Machine Update: Stage 1: Post Creation Instance Initialization

[elankath]

How to categorize this issue?

/area control-plane
/kind enhancement
/priority 3

What would you like to be added:
Enhance the Machine Controller triggerCreationFlow to correctly handle post-creation instance initialization steps in Driver.InitializeMachine with appropriate retry handling.

Why is this needed:

Today the driver.Driver facade represents the boundary between the the machine-controller and its various provider specific implementations.

We have abstract operations for creation/deletion and listing of machines (actually compute instances) but we do not correctly handle post-creation startup logic. Nor do we provide an abstract operation to represent the hot update of an instance after creation.

We have found this to be necessary for several use cases. Today in the MCM AWS Provider, we already misuse driver.GetMachineStatus which is supposed to be a read-only operation obtaining the status of an instance.

Each AWS EC2 instance performs source/destination checks by default.
For EC2 NAT instances
these should be disabled. This is done by issueing
a ModifyInstanceAttribute request with the SourceDestCheck set to false. The MCM AWS Provider, decodes the AWSProviderSpec, reads providerSpec.SrcAndDstChecksEnabled and correspondingly issues the call to modify the already launched instance. owever, this should be done as an action after creating the instance and should not be part of the VM status retrieval.

Similarly, there is a pending PR to add the Ipv6AddessCount and Ipv6PrefixCount to enable the assignment of an ipv6 address and an ipv6 prefix to instances. This requires constructing and issueing an AssignIpv6Addresses request after the instance is started.

To mark this issue as completed, following components should be updates:-

• mcm VM Instance Initialization: Driver.InitializeMachine #898
• mcm-provider-aws [ci:component:github.com/gardener/machine-controller-manager:v0.52.0->v0.53.0] machine-controller-manager-provider-aws#162
• mcm-provider-az [ci:component:github.com/gardener/machine-controller-manager:v0.52.0->v0.53.0] machine-controller-manager-provider-azure#144
• mcm-provider-gcp [ci:component:github.com/gardener/machine-controller-manager:v0.52.0->v0.53.0] machine-controller-manager-provider-gcp#118
• mcm-provider-alicloud [ci:component:github.com/gardener/machine-controller-manager:v0.52.0->v0.53.0] machine-controller-manager-provider-alicloud#75
• mcm-provider-openstack Bump github.com/gardener/machine-controller-manager from 0.52.0 to 0.53.0 machine-controller-manager-provider-openstack#124

[elankath]

Re-opening as coding PR is associated.