Why This Talk?
> Numerous technologies
> Deployment: pretty old problem
> High productivity gains possible
> Microservices: A lot more to deploy
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Why This Talk?
> Easier deployment = easier to change software
> Goal of software architecture
> Dev moving towards DevOps
> Infrastructure as Code
> i.e. deployment becomes part of software
architecture
Package Manager
> Simple format
> Easy to distribute to many servers
> Packages software
> Defines dependencies
> Can also run scripts
> Can also include configurations
Package Manager:
Challenges
> Usually depend on OS and Linux distro
> deb for Debian, msi for Windows etc.
> What if the installation aborts?
> What if the system is inconsistent?
> Dependencies might cause problems
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Package Manager:
Challenges
> No ideal tool for configuration
> Manual changes might be needed
> Systems might become inconsistent
> What about wiring the hosts together?
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Package Managers
are widely used
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Package Managers
are widely used
…and only a part of
the full solution
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Nix
> Runs on Linux and Mac OS X
> Declarative approach: Define desired state
> Atomic upgrades and rollbacks
> Rollbacks enable experiments
> Fixes some issues
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Ubuntu Snappy / Flatpak
> Package application with all libraries
> …instead of defining dependencies
> Applications are portable across distros
> Enables rollbacks…
> ...independent updates of distro and app
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Ubuntu Snappy / Flatpak
> Packaging is all about dependencies
> Basically no packages and dependencies
any more
> Self-contained like Docker images
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What we still need…
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> Configuration
> Updates? Rollbacks?
> Make sure installation was successful
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Configuration
> Templates
> Configuration database catalogs servers
> E.g. add web servers to load balancer
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> Configuration
> Updates? Rollbacks?
> Make sure installation was successful
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Idempotency
> Idea: Start installation as often as you like
> …result is the same
> First run on fresh system: install everything
> Run directly afterwards: Do nothing
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Idempotency
> Configuration describes desired state
> Updates become trivial
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Idempotency
> Not: Install this package!
> But: This package should be installed
> Package already Installed do nothing
> Package not installed install
> Not: Create this file!
> But: File should look like this.
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> Configuration
> Updates? Rollbacks?
> Make sure installation was successful
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Chef
> Idempotent
> Templates for configuration
> Centralized server to store information
Idempotency: Challenges
> Configuration complex
> No simple script
> …but description of desired state
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Idempotency: Challenges
> Not described? Won’t be “repaired”
> Servers are updated stepwise
> …not from scratch
> Not every starting point might work
> Really reproducible?
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Why Updates??
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Checkout
V1
Checkout
V2
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Checkout
V1
Load Balancer
Database
Checkout
V2
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Pet
or Cattle?
Update
Replace
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No more updates!
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Immutable Server
> Never change a server
> Never update a server
> Always install from scratch
> Fully and reliably reproducible
> Very simple concept
> i.e. no sophisticated tools
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Immutable Server
seem like a lot of
overhead – how could
they work?
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Application Deployment
> Install operating system
> Install Tomcat
> Change configuration files
> Add application
Volatile
Stable
Easy to write a script
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Docker =
Simple Deployment
> Dockerfile
> Just a shell script
> Installation from scratch
> Behind the scenes: Optimization
> Every Dockerfile line = filesystem snapshot
> Reuse snapshots for all other Dockerfiles
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Docker Filesystem
> Each installation steps
creates a file system
snapshot
> Read go through all
layers in order
Ubuntu
Tomcat
Configuration
Application
read
Docker Filesystem
> Application changes
> Just last layer recreated
> …which is needed anyway
Ubuntu
Tomcat
Configuration
Application
Application V2
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You could use
Chef + Docker
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You could use
Chef + Docker
…but why?
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Chef... might be
useful to deploy
Docker hosts.
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You think you are
creating a server from
scratch…
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You think you are
creating a server from
scratch…
...but everything is
cached
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Why care about
servers?
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Why Care About Server?
> Applications are what provides value
> Standardize environment
> …and deploy application on the
environment
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Issues With PaaS
> Standardized infrastructure
> Not flexible
> Hard to migrate existing applications
> Installing PaaS on premise hard
> Enterprise=On-Premise
> Huge success for apps in the Public Cloud
Docker Compose
> Coordinate many containers
> Define containers…
> ...and networking
> Might use Docker Swarm for cluster
> Limited to Docker, though
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Kubernetes
> Pods: Wired Docker containers
> Service discovery
> Configuration
> Load balancing
> Limited to Docker
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Conclusion
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Package Managers
Well established
Can deploy large server farms
Updates?
Configuration?
New approaches are self-contained and
enable rollbacks
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Idempotent Tools
Updates
Configuration / templates
Book keeping of servers
Truly reproducible?
Complex?
Updates = pets = anti-pattern
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Docker
Enable immutable server
Simple scripts
Tools for coordination
New infrastructure (e.g. Kubernetes)
Updates = pets = anti-pattern
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Orchestration
> Needed to create the rest of the
environment
> Terraform
> …or a Docker tool
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EMail conli2016@ewolff.com to get:
Slides
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