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Provider vSphere

Gardener extension controller for the vSphere cloud provider

Gardener Extension for vSphere provider

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Overview

The Gardener Extension for vSphere is a GEP-1 provider implementation that allows Gardener to leverage vSphere clusters for machine provisioning.

vSphere is an undeniable class leader for commercially supported virtual machine orchestration. The Gardener extension for vSphere provider compliments this leadership by allowing Gardener to create Kubernetes nodes within vSphere.

Like other Gardener provider extensions, the vSphere provider pairs with a provider-specific Machine Controller Manager providing node services to Kubernetes clusters. This extension provides complimentary APIs to Gardener. A Gardener-hosted Kubernetes cluster does not know anything about it’s environment (such as bare metal vs. public cloud or within a hyperscaler vs. standalone), only that the MCM abstraction can manage requests such as cluster autoscaling.

An example for a ControllerRegistration resource that can be used to register this controller to Gardener can be found here.

Please find more information regarding the extensibility concepts and the architecture details in the GEP-1 proposal.

Use Cases

The primary use case for this extension is organizations who wish to deploy a substantial Gardener landscape and use vSphere for data center fleet management. We intentionally sidestep prescribing any particular extension as this is an intimately local determination and the benefits of different solutions are more than adequately debated in industry literature.

While we may inadvertently duplicate some documentation in the mainline Gardener documentation, it is only to reduce tedium as new evaluators and developers come up-to-speed with the concepts relevant to successful deployment. We refer directly to the mainline Gardener documentation for the most up-to-date information.

Supported Kubernetes versions

This extension controller supports the following Kubernetes versions:

VersionSupportConformance test results
Kubernetes 1.281.28.0+N/A
Kubernetes 1.271.27.0+N/A
Kubernetes 1.261.26.0+Gardener v1.26 Conformance Tests
Kubernetes 1.251.25.0+Gardener v1.25 Conformance Tests
Kubernetes 1.241.24.0+Gardener v1.24 Conformance Tests

Older versions of the extension (v0.16.0 and earlier) are supported prior to current releases.

Please take a look here to see which versions are supported by Gardener in general.


Deployment patterns

As with any production software, deployment of Gardener and this extension should be considered in the context of both lifecycle and automation. Orgs should aspire to have apply

How to start using or developing this extension controller locally

You can run the controller locally on your machine by executing make start.

Static code checks and tests can be executed by running make verify. We are using Go modules for Golang package dependency management and Ginkgo/Gomega for testing.

Feedback and Support

Feedback and contributions are always welcome. Please report bugs or suggestions as GitHub issues or join our Slack channel #gardener (please invite yourself to the Kubernetes workspace here).

Learn more!

Please find further resources about out project here:

1 - Create a Kubernetes Cluster on AWS with Gardener

Overview

Gardener allows you to create a Kubernetes cluster on different infrastructure providers. This tutorial will guide you through the process of creating a cluster on AWS.

Prerequisites

  • You have created an AWS account.
  • You have access to the Gardener dashboard and have permissions to create projects.

Steps

  1. Go to the Gardener dashboard and create a Project.

  2. Choose Secrets, then the plus icon and select AWS.

  3. To copy the policy for AWS from the Gardener dashboard, click on the help icon for AWS secrets, and choose copy .

  4. Create a new policy in AWS:

    1. Choose Create policy.

    2. Paste the policy that you copied from the Gardener dashboard to this custom policy.

    3. Choose Next until you reach the Review section.

    4. Fill in the name and description, then choose Create policy.

  5. Create a new technical user in AWS:

    1. Type in a username and select the access key credential type.

    2. Choose Attach an existing policy.

    3. Select GardenerAccess from the policy list.

    4. Choose Next until you reach the Review section.

  6. On the Gardener dashboard, choose Secrets and then the plus sign . Select AWS from the drop down menu to add a new AWS secret.

  7. Create your secret.

    1. Type the name of your secret.
    2. Copy and paste the Access Key ID and Secret Access Key you saved when you created the technical user on AWS.
    3. Choose Add secret.

    After completing these steps, you should see your newly created secret in the Infrastructure Secrets section.

  8. To create a new cluster, choose Clusters and then the plus sign in the upper right corner.

  9. In the Create Cluster section:

    1. Select AWS in the Infrastructure tab.
    2. Type the name of your cluster in the Cluster Details tab.
    3. Choose the secret you created before in the Infrastructure Details tab.
    4. Choose Create.
  10. Wait for your cluster to get created.

Result

After completing the steps in this tutorial, you will be able to see and download the kubeconfig of your cluster.

2 - Deployment

Deployment of the AWS provider extension

Disclaimer: This document is NOT a step by step installation guide for the AWS provider extension and only contains some configuration specifics regarding the installation of different components via the helm charts residing in the AWS provider extension repository.

gardener-extension-admission-aws

Authentication against the Garden cluster

There are several authentication possibilities depending on whether or not the concept of Virtual Garden is used.

Virtual Garden is not used, i.e., the runtime Garden cluster is also the target Garden cluster.

