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Roberto Carratalá

Linux Geek. Devops & Kubernetes enthusiast. Architect @ Red Hat.

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How to deploy fully automated a Kafka cluster using AMQStreams / Strimzi? And how to deploy Kafka clusters without being cluster-admin, using always regular users or local admins to the namespace?

Let’s dig in!

Overview of AMQStreams / Strimzi / Kafka

AMQ Streams provides Operators for managing a Kafka cluster running within an OpenShift cluster.

  • Cluster Operator: Deploys and manages Apache Kafka clusters, Kafka Connect, Kafka MirrorMaker, Kafka Bridge, Kafka Exporter, and the Entity Operator

  • Entity Operator: Comprises the Topic Operator and User Operator

  • Topic Operator: Manages Kafka topics

  • User Operator: Manages Kafka users

The Cluster Operator can deploy the Topic Operator and User Operator as part of an Entity Operator configuration at the same time as a Kafka cluster.

Description of this scenario

The goal in this blog post is to deploy a Kafka cluster in Openshift, using the AMQStreams 1.4 operators (based in Strimzi version 0.17.x and Kafka 2.4.0) deployed as a cluster-admin, and giving strimzi-admin to a regular user to deploy Kafka clusters without being cluster-admin.

Tested and working with 3.11 and 4.3.x.

Installation AMQStreams operator

In the first part of this blog, the AMQStreams Kafka cluster operator, needs to be set deployed as a cluster-admin.

The namespaces used for this installation will be:

  • Namespace for deploy the AMQStreams Cluster Operator: kafkaproject
  • Namespace for deploy the Kafka Cluster / Kafka Topics: test-kafka

Installation of AMQStreams 1.4 Cluster Kafka Operators

This steps need to be implemented with a user with cluster-admin role, such as system:admin.

  1. Download the bits of AMQStreams 1.4 in AMQStreams download site

  2. Extract the files needed for the installation:

$ mkdir $HOME/amq_1.4_install
$ unzip amq-streams-1.4.0-ocp-install-examples.zip -d $HOME/amq_1.4_install
$ export AMQ_STREAMS_HOME=$HOME/amq_1.4_install
  1. Login as an cluster-admin user, in our case with the name admin:
$ oc login -u admin -p xxxxxx
$ oc get users admin
NAME      UID                                    FULL NAME   IDENTITIES
admin     5ac66c87-9376-11ea-ac11-02ec1020384e               htpasswd_auth:admin
  1. With this user cluster admin (only used for deploying the cluster-operator), create the namespace/ project for the AMQStreams Kafka Cluster Operator
$ oc new-project kafkaproject
$ cd $AMQ_STREAMS_HOME
  1. Modify the installation files (rolebindings among others) to reference the new kafkaproject namespace where you will install the AMQ Streams Kafka Cluster Operator.
$ sed -i 's/namespace: .*/namespace: kafkaproject/' install/cluster-operator/*RoleBinding*.yaml
  1. Deploy the CRDs and role-based access control (RBAC) resources to manage the CRDs.
$ oc project kafkaproject
$ oc apply -f install/cluster-operator/
  • Check that the cluster operator is deployed properly.
$ oc get pod
NAME                                        READY     STATUS    RESTARTS   AGE
strimzi-cluster-operator-66f9b9c68d-jk6w2   0/1       Running   0          1m

Prepare and adjust the roles and bindings to allow users interact to the kafka cluster operator/crd

For allow to deploy and manage by a regular user (non cluster-admin), the Kafka CRDs created in the installation of the AMQStreams operators, some adjusts need to be done.

  1. Create a new test-kafka namespace where you will deploy your Kafka cluster.
$ oc new-project test-kafka
  1. Give access to my-kafka-project to a non-admin user andrew.

Our developer Andrew, wanted to create kafka clusters but without have the cluster-admin privileges.

Andrew is a regular user with non privileged within the group of “system:authenticated:oauth”.

This user have no privileges for read/modify the resources in the namespace that will be used for deploy the kafka cluster:

# oc get pvc --as=andrew
No resources found.
Error from server (Forbidden): persistentvolumeclaims is forbidden: User "andrew" cannot list
persistentvolumeclaims in the namespace "test-kafka": no RBAC policy matched

NOTE: For determine the full list of verbs that can the user perform use:

oc policy can-i --list --as=andrew
  1. give to Andrew user local admin privileges (namespace-wide):
oc adm policy add-role-to-user admin andrew -n test-kafka
role "admin" added: "andrew"

Check that the user andrew only have capabilities of admin in the namespace test-kafka:

# oc get node --as=andrew
No resources found.
Error from server (Forbidden): nodes is forbidden: User "andrew" cannot list nodes at the cluster
scope: no RBAC policy matched

$ oc get pvc --as=andrew -n test-kafka
 No resources found.

$ oc get secret --as=andrew -n test-kafka
NAME                       TYPE                                  DATA      AGE
builder-dockercfg-j9b4m    kubernetes.io/dockercfg               1         2h
builder-token-7fxmp        kubernetes.io/service-account-token   4         2h
builder-token-kx8zm        kubernetes.io/service-account-token   4         2h
default-dockercfg-pgs8j    kubernetes.io/dockercfg               1         2h

As we can see, Andrew can list PVCs and secrets into the namespace test-kafka, but not list nodes.

