Deployment and Cloudsproblems and solutions

Deployment tools for the pre-cloud age

● push approach○ Fabric○ Capistrano○ MCollective○ Puppet

● pull approach○ Chef○ Puppet

● push approach is good for deployment from scratch● pull approach is good for continuous support for existing

environment

Push approach

Host

Host

Host

Deployment script

Deployment manager

SSH

Pull approach

Agent

Agent

Agent

Deployment state

Master

Differences between traditional and cloud deployment

● Traditional deployment○ Resources in form of servers is already available

with OS and remote administration tools already installed

● Cloud deployment○ Resources in form of VMs, DB schemas, NoSQL

storages should be requested during deployment process

○ Additional hardware resources can be requested and freed during environment lifetime

○ Cloud deployment usually manages larger amounts of resources (especially during load spikes)

Problems of the traditional tools in cloud environments

● No support for cloud resource provisioning as part of the deployment

● Cloud and local resources are managed by different tools

● Deployment tools do not take lesser stability of cloud environment into the account

● Additional features of cloud environments (golden images etc.) are not supported

● And is not supported by traditional deployment tool

● Pull approach is not suitable for resource provisioning

● VMs is not the only type of resource, service instances (e. g. DB schemas) are also possible types of resources

● The popular approach is to use two separate tools: one tool for deployment and another tool for resource provisioning (e.g. AWS CloudFormation and Puppet)

Resource provisioning is not a part of the deployment process

Local and cloud resources are managed differently

● Local virtualization systems and public clouds provide different API and management tools

● Local services (e.g. DBs, NoSQL storages) require explicit actions to be installed and started while cloud service instances are created via cloud API

● There is no single place to search for a resource of the particular environment

Local DC

Hybrid environment

VM DBaaSVM

VMVMDeployment

managerDeployment

state

Lesser stability of cloud environment is not taken into the

account

● Request to create several hundred of VMs is not unusual for the cloud environment

● Recoverable resource provisioning failures are not uncommon

● There is no need to redeploy hundreds of environment VMs if one is failed

Cloud oriented deployment tools

● PaaS● Juju● Pallet● Knife cloud instances

Chef knife cloud instances

● Also was known as chef bootstrap● Prepares cloud VM instance with Chef

support● Assigns a role to newly created VM● Initiates execution of recipes associated with

VM role○ Chef server is required to download recipes

knife ec2 server create -r "role[webserver]" -I ami-2d4aa444 --flavor m1.small -G www,default -x ubuntu -N server01

Pallet

● Resource provisioning is part of the deployment

● Is similar to fabric or capistrano but it allows to request cloud resources using special commands

● Deployment process is defined as the set of actions

○ Action set is defined as the closure script

Juju

● A single unit of management is service, e.g. web server or DB

● Required resources are requested automatically on the cloud during the service creation

juju bootstrapjuju deploy local:oneiric/mysqljuju deploy local:oneiric/wordpressjuju add-relation wordpress mysqljuju expose wordpress

Platform as a Service (PaaS)

● NoOPS: deployment of application and services is done by PaaS itself

● User works with PaaS API instead of the remote administration tools of OS

● High-level logic of PaaS service management is still required○ e.g. AWS CloudFormation

● PaaS examples○ Heroku○ Cloud Foundry○ Google AppEngine