Automounted Service Account Token The easiest way to deploy the gardener-extension-admission-aws component will be to not provide kubeconfig at all. This way in-cluster configuration and an automounted service account token will be used. The drawback of this approach is that the automounted token will not be automatically rotated.

Service Account Token Volume Projection Another solution will be to use Service Account Token Volume Projection combined with a kubeconfig referencing a token file (see example below).

apiVersion: v1
kind: Config
clusters:
- cluster:
    certificate-authority-data: <CA-DATA>
    server: https://default.kubernetes.svc.cluster.local
  name: garden
contexts:
- context:
    cluster: garden
    user: garden
  name: garden
current-context: garden
users:
- name: garden
  user:
    tokenFile: /var/run/secrets/projected/serviceaccount/token

This will allow for automatic rotation of the service account token by the kubelet. The configuration can be achieved by setting both .Values.global.serviceAccountTokenVolumeProjection.enabled: true and .Values.global.kubeconfig in the respective chart’s values.yaml file.

Virtual Garden is used, i.e., the runtime Garden cluster is different from the target Garden cluster.

Service Account The easiest way to setup the authentication will be to create a service account and the respective roles will be bound to this service account in the target cluster. Then use the generated service account token and craft a kubeconfig which will be used by the workload in the runtime cluster. This approach does not provide a solution for the rotation of the service account token. However, this setup can be achieved by setting .Values.global.virtualGarden.enabled: true and following these steps:

  1. Deploy the application part of the charts in the target cluster.
  2. Get the service account token and craft the kubeconfig.
  3. Set the crafted kubeconfig and deploy the runtime part of the charts in the runtime cluster.

Client Certificate Another solution will be to bind the roles in the target cluster to a User subject instead of a service account and use a client certificate for authentication. This approach does not provide a solution for the client certificate rotation. However, this setup can be achieved by setting both .Values.global.virtualGarden.enabled: true and .Values.global.virtualGarden.user.name, then following these steps:

  1. Generate a client certificate for the target cluster for the respective user.
  2. Deploy the application part of the charts in the target cluster.
  3. Craft a kubeconfig using the already generated client certificate.
  4. Set the crafted kubeconfig and deploy the runtime part of the charts in the runtime cluster.

Projected Service Account Token This approach requires an already deployed and configured oidc-webhook-authenticator for the target cluster. Also the runtime cluster should be registered as a trusted identity provider in the target cluster. Then projected service accounts tokens from the runtime cluster can be used to authenticate against the target cluster. The needed steps are as follows:

  1. Deploy OWA and establish the needed trust.
  2. Set .Values.global.virtualGarden.enabled: true and .Values.global.virtualGarden.user.name. Note: username value will depend on the trust configuration, e.g., <prefix>:system:serviceaccount:<namespace>:<serviceaccount>
  3. Set .Values.global.serviceAccountTokenVolumeProjection.enabled: true and .Values.global.serviceAccountTokenVolumeProjection.audience. Note: audience value will depend on the trust configuration, e.g., <cliend-id-from-trust-config>.
  4. Craft a kubeconfig (see example below).
  5. Deploy the application part of the charts in the target cluster.
  6. Deploy the runtime part of the charts in the runtime cluster.
apiVersion: v1
kind: Config
clusters:
- cluster:
    certificate-authority-data: <CA-DATA>
    server: https://virtual-garden.api
  name: virtual-garden
contexts:
- context:
    cluster: virtual-garden
    user: virtual-garden
  name: virtual-garden
current-context: virtual-garden
users:
- name: virtual-garden
  user:
    tokenFile: /var/run/secrets/projected/serviceaccount/token

3 - Dual Stack Ingress

Using IPv4/IPv6 (dual-stack) Ingress in an IPv4 single-stack cluster

Motivation

IPv6 adoption is continuously growing, already overtaking IPv4 in certain regions, e.g. India, or scenarios, e.g. mobile. Even though most IPv6 installations deploy means to reach IPv4, it might still be beneficial to expose services natively via IPv4 and IPv6 instead of just relying on IPv4.

Disadvantages of full IPv4/IPv6 (dual-stack) Deployments

Enabling full IPv4/IPv6 (dual-stack) support in a kubernetes cluster is a major endeavor. It requires a lot of changes and restarts of all pods so that all pods get addresses for both IP families. A side-effect of dual-stack networking is that failures may be hidden as network traffic may take the other protocol to reach the target. For this reason and also due to reduced operational complexity, service teams might lean towards staying in a single-stack environment as much as possible. Luckily, this is possible with Gardener and IPv4/IPv6 (dual-stack) ingress on AWS.

Simplifying IPv4/IPv6 (dual-stack) Ingress with Protocol Translation on AWS

Fortunately, the network load balancer on AWS supports automatic protocol translation, i.e. it can expose both IPv4 and IPv6 endpoints while communicating with just one protocol to the backends. Under the hood, automatic protocol translation takes place. Client IP address preservation can be achieved by using proxy protocol.

This approach enables users to expose IPv4 workload to IPv6-only clients without having to change the workload/service. Without requiring invasive changes, it allows a fairly simple first step into the IPv6 world for services just requiring ingress (incoming) communication.

