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* Adding annotations and labels to namespaces

Signed-off-by: Garcia De La Villa, Alvaro <alvaro.garcia@lexisnexisrisk.com>

* Reverting namespace object and adding namespaceAttributes

Signed-off-by: Garcia De La Villa, Alvaro <alvaro.garcia@lexisnexisrisk.com>

* Commenting namespace value and deleting unused attributes

Signed-off-by: Garcia De La Villa, Alvaro <alvaro.garcia@lexisnexisrisk.com>
Latest commit 5e00179 Oct 25, 2018

README.md

Magic Namespace

Magic Namespace provides an easy, comprehensive option for cluster operators to manage namespaces and observe good security practices in multi-tenant, RBAC-enabled Kubernetes clusters.

Introduction

So you've got a multi-tenant cluster? Let's assume your cluster is RBAC-enabled. If it isn't, go fix that first. You're playing with fire. Until you fix that, you don't need Magic Namespace. Go fix it. We'll wait...

In a multi-tenant cluster, a cluster operator (someone with full, unrestricted privileges across the entire cluster), will manage users, groups, service accounts, roles, and user/group bindings to roles-- all to either permit or prevent subjects from performing certain actions in different namespaces.

A common paradigm that has emerged is that teams are given their own namespace and some degree of latitude to administer that namespace, whilst not being permitted to perform actions on other teams' namespaces.

Now bring Helm/Tiller into the equation. In an RBAC-enabled cluster, Tiller is so often granted the cluster-admin role-- which gives it "root" access to the entire cluster. While such a Tiller may be suitable for use by a cluster operator, it's not suitable for use by other teams, as it presents them with an easy avenue for escalating their privileges.

To compensate for this, a pattern that has emmerged to complement the namespace-per-team pattern is the tiller-per-namespace pattern. This has been widely adopted in multi-tenant, RBAC-enabled clusters. Until now, cluster operators have tended to create their own bespoke scripts for performing all requisite setup to implement these patterns.

Magic Namespace takes the pain out of this setup. It offers cluster operators an easy, comprehensive avenue for using their Tiller to manage namespaces, service accounts, other Tillers, and role bindings for their consituent teams. Magic Namespace permits cluster operators to manage all of this using familiar Helm-based workflows.

How it Works

By default, Magic Namespace creates a service account for Tiller in the designated namespace and binds it to the admin role for that namespace. It also creates a deployment that utilizes this service account. This can be disabled or configured further, but the default behavior is sensible. In fact, the defaults closes a variety of known Tiller-based attack vectors.

Magic Namespace also offers cluster operators to define additional service accounts and role bindings for use within the namespace. Typically, it would be a good idea to define at least one role binding that grants a user or group administrative privileges in the namespace. Absent this, the namespace's own Tiller will function, but no user (other than the cluster operator) will be capable of interacting with it via Helm.

Prerequisites

  • A Kubernetes cluster with RBAC enabled

Installing the Chart

To install the chart to create the foo namespace (if it doesn't already exist) and useful resources (Tiller, service accounts, etc.) within that namespace:

$ helm install stable/magic-namespace --name foo --namespace foo

Typically, you will want to bind at least one user or group to the admin role in this namespace. Here are steps to follow:

First, make a copy of the default values.yaml:

$ helm inspect values stable/magic-namespace > ~/my-values.yaml

Edit ~/my-values.yaml accordingly. Here is a sample role binding:

...

roleBindings:
- name: admin-group-admin
  role:
    ## Valid values are "Role" or "ClusterRole"
    kind: ClusterRole
    name: admin
  subject:
    ## Valid values are "User", "Group", or "ServiceAccount"
    kind: Group
    name: <group>

...

Deploy as follows:

$ helm install stable/magic-namespace \
  --name foo \
  --namespace foo \
  --values ~/my-values.yaml

Uninstalling the Chart

Deleting a release of a Magic Namespace will not delete the namespace, unless you have used the optional namespace setting. It will only delete the Tiller, service accounts, role bindings, etc. from that namespace. This is actually desirable behavior, as anything the team has deployed within that namespace is likely to be unaffected, though further deployments to and management of that namespace will not be possible by anyone other than the cluster operator.

If you have used the namespace setting, deleting the release will cleanup all releases deployed with the tiller in the Magic Namespace, along with the namespace. If other tillers, such as the one in kube-system have deployed charts into the Magic Namespace, they will get orphaned when the namespace is removed, but they can still be removed with the standard helm delete <name> --purge command.

$ helm delete foo --purge

Configuration

The following table lists the most common, useful, and interesting configuration parameters of the Magic Namespace chart and their default values. Please reference the default values.yaml to understand further options.

Parameter Description Default
tiller.enabled Whether to include a Tiller in the namespace true
tiller.replicaCount The number of Tiller replicas to run 1
tiller.image.repository The Docker image to use for Tiller, minus version/label gcr.io/kubernetes-helm/tiller
tiller.image.tag The specific version/label of the Docker image used for Tiller v2.8.1
tiller.image.pullPolicy The pull policy to utilize when pulling Tiller images from a Docker repsoitory IfNotPresent
tiller.maxHistory The maximum number of releases Tiller should remember. A value of 0 is interpreted as no limit. 0
tiller.role.type Identify the kind of role (Role or ClusterRole) that will be referenced in the role binding for Tiller's service account. There is seldom any reason to override this. ClusterRole
tiller.role.type Identify the name of the Role or ClusterRole that will be referenced in the role binding for Tiller's service account. There is seldom any reason to override this. admin
tiller.includeService This deploys a service resource for Tiller. This is not generally needed. Please understand the security implications of this before overriding the default. false
tiller.onlyListenOnLocalhost This prevents Tiller from binding to 0.0.0.0. This is generally advisable to close known Tiller-based attack vectors. Please understand the security implications of this before overriding the default. true
serviceAccounts An optional array of names of additional service account to create nil
roleBindings An optional array of objects that define role bindings nil
roleBindings[n].role.kind Identify the kind of role (Role or ClusterRole) to be used in the role binding
roleBindings[n].role.name Identify the name of the role to be used in the role binding
roleBindings[n].subject.kind Identify the kind of subject (User, Group, or ServiceAccount ) to be used in the role binding
roleBindings[n].subject.name Identify the name of the subject to be used in the role binding
namespace Specify a namespace to be created and used, overriding the one on the command line
namespaceAttributes.annotations Specify annotations to be attached to the namespace
namespaceAttributes.lables Specify labels to be attached to the namespace