App Engine

Question 1

What is App Engine?

Answer 1

Platform as a Service that provides a managed platform for running applications

Question 2

What are the 4 components of App Engine?

Answer 2

1. Application
2. Service
3. Version
4. Instance

Question 3

What is an App Engine application?

Answer 3

A high level resource created in a project. Each project can have one App Engine Application.

Question 4

What is an App Engine service

Answer 4

The service is the code executed in the app. It is typically structured to perform a single function. Services are defined by their source code and their configuration.

Question 5

What is an App Engine version?

Answer 5

The source code and configuration of a service constitutes a version of the app. A service can have multiple versions.

Question 6

What is an App Engine instance?

Answer 6

When a version executes, it creates an instance of the app.

Question 7

What environments can you run in App Engine?

Answer 7

1. Standard Environment

2. Flexible Environment

Question 8

What are some key points of the Standard Environment?

Answer 8

1. runs application in a pre-configured language specific sandbox
2. fastest spin up time and less expensive
3. suited for apps written in one of the supported languages and you don’t need OS packages or other compiled software external to the app
4. Two types: 1st generation and 2nd generation

Question 9

What are key points about 1st generation Standard Environment implementations?

Answer 9

1. Supports Python 2.7, PHP 5.5 or Go 1.9
2. only a select set of white-listed extensions and libraries are allowed
3. restricted network access

Question 10

What are key points about 2nd generation Standard Environment implementations?

Answer 10

1. java 8, Python 3.7, Php 7.2, Node.js 8 and Go 1.11
2. any language extenstion
3. full network access
4. can scale down to 0 instances if there is no load

Question 11

What are some key points about a Flexible Environment implementation?

Answer 11

1. based on Docker Containers
2. users can customize runtime environments by configuring container
3. native support for Java 8, Eclipse Jetty 9, Python 2.7, Python 3.6, Node.js, Ruby, PHP, .Net and Go
4. good option when you can package applications and services into a small set of containers
5. works well when you have 3rd party software or libraries that need to run along side application
6. slower spin up time and more expensive.
7. will scale down but will always have at least one instance running
8. the health is monitored by Google
9. can work with OS background processes and write to local disk

Question 12

How can you delegate workload in App Engine?

Answer 12

Through push queues, pull queues or cron jobs

Question 13

How do you deploy an App Engine with a .yaml file?

Answer 13

1. gcloud app deploy [.yaml CONFIG FILE NAME]
2. app.yaml is default, so no need to specify if that is the config file name
3. must be run in directory containing .yaml file
4. once deployed, output will provide url to view result of deployed service ([project name].appspot.com)

Question 14

How do you stop an app engine instance via the shell?

Answer 14

gcloud app versions stop [v1 v2…]

pass in list of versions to stop

Question 15

What type of instances can be running in App Engine?

Answer 15

1. dynamic instances - based on load

2. resident instances - running all the time

Question 16

What are some key points of dynamic instances of an App Engine app?

Answer 16

1. it is optimized for cost savings by shutting down unused resources
2. uses two types of scaling - automatic and basic

Question 17

What are the two types of scaling for dynamic instances of an App Engine app?

Answer 17

1. Automatic Scaling

2. Basic Scaling

Question 18

What parameters are used in a yaml file to manage automatic scaling?

Answer 18

Add automatic_scaling to .yaml file along with parameters:

1. target_cpu_utilization - max cpu usage before additional instances are started
2. target_throughput_utilization - (0.5 to 0.95)
3. max_concurrent_requests default 10, max 80
4. max_instances
5. min_instances
6. max_pending_latency - max time a request waits in the queue to be processed.
7. min_pending_latency

Question 19

What parameters are used in a yaml file to manage basic scaling?

Answer 19

add basic_scaling to .yaml file followed by parameters:

1. ide_timeout
2. max_instances

Question 20

What type of scaling do resident instances allow?

Answer 20

Manual scaling. can add manual_scaling to .yaml file along with the parameter instances

Question 21

What are the ways you can split traffic between App Engine versions?

Answer 21

1. IP address - client is always routed to the same version as long as their IP doesn’t change
2. HTTP Cookie - preferred way to split. will send user to same version even if their IP changes
3. Random - default - distributes workload evenly

Question 22

How do you split traffic via shell?

Answer 22

gcloud app services set-traffic [SERVICE NAME] [SPLIT METHOD]

• -splits v1=.4, v2=.6 for a 40/60 split
• -migrate - indicates traffic should be migrated from previous version to new version
• -split-by - ip, random or cookie