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Docker Containers Deep DiveBest of Red Hat Summit
Will Kinard
October 4, 2016
Agenda
2
• Intro
• Containerization 101
• Use Cases
• Build, Ship, Run
• OpenShift
• Q&A
3
• DevOps Advisory and Implementation
Services
• Docker Consulting and Integration
• CloudBees Jenkins Consulting
AboutThe Container Enablement Company
• Continuous Integration,
Delivery, and Deployment
• Application Modernization
• Cloud Migration
Container Tech Isn’t New
4
2000
2002
2004
2006
2007
1979
2008
2013
ChrootFilesystem isolation
FreeBSD JailsEarly container technology
Linux NamespacesProcess isolation
Solaris ZonesSimilar to jails; snapshots, cloning
Google Process ContainersProcess aggregation for resource management
Linux Control GroupsProcess containers renamed and merged into kernel 2.6.24
LXC Linux ContainersUserland tooling
DotCloud Docker Inc.Introduction of Docker Open Source Project
Docker Open Source Project
GitHub (github.com/docker/docker)
• 2900+ Contributors
• 10,000+ Active Forks
• 34,000+ Stars
Docker Hub (hub.docker.com)
• 6B+ Image Downloads
• 500,000+ Dockerized Applications
• Exponential growth
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0
1
2
3
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5
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2013 2014 2015 2016
Docker Pulls - Billions
What is a Docker Container ?
• Method to run applications in isolation
• Isolation includes namespacing pid, network, users, restricting
root, cpu and memory limits, and providing separate
filesystem
• Many of the technologies are old, but haven't been packaged
in an easy to use toolset before Docker
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“Docker containers wrap up a piece of software in a complete filesystem that contains everything it needs
to run: code, runtime, system tools, system libraries – anything you can install on a server.” (https://www.docker.com/what-docker)
Containerized Deployment and Scaling
Each virtual machine
includes:
- application
- binaries and
libraries
- entire guest
operating system
Containers:
- Include application and all dependencies
- Share kernel with other containers
- Run as an isolated process not tied to any
specific infrastructure
Virtual Machines Containers
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We’re not trying to replace your VMs
Virtual Machine:
Host Virtualization
Containers are used in
partnership with current IaaS
stacks.
Docker and other container
platforms still need a host.
Container:
Application Virtualization
Take advantage of the streamlined
process for VM based IaaS and gain
efficiencies in:
• Higher density workloads
• Scale
• Portability
• Security
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Portability is Empowering
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Portability is Empowering
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Portability is Empowering
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• Containers are designed to be disposable
• New containers go back to a clean image state
• Running containers write to an isolated space
Immutable
• Data is stored outside of the container
• Separates data from your application
13
Application Development (Build & Ship)
Problem: Code migration issues: Dev Test Prod. Painful and slow software delivery.
Solution: Developer Self-Service. Automate and consolidate with Docker.
Docker packages applications and their dependencies into containers to allow for easy transport from a
developers laptop to any target test or prod environment. This accelerates the software lifecycle,
increases reliability, and reduces job time.
- Begin with a “Trusted Known State”
- Control and Approve Content
- Track Promotion CryptographicallyDeveloper
Version
control
Sysadmin
QA / QE
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Application Modernization / Cloud Migration
Problem: Legacy applications: brittle, and difficult to change/bug fix/upgrade
Hard to scale, obsolete APIs, costly and difficult to support and maintain.
Solution: Microservices architecture. Technology diversity. Modular boundaries.
Mulit-tier applications can be deployed in parts and each tier is an independent container. Each of the containers
can be used for a single service. Legacy applications can be migrated to the cloud through either a “lift & shift” or
“refactoring” methodology, or potentially a combination.
BuildDocker Images
• Images are the definition. They include
the filesystem, environment variables,
and default entry points.
• Containers are an instance of an
image. They isolate the application
from the host, and even from other
containers.
