Cloudstack autoscaling

Auto Scaling with Apache CloudStack

Paul GosdenTechnical lead of networking services division

[email protected]: @ShapeBlue

@ShapeBlue #CloudStack #CCCEU13

What is AutoScale?AutoScale allows systems to dynamically react to a set of defined metrics and to scale resources accordingly.Providing : -

High AvailabilityCost SavingEnergy Saving

Overview


Applications or services that see elasticity in their demand.Launching a new website with unknown visitor numbersViral marketing campaigns, these can present unpredictable traffic loads as some work and some don’tAn analytical application might scale out the servers performing in a calculation process – using 20 machines for 1 hour, rather than 1 machine for 20 hours

Use Cases


A new web company designs and builds an application based on a web service that supplies concert ticketsLow capital reserves – Limited resources for Compute platformDesigned their application to be statelessLimited budget for advertising so are using social media in the hope that it goes viral

Example Life Cycle


Initial Configuration

CloudStack

Application Template

Account Infrastructure

End user configures the CloudStack AutoScale policy on the network

End User

Netscaler



CloudStack



CloudStack configures the Netscaler via the NITRO API

Netscaler



CloudStack



Netscaler makes the API call back to CloudStack to launch the Minimum amount of instances in the policy

Netscaler



CloudStack



CloudStack launches the Instances from the Application Template

Netscaler


Process

CloudStack



The Netscaler will wait for the quiet period to finish to allow the servers to boot and bring the applications on-line

Netscaler


Process

CloudStack



The Netscaler binds the IP’s of the Instances to the service group hosted on the Netscaler

Netscaler


Lifecycle

CloudStack



Users start to visit the site and the Netscaler monitors the SNMP metrics from the instances

NetscalerUsers


Lifecycle

CloudStack



User count continues to rise and the server group starts to hit the metrics set in the auto scale policy

NetscalerUsers


Lifecycle

CloudStack



The Netscaler then uses its API command to contact CloudStack to launch more instances

NetscalerUsers


Lifecycle

CloudStack



The Instance is again given its quite time to boot and start the application

NetscalerUsers


Lifecycle

CloudStack



The instance is now running and registered to the NetScaler service group online and all servers are back under the counters for the Auto Scale

NetscalerUsers


Lifecycle

CloudStack



This process will be repeated as needed until the policy hits the max instances count

NetscalerUsers


Lifecycle

CloudStack



If user numbers reduce the server again hits the AutoScale scale down policy counters

NetscalerUsers


Lifecycle

CloudStack



The Netscaler sends the API command to the CloudStack Server to destroy under utilised instances

NetscalerUsers


Lifecycle

CloudStack



The System is now back to running the appropriate amount of instances as needed

NetscalerUsers


Should be driven by the end userVM Template with appropriate setupCustomer account with API enabledCustomer CloudStack Isolated Network stood up with a min of one VM running to provision the virtual router

User System Requirements


SNMP needs to be enabled on boot and configured with community name and portIf needed allow port 161 for UDP access via the firewallApplication to be launched on first boot

For example on a web application the web server would need to be running and the application to be configured

with database settings to automatically join the pool.Alternative is to have a configuration management system configure the VM as a post-provisioning action E.G. Puppet or Chef

Creation of Templates


Adding the AutoScale Policy


AutoScale Configuration Screen


AutoScale Configuration Wizard

Selected template Compute offering for the selected instance. i.e. CPU, no of CPU’s, RAM etc. Min Instance – VMs count, if a VM is in a down state it is not counted in the min

count and the AutoScale feature will spin up another instance Max Instance – VMs count Remember that the domain limits on adding instances

needs to be large enough for this to scale as needed


Duration that the policy counters need to be at the specific range across the group




Polling Interval in seconds for the SNMP monitoring Quiet time to allow for boot and application registration


API to list existing countershttp://192.168.21.76:8096/client/api/?command=listCounters

API to add a new counter (OID)http://192.168.21.76:8096/client/api?command=createCounter&name=WindowsCPUPercentage&source=snmp&value=1.3.6.1.2.1.25.3.3.1.2.2

Adding OIDS


Netscaler GUI checks


Apache CloudStack 4.1 +Citrix Netscaler 10.0 Build 71.6016.e +

Version Requirements


Basic Zone needs NetScaler EIP and ELB as network offeringAdvanced Zone needs a Network offering utilising a NetScaler for load balancingSet Global Config Parameter "endpointe.url" with the management server IP or floating IP if load balanced

Administrator Considerations


No special configuration is required on the NetScalerSetup the Citrix Netscaler with appropriate NSIPNetScaler should be added into CloudStack in the standard way, as an external device in either dedicated or shared modeA network offering will need to be created, utilising NetScaler as the Load Balancer

Configuration of the Citrix Netscaler

Cloudstack autoscaling

Technology

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