  1. Give permission to the Cluster Operator to watch the my-kafka-project namespace.
$ oc set env deploy/strimzi-cluster-operator STRIMZI_NAMESPACE=kafkaproject,test-kafka -n
 kafkaproject
 deployment.extensions/strimzi-cluster-operator updated
$ oc apply -f install/cluster-operator/020-RoleBinding-strimzi-cluster-operator.yaml -n test-kafka
 rolebinding.rbac.authorization.k8s.io/strimzi-cluster-operator created

$ oc apply -f install/cluster-operator/032-RoleBinding-strimzi-cluster-operator-topic-operator-delegation.yaml -n test-kafka
 rolebinding.rbac.authorization.k8s.io/strimzi-cluster-operator-topic-operator-delegation created

$ oc apply -f install/cluster-operator/031-RoleBinding-strimzi-cluster-operator-entity-operator-delegation.yaml -n test-kafka
 rolebinding.rbac.authorization.k8s.io/strimzi-cluster-operator-entity-operator-delegation created

The commands create role bindings that grant permission for the Cluster Operator to access the Kafka cluster.

  1. Create a new cluster role strimzi-admin.
# oc apply -f install/strimzi-admin
clusterrole.rbac.authorization.k8s.io/strimzi-admin created

This cluster role defines the strimzi-admin, a role that allow the interaction with the CRDs and the kafka cluster operator:

$ cat install/strimzi-admin/010-ClusterRole-strimzi-admin.yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: strimzi-admin
  labels:
    app: strimzi
rules:
- apiGroups:
  - "kafka.strimzi.io"
  resources:
  - kafkas
  - kafkaconnects
  - kafkaconnects2is
  - kafkamirrormakers
  - kafkausers
  - kafkatopics
  - kafkabridges
  - kafkaconnectors
  - kafkamirrormaker2s
  verbs:
  - get
  - list
  - watch
  - create
  - delete
  - patch
  - update
  1. Check that the local admin user andrew can’t list any crd of kafka:
$ oc get kafkausers --as=andrew
Error from server (Forbidden): kafkausers.kafka.strimzi.io is forbidden: User "andrew" cannot list kafkausers.kafka.strimzi.io in the namespace "test-kafka": no RBAC policy matched
# oc get kafkaconnects --as=andrew
No resources found.
Error from server (Forbidden): kafkaconnects.kafka.strimzi.io is forbidden: User "andrew" cannot list kafkaconnects.kafka.strimzi.io in the namespace "test-kafka": no RBAC policy matched
  1. Apply the clusterroles to the user andrew to allow them to manage objects from the kafka crds (and also interaction with the kafka cluster operator):
$ oc adm policy add-cluster-role-to-user strimzi-admin andrew
cluster role "strimzi-admin" added: "andrew"

Check that the andrew user can now to manage kafka crds objects:

$ oc get kafkaconnects --as=andrew
No resources found.

Deploy Kafka Clusters as a regular user

  1. Login as andrew and switch to the namespace test-kafka
$ oc login -u andrew
$ oc project test-kafka
$ oc whoami
andrew
  1. Create a new my-cluster Kafka cluster with 3 Zookeeper and 3 broker nodes.
$ cat << EOF | oc create -f -
apiVersion: kafka.strimzi.io/v1beta1
kind: Kafka
metadata:
  name: my-cluster
spec:
  kafka:
    replicas: 3
    listeners:
      plain: {}
      tls: {}
      external:
        type: route
    storage:
      type: ephemeral
  zookeeper:
    replicas: 3
    storage:
      type: ephemeral
  entityOperator:
    topicOperator: {}
EOF
kafka.kafka.strimzi.io/my-cluster created
# oc get pod -n test-kafka
NAME                                         READY     STATUS    RESTARTS   AGE
my-cluster-entity-operator-556b956cf-zm4ls   2/2       Running   0          1m
my-cluster-kafka-0                           2/2       Running   0          2m
my-cluster-kafka-1                           2/2       Running   0          2m
my-cluster-kafka-2                           2/2       Running   0          2m
my-cluster-zookeeper-0                       2/2       Running   0          4m
my-cluster-zookeeper-1                       2/2       Running   0          4m
my-cluster-zookeeper-2                       2/2       Running   0          4m

$ oc get kafka my-cluster
NAME         DESIRED KAFKA REPLICAS   DESIRED ZK REPLICAS
my-cluster   3                        3

Deploy a Topic in your Kafka cluster

  1. When your cluster is ready, create a topic to publish and subscribe from your external client.
cat << EOF | oc create -f -
apiVersion: kafka.strimzi.io/v1beta1
kind: KafkaTopic
metadata:
  name: rober-topic
  labels:
    strimzi.io/cluster: "my-cluster"
spec:
  partitions: 3
  replicas: 3
EOF
kafkatopic.kafka.strimzi.io/rober-topic created
$ oc get kafkatopic
NAME          PARTITIONS   REPLICATION FACTOR
rober-topic   3            3

And that’s it! Hope that helps!

Happy AMQStreaming!