Kubernetes API Access from Pod

Question

I'm trying to access the Kubernetes API in order to discover pods from within a deployed container. Although I'll do this programatically, right now, I'm just using cURL to check for issues.

I run this from a pod terminal:

curl -vvv -H "Authorization: Bearer $(</var/run/secrets/kubernetes.io/serviceaccount/token)" "https://kubernetes.default/api/v1/namespaces/$(</var/run/secrets/kubernetes.io/serviceaccount/namespace)/endpoints" --cacert /var/run/secrets/kubernetes.io/serviceaccount/ca.crt

And I get a 403 result:

* About to connect() to kubernetes.default port 443 (#0)
*   Trying 172.30.0.1...
* Connected to kubernetes.default (172.30.0.1) port 443 (#0)
* Initializing NSS with certpath: sql:/etc/pki/nssdb
*   CAfile: /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
  CApath: none
* NSS: client certificate not found (nickname not specified)
* SSL connection using TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
* Server certificate:
*       subject: CN=10.0.75.2
*       start date: Nov 23 16:55:27 2017 GMT
*       expire date: Nov 23 16:55:28 2019 GMT
*       common name: 10.0.75.2
*       issuer: CN=openshift-signer@1511456125
> GET /api/v1/namespaces/myproject/endpoints HTTP/1.1                                                                                            s/$(</var/run/secrets/kubernetes.io/serv
> User-Agent: curl/7.29.0
> Host: kubernetes.default
> Accept: */*> Authorization: Bearer eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJteXByb2plY3QiLCJrdWJlcm5ldGVzLmlvL3NlcnZpY2VhY2NvdW50L3NlY3JldC5uYW1lIjoiZGVmYXVsdC10b2tlbi00cXZidCIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VydmljZS1hY2NvdW50Lm5hbWUiOiJkZWZhdWx0Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQudWlkIjoiMjg3NzAzYjEtZDA4OC0xMWU3LTkzZjQtNmEyNGZhYWZjYzQxIiwic3ViIjoic3lzdGVtOnNlcnZpY2VhY2NvdW50Om15cHJvamVjdDpkZWZhdWx0In0.yl2HUhmxjrb4UqkAioq1TixWl_YqUPoxSvQPPSgl9Hzr97Hjm7icdL_mdptwEnOSErfzqSUBiMKJcIRdIa3Z7mfkgEk-f2H-M7TUU8GpXmD2Zex6Bcn_dq-Hsoed6W2PYpeFDoy98p5rSNTUL5MPMATOodeAulB0NG_zF01-8qTbLO_I6FRa3BCVXVMaZWBoZgwZ1acQbd4fJqDRsYmQMSi5P8a3nYgjBdifkQeTTb3S8Kmnszct41LoUlh9Xv29YVEyr1uQc5DSLAgQKj_NdSxkVq-MJP8z1PWV3OmHULNChocXr7RGKaNwlVpwpgNqsDAOqIyE1ozxlntIrotLBw
>
< HTTP/1.1 403 Forbidden
< Cache-Control: no-store
< Content-Type: application/json
< Date: Thu, 23 Nov 2017 22:18:01 GMT
< Content-Length: 282
<
{
  "kind": "Status",
  "apiVersion": "v1",
  "metadata": {},
  "status": "Failure",
  "message": "User \"system:serviceaccount:myproject:default\" cannot list endpoints in project \"myproject\"",
  "reason": "Forbidden",
  "details": {
    "kind": "endpoints"
  },
  "code": 403
}
* Connection #0 to host kubernetes.default left intact

I've tried to access a number of resources, like, endpoints, pods, etc. I've also omitted the namespace (as to access the whole cluster resources) to no avail.

I'm currently using OpenShift Origin, clean (just ran oc cluster up and deployed a test image to access the terminal in the web console).

Answer 1

It looks like you're on fully RBAC enabled cluster, and your default service account system:serviceaccount:myproject:default , as expected, is unauthorised. You should create and use dedicated service account for this pod and explicitly grant it access to what it needs to read.

https://kubernetes.io/docs/admin/authorization/rbac/

Answer 2

Pass an authorization token bearer within curl command. Without it, it's expected to be unauthorized.

More at: kubernetes documentation