Notes from Day 1 and Day 3.

Here are notes from the second day of the conference:

Inspiration over Perspiration: Java App Deployment for the 21st century, Axel Fontaine:

  • deploying machine image instead of deploying application artifact on server stack,
  • there is problem though – machine images are too big to send them over the net,
  • running servers in production should be like backpacking – take only bare minimum that’s needed to run application,
  • bare minimum set: application, application server, language, libraries and OS kernel (that’s bootable pack, up to 100MB),
  • alternatives: Iaas/Paas, Docker/Packer, OSV by Cisco (not production ready though),
    • easy to start -> boxfuse up war file,
    • runs on VM using e.g. VMWare,
    • nice support to track running images,
    • easy way to run the image in the cloud – but requires reasonable and stable network connection
  • logging in the cloud – logstash, logentries,
  • advantages: focus on solution application, promote images – do not do patching, less is more – better minimum, what is tested is what i want to run,
  • drawbacks: adds complication orchestrating couple of dedicated services.

Patterns for Organic Architecture – let it grow!, Jarosław Pałka:

  • architexture is a process,
  • you can’t reason about what you can’t measure,,
  • sow and cherish
    • capture data about system:
      • find stable parst of system in SCM
      • Michael Feathers quadrant: uglystables, designflaw, tools and breedinggrounds,
      • find fragile parts of the system,
      • show hidden dependencies of the system,
    • refactoring:
      • not always good :),
      • is it worth it?,
      • technical debt -> give it a MEANING,
      • don’t ask for permissions,
    • visualise – but not everything, focus on limited number of metrics,
  • sow and harvest
    • modularization into stable parts of the system,
    • set up rules to split the code,
    • no big design upfront (step by step),
    • simply you don’t know every answer to question,
  • composting
    • complexity will arise – it is still growing,
    • know how users use application,
    • know features that are in use,
    • tools to track the code (logs, instrumentation, aspects, bug tracker, byteman, support people),
    • don’t use expensive tools – you are the developer, use your creativity,
    • do not comment out the code – just throw it away (scm will remember),
  • gains: shorter feedback!
  • do not sacrifice resilience of the system for developers’ short-term productivity.

Hazelcast 3 – In-Memory DataGrid, Christoph Engelbert:

  • Collection API, Concurrency API and map reduce,
  • data partitioning and distribution – automatic discovery of nodes through multicast,
  • executor service to run task (one can specify node to run a task),
  • SQL like queries,
  • transaction support,
  • link to project.

How to get started with Scala with examples, Jacek Laskowski:

I haven’t seen the presentation from the beginning. However I had opportunity to see intro to Scalania project. It seems to be a really good thing for people wanting to learn Scala. I’m going to check out the project and work out the exercises. Here is the link to Jacek’s project.

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