hypervisor to create and control virtual machines.
Thin provisioning
The method of allocating only the space needed for a virtual machine disk and allowing the disk to grow as more storage is needed.
Thick provisioning
The method of pre-allocating the full amount of storage for a virtual machine disk.
Container template format
The template format used by a vendor's container engine, including OCI, Docker, and JSON.
VM template format
The template format used by a vendor's hypervisor, including VM, VMware, OVF, and OVA.
Virtualization and Hypervisors
The traditional computing model involves an operating system that interacts directly with the computer hardware. This model is inefficient. Virtualization improves the efficiency of a server. Virtualization: > Pools multiple operating systems on the same physical hardware. - Each operating system runs independently and runs its own set of applications. - The independent operating systems are called virtual machines, or VMs. > Is implemented by hypervisor software. - A Type 1 Hypervisor: - Is also called a native or bare-metal hypervisor. - Runs directly on the computer's hardware to manage the guest VMs. - A Type 2 Hypervisor is a software application that runs on top of a conventional operating system to manage the guest VMs.
There are three types of virtualization environments. Match the virtualization type on the left with the description on the right. Virtualization types may be used more than once.
The virtual machine completely simulates a physical computer system. Full virtualization Operating systems do not need modification to run within virtual machines. Full virtualization Only some of the components of a virtual machine are virtualized. Partial virtualization Handles some of the virtualization processing the hypervisor would normally perform. Hardware-Assisted Virtualization Full virtualization presents a virtual hardware environment, which emulates a physical hardware environment, provides the best isolation and security for VMs, and requires extra time and processing power to provide virtual hardware emulation. Paravirtualization improves performance by allowing the guest operating system to communicate directly with some of the host's physical hardware and is implemented by modifying the guest operating system with special device drivers. Hardware-assisted virtualization greatly improves a full virtualization environment and handles some of the virtualization processing the hypervisor would normally perform.
Virtual Machine Management Tools
There are three popular toolsets used by Linux-based hypervisors to manage virtual machines: libvirt, virsh, and vmm.
Types of Virtualization
There are three types of virtualization environments:
Your company is deploying ten new virtual machines. You have planned the disk space for anticipated future growth. However, the hypervisor currently doesn't have enough disk space for the all the disks that need to be allocated. You have placed an order for additional storage that will be added to the hypervisor. You must have all ten servers operational before your order will arrive. You determine that overbooking the storage space will work in the short term. Which of the following storage provisioning options should be selected? Thin provisioning Persistent Thick provisioning Non-persistent
Thin provisioning A thin provisioned virtual disk consumes only the space that it needs initially, and then grows according to demand. The benefits of thin provisioning are that the disk is provisioned quickly and storage space is saved. Thick provisioning will not work because there is not sufficient space to allocate for all virtual disks. Persistent and non-persistent are disk modes that determine what happens when the virtual machine is shut down.
VMware
VMware is a hypervisor vendor. A VMware template consists of a *.vmx configuration file and *.vmdk virtual disk files. It may include other VMware-specific files.
vmm
Virtual Machine Manager (vmm) is a popular graphical tool for managing virtual machines on a Linux host. It's also known as virt-manager since the graphical interface can be started using the virt-manager command. It also comes with command line tools: > The virt-install command is used to provision operating sytems into VMs. > The virt-clone command clones existing VMs. > The virt-convert command converts OVF VMs to run with libvert.
13.2.4 Virtual Machine Facts
Virtual machines allow you to run multiple operating systems on the same physical hardware using a hypervisor. As a Linux administrator, you should be familiar with virtual machine concepts that are common to all hypervisor implementations. This lesson covers the following topics: Virtual machine templates Virtual machine template formats Cloud and container templates Bootstrapping techniques Virtual machine disk storage Virtual machine management tools
Non-Persistent
When disks are configured in non-persistent mode, any data written to the disk is lost when the virtual machine is powered off. Non-persistent mode is useful for software testing or for doing demonstrations. > Keep your virtual disk in persistent mode until your virtual machine is customized properly. > Shut down the virtual machine and switch the virtual disk to non-persistent mode. > Every time the virtual machine is shut down, the virtual disk reverts to the state it was in when non-persistent mode was set.
When using templates to deploy virtual machines, one challenge is that all VMs will have the same settings, such as hostname, security identifiers, and even the same IP address. Which of the following allow a VM to be provisioned with unique settings and configurations? container images bootstrapping OVA template OVF template
bootstrapping Bootstrapping is the automated process of provisioning a virtual machine with unique settings and configurations. Bootstrapping customizes a virtual machine during installation (or, more specifically, when the virtual machine first boots) without requiring user input. A container image is used to create multiple similar containers when copied, each running the same applications. An OVF and OVA template will not provide unique settings when provisioning a VM.
The /etc/cloud/cloud.cfg file controls the cloud-init modules that are run. The modules represent configuration stages. Which of the following are the three configuration stages used by Cloud-init? (Select THREE.) init stage anaconda stage distribution stage development stage config stage final stage kickstart stage
init stage config stage final stage Cloud-init has three configuration stages: the init stage, the config stage, and the final stage. Kickstart is bootstrapping technology independent of cloud-init.
Which of the following is an open-source application programming interface (API) that's used for creating, monitoring, migrating, starting, and stopping virtual machines? vmm OVF virsh libvirt
libvirt libvirt is an open-source application programming interface (API) that's used for creating, monitoring, migrating, starting, and stopping virtual machines. virsh is a command line tool for controlling virtualization. vmm is a popular graphical tool for managing virtual machines on a Linux host. OVF stands for open virtualization format. The term OVF is used for both the packaging standard and a virtual machine package stored in an OVF package. An OVF package consists of a directory that contains virtual machine files created with the OVF format. Virtual machine templates can be exchanged as OVF packages.
Which of the following are three popular toolsets Linux-based hypervisors use to manage virtual machines? (Select THREE). vhd sdk vmdk libvirt vmm virsh vnc
libvirt vmm virsh libvirt, virsh, and vmm are three popular toolsets Linux-based hypervisors use to manage virtual machines. vmdk is a virtual disk file used by VMware. sdk is a software developers kit. vnc provides remote access. vhd is a virtual disk format.
Which of the following command line tools are used to control virtualization by using arguments such as list, start, and shutdown? vmm libvirt virsh vmx
virsh virsh is a command line tool for controlling virtualization. The virsh tool has many arguments that are, essentially, commands in and of themselves. For example, virsh list displays the virtual machines running on the hypervisor, virsh start starts a virtual machine, and virsh shutdown cleanly shuts down a virtual machine. libvirt is an open-source application programming interface (API) that's used for creating, monitoring, migrating, starting, and stopping virtual machines. vmm is a popular graphical tool for managing virtual machines on a Linux host.
Which of the following tools provides a graphical interface for managing virtual machines on a Linux host? vhdx libvirt vmm virtsh
vmm Virtual Machine Manager (vmm) is a popular graphical tool for managing virtual machines on a Linux host. It's also known as virt-manager since the graphical interface can be started using the virt-manager command. It also comes with command line tools like virt-install, which is used to provision operating sytems into VMs; virt-clone, which clones existing VMs; and virt-convert, which converts OVF VMs to run with libvert. libvirt is an open-source application programming interface (API) that's used for creating, monitoring, migrating, starting, and stopping virtual machines. virsh is a command line tool for controlling virtualization. vhdx is a virtual disk file used by hypervisors.
