Grant users access to Kubernetes with an external OIDC provider
Amazon EKS supports using OpenID Connect (OIDC) identity providers as a method to authenticate users to your cluster. OIDC identity providers can be used with, or as an alternative to AWS Identity and Access Management (IAM). For more information about using IAM, see Grant IAM users and roles access to Kubernetes APIs. After configuring authentication to your cluster, you can create Kubernetes
roles
and clusterroles
to assign permissions to the roles, and then bind the roles to the identities using Kubernetes
rolebindings
and clusterrolebindings
. For more information, see Using RBAC Authorization
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You can associate one OIDC identity provider to your cluster.
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Kubernetes doesn’t provide an OIDC identity provider. You can use an existing public OIDC identity provider, or you can run your own identity provider. For a list of certified providers, see OpenID Certification
on the OpenID site. -
The issuer URL of the OIDC identity provider must be publicly accessible, so that Amazon EKS can discover the signing keys. Amazon EKS doesn’t support OIDC identity providers with self-signed certificates.
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You can’t disable IAM authentication to your cluster, because it’s still required for joining nodes to a cluster.
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An Amazon EKS cluster must still be created by an AWS IAM principal, rather than an OIDC identity provider user. This is because the cluster creator interacts with the Amazon EKS APIs, rather than the Kubernetes APIs.
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OIDC identity provider-authenticated users are listed in the cluster’s audit log if CloudWatch logs are turned on for the control plane. For more information, see Enable or disable control plane logs.
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You can’t sign in to the AWS Management Console with an account from an OIDC provider. You can only View Kubernetes resources in the AWS Management Consoleview Kubernetes resources in the console by signing into the AWS Management Console with an AWS Identity and Access Management account.
Associate an OIDC identity provider
Before you can associate an OIDC identity provider with your cluster, you need the following information from your provider:
- Issuer URL
-
The URL of the OIDC identity provider that allows the API server to discover public signing keys for verifying tokens. The URL must begin with
https://
and should correspond to theiss
claim in the provider’s OIDC ID tokens. In accordance with the OIDC standard, path components are allowed but query parameters are not. Typically the URL consists of only a host name, likehttps://server.example.org
orhttps://example.com
. This URL should point to the level below.well-known/openid-configuration
and must be publicly accessible over the internet. - Client ID (also known as audience)
-
The ID for the client application that makes authentication requests to the OIDC identity provider.
You can associate an identity provider using eksctl
or the AWS Management Console.
Associate an identity provider using eksctl
-
Create a file named
associate-identity-provider.yaml
with the following contents. Replace theexample values
with your own. The values in theidentityProviders
section are obtained from your OIDC identity provider. Values are only required for thename
,type
,issuerUrl
, andclientId
settings underidentityProviders
.--- apiVersion: eksctl.io/v1alpha5 kind: ClusterConfig metadata: name: my-cluster region: your-region-code identityProviders: - name: my-provider type: oidc issuerUrl: https://example.com clientId: kubernetes usernameClaim: email usernamePrefix: my-username-prefix groupsClaim: my-claim groupsPrefix: my-groups-prefix requiredClaims: string: string tags: env: dev
Important
Don’t specify
system:
, or any portion of that string, forgroupsPrefix
orusernamePrefix
. -
Create the provider.
eksctl associate identityprovider -f associate-identity-provider.yaml
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To use
kubectl
to work with your cluster and OIDC identity provider, see Using kubectlin the Kubernetes documentation.
Associate an identity provider using the AWS Console
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Open the Amazon EKS console
. -
Select your cluster, and then select the Access tab.
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In the OIDC Identity Providers section, select Associate Identity Provider.
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On the Associate OIDC Identity Provider page, enter or select the following options, and then select Associate.
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For Name, enter a unique name for the provider.
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For Issuer URL, enter the URL for your provider. This URL must be accessible over the internet.
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For Client ID, enter the OIDC identity provider’s client ID (also known as audience).
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For Username claim, enter the claim to use as the username.
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For Groups claim, enter the claim to use as the user’s group.
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(Optional) Select Advanced options, enter or select the following information.
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Username prefix – Enter a prefix to prepend to username claims. The prefix is prepended to username claims to prevent clashes with existing names. If you do not provide a value, and the username is a value other than
email
, the prefix defaults to the value for Issuer URL. You can use the value-
to disable all prefixing. Don’t specifysystem:
or any portion of that string. -
Groups prefix – Enter a prefix to prepend to groups claims. The prefix is prepended to group claims to prevent clashes with existing names (such as
system: groups
). For example, the valueoidc:
creates group names likeoidc:engineering
andoidc:infra
. Don’t specifysystem:
or any portion of that string.. -
Required claims – Select Add claim and enter one or more key value pairs that describe required claims in the client ID token. The pairs describe required claims in the ID Token. If set, each claim is verified to be present in the ID token with a matching value.
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To use
kubectl
to work with your cluster and OIDC identity provider, see Using kubectlin the Kubernetes documentation.
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-
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Example IAM policy
If you want to prevent an OIDC identity provider from being associated with a cluster, create and associate the following IAM policy to the IAM accounts of your Amazon EKS administrators. For more information, see Creating IAM policies and Adding IAM identity permissions in the IAM User Guide and Actions in the Service Authorization Reference.
{ "Version": "2012-10-17", "Statement": [ { "Sid": "denyOIDC", "Effect": "Deny", "Action": [ "eks:AssociateIdentityProviderConfig" ], "Resource": "arn:aws:eks:us-west-2.amazonaws.com:111122223333:cluster/" }, { "Sid": "eksAdmin", "Effect": "Allow", "Action": [ "eks:" ], "Resource": "*" } ] }
The following example policy allows OIDC identity provider association if the clientID
is kubernetes
and the issuerUrl
is
https://cognito-idp.us-west-2amazonaws.com/*
.
{ "Version": "2012-10-17", "Statement": [ { "Sid": "AllowCognitoOnly", "Effect": "Deny", "Action": "eks:AssociateIdentityProviderConfig", "Resource": "arn:aws:eks:us-west-2:111122223333:cluster/my-instance", "Condition": { "StringNotLikeIfExists": { "eks:issuerUrl": "https://cognito-idp.us-west-2.amazonaws.com/" } } }, { "Sid": "DenyOtherClients", "Effect": "Deny", "Action": "eks:AssociateIdentityProviderConfig", "Resource": "arn:aws:eks:us-west-2:111122223333:cluster/my-instance", "Condition": { "StringNotEquals": { "eks:clientId": "kubernetes" } } }, { "Sid": "AllowOthers", "Effect": "Allow", "Action": "eks:", "Resource": "*" } ] }
Partner validated OIDC identity providers
Amazon EKS maintains relationships with a network of partners that offer support for compatible OIDC identity providers. Refer to the following partners' documentation for details on how to integrate the identity provider with Amazon EKS.
Partner | Product | Documentation |
---|---|---|
PingIdentity |
Amazon EKS aims to give you a wide selection of options to cover all use cases. If you develop a commercially supported OIDC compatible identity provider that is not listed here, then contact our partner team at aws-container-partners@amazon.com