Necessary Shoot Cluster Configuration Changes for IPv4/IPv6 (dual-stack) Ingress

To be able to utilize IPv4/IPv6 (dual-stack) Ingress in an IPv4 shoot cluster, the cluster needs to meet two preconditions:

  1. dualStack.enabled needs to be set to true to configure VPC/subnet for IPv6 and add a routing rule for IPv6. (This does not add IPv6 addresses to kubernetes nodes.)
  2. loadBalancerController.enabled needs to be set to true as well to use the load balancer controller, which supports dual-stack ingress.
apiVersion: core.gardener.cloud/v1beta1
kind: Shoot
...
spec:
  provider:
    type: aws
    infrastructureConfig:
      apiVersion: aws.provider.extensions.gardener.cloud/v1alpha1
      kind: InfrastructureConfig
      dualStack:
        enabled: true
    controlPlaneConfig:
      apiVersion: aws.provider.extensions.gardener.cloud/v1alpha1
      kind: ControlPlaneConfig
      loadBalancerController:
        enabled: true
...

When infrastructureConfig.networks.vpc.id is set to the ID of an existing VPC, please make sure that your VPC has an Amazon-provided IPv6 CIDR block added.

After adapting the shoot specification and reconciling the cluster, dual-stack load balancers can be created using kubernetes services objects.

Creating an IPv4/IPv6 (dual-stack) Ingress

With the preconditions set, creating an IPv4/IPv6 load balancer is as easy as annotating a service with the correct annotations:

apiVersion: v1
kind: Service
metadata:
  annotations:
    service.beta.kubernetes.io/aws-load-balancer-ip-address-type: dualstack
    service.beta.kubernetes.io/aws-load-balancer-scheme: internet-facing
    service.beta.kubernetes.io/aws-load-balancer-nlb-target-type: instance
    service.beta.kubernetes.io/aws-load-balancer-type: external
  name: ...
  namespace: ...
spec:
  ...
  type: LoadBalancer

In case the client IP address should be preserved, the following annotation can be used to enable proxy protocol. (The pod receiving the traffic needs to be configured for proxy protocol as well.)

    service.beta.kubernetes.io/aws-load-balancer-proxy-protocol: "*"

Please note that changing an existing Service to dual-stack may cause the creation of a new load balancer without deletion of the old AWS load balancer resource. While this helps in a seamless migration by not cutting existing connections it may lead to wasted/forgotten resources. Therefore, the (manual) cleanup needs to be taken into account when migrating an existing Service instance.

For more details see AWS Load Balancer Documentation - Network Load Balancer.

4 - Local Setup

admission-aws

admission-aws is an admission webhook server which is responsible for the validation of the cloud provider (AWS in this case) specific fields and resources. The Gardener API server is cloud provider agnostic and it wouldn’t be able to perform similar validation.

Follow the steps below to run the admission webhook server locally.

  1. Start the Gardener API server.

    For details, check the Gardener local setup.

  2. Start the webhook server

    Make sure that the KUBECONFIG environment variable is pointing to the local garden cluster.

    make start-admission
    
  3. Setup the ValidatingWebhookConfiguration.

    hack/dev-setup-admission-aws.sh will configure the webhook Service which will allow the kube-apiserver of your local cluster to reach the webhook server. It will also apply the ValidatingWebhookConfiguration manifest.

    ./hack/dev-setup-admission-aws.sh
    

You are now ready to experiment with the admission-aws webhook server locally.

5 - Operations

Using the AWS provider extension with Gardener as operator

The core.gardener.cloud/v1beta1.CloudProfile resource declares a providerConfig field that is meant to contain provider-specific configuration. Similarly, the core.gardener.cloud/v1beta1.Seed resource is structured. Additionally, it allows to configure settings for the backups of the main etcds’ data of shoot clusters control planes running in this seed cluster.

This document explains what is necessary to configure for this provider extension.

CloudProfile resource

In this section we are describing how the configuration for CloudProfiles looks like for AWS and provide an example CloudProfile manifest with minimal configuration that you can use to allow creating AWS shoot clusters.

CloudProfileConfig

The cloud profile configuration contains information about the real machine image IDs in the AWS environment (AMIs). You have to map every version that you specify in .spec.machineImages[].versions here such that the AWS extension knows the AMI for every version you want to offer. For each AMI an architecture field can be specified which specifies the CPU architecture of the machine on which given machine image can be used.

An example CloudProfileConfig for the AWS extension looks as follows:

apiVersion: aws.provider.extensions.gardener.cloud/v1alpha1
kind: CloudProfileConfig
machineImages:
- name: coreos
  versions:
  - version: 2135.6.0
    regions:
    - name: eu-central-1
      ami: ami-034fd8c3f4026eb39
      # architecture: amd64 # optional

