Reference
Google Kubernetes Engine
Pods authenticate with the service account they run as.
Pods authenticate with the service account they run as.
What proves the identity
The token has to come from https://container.googleapis.com/v1/projects/acme-prod/locations/us-central1/clusters/api, and its sub claim has to match the workload you named. penv compares that claim byte for byte, with no wildcards.
Every token also has to name your workspace as its audience. Ask for this audience and no other. A token requested for two audiences fails every exchange.
What the console asks for
| Field | Example | Advanced | What it pins |
|---|---|---|---|
| Project ID | acme-prod | no | Use the project id. The project number and the display name are different values. |
| Location | us-central1 | no | The cluster's region or zone. |
| Cluster name | api | no | |
| Namespace | production | no | |
| Service account | api | no |
The console also asks which project and environment this identity reaches and which role it gets, with the credential lifetime behind Advanced.
What the trust holds
Built from the example answers above:
| What | Value |
|---|---|
| Issuer | https://container.googleapis.com/v1/projects/acme-prod/locations/us-central1/clusters/api |
| Claim compared | sub |
| Subject | system:serviceaccount:production:api |
| Identity name | gke-api-production-api |
penv names the identity for you, so the form never asks for one.
The snippet the console prints
volumes:
- name: penv-token
projected:
sources:
- serviceAccountToken:
path: token
# Ask for this audience and no other. A token requested for two audiences fails every exchange.
audience: YOUR_WORKSPACE_ID
expirationSeconds: 3600
containers:
- name: api
volumeMounts:
# Without this the volume above exists and no container can read it.
- name: penv-token
mountPath: /var/run/secrets/penv
readOnly: true
# in the container:
# T=$(cat /var/run/secrets/penv/token)
# C=$(curl -sS "https://penv.cloud/api/v1/auth/oidc" \Related
- Machine identity
- Connect a Platform in the console
- Google Kubernetes Engine documentation, where the value people get wrong is always the subject