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logoTetrate Service BridgeVersion: 1.6.x

Multicluster Access Control

When traffic is forwarded by a gateway, by default it takes on the identity of that gateway. This default behavior allows an administrator to easily configure access controls for all external traffic. For example, an administrator may wish to classify all gateway-sourced traffic as internet-sourced and potentially not trusted, and create access-control rules accordingly.

In a multi-cluster environment, you may wish to perform more fine-grained access control. TSB can preserve the identity of a request through gateway hops. This makes it possible to perform cross-cluster authentication, so that you can:

  • propagate the consumer identity to the remote service it has called
  • configure detailed access control between consumers and services in different TSB-managed clusters
  • apply detailed access control rules to failover targets, so that they are not exposed to too-broad a set of consumers

The examples in this documentation assume you are familiar with TSB concepts, Ingress Gateways, Tier-1 Gateways and EastWest gateways.

GitOps

Following examples use TSB GitOps feature that allow you to apply TSB configurations using kubectl. See Enabling GitOps to enable GitOps in your TSB environment and How GitOps works to understand you can leverage GitOps workflows with TSB.

What you need to know​

Service identities are not propagated through gateway hops by default because when a request goes through the gateway, due to TLS termination at gateways, the request takes the identity of the gateway instead of original source. TSB achieves identity propagation using an internal WASM extension on each gateway hop. This extension checks the validity of the client identity, and then append the clients identity to the requests XFCC header and then forwards the request.

You enable this behavior adding the enableHttpMeshInternalIdentityPropagation key in the xcp component in ControlPlane CR or Helm values.

You also need to add imagePullSecret for your TSB images registry in ControlPlane CR or Helm values so that required identity propagation WASM extensions can be pulled.

spec:
  ...
  imagePullSecrets:
  - name: gcr-secret
  components:
    xcp:
      centralAuthMode: JWT
      configProtection: {}
      enableHttpMeshInternalIdentityPropagation: true
      kubeSpec:
        ..
        ..
note

imagePullSecret is required since WASM image pull is not performed by Kubernetes but manually by the istio-agent in the sidecar and internal secrets used by the Kubernetes cluster to pull images can't be just leveraged.

Verify that ENABLE_HTTP_MESH_INTERNAL_IDENTITY_PROPAGATION is then enabled in XCP edge:

kubectl get deployment edge -n istio-system -o yaml | grep ENABLE_HTTP_MESH_INTERNAL_IDENTITY_PROPAGATION -A 1

For assistance, check the Troubleshooting instructions at the end of this page.

Use case 1: Propagating Service Identities through Tier 1 and Tier 2 gateways​

Configure two clusters cluster-1 and cluster-2, sharing the same root of trust. If necessary, follow this guide](https://istio.io/latest/docs/tasks/security/cert-management/plugin-ca-cert/) and the [repo to setup istio root and intermediate certs.

In tier-1 cluster:

  • Create a dedicated cluster for deploying tier-1 gateway.
  • Configure networkReachability setting to make sure reachability from cluster-1 to tier-1 and from tier-1 to cluster-2 are established.

In cluster-1:

  • create a tenant tenant-1 and its namespace tenant-1-ns, workspace tenant-1-ws and groups.
  • deploy the sleep pod, or a similar text client in the tenant-1-ns.

In cluster-2:

  • create a tenant tenant-2 and its namespace tenant-2-ns, workspace tenant-2-ws and groups.
  • deploy the bookinfo app into tenant-2-ns and an ingress gateway.

