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Accessing using OpenID Connect

Headlamp supports OIDC for cluster users to effortlessly log in using a "Sign in" button.

screenshot the login dialog for a cluster

To use OIDC, Headlamp needs to know how to configure it, so you have to provide the following OIDC-related arguments to Headlamp from your OIDC provider:

  • the client ID: -oidc-client-id or env var HEADLAMP_CONFIG_OIDC_CLIENT_ID
  • the client secret: -oidc-client-secret or env var HEADLAMP_CONFIG_OIDC_CLIENT_SECRET
  • the issuer URL: -oidc-idp-issuer-url or env var HEADLAMP_CONFIG_OIDC_IDP_ISSUER_URL
  • (optionally) the OpenId scopes: -oidc-scopes or env var HEADLAMP_CONFIG_OIDC_SCOPES

and you have to tell the OIDC provider about the callback URL, which in Headlamp it is your URL + the /oidc-callback path, e.g.: https://YOUR_URL/oidc-callback.

Callback URL​

You must tell your OIDC provider the callback URL that Headlamp will use after login. This is your Headlamp URL plus /oidc-callback, for example:

https://YOUR_URL/oidc-callback

ℹ️ Note: If you're running Headlamp behind an ingress or load balancer (e.g., NGINX, AWS ALB/NLB), make sure it forwards the X-Forwarded-Proto header. Otherwise, Headlamp may generate the callback URL using http instead of https, which can cause a mismatch with your OIDC provider.

For NGINX ingress, you can add:

nginx.ingress.kubernetes.io/configuration-snippet: |
  proxy_set_header X-Forwarded-Proto $scheme;

Troubleshooting: Real time updates not working, Large JWT Tokens with Ingress NGINX​

If you notice real time updates not working, this could be the cause.

If your OIDC provider issues large JWT tokens (e.g., >8KB), you may encounter issues with WebSocket connections or authentication headers being truncated when using Headlamp behind an Ingress NGINX controller.

To resolve this, increase the header buffer size using the following annotation in your NGINX Ingress resource:

nginx.ingress.kubernetes.io/server-snippet: |-
  large_client_header_buffers 4 64k;

ℹ️ Note: Regular HTTP requests may still work even with large tokens, but WebSocket connections are more sensitive to header size limits and may fail unless this buffer is increased.

Scopes​

Besides the mandatory openid scope, Headlamp also requests the optional profile and email scopes. Scopes can be overridden by using the -oidc-scopes option. Remember to include the default ones if you need them when using that option. For example, if you need to keep the default scopes and add Github's repo, then add them all to the option:

-oidc-scopes=profile,email,repo

Note: Before Headlamp 0.3.0, a scope groups was also included, as it's used by Dex and other services, but since it's not part of the default spec, it was removed in the mentioned version.

Token Validation Overrides​

In the event your OIDC Provider issues access_tokens from a different Issuer URL or clientID audience than its id_tokens (i.e. Azure Entra ID) you may have need of the following parameters to configure what is used in validation of tokens.

  • -oidc-validator-client-id=<clientID audience to validate in token> or env var HEADLAMP_CONFIG_OIDC_VALIDATOR_CLIENT_ID which is the clientID headlamp should be verifying in the aud field of the token provided back from the OIDC provider.
  • -oidc-validator-idp-issuer-url=<issuerURL to use in validation> or env var HEADLAMP_CONFIG_OIDC_VALIDATOR_IDP_ISSUER_URL which is the IssuerURL headlamp should be verifying in the iss field of the token provided back from the OIDC Provider

Use Access Tokens instead of ID Tokens​

Be default, headlamp leverages the id_token provided back from the OIDC Provider after authentication returned to the /oidc-callback endpoint. For some Identity Providers like Azure Entra ID, the access_token is what is used for authorization to Kubernetes clusters. To instruct headlamp to use the access_token instead of the id_token, the following flag can be used.

  • -oidc-use-access-token=true or env var HEADLAMP_CONFIG_OIDC_USE_ACCESS_TOKEN

Example: OIDC with Keycloak in Minikube​

If you are interested in a comprehensive example of using OIDC and Headlamp, you can check the tutorial on setting up OIDC with Keycloack in Minikube.

Example: OIDC with Entra ID in AKS​

If you are interested in a comprehensive tutorial of using OIDC and Headlamp in AKS, you can check the tutorial on setting up OIDC with Entra ID in AKS.

For quick reference if you are already familiar with setting up Entra ID,

  • Add the callback URL (e.g. https://YOUR_URL/oidc-callback) to your Azure App Registration's redirectURIs
  • Set -oidc-client-id to your Azure App Registration's clientID
  • Set -oidc-client-secret to your Azure App Registration's clientSecret
  • Set -oidc-idp-issuer-url to https://login.microsoftonline.com/<Your Azure Directory (tenant) ID>/v2.0
  • Set -oidc-scopes to 6dae42f8-4368-4678-94ff-3960e28e3630/user.read,openid,email,profile
  • Set --oidc-validator-idp-issuer-url to https://sts.windows.net/<Your Directory (tenant) ID>/
  • Set -oidc-validator-client-id to 6dae42f8-4368-4678-94ff-3960e28e3630
  • Set -oidc-use-access-token=true

Example: OIDC with Dex​

If you are using Dex and want to configure Headlamp to use it for OIDC, then you have to:

  • Add the callback URL (e.g. https://YOUR_URL/oidc-callback) to Dex's staticClient.redirectURIs
  • Set -oidc-client-id as Dex's staticClient.id
  • Set -oidc-client-secret as Dex's staticClient.secret
  • Set -oidc-idp-issuer-url as Dex's URL (same as in --oidc-issuer-url in the Kubernetes APIServer)
  • Set -oidc-scopes if needed, e.g. -oidc-scopes=profile,email,groups

Note If you already have another static client configured for Kubernetes for the apiserver's OIDC (OpenID Connect) configuration, use a single static client ID i.e -oidc-client-id for both Dex and Headlamp. Additionally, the redirectURIs need to be specified for each client.