Setup Multi User

Fleet uses Kubernetes RBAC where possible.

One addition on top of RBAC is the GitRepoRestriction resource, which can be used to control GitRepo resources in a namespace.

A multi-user fleet setup looks like this:

  • tenants don’t share namespaces, each tenant has one or more namespaces on the upstream cluster, where they can create GitRepo resources
  • tenants can’t deploy cluster wide resources and are limited to a set of namespaces on downstream clusters
  • clusters are in a separate namespace

Shared Clusters

Setup Multi User - 图2important information

The isolation of tenants is not complete and relies on Kubernetes RBAC to be set up correctly. Without manual setup from an operator tenants can still deploy cluster wide resources. Even with the available Fleet restrictions, users are only restricted to namespaces, but namespaces don’t provide much isolation on their own. E.g. they can still consume as many resources as they like.

However, the existing Fleet restrictions allow users to share clusters, and deploy resources without conflicts.

Example User

This would create a user ‘fleetuser’, who can only manage GitRepo resources in the ‘project1’ namespace.

  1. kubectl create serviceaccount fleetuser
  2. kubectl create namespace project1
  3. kubectl create -n project1 role fleetuser --verb=get --verb=list --verb=create --verb=delete --resource=gitrepos.fleet.cattle.io
  4. kubectl create -n project1 rolebinding fleetuser --serviceaccount=default:fleetuser --role=fleetuser

If we want to give access to multiple namespaces, we can use a single cluster role with two role bindings:

  1. kubectl create clusterrole fleetuser --verb=get --verb=list --verb=create --verb=delete --resource=gitrepos.fleet.cattle.io
  2. kubectl create -n project1 rolebinding fleetuser --serviceaccount=default:fleetuser --clusterrole=fleetuser
  3. kubectl create -n project2 rolebinding fleetuser --serviceaccount=default:fleetuser --clusterrole=fleetuser

This makes sure, tenants can’t interfere with GitRepo resources from other tenants, since they don’t have access to their namespaces.

Allow Access to Clusters

This assumes all GitRepos created by ‘fleetuser’ have the team: one label. Different labels could be used, to select different cluster namespaces.

In each of the user’s namespaces, as an admin create a BundleNamespaceMapping.

  1. kind: BundleNamespaceMapping
  2. apiVersion: fleet.cattle.io/v1alpha1
  3. metadata:
  4.   name: mapping
  5.   namespace: project1
  7. # Bundles to match by label.
  8. # The labels are defined in the fleet.yaml # labels field or from the
  9. # GitRepo metadata.labels field
  10. bundleSelector:
  11.   matchLabels:
  12.     team: one
  13.     # or target one repo
  14.     #fleet.cattle.io/repo-name: simpleapp
  16. # Namespaces, containing clusters, to match by label
  17. namespaceSelector:
  18.   matchLabels:
  19.     kubernetes.io/metadata.name: fleet-default
  20.     # the label is on the namespace
  21.     #workspace: prod

The target section in the GitRepo resource can be used to deploy only to a subset of the matched clusters.

Restricting Access to Downstream Clusters

Admins can further restrict tenants by creating a GitRepoRestriction in each of their namespaces.

  1. kind: GitRepoRestriction
  2. apiVersion: fleet.cattle.io/v1alpha1
  3. metadata:
  4.   name: restriction
  5.   namespace: project1
  7. allowedTargetNamespaces:
  8.   - project1simpleapp

This will deny the creation of cluster wide resources, which may interfere with other tenants and limit the deployment to the ‘project1simpleapp’ namespace.

An Example GitRepo Resource

A GitRepo resource created by a tenant, without admin access could look like this:

  1. kind: GitRepo
  2. apiVersion: fleet.cattle.io/v1alpha1
  3. metadata:
  4.   name: simpleapp
  5.   namespace: project1
  6.   labels:
  7.     team: one
  9. spec:
  10.   repo: https://github.com/rancher/fleet-examples
  11.   paths:
  12.   - bundle-diffs
  14.   targetNamespace: project1simpleapp
  16.   # do not match the upstream/local cluster, won't work
  17.   targets:
  18.   - name: dev
  19.     clusterSelector:
  20.       matchLabels:
  21.         env: dev

This includes the team: one label and and the required targetNamespace.

Together with the previous BundleNamespaceMapping it would target all clusters with a env: dev label in the ‘fleet-default’ namespace.

Setup Multi User - 图3note

BundleNamespaceMappings do not work with local clusters, so make sure not to target them.