Verify that a request from the cluster-1 sleep pod can reach a service in the bookinfo app in cluster-2 via the Tier1 gateway. For example, you might use a command similar to the one below to invoke curl from the sleep pod against the Tier1 gateway.

export GATEWAY_IP=34.68.3.192   # use your Tier1 gateway IP
export POD=`kubectl get pod -n tenant-1 -l app=sleep -o jsonpath='{.items[0].metadata.name}')`
kubectl exec $POD -c sleep -- curl -sS "http://bookinfo.tetrate.io/api/v1/products" -v --resolve "bookinfo.tetrate.io:80:$GATEWAY_IP" -H "X-B3-Sampled: 1"
Output
* Added bookinfo.tetrate.io:80:34.68.3.192 to DNS cache
* Hostname bookinfo.tetrate.io was found in DNS cache
*   Trying 34.68.3.192:80...
* Connected to bookinfo.tetrate.io (34.68.3.192) port 80 (#0)
> GET /api/v1/products HTTP/1.1
> Host: bookinfo.tetrate.io
> User-Agent: curl/7.86.0-DEV
> Accept: */*
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< content-type: application/json
< content-length: 395
< server: envoy
< date: Fri, 25 Nov 2022 04:05:03 GMT
< x-envoy-upstream-service-time: 30
<
{ [395 bytes data]
[{"id": 0, "title": "The Comedy of Errors", "descriptionHtml": "<a href=\"https://en.wikipedia.org/wiki/The_Comedy_of_Errors\">Wikipedia Summary</a>: The Comedy of Errors is one of <b>William Shakespeare's</b> early plays. It is his shortest and one of his most farcical comedies, with a major part of the humour coming from slapstick and mistaken identity, in addition to puns and word play."}]
* Connection #0 to host bookinfo.tetrate.io left intact

Denying Access at a Workspace level​

Apply a deny rule to deny communications from tenant-1-ws in cluster-1 to tenant-2-ws in cluster-2:

apiVersion: tsb.tetrate.io/v2
kind: WorkspaceSetting
metadata:
  name: tenant-2-wss
  annotations:
    tsb.tetrate.io/organization: tetrate
    tsb.tetrate.io/tenant: tenant-2
    tsb.tetrate.io/workspace: tenant-2-ws
spec:
  defaultSecuritySetting: 
    authenticationSettings:
      trafficMode: REQUIRED
    authorization: 
      mode: RULES
      rules:
        deny:
        - from:
            fqn: organizations/tetrate/tenants/tenant-1/workspaces/tenant-1-ws
          to:
            fqn: organizations/tetrate/tenants/tenant-2/workspaces/tenant-2-ws
kubectl apply -f tenant-2-wss.yaml

Test again a request from the cluster-1 sleep pod to the bookinfo app via the Tier1 gateway. This time, the Tier1 gateway should deny the request and return an RBAC: access denied message.

Allowing Tenant access and Denying Service access​

You can also allow access at a Tenant level, and then deny access at a service level using ServiceSecuritySetting. This allows for more fine-grained security rules.

First, apply a rule to allow access at a tenant level:

apiVersion: tsb.tetrate.io/v2
kind: TenantSetting
metadata:
  name: tenant-setting
  annotations: 
    tsb.tetrate.io/organization: tetrate
    tsb.tetrate.io/tenant: tenant-2
spec:
  displayName: default-setting
  defaultSecuritySetting:
    authenticationSettings:
      trafficMode: REQUIRED
    authorization:
      mode: RULES
      rules:
        allow:
        - from:
            fqn: organizations/tetrate/tenants/tenant-1
          to:
            fqn: organizations/tetrate/tenants/tenant-2
kubectl apply -f tenant-setting.yaml

Verify that the sleep pod in tenant-1 can access the bookinfo products service in tenant-2, as above.

The security Group is defined as follows:

apiVersion: security.tsb.tetrate.io/v2
kind: Group
metadata:
  name: tenant-2-sg
  annotations:
    tsb.tetrate.io/organization: tetrate
    tsb.tetrate.io/tenant: tenant-2
    tsb.tetrate.io/workspace: tenant-2-ws
spec:
  displayName: tenant-2-security-group
  namespaceSelector:
    names:
      - "cluster-2/tenant-2-ns"
  configMode: BRIDGED