Example CloudProfile manifest

Please find below an example CloudProfile manifest:

apiVersion: core.gardener.cloud/v1beta1
kind: CloudProfile
metadata:
  name: aws
spec:
  type: aws
  kubernetes:
    versions:
    - version: 1.27.3
    - version: 1.26.8
      expirationDate: "2022-10-31T23:59:59Z"
  machineImages:
  - name: coreos
    versions:
    - version: 2135.6.0
  machineTypes:
  - name: m5.large
    cpu: "2"
    gpu: "0"
    memory: 8Gi
    usable: true
  volumeTypes:
  - name: gp2
    class: standard
    usable: true
  - name: io1
    class: premium
    usable: true
  regions:
  - name: eu-central-1
    zones:
    - name: eu-central-1a
    - name: eu-central-1b
    - name: eu-central-1c
  providerConfig:
    apiVersion: aws.provider.extensions.gardener.cloud/v1alpha1
    kind: CloudProfileConfig
    machineImages:
    - name: coreos
      versions:
      - version: 2135.6.0
        regions:
        - name: eu-central-1
          ami: ami-034fd8c3f4026eb39
          # architecture: amd64 # optional

Seed resource

This provider extension does not support any provider configuration for the Seed’s .spec.provider.providerConfig field. However, it supports to manage backup infrastructure, i.e., you can specify configuration for the .spec.backup field.

Backup configuration

Please find below an example Seed manifest (partly) that configures backups. As you can see, the location/region where the backups will be stored can be different to the region where the seed cluster is running.

apiVersion: v1
kind: Secret
metadata:
  name: backup-credentials
  namespace: garden
type: Opaque
data:
  accessKeyID: base64(access-key-id)
  secretAccessKey: base64(secret-access-key)
---
apiVersion: core.gardener.cloud/v1beta1
kind: Seed
metadata:
  name: my-seed
spec:
  provider:
    type: aws
    region: eu-west-1
  backup:
    provider: aws
    region: eu-central-1
    secretRef:
      name: backup-credentials
      namespace: garden
  ...

Please look up https://docs.aws.amazon.com/general/latest/gr/aws-sec-cred-types.html#access-keys-and-secret-access-keys as well.

Permissions for AWS IAM user

Please make sure that the provided credentials have the correct privileges. You can use the following AWS IAM policy document and attach it to the IAM user backed by the credentials you provided (please check the official AWS documentation as well):

Click to expand the AWS IAM policy document!
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "s3:*",
      "Resource": "*"
    }
  ]
}

6 - Usage

Using the AWS provider extension with Gardener as end-user

The core.gardener.cloud/v1beta1.Shoot resource declares a few fields that are meant to contain provider-specific configuration.

In this document we are describing how this configuration looks like for AWS and provide an example Shoot manifest with minimal configuration that you can use to create an AWS cluster (modulo the landscape-specific information like cloud profile names, secret binding names, etc.).

Provider Secret Data

Every shoot cluster references a SecretBinding which itself references a Secret, and this Secret contains the provider credentials of your AWS account. This Secret must look as follows:

apiVersion: v1
kind: Secret
metadata:
  name: core-aws
  namespace: garden-dev
type: Opaque
data:
  accessKeyID: base64(access-key-id)
  secretAccessKey: base64(secret-access-key)

The AWS documentation explains the necessary steps to enable programmatic access, i.e. create access key ID and access key, for the user of your choice.

⚠️ For security reasons, we recommend creating a dedicated user with programmatic access only. Please avoid re-using a IAM user which has access to the AWS console (human user).

⚠️ Depending on your AWS API usage it can be problematic to reuse the same AWS Account for different Shoot clusters in the same region due to rate limits. Please consider spreading your Shoots over multiple AWS Accounts if you are hitting those limits.

Permissions

Please make sure that the provided credentials have the correct privileges. You can use the following AWS IAM policy document and attach it to the IAM user backed by the credentials you provided (please check the official AWS documentation as well):

Click to expand the AWS IAM policy document!
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "autoscaling:*",
      "Resource": "*"
    },
    {
      "Effect": "Allow",
      "Action": "ec2:*",
      "Resource": "*"
    },
    {
      "Effect": "Allow",
      "Action": "elasticloadbalancing:*",
      "Resource": "*"
    },
    {
      "Action": [
        "iam:GetInstanceProfile",
        "iam:GetPolicy",
        "iam:GetPolicyVersion",
        "iam:GetRole",
        "iam:GetRolePolicy",
        "iam:ListPolicyVersions",
        "iam:ListRolePolicies",
        "iam:ListAttachedRolePolicies",
        "iam:ListInstanceProfilesForRole",
        "iam:CreateInstanceProfile",
        "iam:CreatePolicy",
        "iam:CreatePolicyVersion",
        "iam:CreateRole",
        "iam:CreateServiceLinkedRole",
        "iam:AddRoleToInstanceProfile",
        "iam:AttachRolePolicy",
        "iam:DetachRolePolicy",
        "iam:RemoveRoleFromInstanceProfile",
        "iam:DeletePolicy",
        "iam:DeletePolicyVersion",
        "iam:DeleteRole",
        "iam:DeleteRolePolicy",
        "iam:DeleteInstanceProfile",
        "iam:PutRolePolicy",
        "iam:PassRole",
        "iam:UpdateAssumeRolePolicy"
      ],
      "Effect": "Allow",
      "Resource": "*"
    },
    // The following permission set is only needed, if AWS Load Balancer controller is enabled (see ControlPlaneConfig)
    {
      "Effect": "Allow",
      "Action": [
        "cognito-idp:DescribeUserPoolClient",
        "acm:ListCertificates",
        "acm:DescribeCertificate",
        "iam:ListServerCertificates",
        "iam:GetServerCertificate",
        "waf-regional:GetWebACL",
        "waf-regional:GetWebACLForResource",
        "waf-regional:AssociateWebACL",
        "waf-regional:DisassociateWebACL",
        "wafv2:GetWebACL",
        "wafv2:GetWebACLForResource",
        "wafv2:AssociateWebACL",
        "wafv2:DisassociateWebACL",
        "shield:GetSubscriptionState",
        "shield:DescribeProtection",
        "shield:CreateProtection",
        "shield:DeleteProtection"
      ],
      "Resource": "*"
    }
  ]
}

