Clouds in the Open: The Operations Evolution of Open Source & Public Clouds

Jun 24 2013   10:19PM GMT

CCC13 Live Blog: Putting the PaaS in CloudStack

Aaron Delp Aaron Delp Profile: Aaron Delp

Disclaimer – This is a live blog from the CloudStack Collab Conference. Might have a bunch of errors in formatting, etc.  I’m just typing as fast as I can.  Also, I work for Citrix and I focus on CloudPlatform, the commercial version of CloudStack.  Just want to be up front with everyone.

Title: Putting the PaaS in CloudStack by Steven Citron-Pousty (@TheSteve0) from Red Hat

  • (hosted from here)
  • This is an OpenShift focus
  • OpenShift doesn’t really care about the underlying infrastructure (makes it CloudStack compatible)
  • Talking about different PaaS and vendors in the market
  • Predicts all development will be PaaS based in 2-3 years
  • OpenShift has three versions: Origin (opensource) upstream repo to Online (public offering by Red Hat) and Enterprise (private)
  • Online is hosted on AWS, Origin and Enterprise can be on others
  • SELinux containers are used for partitioning and containers
  • cartridges are pre-canned instances (or libraries) to add building block pieces and create environments quickly
  • This allows one click products (i.e. WordPress) to be rolled out and everything will be consistent and then development can start
  • version 2 of the cartridges format was just released
  • The goal – create a “peaceful” environment for Devs and Admins (Opes want stability and performance, devs want the new shiny environment quickly)
  • Neither one really wants to talk to each other more than they have too 🙂
  • Online over provisions resources by orders of magnitude because this way reclamation isn’t needed as much. How many developers give their environments back when done?  Almost none!
  • Now at the command line – shows one command to spin up an entire environment
  • This is more than giving a vm to a dev, this is about splitting a vm into further slices using SELinux into partitions (reminds me of AS/400 LPARs back in the day)
  • Terminology – broker -> management host, orchestrates the nodes
  • node – compute host for gears
  • gear – allocation of resources (slice) on a host
  • cartridge – framework to build applications
  • Each OpenShift Origin server is either a broker host or a node host
  • A broker can host many nodes (i.e the Online version running thousands of hosts uses four brokers)
  • Broker does state, DNS, and authentication over REST
  • Broker then passes an allocation request to a node in a district (a district is a grouping of nodes with like properties)
  • SELinux then securely subdivides the node into instances and creates a secure virtual container called a gear
  • If there is no resource contention for the gear, they can take the entire CPU, when there is contention they get 20%, memory is allocated at 512MB (This prevents noisy neighbor, if you peg a CPU, you will only peg 20% of a CPU) – think of this as network QoS but for CPU’s – The 20% value is configurable, same for other variables
  • Machines spin up and spin down of gears automatically, nodes need to be added/idled by the operator
  • (there was a BUNCH of questions here, I didn’t capture them all, can’t type that fast)
  • hardware pluggable load balancers are a constant request and coming in a near future version, software HA is built in today
  • Flow of a request -> REST API request to broker -> Message bus (ActiveMQ) -> Node spins up a cartridge and gear as requested
  • Once an application is allocated, the broker is out of the flow path and you talk directly to the application node/gear
  • To make a change, developers use git to manage all changes to the environment
  • Multi-tenant networking is built into the product using reverse proxy server internally to the environment
  • Steve discussed the whole flow of data more as questions come in. Great information but too much to type here
  • Want to play and learn more?
  • Installing OpenShift Origin using Puppet and Vagrant here
  • Instructions to run OpenShift on CloudStack here

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