We can then define the deny rule using a ServiceSecuritySetting as follows:

apiVersion: security.tsb.tetrate.io/v2
kind: ServiceSecuritySetting
metadata:
  name: productpage-service-ss
  annotations:
    tsb.tetrate.io/organization: tetrate
    tsb.tetrate.io/tenant: tenant-2
    tsb.tetrate.io/workspace: tenant-2-ws
    tsb.tetrate.io/securityGroup: tenant-2-sg
spec:
  service: tenant-2-ns/productpage.tenant-2-ns.svc.cluster.local
  settings:
    authorization: 
      mode: RULES
      rules:
        deny:
        - from:
            fqn: organizations/tetrate/tenants/tenant-1
          to:
            fqn: organizations/tetrate/tenants/tenant-2/workspaces/tenant-2-ws/securitygroups/tenant-2-sg

Use case 2 - Propagating Service Identities in EastWest gateway failover​

Review the documentation for EastWest failover before you proceed. In this use case, we'll propagate the source identity when a service fails-over to a remote instance.

  • In cluster-1, create the namespaces client-ns belonging to tenant Client, and bookinfo-ns belonging to tenant Bookinfo. Deploy the bookinfo and bookinfo-gateway services into the bookinfo-ns.
  • In cluster-2, create the namespace bookinfo-nsbelonging to tenant Bookinfo. Deploy the bookinfo and bookinfo-gateway services into the bookinfo-ns. - In TSB, configure bookinfo-ns/bookinfo-gateway for EW failover with defaultEastWestGatewaySettings:
apiVersion: tsb.tetrate.io/v2
kind: WorkspaceSetting
metadata:
  name: bookinfo-ws-settings
  annotations:
    tsb.tetrate.io/organization: tetrate
    tsb.tetrate.io/tenant: Bookinfo
    tsb.tetrate.io/workspace: Bookinfo-ws
spec:
  defaultEastWestGatewaySettings:
    - workloadSelector:
        namespace: bookinfo-ns
        labels:
          app: bookinfo-gateway

Apply the following allow rule to permit communications from clients in the Client tenant to services in the Bookinfo tenant:

apiVersion: tsb.tetrate.io/v2
kind: TenantSetting
metadata:
  name: default-setting
  annotations: 
    tsb.tetrate.io/organization: tetrate
    tsb.tetrate.io/tenant: Bookinfo
spec:
  displayName: default-setting
  defaultSecuritySetting:
    authenticationSettings:
      trafficMode: REQUIRED
    authorization:
      mode: RULES
      rules:
        allow:
        - from:
            fqn: organizations/tetrate/tenants/Client
          to:
            fqn: organizations/tetrate/tenants/Bookinfo
        - from:
            fqn: organizations/tetrate/tenants/Bookinfo
          to:
            fqn: organizations/tetrate/tenants/Bookinfo

Verify that a client in Client can access the bookinfo services:

kubectl exec deployment/sleep -n client-ns -c sleep -- curl -s -H "X-B3-Sampled: 1" http://productpage.bookinfo-ns:9080/api/v1/products -v 
kubectl exec deployment/sleep -n client-ns -c sleep -- curl -s -H "X-B3-Sampled: 1" http://details.bookinfo-ns:9080/details/1 -v
kubectl exec deployment/sleep -n client-ns -c sleep -- curl -s -H "X-B3-Sampled: 1" http://reviews.bookinfo-ns:9080/reviews/1 -v
kubectl exec deployment/sleep -n client-ns -c sleep -- curl -s -H "X-B3-Sampled: 1" http://ratings.bookinfo-ns:9080/ratings/1 -v

Now apply a deny rule to prevent direct access to the details, reviews and ratings services from the Clients tenant. For example, to deny access to details:

apiVersion: security.tsb.tetrate.io/v2
kind: ServiceSecuritySetting
metadata:
  name: details-service-ss
  annotations:
    tsb.tetrate.io/organization: tetrate
    tsb.tetrate.io/tenant: Bookinfo
    tsb.tetrate.io/workspace: bookinfo-ws
    tsb.tetrate.io/securityGroup: bookinfo-sg
spec:
  service: bookinfo-ns/details.bookinfo-ns.svc.cluster.local
  settings:
    authorization: 
      mode: RULES
      rules:
        deny:
        - from:
            fqn: organizations/tetrate/tenants/Client
          to:
            fqn: organizations/tetrate/tenants/Bookinfo/workspaces/bookinfo-ws/securitygroups/bookinfo-sg

Repeat the client tests, verifying that a client can access the front-end products service, but none of the back-end details, reviews and ratings services.

