Compute Engine

Question 1

What is Compute Engine?

Answer 1

IaaS which allows users to create VMs, attach to persistent storage and make use of ther GCP services

Question 2

What is Compute Engine made of?

Answer 2

Scalable, high performance virtual machines that are completely customizable.

• over 25 predefined machine types with various numbers of CPUs and memory
• customize 1-64 CPUs with up to 6.5GB RAM per CPU

Question 3

What do compute engine instances run and 3 key points about those instances?

Answer 3

Images that contain an OS, libraries and other code.

• Google provides Linux and Windows Server images
• 3rd party vendors provide other images
• Can create custom image from boot disk or snapshot from an existing VM

Question 4

Where are Compute Engines contained?

Answer 4

Contained in a project and run in a zone and region

- hardware costs and availability can differ between regions

Question 5

What storage options are available for Compute Engine VMs?

Answer 5

1. remote standard persistent disks

2. local solid state drives

Question 6

What are some key points about Compute Engine preemptibility?

Answer 6

1. short lived instances that can persist up to 24 hours
2. low cost
3. may not be available and can terminate at any time with 30 sec notice
4. cannot migrate to a regular VM
5. cannot be set to automatically restart
6. good for apps that are fault tolerant and can withstand interruptions

Question 7

What are some key points of Compute Engine?

Answer 7

1. completely customizable
2. can be made preemptible
3. can create instance groups
4. can set up health checks
5. can attach GPU for math intensive applications

Question 8

What is an instance group and what are some key points?

Answer 8

It lets you manage multiple VMs as a single unit.

1. any gcloud command issued to the group is applied to all VMs in the group
2. instance template is based of an instance and can be used to make identical instances
3. all GCP load balancing requires use of an instance group

Question 9

What are the two types of instance groups.

Answer 9

Unmanaged

• collections of instances with different configurations
• no auto-scaling
• can’t use instance templates

Managed

• collection of instances that are identical
• automatically scale and load balance
• instance that crashes can be automatically recreated
• can be set up with instance template
• zonal or regional

Question 10

What is a health check?

Answer 10

A health check contacts the server and waits for a response. When setting up a health check, you set the frequency, how long to wait for a response and what a given number of successes or failures means in terms of health

Question 11

Key points of VM billing in Compute Engine?

Answer 11

1. billed in 1 sec increments based on machine type
2. discount for sustained usage
3. charged for a minimum of 1 min
4. preemptible can save up to 80%
5. once the instance is stopped, you are not billed

Question 12

Key points of GPUs attached to a VM?

Answer 12

1. not all zones/machine types have GPUs as an option
2. can have 1, 2 or 4 GPUs attached to a machine
3. cannot be attached to shared memory machines

Question 13

What is a snapshot and what are some key points?

Answer 13

A copy of a disk that is useful for backup.

1. first snapshot contains full data - subsequent ones are incremental
2. if application is buffered in memory, make sure to flush it before creating snapshot
3. users must have Compute Storage Admin role to work with a snapshot

Question 14

What is a disk image and what are some key points?

Answer 14

A copy of a disk that is in a suitable format for creating a VM

1. can be made from a disk, snapshot, cloud storage file or another image.
2. can delete or deprecate an image
3. a family is a group of related images which are usually different versions of the same underlying image

Question 15

How do you create a commute engine instance via command line?

Answer 15

gcloud compute instances create [instance name]

Values from default project will be used if not specified

Question 16

How do you view project info via command line?

Answer 16

gcloud compute project-info describe

Question 17

How do you list the vms via command line?

Answer 17

gcloud compute instances list

Question 18

What are some commonly used parameters when creating a VM?

Answer 18

• -boot-disk-size (10GB and 2TB)
• -boot-disk-type
• -labels
• -machine-type : type of machine to use, standard is n1-standard-1
• -preemptible
• -subnet [SUBNET NAME] : to create the vm in a particular VPC

Question 19

How do you view available machine types for creating a VM?

Answer 19

gcloud compute machine-types list

Question 20

VM Management: What is metadata?

Answer 20

Key values pairs that are stored in a metdata serer and can be queried by Compute Engine API. It’s useful if running startup or shutdown scripts and need to change behavior based on metadata values

Question 21

VM Management: What options exist for availability policy?

Answer 21

1. preemptibility
2. automatic restart - auto restart if machine shut down
3. on host maintenance - allows instances to be migrated to other servers during maintenance

Question 22

VM Management: What security options are available?

Answer 22

1. Shielded VM - configured to have additional security measures
2. Secure Boot - only authenticated OS software can run on VM
3. VTPM - Virtual Trusted Platform Module
4. Integrity Monitoring - uses a known baseline of boot measurements to compare current boot measurement
5. SSH keys - can block project wide SSH keys

Question 23

VM Management: What disk options are available? (Not disk types)

Answer 23

1. Specify whether boot disk is deleted when instance is deleted.
2. How encryption will be managed
3. Add new disk setting name, type, r/w parameters, size, encryption

Question 24

VM Management: What networking options are available?

Answer 24

1. add network tags
2. add another network interface to another network
3. choose a VPC and select a subnet
4. specify static IP or custom ephemeral address

Question 25

VM Management: What is sole tenancy?

Answer 25

It ensures that your VMs run on a server only with your other VMs

Question 26

How do you create an instance group via command line?

Answer 26

gcloud compute instance-templates create [template name] 1. you can specify existing VMs as a source of the instance template 2. it can contain instances zonally or regionally