InfrastructureConfig

The infrastructure configuration mainly describes how the network layout looks like in order to create the shoot worker nodes in a later step, thus, prepares everything relevant to create VMs, load balancers, volumes, etc.

An example InfrastructureConfig for the AWS extension looks as follows:

apiVersion: aws.provider.extensions.gardener.cloud/v1alpha1
kind: InfrastructureConfig
enableECRAccess: true
dualStack:
  enabled: false
networks:
  vpc: # specify either 'id' or 'cidr'
  # id: vpc-123456
    cidr: 10.250.0.0/16
  # gatewayEndpoints:
  # - s3
  zones:
  - name: eu-west-1a
    internal: 10.250.112.0/22
    public: 10.250.96.0/22
    workers: 10.250.0.0/19
  # elasticIPAllocationID: eipalloc-123456
ignoreTags:
  keys: # individual ignored tag keys
  - SomeCustomKey
  - AnotherCustomKey
  keyPrefixes: # ignored tag key prefixes
  - user.specific/prefix/

The enableECRAccess flag specifies whether the AWS IAM role policy attached to all worker nodes of the cluster shall contain permissions to access the Elastic Container Registry of the respective AWS account. If the flag is not provided it is defaulted to true. Please note that if the iamInstanceProfile is set for a worker pool in the WorkerConfig (see below) then enableECRAccess does not have any effect. It only applies for those worker pools whose iamInstanceProfile is not set.

Click to expand the default AWS IAM policy document used for the instance profiles!
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "ec2:DescribeInstances"
      ],
      "Resource": [
        "*"
      ]
    },
    // Only if `.enableECRAccess` is `true`.
    {
      "Effect": "Allow",
      "Action": [
        "ecr:GetAuthorizationToken",
        "ecr:BatchCheckLayerAvailability",
        "ecr:GetDownloadUrlForLayer",
        "ecr:GetRepositoryPolicy",
        "ecr:DescribeRepositories",
        "ecr:ListImages",
        "ecr:BatchGetImage"
      ],
      "Resource": [
        "*"
      ]
    }
  ]
}

The dualStack.enabled flag specifies whether dual-stack or IPv4-only should be supported by the infrastructure. When the flag is set to true an Amazon provided IPv6 CIDR block will be attached to the VPC. All subnets will receive a /64 block from it and a route entry is added to the main route table to route all IPv6 traffic over the IGW.

The networks.vpc section describes whether you want to create the shoot cluster in an already existing VPC or whether to create a new one:

  • If networks.vpc.id is given then you have to specify the VPC ID of the existing VPC that was created by other means (manually, other tooling, …). Please make sure that the VPC has attached an internet gateway - the AWS controller won’t create one automatically for existing VPCs. To make sure the nodes are able to join and operate in your cluster properly, please make sure that your VPC has enabled DNS Support, explicitly the attributes enableDnsHostnames and enableDnsSupport must be set to true.
  • If networks.vpc.cidr is given then you have to specify the VPC CIDR of a new VPC that will be created during shoot creation. You can freely choose a private CIDR range.
  • Either networks.vpc.id or networks.vpc.cidr must be present, but not both at the same time.
  • networks.vpc.gatewayEndpoints is optional. If specified then each item is used as service name in a corresponding Gateway VPC Endpoint.

The networks.zones section contains configuration for resources you want to create or use in availability zones. For every zone, the AWS extension creates three subnets:

For every subnet, you have to specify a CIDR range contained in the VPC CIDR specified above, or the VPC CIDR of your already existing VPC. You can freely choose these CIDRs and it is your responsibility to properly design the network layout to suit your needs.

Also, the AWS extension creates a dedicated NAT gateway for each zone. By default, it also creates a corresponding Elastic IP that it attaches to this NAT gateway and which is used for egress traffic. The elasticIPAllocationID field allows you to specify the ID of an existing Elastic IP allocation in case you want to bring your own. If provided, no new Elastic IP will be created and, instead, the Elastic IP specified by you will be used.

⚠️ If you change this field for an already existing infrastructure then it will disrupt egress traffic while AWS applies this change. The reason is that the NAT gateway must be recreated with the new Elastic IP association. Also, please note that the existing Elastic IP will be permanently deleted if it was earlier created by the AWS extension.

