My team is looking at changing the way we manage Oracle.  First, we are looking at migrating off of Exadata and onto a different architecture.  But more fundamentally, we are questioning how we deliver database services and how we can drive innovation within the company by changing our processes and/or technologies.

Docker has come up as one such technology.  We have a lot of developers moving toward microcservice architectures and they need a good way to quickly spin up databases for development.  We also need to better standardize our processes across data platforms and improve our ability to scale environments based on a number of factors.  Adeesh Fulay did a great job of showing the state of containers as it pertains to the Oracle database.  The short is that Oracle and LXC are very mature, while Docker is quickly closing.  I am still very interested in seeing how we can leverage Docker containers and orchestration to improve our efficiency with Oracle as well as our other platforms.  My notes are:

Why Containers?

• Comparison to Shipping Goods
• Intermodal Shipping Contianer
• Issue similar with IT
  • App with list of steps to deploy
  • Prone to mistakes
  • Need to solve dependency challenges
  • Also need to make good on promise of virtualization to provide mobility
• Docker
  • Developer: Build once, Run anywhere
  • Operator: Configure once, Run Anything

Linux Container Overview

• VM contains app and: Guest OS, libraries, etc.
• Containers: No OS or Hypervisor
  • Own network interface
  • file system
  • Isolation (security) – linux kernel’s namespaces
  • Isolation(resource usage) – linux kernel’s cgroups
• Why
  • OS-Based Lightweight Virtualization technology
  • Content & Resource Isolation
  • Better Performance
  • Better Efficiency and smaller footprint
  • Build, Ship, Deploy anywhere
  • Separation of Duties
• Types
  • Application Containers
    • Docker
      • Requires application to be repackaged and reconfigured to work with Docker image format
    • One container, one app (primary app)
    • patch by replacing containers
    • good for modern applications
  • System Containers
    • Each container runs an entire service stack
    • LXC, OpenVZ, Solaris Zones
      • No need to reconfigure applications
    • Patch in place
    • good for legacy apps
  • Oracle and Docker
    • https://github.com/oracle/docker-images
    • General
      • OracleJava
      • OpenJDK
    • Databases
      • RDBMS
      • MySQL
      • NoSQL
    • Middleware
      • Glassfish
      • WebLogic
      • etc..
  • No RAC on Docker
  • LXC Support http://ww.oracle.com/technetwork/database

Look Under the Hood

• LXC is more mature with Oracle
• Docker Host
  • daemon/engine – manages networking, images, containers, (data) volumes, plugins, orchestration, etc.
  • images
    • Images are made up of multiple r/o layers
    • Containers are a thin r/w layer on top
    • Layers are shared by multiple images
    • storage drivers
      • AUFS (Ubuntu, OSX)
      • Device mapper (RHEL, CentOS)
      • BTRFS (Oracle Linux)
      • Overlay, Overlay 2
      • ZFS
    • Layer default location: /var/lib/docker
    • https://adeeshfulay.wordpress.com/2017/09/28/understnding-docker-images…….
  • Dockerfile
    • Instructions for turning base image into a new docker image
  • containers
    • Like a directory. It is created from an image, and contains everything required to run an app.  Containers like VMs have state and are portable.
    • Containerd: Simple daemon that uses run times to manage
  • Volumes
    • Supports local or shared/distributed
    • Choose between mobility & performance
    • Docker outsourced issue of storage to other vendors
  • Networking
    • Types:
      • None: no external network
      • Host: shard host n/w stack
      • Bridge: NATing, exposing ports, poor performce
      • macvlan: uses host subnet, VLAN, swarm mode
      • Overlay: multi-host VXLAN, swarm mode
      • 3rd Party: OpenvSwitch, Weave, etc..
  • Orchestration
    • kubernetes
    • Mesos
    • Docker Swarm
    • Rancher
    • Nomad
    • ROBIN
• Docker client
  • docker build
  • docker pull
  • docker run
• Registry – Public or Private contains pre-build images
  • https://hub.docker.com

Getting Hands Dirty

Containerized Databases

Oracle late to the party but quickly catching up.  Has joined CNCF.  Working with kubernetes.  Using in Oracle cloud.

Advantages

• Advantages of VMs without the performance penalty