[GCE] Support Managed Instance Groups

[supertom]

[GCE] Support for Managed Instance Groups

Description

This PR aims to add support for Managed Instance Groups (MIGs) on GCE. Basic support for AutoScalers has also been added.

The following methods have been added (with supporting classes).

• gce.ex_get_instancetemplate(template)
• gce.ex_list_instancetemplates()
• gce.ex_get_instancegroupmanager(name, zone)
• gce.ex_list_instancegroupmanagers()
• gce.ex_create_instancegroupmanager(name, zone, template, size)
• gce.ex_destroy_instancegroupmanager(instance_group)
• gce.ex_instancegroupmanager_resize(instance_group, num_instances)
• gce.ex_instancegroupmanager_recreate_instances(instance_group, list_of_instances)
• gce.ex_instancegroupmanager_list_managed_instances(instance_group)
• gce.ex_get_autoscaler(as_name, as_zone)
• gce.ex_create_autoscaler(as_name, as_zone, my_instance_group, autoscaler_policy, description)
• gce.ex_list_autoscalers(as_zone)

(Some) Tests and fixtures have also been added.

Useful Links

• Creating Groups of Instances on GCE
• API docs
• API docs (AutoScalers)

Example Usage

print gce.ex_list_autoscalers()
print gce.ex_list_instancetemplates()
print gce.ex_list_instancegroupmanagers()
print gce.ex_instancegroupmanagers_list_managed_instances()

# Create an Instance Group
ig_name = 'my-instance-group-foo7'
ig_zone = 'us-central1-c'
it_name = 'my-instance-template-1'

template = gce.ex_get_instancetemplate(it_name)
instance_group = gce.ex_create_instancegroupmanager(ig_name, ig_zone, template, 5, 'base-foo', "my description")
print instance_group

print gce.ex_instancegroupmanager_resize(instance_group, 4)
print gce.ex_instancegroupmanager_recreate_instances(instance_group)

# add autoscaling to the instance group
autoscaler_policy = {
  "maxNumReplicas": 7,
  "minNumReplicas": 4,
  "coolDownPeriodSec": 35,
  "cpuUtilization": {"utilizationTarget": .66}
}

new_as = gce.ex_create_autoscaler(
  as_name, as_zone, my_instance_group, autoscaler_policy,
  description='My desc for this autoscaler')
print new_as
print gce.ex_list_autoscalers(as_zone)

# Update AutoScaler
updated_as = gce.ex_get_autoscaler(as_name, as_zone)
updated_as.policy['coolDownPeriodSec'] = 71
updated_as.policy['cpuUtilization']['utilizationTarget'] = .14
print gce.ex_update_autoscaler(updated_as)

# Delete the Instance Group.  VMs are also deleted.
deleted = gce.ex_destroy_instancegroupmanager(instance_group)
print deleted # returns True

Status

• ready_for_review

Checklist (tick everything that applies)

• Code linting (required, can be done after the PR checks)
• Documentation
• Tests
• ICLA (required for bigger changes)

[tonybaloney]

Good work Tom. Do you have an ICLA signed btw?

[erjohnso]

Consider also allowing GCEZone. Same with other methods.

[erjohnso]

Small nit about allowing other param types, but otherwise LGTM!

[supertom]

@tonybaloney I thought I did have an ICLA on file, but I didn't, so thanks for asking. It's now on file with Apache.

[tonybaloney]

That's cool @supertom, I don't have access to check them. I won't ask again!