You can configure Gateway VPC Endpoints by adding items in the optional list networks.vpc.gatewayEndpoints. Each item in the list is used as a service name and a corresponding endpoint is created for it. All created endpoints point to the service within the cluster’s region. For example, consider this (partial) shoot config:

spec:
  region: eu-central-1
  provider:
    type: aws
    infrastructureConfig:
      apiVersion: aws.provider.extensions.gardener.cloud/v1alpha1
      kind: InfrastructureConfig
      networks:
        vpc:
          gatewayEndpoints:
          - s3

The service name of the S3 Gateway VPC Endpoint in this example is com.amazonaws.eu-central-1.s3.

If you want to use multiple availability zones then add a second, third, … entry to the networks.zones[] list and properly specify the AZ name in networks.zones[].name.

Apart from the VPC and the subnets the AWS extension will also create DHCP options and an internet gateway (only if a new VPC is created), routing tables, security groups, elastic IPs, NAT gateways, EC2 key pairs, IAM roles, and IAM instance profiles.

The ignoreTags section allows to configure which resource tags on AWS resources managed by Gardener should be ignored during infrastructure reconciliation. By default, all tags that are added outside of Gardener’s reconciliation will be removed during the next reconciliation. This field allows users and automation to add custom tags on AWS resources created and managed by Gardener without loosing them on the next reconciliation. Tags can ignored either by specifying exact key values (ignoreTags.keys) or key prefixes (ignoreTags.keyPrefixes). In both cases it is forbidden to ignore the Name tag or any tag starting with kubernetes.io or gardener.cloud.
Please note though, that the tags are only ignored on resources created on behalf of the Infrastructure CR (i.e. VPC, subnets, security groups, keypair, etc.), while tags on machines, volumes, etc. are not in the scope of this controller.

ControlPlaneConfig

The control plane configuration mainly contains values for the AWS-specific control plane components. Today, the only component deployed by the AWS extension is the cloud-controller-manager.

An example ControlPlaneConfig for the AWS extension looks as follows:

apiVersion: aws.provider.extensions.gardener.cloud/v1alpha1
kind: ControlPlaneConfig
cloudControllerManager:
  featureGates:
    RotateKubeletServerCertificate: true
  useCustomRouteController: true
#loadBalancerController:
#  enabled: true
#  ingressClassName: alb
storage:
  managedDefaultClass: false

The cloudControllerManager.featureGates contains a map of explicitly enabled or disabled feature gates. For production usage it’s not recommend to use this field at all as you can enable alpha features or disable beta/stable features, potentially impacting the cluster stability. If you don’t want to configure anything for the cloudControllerManager simply omit the key in the YAML specification.

The cloudControllerManager.useCustomRouteController controls if the custom routes controller should be enabled. If enabled, it will add routes to the pod CIDRs for all nodes in the route tables for all zones.

The storage.managedDefaultClass controls if the default storage / volume snapshot classes are marked as default by Gardener. Set it to false to mark another storage / volume snapshot class as default without Gardener overwriting this change. If unset, this field defaults to true.

If the AWS Load Balancer Controller should be deployed, set loadBalancerController.enabled to true. In this case, it is assumed that an IngressClass named alb is created by the user. You can overwrite the name by setting loadBalancerController.ingressClassName.

Please note, that currently only the “instance” mode is supported.

Examples for Ingress and Service managed by the AWS Load Balancer Controller:

  1. Prerequites

Make sure you have created an IngressClass. For more details about parameters, please see AWS Load Balancer Controller - IngressClass

apiVersion: networking.k8s.io/v1
kind: IngressClass
metadata:
  name: alb # default name if not specified by `loadBalancerController.ingressClassName` 
spec:
  controller: ingress.k8s.aws/alb
  1. Ingress
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  namespace: default
  name: echoserver
  annotations:
    # complete set of annotations: https://kubernetes-sigs.github.io/aws-load-balancer-controller/v2.4/guide/ingress/annotations/
    alb.ingress.kubernetes.io/scheme: internet-facing
    alb.ingress.kubernetes.io/target-type: instance # target-type "ip" NOT supported in Gardener
spec:
  ingressClassName: alb
  rules:
    - http:
        paths:
        - path: /
          pathType: Prefix
          backend:
            service:
              name: echoserver
              port:
                number: 80

For more details see AWS Load Balancer Documentation - Ingress Specification

  1. Service of Type LoadBalancer

This can be used to create a Network Load Balancer (NLB).

apiVersion: v1
kind: Service
metadata:
  annotations:
    # complete set of annotations: https://kubernetes-sigs.github.io/aws-load-balancer-controller/v2.4/guide/service/annotations/
    service.beta.kubernetes.io/aws-load-balancer-nlb-target-type: instance # target-type "ip" NOT supported in Gardener
    service.beta.kubernetes.io/aws-load-balancer-scheme: internet-facing
  name: ingress-nginx-controller
  namespace: ingress-nginx
  ...
spec:
  ...
  type: LoadBalancer
  loadBalancerClass: service.k8s.aws/nlb # mandatory to be managed by AWS Load Balancer Controller (otherwise the Cloud Controller Manager will act on it)

For more details see AWS Load Balancer Documentation - Network Load Balancer

WorkerConfig

The AWS extension supports encryption for volumes plus support for additional data volumes per machine. For each data volume, you have to specify a name. By default (if not stated otherwise), all the disks (root & data volumes) are encrypted. Please make sure that your instance-type supports encryption. If your instance-type doesn’t support encryption, you will have to disable encryption (which is enabled by default) by setting volume.encrpyted to false (refer below shown YAML snippet).

