Aerospike Kubernetes Operator

Overview

The Aerospike Kubernetes Operator automates the deployment and management of Aerospike enterprise clusters on Kubernetes. The Operator provides a controller that manages a Custom Resource Definition (CRD) to extend the Kubernetes API for Aerospike Enterprise clusters. Aerospike cluster deployment and life cycle management are performed by updating an Aerospike cluster Custom Resource (CR).

Documentation

For full documentation please visit the official documentation.

What features does it provide?

The goal of the Operator is to give you the ability to deploy multi-node Aerospike clusters, recover automatically from node failures, scale up or down automatically as load changes, ensure nodes are evenly split across racks or zones, automatically update to new versions of Aerospike and manage configuration changes in your clusters.

The Operator supports the following capabilities:

• Deploy Aerospike clusters
• Scale up and down existing Aerospike clusters
• Version upgrade and downgrade
• Configure persistent storage and resource allocation
• Standardize and validate configurations
• Cluster security management

Building and quick start

Generate CRD manifests

make generate
make manifests

Build and push operator image

Run the following command with the appropriate name and version for the operator's image.

IMAGE_TAG_BASE=aerospike/aerospike-kubernetes-operator-nightly
VERSION=2.4.0
make docker-buildx IMG=${IMAGE_TAG_BASE}:${VERSION} PLATFORMS=linux/amd64

Note: Change PLATFORMS var as per host machine or remove it to build multi-arch image

Developer testing

You can use the following for quickly trying out the operator without using OLM.

Deploy

Make sure cert-manager is deployed on your Kubernetes cluster using instructions here.

To deploy the operator build in the previous step run

make deploy IMG=${IMAGE_TAG_BASE}:${VERSION}

Undeploy

To undeploy run

make undeploy IMG=${IMAGE_TAG_BASE}:${VERSION}

Note: This will also delete the deployed Aerospike clusters because the CRD definitions and all operator related objects are deleted.

Operator Lifecycle Manager (OLM) integration bundle

Operator Lifecycle Manager (OLM) is a tool to help manage the Operators running on your cluster. This is the preferred way to manage Kubernetes operators in production. This section describes how to generate the OLM bundle and run the operator using OLM.

Install operator-sdk

Install operator-sdk version 1.10.1 using the installation guide

Build the bundle

Make sure the operator's image has also been pushed.

Set up the environment with image names.

export ACCOUNT=aerospike
export IMAGE_TAG_BASE=${ACCOUNT}/aerospike-kubernetes-operator
export VERSION=2.4.0
export IMG=docker.io/${IMAGE_TAG_BASE}-nightly:${VERSION}
export BUNDLE_IMG=docker.io/${IMAGE_TAG_BASE}-bundle-nightly:${VERSION}

Create the bundle

make bundle

Build bundle image and publish

make bundle-build bundle-push

Deploy operator with OLM

Install OLM if not already done

operator-sdk olm install

Create aerospike namespace if it does not exist

kubectl create namespace aerospike

Deploy the operator targeting a single namespace

Run the operator bundle

operator-sdk run bundle $BUNDLE_IMG --namespace=aerospike

Deploy the operator targeting multiple namespaces

Assuming you want the operator to target two other namespaces ns1 and ns2, deploy the operator with MultiNamespace install mode.

operator-sdk run bundle $BUNDLE_IMG --namespace=aerospike --install-mode MultiNamespace=ns1,ns2

For each additional targeted namespace

• Create the operator service account for that namespace

# Replace ns1 with your target namespace
kubectl -n ns1 create  serviceaccount aerospike-operator-controller-manager

• Find the cluster role binding created for the operator and add the service account created above

kubectl get clusterrolebindings.rbac.authorization.k8s.io  | grep aerospike-kubernetes-operator
aerospike-kubernetes-operator.v2.4.0-74b946466d                 ClusterRole/aerospike-kubernetes-operator.v2.4.0-74b946466d   41m

In the example above the name of the cluster role binding is aerospike-kubernetes-operator.v2.4.0-74b946466d

Edit the role binding and add a new subject entry for the service account

# Replace aerospike-kubernetes-operator.v2.4.0-5-dev-74b946466d with the name of the cluster role binding found above
kubectl edit clusterrolebindings.rbac.authorization.k8s.io  aerospike-kubernetes-operator.v2.4.0-5-dev-74b946466d

In the editor that is launched append the following lines to the subjects section as shown below

  # A new entry for ns1.
  # Replace ns1 with your namespace
  - kind: ServiceAccount
    name: aerospike-operator-controller-manager
    namespace: ns1

Here is a full example

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  creationTimestamp: "2021-09-16T10:48:36Z"
  labels:
    olm.owner: aerospike-kubernetes-operator.v2.4.0-5-dev
    olm.owner.kind: ClusterServiceVersion
    olm.owner.namespace: test
    operators.coreos.com/aerospike-kubernetes-operator.test: ""
  name: aerospike-kubernetes-operator.v2.4.0-5-dev-74b946466d
  resourceVersion: "51841234"
  uid: be546dd5-b21e-4cc3-8a07-e2fe5fe5274c
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: aerospike-kubernetes-operator.v2.4.0-5-dev-74b946466d
subjects:
  - kind: ServiceAccount
    name: aerospike-operator-controller-manager
    namespace: aerospike

  # New entry
  - kind: ServiceAccount
    name: aerospike-operator-controller-manager
    namespace: ns1

Save and ensure that the changes are applied.

Deploy your Aerospike clusters

Deploy Aerospike clusters using the Operator documentation here.

Undeploy operator with OLM

operator-sdk cleanup aerospike-kubernetes-operator --namespace=aerospike

Running tests

The operator tests require following prerequisites

• A running Kubernetes cluster with at least 3 nodes with at least 12 CPUs
• A storage class named "ssd" that allows provisioning of filesystem and block devices
• The kubectl command configured to use the above cluster
• OLM bundle image created with as described here
• No production services should be running on this cluster - including the operator or production Aerospike clusters

The operator tests create and use three namespaces

• test
• test1
• test2

Run the entire test suite

./test/test.sh $BUNDLE_IMG

Run tests matching a regex

./test/test.sh $BUNDLE_IMG '-ginkgo.focus=".*MultiCluster.*"'

Architecture

The Aerospike Kubernetes Operator has a custom controller (written in go) that allows us to embed specific lifecycle management logic to effectively manage the state of an Aerospike cluster. It does so by managing a Custom Resource Definition (CRD) to extend the Kubernetes API for Aerospike clusters. Regular maintenance to the Aerospike cluster deployment and management can be performed by updating an Aerospike cluster Custom Resource (CR).

The Operator is deployed with StatefulSet and operates as a headless service to handle the DNS resolution of pods in the deployment. Kubernetes StatefulSets is the workload API object that is used to manage stateful applications. It is important because it manages the deployment and scaling of a set of Pods, and provides guarantees about the ordering and uniqueness of these Pods (e.g. as unique addressable identities).

A layered approach is taken to orchestration which allows the Operator to manage Aerospike Cluster tasks outside the Aerospike deployment.

See also

• Kubernetes