Finally, scale down the details, reviews and ratings services to zero. This will provoke a failover.

  • Without service identity propagation, the client requests to the details, reviews and ratings services would now succeed because they would take on the identity of the gateway in cluster-2 (the Bookinfo tenant).
  • With service identity propagation, the client requests to the details, reviews and ratings services continue to be denied as the identity of the originator is forwarded through gateway hops.

Troubleshooting​

  1. Identity propagation is enabled from TSB ControlPlane CR by adding enableHttpMeshInternalIdentityPropagation to the xcp component:
spec:
  ...
  components:
    xcp:
      centralAuthMode: JWT
      configProtection: {}
      enableHttpMeshInternalIdentityPropagation: true
      kubeSpec:
        ..
        ..

Verify that ENABLE_HTTP_MESH_INTERNAL_IDENTITY_PROPAGATION is enabled in XCP edge:

kubectl get deployment edge -n istio-system -o yaml | grep ENABLE_HTTP_MESH_INTERNAL_IDENTITY_PROPAGATION -A 1
  1. Ensure that imagePullSecret has been configured in the ControlPlane CR. The XCP operator will install the required WASM extension for XFCC header propagation, using the imagePullSecret configured in the ControlPlane CR.
spec:
  hub: gcr.io/sreehari-test-1  
  imagePullSecrets:
  - name: gcr-secret
  managementPlane:
    ...
  components:
    ...
  1. Verify that the secret has been created in istio-system namespace in the control plane cluster.
kubectl get secrets -n istio-system | grep gcr
Output
gcr-secret        kubernetes.io/dockerconfigjson        1      6m18s

Istio will use this secret to pull the xfcc-guard WASM extension and deploy it on the Envoy gateways. The extension provides the plugins xfcc-extractor, xfcc-hasher and xfcc-validator.

  1. Verify that the Istio wasmplugin extension has been successfully installed by the XCP operator in the ControlPlane cluster.
kubectl get wasmplugins.extensions.istio.io -A
Output
NAMESPACE      NAME             AGE
istio-system   xfcc-extractor   5m
istio-system   xfcc-hasher      5m
istio-system   xfcc-validator   5m
  1. Verify that the WASM extensions are configured with the imagePullSecret configured in the ControlPlane CR.
kubectl get wasmplugins.extensions.istio.io xfcc-extractor -n istio-system -o yaml
Output
apiVersion: extensions.istio.io/v1alpha1
kind: WasmPlugin
metadata:
  annotations:
    xcp.tetrate.io/contentHash: 56e3bd2983a4582346e0b295d4795ced
    xcp.tetrate.io/created-by-installer: "true"
  creationTimestamp: "2022-11-29T09:27:56Z"
  generation: 8
  labels:
    install.xcp.tetrate.io/owner-kind: EdgeXcp
    install.xcp.tetrate.io/owner-name: edge-xcp
    install.xcp.tetrate.io/owner-version: v1alpha1
  name: xfcc-extractor
  namespace: istio-system
  ownerReferences:
  - apiVersion: install.xcp.tetrate.io/v1alpha1
    blockOwnerDeletion: true
    controller: true
    kind: EdgeXcp
    name: edge-xcp
    uid: 446c6ba1-800e-4427-89bc-8cfebb3d8d4c
  resourceVersion: "51516293"
  uid: 358b507f-2ad4-4c60-8701-975ec8c397b4
spec:
  imagePullPolicy: IfNotPresent
  imagePullSecret: gcr-secret
  phase: AUTHZ
  pluginConfig:
    mode: extractor
  pluginName: xfcc-extractor
  priority: 10
  url: oci://gcr.io/sreehari-test-1/xcp-guard:v1.6.0-rc3