Page Comparison

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Horizontal scaling of VMs enables users to configure an automatic response to changing demands for resources. To scale out, the platform clones the base VM and deploys the clones. To scale in, Abiquo will delete clone machines but it will just undeploy the base machine. Scaling operations are subject to all standard Abiquo constraints, such as privileges and allocation limits.

 To clone the base virtual machine, the platform will do the following steps:

1. Create disks using the following:
   
   1. Copies of content of disks from the VM template
   2. Empty disks or volumes for each additional disk used in the VM
   3. Disk controllers used in the VM
2. Apply ALL configuration used in the VM, for example:
   
   1. CPU and RAM
   2. Network connections of the same type (e.g. private network)
   3. Assignment of firewall policies and attachment to load balancers
   4. Chef recipes, backups, cloud-init, variables, and so on
   5. Metrics. The group of metrics from clone machines and the base machine (if it is deployed) can activate alarms in the base machine, even if it is not deploye
   6. Exception – Alarms: the scaling group has only one alarm in the base machine

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When scaling, the platform will search for a rule that is valid for the specific time range, or for a default rule. It will create or delete/undeploy the number of VMs in the rule, then wait for the cooldown period before accepting another scaling request. 

To scale out, the platform does not deploy VMs that are undeployed in the scaling group. To clone the base virtual machine, the platform will do the following steps:

1. Create disks using the following:
   
   1. Copies of content of disks from the VM template
   2. Empty disks or volumes for each additional disk used in the VM
   3. Disk controllers used in the VM
2. Apply ALL configuration used in the VM, for example:
   
   1. CPU and RAM
   2. Network connections of the same type (e.g. private network)
   3. Assignment of firewall policies and attachment to load balancers
   4. Chef recipes, backups, cloud-init, variables, and so on
   5. Metrics. The group of metrics from clone machines and the base machine (if it is deployed) can activate alarms in the base machine, even if it is not deploye
   6. Exception – Alarms: the scaling group has only one alarm in the base machine

To scale in,  Abiquo currently selects the virtual machines to delete or undeploy using first in, first out (FIFO). The platform deletes and undeploys VMs without requesting user confirmation when there are disks that are not stored in the Apps library (ISO configuration drive or additional hard disk). 

Perform maintenance on the scaling group

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