Kubernetes Auth

Learn how to authenticate with Infisical in Kubernetes

Kubernetes Auth is a Kubernetes-native authentication method for applications (e.g. pods) to access Infisical.

Diagram

The following sequence digram illustrates the Kubernetes Auth workflow for authenticating applications running in pods with Infisical.

Concept

At a high-level, Infisical authenticates an application in Kubernetes by verifying its identity and checking that it meets specific requirements (e.g. it is bound to an allowed service account) at the /api/v1/auth/kubernetes-auth/login endpoint. If successful, then Infisical returns a short-lived access token that can be used to make authenticated requests to the Infisical API.

To be more specific:

1. The application deployed on Kubernetes retrieves its service account credential that is a JWT token at the /var/run/secrets/kubernetes.io/serviceaccount/token pod path.
2. The application sends the JWT token to Infisical at the /api/v1/auth/kubernetes-auth/login endpoint after which Infisical forwards the JWT token to the Kubernetes API Server at the TokenReview API for verification and to obtain the service account information associated with the JWT token. Infisical is able to authenticate and interact with the TokenReview API by using a long-lived service account JWT token itself (referred to onward as the token reviewer JWT token).
3. Infisical checks the service account properties against set criteria such Allowed Service Account Names and Allowed Namespaces.
4. If all is well, Infisical returns a short-lived access token that the application can use to make authenticated requests to the Infisical API.

We recommend using one of Infisical’s clients like SDKs or the Infisical Agent to authenticate with Infisical using Kubernetes Auth as they handle the authentication process including service account credential retrieval for you.

Guide

In the following steps, we explore how to create and use identities for your applications in Kubernetes to access the Infisical API using the Kubernetes Auth authentication method.

1. Obtaining the token reviewer JWT for Infisical

   1.1. Start by creating a service account in your Kubernetes cluster that will be used by Infisical to authenticate with the Kubernetes API Server.

   infisical-service-account.yaml

   apiVersion: v1
   kind: ServiceAccount
   metadata:
     name: infisical-auth
     namespace: default
   
   

   kubectl apply -f infisical-service-account.yaml
   

   1.2. Bind the service account to the system:auth-delegator cluster role. As described here, this role allows delegated authentication and authorization checks, specifically for Infisical to access the TokenReview API. You can apply the following configuration file:

   cluster-role-binding.yaml

   apiVersion: rbac.authorization.k8s.io/v1
   kind: ClusterRoleBinding
   metadata:
     name: role-tokenreview-binding
     namespace: default
   roleRef:
     apiGroup: rbac.authorization.k8s.io
     kind: ClusterRole
     name: system:auth-delegator
   subjects:
     - kind: ServiceAccount
       name: infisical-auth
       namespace: default
   

   kubectl apply -f cluster-role-binding.yaml
   

   1.3. Next, create a long-lived service account JWT token (i.e. the token reviewer JWT token) for the service account using this configuration file for a new Secret resource:

   service-account-token.yaml

   apiVersion: v1
   kind: Secret
   type: kubernetes.io/service-account-token
   metadata:
     name: infisical-auth-token
     annotations:
       kubernetes.io/service-account.name: "infisical-auth"
   

   kubectl apply -f service-account-token.yaml
   

   1.4. Link the secret in step 1.3 to the service account in step 1.1:

   kubectl patch serviceaccount infisical-auth -p '{"secrets": [{"name": "infisical-auth-token"}]}' -n default
   

   1.5. Finally, retrieve the token reviewer JWT token from the secret.

   kubectl get secret infisical-auth-token -n default -o=jsonpath='{.data.token}' | base64 --decode
   

   Keep this JWT token handy as you will need it for the Token Reviewer JWT field when configuring the Kubernetes Auth authentication method for the identity in step 2.

2. Creating an identity

   To create an identity, head to your Organization Settings > Access Control > Machine Identities and press Create identity.

   When creating an identity, you specify an organization level role for it to assume; you can configure roles in Organization Settings > Access Control > Organization Roles.

   Now input a few details for your new identity. Here’s some guidance for each field:

   • Name (required): A friendly name for the identity.
   • Role (required): A role from the Organization Roles tab for the identity to assume. The organization role assigned will determine what organization level resources this identity can have access to.

   Once you’ve created an identity, you’ll be prompted to configure the authentication method for it. Here, select Kubernetes Auth.