The following YAML is a snippet of a Shoot resource:

spec:
  provider:
    workers:
    - name: cpu-worker
      ...
      volume:
        type: gp2
        size: 20Gi
        encrypted: false
      dataVolumes:
      - name: kubelet-dir
        type: gp2
        size: 25Gi
        encrypted: true

Note: The AWS extension does not support EBS volume (root & data volumes) encryption with customer managed CMK. Support for customer managed CMK is out of scope for now. Only AWS managed CMK is supported.

Additionally, it is possible to provide further AWS-specific values for configuring the worker pools. It can be provided in .spec.provider.workers[].providerConfig and is evaluated by the AWS worker controller when it reconciles the shoot machines.

An example WorkerConfig for the AWS extension looks as follows:

apiVersion: aws.provider.extensions.gardener.cloud/v1alpha1
kind: WorkerConfig
volume:
  iops: 10000
  throughput: 200 
dataVolumes:
- name: kubelet-dir
  iops: 12345
  throughput: 150
  snapshotID: snap-1234
iamInstanceProfile: # (specify either ARN or name)
  name: my-profile
instanceMetadataOptions:
  httpTokens: required
  httpPutResponseHopLimit: 2
# arn: my-instance-profile-arn
nodeTemplate: # (to be specified only if the node capacity would be different from cloudprofile info during runtime)
  capacity:
    cpu: 2
    gpu: 0
    memory: 50Gi

The .volume.iops is the number of I/O operations per second (IOPS) that the volume supports. For io1 and gp3 volume type, this represents the number of IOPS that are provisioned for the volume. For gp2 volume type, this represents the baseline performance of the volume and the rate at which the volume accumulates I/O credits for bursting. For more information about General Purpose SSD baseline performance, I/O credits, IOPS range and bursting, see Amazon EBS Volume Types (http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/EBSVolumeTypes.html) in the Amazon Elastic Compute Cloud User Guide.
Constraint: IOPS should be a positive value. Validation of IOPS (i.e. whether it is allowed and is in the specified range for a particular volume type) is done on aws side.

The volume.throughput is the throughput that the volume supports, in MiB/s. As of 16th Aug 2022, this parameter is valid only for gp3 volume types and will return an error from the provider side if specified for other volume types. Its current range of throughput is from 125MiB/s to 1000 MiB/s. To know more about throughput and its range, see the official AWS documentation here.

The .dataVolumes can optionally contain configurations for the data volumes stated in the Shoot specification in the .spec.provider.workers[].dataVolumes list. The .name must match to the name of the data volume in the shoot. It is also possible to provide a snapshot ID. It allows to restore the data volume from an existing snapshot.

The iamInstanceProfile section allows to specify the IAM instance profile name xor ARN that should be used for this worker pool. If not specified, a dedicated IAM instance profile created by the infrastructure controller is used (see above).

The instanceMetadataOptions controls access to the instance metadata service (IMDS) for members of the worker. You can do the following operations:

  • access IMDSv1 (default)
  • access IMDSv2 - httpPutResponseHopLimit >= 2
  • access IMDSv2 only (restrict access to IMDSv1) - httpPutResponseHopLimit >=2, httpTokens = "required"
  • disable access to IMDS - httpTokens = "required"

Note: The accessibility of IMDS discussed in the previous point is referenced from the point of view of containers NOT running in the host network. By default on host network IMDSv2 is already enabled (but not accessible from inside the pods). It is currently not possible to create a VM with complete restriction to the IMDS service. It is however possible to restrict access from inside the pods by setting httpTokens to required and not setting httpPutResponseHopLimit (or setting it to 1).

You can find more information regarding the options in the AWS documentation.

Example Shoot manifest (one availability zone)

Please find below an example Shoot manifest for one availability zone:

apiVersion: core.gardener.cloud/v1beta1
kind: Shoot
metadata:
  name: johndoe-aws
  namespace: garden-dev
spec:
  cloudProfileName: aws
  region: eu-central-1
  secretBindingName: core-aws
  provider:
    type: aws
    infrastructureConfig:
      apiVersion: aws.provider.extensions.gardener.cloud/v1alpha1
      kind: InfrastructureConfig
      networks:
        vpc:
          cidr: 10.250.0.0/16
        zones:
        - name: eu-central-1a
          internal: 10.250.112.0/22
          public: 10.250.96.0/22
          workers: 10.250.0.0/19
    controlPlaneConfig:
      apiVersion: aws.provider.extensions.gardener.cloud/v1alpha1
      kind: ControlPlaneConfig
    workers:
    - name: worker-xoluy
      machine:
        type: m5.large
      minimum: 2
      maximum: 2
      volume:
        size: 50Gi
        type: gp2
    # The following provider config is valid if the volume type is `io1`.
    # providerConfig:
    #   apiVersion: aws.provider.extensions.gardener.cloud/v1alpha1
    #   kind: WorkerConfig
    #   volume:
    #     iops: 10000
      zones:
      - eu-central-1a
  networking:
    nodes: 10.250.0.0/16
    type: calico
  kubernetes:
    version: 1.24.3
  maintenance:
    autoUpdate:
      kubernetesVersion: true
      machineImageVersion: true
  addons:
    kubernetesDashboard:
      enabled: true
    nginxIngress:
      enabled: true

