GCP App Engine Flashcards
What is App Engine?
A PaaS that allows you to run your code without worrying about infrastructure.
It manages scale up and down, and the setup of the app’s runtime, traffic control (e.g. A/B testing) and comes into two versions: standard and flexible.
What is App Engine environment?
An App Engine Environment is one of the two App engine offerings: standard and flexible.
What is App Engine flexible?
App Engine Flexible is a service that runs your code in App Engine as containers.
It uses compute virtual machines and allows you some control over them by letting you attach local disks and access background processes.
What runtimes does App Engine Standard support?
PHP, Python, Ruby, GO, Java, Node
Can I use C in App Engine?
Only if you use the App Engine Flexible offering as the standard offering doesn’t support custom runtimes or languages.
Flexible environment allows you to deploy custom code as containers.
When would you use App Engine Standard?
When you need a low cost solution, where you pay only for what you need and when you need it.
For example, your application can scale to 0 instances when there is no traffic.
Also when you need quick startup (seconds) and a solution that can handle sudden and extreme spikes of traffic which require immediate scaling
Source - https://cloud.google.com/appengine/docs/the-appengine-environments
When would you use App Engine Flexible?
When you have an application that receives consistent traffic, experience regular traffic fluctuations, or meet the parameters for scaling up and down gradually.
Also when you need to deploy code that uses a custom runtime or source code written in other programming languages and/or depends on a native framework and when you want to access the resources or services of your Google Cloud project that reside in the Compute Engine network.
Source - https://cloud.google.com/appengine/docs/the-appengine-environments
What’s the difference between App Engine Flexible and Compute Engine?
Flexible environment VM instances are restarted on a weekly basis. During restarts, Google’s management services apply any necessary operating system and security updates.
You always have root access to Compute Engine VM instances. By default, SSH access to the VM instances in the flexible environment is disabled. If you choose, you can enable root access to your app’s VM instances.
Code deployments can take longer as container images are built by using the Cloud Build service.
The geographical region of a flexible environment VM instance is determined by the location that you specify for the App Engine application of your Google Cloud project. Google’s management services ensures that the VM instances are co-located for optimal performance.
Source - https://cloud.google.com/appengine/docs/the-appengine-environments
How would you migrate from App Engine Standard to App Engine Flexible?
The App Engine flexible environment does not provide the API libraries present in the App Engine SDK. To migrate your application from the App Engine standard environment to the flexible environment, you must update your code to use services and APIs that are available across all Google Cloud environments.
Source - https://cloud.google.com/appengine/docs/flexible/migrating
What does the path /_ah/ do?
9
/_ah/ is a reserved URL path used by App Engine for features (mail, warmup, login, etc.) or administrative purposes.
Script handler and static file handler paths will never match this path.
Source - https://stackoverflow.com/questions/4408042/what-does-ah-mean-in-google-app-engine