   Here’s some more guidance on each field:

   • Kubernetes Host / Base Kubernetes API URL: The host string, host:port pair, or URL to the base of the Kubernetes API server. This can usually be obtained by running kubectl cluster-info.
   • Token Reviewer JWT: A long-lived service account JWT token for Infisical to access the TokenReview API to validate other service account JWT tokens submitted by applications/pods. This is the JWT token obtained from step 1.5.
   • Allowed Service Account Names: A comma-separated list of trusted service account names that are allowed to authenticate with Infisical.
   • Allowed Namespaces: A comma-separated list of trusted namespaces that service accounts must belong to authenticate with Infisical.
   • Allowed Audience: An optional audience claim that the service account JWT token must have to authenticate with Infisical.
   • CA Certificate: The PEM-encoded CA cert for the Kubernetes API server. This is used by the TLS client for secure communication with the Kubernetes API server.
   • Access Token TTL (default is 2592000 equivalent to 30 days): The lifetime for an acccess token in seconds. This value will be referenced at renewal time.
   • Access Token Max TTL (default is 2592000 equivalent to 30 days): The maximum lifetime for an acccess token in seconds. This value will be referenced at renewal time.
   • Access Token Max Number of Uses (default is 0): The maximum number of times that an access token can be used; a value of 0 implies infinite number of uses.
   • Access Token Trusted IPs: The IPs or CIDR ranges that access tokens can be used from. By default, each token is given the 0.0.0.0/0, allowing usage from any network address.
3. Adding an identity to a project

   To enable the identity to access project-level resources such as secrets within a specific project, you should add it to that project.

   To do this, head over to the project you want to add the identity to and go to Project Settings > Access Control > Machine Identities and press Add identity.

   Next, select the identity you want to add to the project and the project level role you want to allow it to assume. The project role assigned will determine what project level resources this identity can have access to.

4. Accessing the Infisical API with the identity

   To access the Infisical API as the identity, you should first make sure that the pod running your application is bound to a service account specified in the Allowed Service Account Names field of the identity’s Kubernetes Auth authentication method configuration in step 2.

   Once bound, the pod will receive automatically mounted service account credentials that is a JWT token at the /var/run/secrets/kubernetes.io/serviceaccount/token path. This token should be used to authenticate with Infisical at the /api/v1/auth/kubernetes-auth/login endpoint.

   For information on how to configure sevice accounts for pods, refer to the guide here.

   We provide a code example below of how you might retrieve the JWT token and use it to authenticate with Infisical to gain access to the Infisical API.

   Sample code for inside an application

   The shown example uses Node.js but you can use any other language to retrieve the service account JWT token and use it to authenticate with Infisical.

   const fs = require("fs");
   try {
       const tokenPath = "/var/run/secrets/kubernetes.io/serviceaccount/token";
       const jwtToken = fs.readFileSync(tokenPath, "utf8");
   
       const infisicalUrl = "https://app.infisical.com"; // or your self-hosted Infisical URL
       const identityId = "<your-identity-id>";
   
       const { data } = await axios.post(
           `{infisicalUrl}/api/v1/auth/kubernetes-auth/login`,
           {
               identityId,
               jwt,
           }
       );
   
       console.log("result data: ", data); // access token here
   } catch(err) {
       console.error(err);
   }
   

   We recommend using one of Infisical’s clients like SDKs or the Infisical Agent to authenticate with Infisical using Kubernetes Auth as they handle the authentication process including service account credential retrieval for you.

   Each identity access token has a time-to-live (TLL) which you can infer from the response of the login operation; the default TTL is 7200 seconds which can be adjusted.

   If an identity access token exceeds its max ttl, it can no longer authenticate with the Infisical API. In this case, a new access token should be obtained by performing another login operation.

FAQ

Why is the Infisical API rejecting my service account JWT token?

There are a few reasons for why this might happen:

• The Kubernetes Auth authentication method configuration is invalid.
• The service account JWT token has expired is malformed or invalid.
• The service account associated with the JWT token does not meet the criteria set forth in the Kubernetes Auth authentication method configuration such as Allowed Service Account Names and Allowed Namespaces.

Why is the Infisical API rejecting my access token?

There are a few reasons for why this might happen:

• The access token has expired.
• The identity is insufficently permissioned to interact with the resources you wish to access.
• The client access token is being used from an untrusted IP.

What is access token renewal and TTL/Max TTL?

A identity access token can have a time-to-live (TTL) or incremental lifetime after which it expires.

In certain cases, you may want to extend the lifespan of an access token; to do so, you must set a max TTL parameter.

A token can be renewed any number of time and each call to renew it will extend the toke life by increments of access token TTL. Regardless of how frequently an access token is renewed, its lifespan remains bound to the maximum TTL determined at its creation