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BuildDockerfiles
• Write your image definition in a Dockerfile
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• Turn that Dockerfile into an image with
• Develop a new app or “lift and shift” your current codebase
• Union file system
• Multiple RO layers are stacked
• Containers add a single RW layer to
isolate changes
• Layers are cached for fast builds
• Layers are named with a hash inside
the engine
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Docker Images
Docker for Mac / Windows
• Docker tools for the developer
• OS native clients using internally
available virtualization: xhyve and
Hyper-V
• Full Docker CLI from native OS
shell
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Red Hat Container Dev Kit
• Pre-built container development
environment
• Choice of virtualization platforms:
Virtualbox, Hyper-V, Linux KVM
• Eclipse and docker CLI integration
ShipDocker Registry (and Hub)
• Push and pull to central registry
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• Organized as repositories that contain
multiple tags
• Multiple options: run your own, Docker
Hub, OpenShift, 3rd parties
Run
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• Run your image
• Launches a container base on your image
• Options for:
Volumes: link external data into the container for persistence
Networking: bridged, overlay, access with exposed ports
RunDistributed
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• Fault tolerant
• Blue/Green Deployment
• Seamless rollbacks
Distributed
Docker Compose
• Packages multiple containers together
• Defines parameters for ‘docker run’
• Configuration is stored in ‘docker-
compose.yml’
• Allows containers to be scaled, but
without orchestration
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Docker on Red Hat
RHEL
Consistent performance and reliability
Certification and Support
SELinux Security
Atomic Host
• Minimal footprint operating system
• Linux container optimized
• Reliability and security of RHEL
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Red Hat OpenShift Container Platform V3
OpenShift and Kubernetes add the ability to orchestrate
docker containers across multi-host installations.
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• Self-service Platform
• Multi-language Support
• Application Persistence
• Automation
• OpenvSwitch Integration
Load Docker Images to OpenShift!
# oc new-project rhsummit# oc new-app gitlab/gitlab-ce
Appendix
26
This is Important
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• Isolated space for a running application
• All containers run on the same kernel unlike a VM
• Eliminates the overhead of an OS and services
Come Again?
Docker Containers – Run… Anywhere?
Linux:
Kernel Version 3.10+
• Ubuntu 13.10+
• Fedora 20+
• RHEL 7+
• CentOS 7.1+
• Gentoo
• ArchLinux
• openSUSE 13.1+
• CRUX 3.0+
Windows (Really!):
• Docker for Windows
• Windows Server 2016 (TP5)
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Docker for ARM!
Production Operations / Data CenterProblem: Inefficiency of VMs .. O/S duplication… Lengthy boot and replication times.
Hardware, Storage, and Hypervisor costs $$.
Solution: Docker’s containers as a service (CaaS) and orchestration platform. Policy driven architecture.
Deployment flexibility (On-Premise, Cloud, Hybrid).
Docker containers share resources with the host OS, which makes them significantly more efficient than VMs.
Containers can be started and stopped in a fraction of a second. They are lightweight, fast, and maximize
consolidation. Swisscom reduced their VM footprint from 400 to 20 for a database as a service offering, driving
tremendous cost savings.
ControlManage and secure
at scale
PortabilityFrictionless
Movement & Trust
AgilityInnovation at
speed
+ +Build Ship Run
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Isolated
• Isolated filesystem
• Namespace for isolating pids
• cgroups for limiting memory and CPU
• Separate network stack
• Restricted root capabilities
Docker Notary
• Open source project on github
(github.com/docker/notary)
• Trusted cross platform content
distribution
• Platform agnostic in delivering
content
• Publisher key validates integrity
of content
33
Portable
• Run Docker containers
unchanged in any
environment, on any
infrastructure
• Move applications at
will between
environments and
infrastructures
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At Scale
Docker containers spin up and down in seconds,
making it easy to scale application services to
satisfy peak customer demand, and then reduce
running containers when demand ebbs.
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