DevOps and OpenStack December 2012
But What About Docker?
- But what about Docker? Containers and PaaS and VMs, oh my!
- What’s a Run-Time Environment? • CPU cycles • Disk I/O • Network access • Other physical resources (GPUs, HBAs)
- RTE Criteria • Isolation • Launch speed • Run-time performance But also… • Multi-server orchestration • HA characteristics • Update mechanisms
- An ecosystem of tools Process Applications Services Container Virtual Server Bare Metal
- Containers (and Docker)
- Some Background • Containers started out at Sun in the 90s. • They are an extension of traditional OSlevel isolation primitives, including filesystem ACLs, to control access to shared physical resources. • They have matured with network namespaces and overlay filesystems
- Docker: Making containers easy command line tools • Great • Well-integrated overlay filesystems • Well-integrated network management
- So… containers via Docker Pros: • Wickedly fast • Simple to deploy • Abstracted from the base OS Cons: • No windows • No *nix • Doesn’t address the hard problems (multiserver, multi-tier, in-place upgrades, or HA)
- So why is it so popular!? • UX matters. • UX matters… a LOT. • • • • Built-in emulator for learning. Built-in hosted image repository. Good json output. Really damn easy install.
- Micro-OS for Fun and Profit
- Micro-OS Ecosystem • • • • • Iocane (Piston Cloud) SmartOS (Joyent) CoreOS (Alex Polvi) OSv (Cloudius Systems) Mirage (XenServer)
- Containers and (Micro) OSs App App App App App Container OS OS Container Hypervisor Host OS Physical Server
- PaaS
- What isn’t PaaS? • It’s not the method of isolation • It’s not the operating system What is PaaS? • Automation of app placement & scaling • Orchestration of services and infrastructure
- Understanding PaaS Turning this… .war …into this: .jar LB .tar.gz App App App dependencies libraries service manifest DB Multi-server run time environment(s)
- Takeaways
- Takeaways • Everything in cloud competes with everything else, at a 40% overlap. • Most PaaS use some kind of process isolation (containers or whatever) internally. • The process isolation isn’t the hard part. • UX matters.