Example Shoot manifest (three availability zones)

Please find below an example Shoot manifest for three availability zones:

apiVersion: core.gardener.cloud/v1beta1
kind: Shoot
metadata:
  name: johndoe-aws
  namespace: garden-dev
spec:
  cloudProfileName: aws
  region: eu-central-1
  secretBindingName: core-aws
  provider:
    type: aws
    infrastructureConfig:
      apiVersion: aws.provider.extensions.gardener.cloud/v1alpha1
      kind: InfrastructureConfig
      networks:
        vpc:
          cidr: 10.250.0.0/16
        zones:
        - name: eu-central-1a
          workers: 10.250.0.0/26
          public: 10.250.96.0/26
          internal: 10.250.112.0/26
        - name: eu-central-1b
          workers: 10.250.0.64/26
          public: 10.250.96.64/26
          internal: 10.250.112.64/26
        - name: eu-central-1c
          workers: 10.250.0.128/26
          public: 10.250.96.128/26
          internal: 10.250.112.128/26
    controlPlaneConfig:
      apiVersion: aws.provider.extensions.gardener.cloud/v1alpha1
      kind: ControlPlaneConfig
    workers:
    - name: worker-xoluy
      machine:
        type: m5.large
      minimum: 3
      maximum: 9
      volume:
        size: 50Gi
        type: gp2
      zones:
      - eu-central-1a
      - eu-central-1b
      - eu-central-1c
  networking:
    nodes: 10.250.0.0/16
    type: calico
  kubernetes:
    version: 1.24.3
  maintenance:
    autoUpdate:
      kubernetesVersion: true
      machineImageVersion: true
  addons:
    kubernetesDashboard:
      enabled: true
    nginxIngress:
      enabled: true

CSI volume provisioners

Every AWS shoot cluster will be deployed with the AWS EBS CSI driver. It is compatible with the legacy in-tree volume provisioner that was deprecated by the Kubernetes community and will be removed in future versions of Kubernetes. End-users might want to update their custom StorageClasses to the new ebs.csi.aws.com provisioner.

Node-specific Volume Limits

The Kubernetes scheduler allows configurable limit for the number of volumes that can be attached to a node. See https://k8s.io/docs/concepts/storage/storage-limits/#custom-limits.

CSI drivers usually have a different procedure for configuring this custom limit. By default, the EBS CSI driver parses the machine type name and then decides the volume limit. However, this is only a rough approximation and not good enough in most cases. Specifying the volume attach limit via command line flag (--volume-attach-limit) is currently the alternative until a more sophisticated solution presents itself (dynamically discovering the maximum number of attachable volume per EC2 machine type, see also https://github.com/kubernetes-sigs/aws-ebs-csi-driver/issues/347). The AWS extension allows the --volume-attach-limit flag of the EBS CSI driver to be configurable via aws.provider.extensions.gardener.cloud/volume-attach-limit annotation on the Shoot resource. If the annotation is added to an existing Shoot, then reconciliation needs to be triggered manually (see Immediate reconciliation), as in general adding annotation to resource is not a change that leads to .metadata.generation increase in general.

Kubernetes Versions per Worker Pool

This extension supports gardener/gardener’s WorkerPoolKubernetesVersion feature gate, i.e., having worker pools with overridden Kubernetes versions since gardener-extension-provider-aws@v1.34.

Shoot CA Certificate and ServiceAccount Signing Key Rotation

This extension supports gardener/gardener’s ShootCARotation and ShootSARotation feature gates since gardener-extension-provider-aws@v1.36.

Flow Infrastructure Reconciler

The extension offers two different reconciler implementations for the infrastructure resource:

  • terraform-based
  • native Go SDK based (dubbed the “flow”-based implementation)

The default implementation currently is the terraform reconciler which uses the https://github.com/gardener/terraformer as the backend for managing the shoot’s infrastructure.

The “flow” implementation is a newer implementation that is trying to solve issues we faced with managing terraform infrastructure on Kubernetes. The goal is to have more control over the reconciliation process and be able to perform fine-grained tuning over it. The implementation is completely backwards-compatible and offers a migration route from the legacy terraformer implementation.

For most users there will be no noticable difference. However for certain use-cases, users may notice a slight deviation from the previous behavior. For example, with flow-based infrastructure users may be able to perform certain modifications to infrastructure resources without having them reconciled back by terraform. Operations that would degrade the shoot infrastructure are still expected to be reverted back.

For the time-being, to take advantage of the flow reconcilier users have to “opt-in” by annotating the shoot manifest with: aws.provider.extensions.gardener.cloud/use-flow="true". For existing shoots with this annotation, the migration will take place on the next infrastructure reconciliation (on maintenance window or if other infrastructure changes are requested). The migration is not revertible.