PCF 01 - Cloud-Foundry-Overview

spaces - every application and service is scoped to a space. Each org contains at least one space. A space provides users with access to a shared location for application development, deployment, and maintenance. Each space role applies only to a particular space.

organizations - an org is a development account that an individual or multiple collaborators can own and use. All collaborators access an org with user accounts. Collaborators in an org share a resource quota plan, applications, services availability, and custom domains.

routes - define how to get to an application

• a unique route exists to each application in every space
• domain can be mapped to multiple spaces
• route can only be mapped to one space
• same application can be deployed in multiple spaces
• each must have a different, unique URL
• development space route: http://myapp-test.cfapps.io
• production space route: http://myapp.cfapps.io

services - any type of add-on that can be provisioned along side your apps

• database, messaging, mail, third-party SaaS provider
• services are usually bound to 1 or more applications
• connection info and credentials are put in an environment variable: VCAP_SERVICES

domains - define routes to apps

users - a user account represents an individual person within the context of a PCF application. A user can have different roles in different spaces within an org, governing what level and type of access they have within that space.

quotas - restrict resources for orgs and spaces

• total memory
• total number of routes
• max application instance size
• total number of services

• How do you login to Cloud Foundry?

cf login [-a API_URL] [-u USERNAME]

• How do you deploy an application? What are three activities involved?

cf push APP_NAME

1. Upload
2. Stage
3. Start

• Can you remember the steps Cloud Foundry goes through when deploying applications? What components are involved?
• What is the difference between a public, private and hybrid cloud?
• What infrastructure does Cloud Foundry runs on?
  • AWS
  • VMware
  • Openstack
  • Azure
• What is BOSH? Why is it useful?

BOSH can provision and deploy software over hundreds of VMs. It also performs monitoring, failure recovery, and software updates with zero-to-minimal downtime.

• What is staging? What does it do?

1. Uploads application packages to staging droplet.
2. Applies Buildpack
3. Builds the application and make it ready to be run.

• Do you know the difference between restarting, restaging and redeploying and application? How does each of these affect the services, environment-variables available on an application?

restart will simply stop your application and start it with the existing droplet.

restage will stop your application, run the application bits through the staging process to create a new droplet, and then start the new droplet. It's a lot like push but without actually pushing new application bits.

You typically restart when you need your applicaiton's environment refreshed and you typically restage when you need/want the buildpack to run without updating the application source.

• What is meant by ephemeral? What are the design implications for an application?

ephemeral -> temporary virtual machines and containers are temporary immutable infrastructure - updates to systems and applications are not done in-place new, updated instances are created instead

• What are the 12 Factor Design patterns? Could you list each one from memory?

1. Processes - Execute the app as one or more stateless processes

2. Concurrency - Scale out via the process model

3. Disposability - Maximize robustness with fast startup and graceful shutdown

4. Logs - Treat logs as event streams

5. Build, release, run - Strictly separate build and run stages

6. Processes - Execute the app as one or more stateless processes

7. Port binding - Export services via port binding

8. Concurrency - Scale out via the process model

9. Disposability - Maximize robustness with fast startup and graceful shutdown

10. Dev/prod parity - Keep development, staging, and production as similar as possible

11. Logs - Treat logs as event streams

12. Admin processes - Run admin/management tasks as one-off processes

• Why does Cloud Foundry rely on environment-variables?

Environment variables are the means by which the Cloud Foundry runtime communicates with a deployed application about its environment.

• Can you manage environment-variables manually? If so how?

  Yes, environment variables can be managed manually!

  • cf set-env my-app my-variable_name my-variable_value
  • cf unset-env my-app my-variable_name my-variable_value
• Can you name two predefined environment-variables available to any application?
  • VCAP_APPLICATION
  • VCAP_SERVICES