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Horizontal autoscaling of virtual machines

Abiquo 4.0 introduces horizontal autoscaling of virtual machines, using scaling groups defined for virtual machines in virtual appliances. Abiquo will clone the base virtual machine to scale the group out, or undeploy machines to scale the group in, according to your scaling rules.

Scaling groups

You can easily create a scaling group using a base virtual machine. You can set the minimum and maximum size for the scaling group, in terms of running virtual machines (deployed and powered on). The minimum size must be greater than or equal to zero, where zero means that the base machine is not deployed. When you save the scaling group, if necessary, Abiquo will create clones of the base machine and deploy them in order to reach the minimum size.

Scaling rules

Scaling rules define how Abiquo will scale the virtual machine group out or in. You will need to specify how many clones of the virtual machine to create or remove in a scaling operation. Scale in rules can be different from scale out rules. If you add a time frame for scaling, Abiquo will only perform the scaling during this interval. If you do not add a time frame, then the rule will be what is called a default rule. You can create one default rule for scaling out and one for scaling in.

Scaling order

When scaling in, Abiquo will choose the oldest virtual machines to undeploy first. When scaling out again, Abiquo will not redeploy virtual machines that are undeployed; instead it will create new clones.

Cooldown period

You can add a cooldown period between scaling operations, which will enable you to ensure that Abiquo waits for your operation to complete before determining if further scaling is required.

Maintenance mode

To edit the scaling group and rules, you can put the scaling group into maintenance mode. This switches off autoscaling and enables you to make changes to your virtual machines, for example, to manually deploy or undeploy machines. Note that in maintenance mode you can undeploy the master virtual machine but you cannot delete it.
When you exit maintenance mode, Abiquo will apply your changes. Then Abiquo will adjust the number of virtual machines in the group to within the minimum and maximum size range.

Workflow

If you are using the Abiquo workflow feature, then this could impede autoscaling by requiring a workflow response before deploying clone machines. Administrators with the privilege to Manage workflow for scaling groups can disable workflow for these virtual machines, or renable it as required.