Cloud Nativeness of an Application

Questions to determine the cloud readiness of your  application to move to the cloud

Q0 - Pick an appropriate path to the cloud:
    1. Java Buildpack
    2. TomEE Buildpack
    3. JBOSS Buildpack
    4. Liberty Buildpack
    5. WebLogic Buildpack
    6. Fat jar (Bundle app server with app)
    7. Docker

Q1 - Does the application rely on persistent file system ? Do you expect the file system to persist across restarts.
     - Disk Caches
     - Transaction Logs
     - Harcoded File Paths
     - Any java.io.* use needs to be looked at

Q2 - Does the app rely on non HTTP inbound protocol routing.
    - TCP support coming in the near future

Q3 - Does the app take a long time to start or stop
    - any dependencies or semantic ordering between apps

Q4 - Does the app use any native code libs  
    - Those libs need to be recompiled for the PCF Stemcell

Q5 - Does the app require distributed XA 2-phase commit transaction ?

Q6 - Is the app packaged as an ear/war/jar file ?
     - JBOSS buildpack and java buildpack do not support ear files

Q7 - Configuration - How is the app configured.
     - Hardcoded property files
     - Generate one artifact configured based on the environment
     - Where is the config coming from

Q8 - All logging to stdout/stderr
    - No log persistence
    - Use Console appenders

Q9 - What do you use for monitoring today
  - Any agents installed on the OS wont work
  - Agents have to bundled with the app or the app server or the buildpack

Q10 - Size of app should be ideally less than 250MB
    - More than that then you have issues with scaling and cf push

Q11 - Favor external caching instead of in-jvm Caches
      - all caching should be done in a distributed cache outside the app JVM
      - in-JVM caches are transient
      - all state to be managed outside the app via backing services
        - punch firewall holes for all backing services

Q12 - Libraries and Frameworks
    - Use cloud native / cloud friendly frameworks like Spring Cloud etc.?

Q13 - Does your app need specialized hardware in terms of specific CPU/Memory/Disk resources
    - Dependency on specific JVMS/JDKs ?

Q14 - No app server specific HA/Clustering or Administration will work in CF

Q15 - OS based registry security will NOT work on the cloud
    - Rely on  3rd party trust protocols like OAuth or SAML or Authentication and Authorization ?