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Install ClickHouse Operator

Prerequisites

  1. Kubernetes instance with the following version considerations:
    1. clickhouse-operator versions before 0.16.0 is compatible with Kubenetes after 1.16 and prior 1.22.
    2. clickhouse-operator versions 0.16.0 and after is compatible Kubernetes version 1.16 and after.
  2. Properly configured kubectl
  3. curl

Verify the Docker manifest is available based on the version table, replacing {OPERATOR_VERSION} with the specific version. For example, for version 0.16.0, the URL would be https://github.com/Altinity/clickhouse-operator/raw/0.16.0/deploy/operator/clickhouse-operator-install-bundle.yaml.

clickhouse-operator version Kubernetes version Docker manifest URL
Current Kubernetes 1.16+ https://raw.githubusercontent.com/Altinity/clickhouse-operator/master/deploy/operator/clickhouse-operator-install-bundle.yaml
Current Kubernetes before 1.16 (Beta) https://github.com/Altinity/clickhouse-operator/raw/master/deploy/operator/clickhouse-operator-install-bundle-v1beta1.yaml
0.16.0 and greater Kubernetes 1.16+ https://github.com/Altinity/clickhouse-operator/raw/{OPERATOR_VERSION}/deploy/operator/clickhouse-operator-install-bundle.yaml
Before 0.16.0 Kubernetes after 1.16 and before 1.22 kubectl apply -f https://github.com/Altinity/clickhouse-operator/raw/{OPERATOR_VERSION}/deploy/operator/clickhouse-operator-install.yaml

clickhouse-operator-install-bundle.yaml file availability. In is located in deploy/operator folder inside clickhouse-operator sources.

Install

Operator installation process is quite straightforward and consists of one main step - deploy ClickHouse operator. We'll apply operator manifest directly from github repo

kubectl apply -f https://raw.githubusercontent.com/Altinity/clickhouse-operator/master/deploy/operator/clickhouse-operator-install-bundle.yaml

The following results are expected:

customresourcedefinition.apiextensions.k8s.io/clickhouseinstallations.clickhouse.altinity.com created
serviceaccount/clickhouse-operator created
clusterrolebinding.rbac.authorization.k8s.io/clickhouse-operator created
deployment.apps/clickhouse-operator configured

Verify operator is up and running

Operator is deployed in kube-system namespace.

kubectl get pods --namespace kube-system

Expected results:

NAME                                   READY   STATUS    RESTARTS   AGE
...
clickhouse-operator-5c46dfc7bd-7cz5l   1/1     Running   0          43m
...

Resources Description

Let's walk over all resources created along with ClickHouse operator, which are:

  1. Custom Resource Definition
  2. Service account
  3. Cluster Role Binding
  4. Deployment

Custom Resource Definition

customresourcedefinition.apiextensions.k8s.io/clickhouseinstallations.clickhouse.altinity.com created

New Custom Resource Definition named ClickHouseInstallation is created. k8s API is extended with new kind ClickHouseInstallation and we'll be able to manage k8s resource of kind: ClickHouseInstallation

Service Account

serviceaccount/clickhouse-operator created

New Service Account named clickhouse-operator is created. A service account provides an identity used to contact the apiserver by the processes that run in a Pod. Processes in containers inside pods can contact the apiserver, and when they do, they are authenticated as a particular Service Account - clickhouse-operator in this case.

Cluster Role Binding

clusterrolebinding.rbac.authorization.k8s.io/clickhouse-operator created

New CluserRoleBinding named clickhouse-operator is created. A role binding grants the permissions defined in a role to a set of users. It holds a reference to the role being granted to the list of subjects (users, groups, or service accounts). In this case Role

roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin

is being granted to

subjects:
  - kind: ServiceAccount
    name: clickhouse-operator
    namespace: kube-system

clickhouse-operator Service Account created earlier. Permissions are granted cluster-wide with a ClusterRoleBinding.

Deployment

deployment.apps/clickhouse-operator configured

New Deployment named clickhouse-operator is created. ClickHouse operator app would be run by this deployment in kube-system namespace.

Verify Resources

Check Custom Resource Definition

kubectl get customresourcedefinitions

Expected result

NAME                                              CREATED AT
...
clickhouseinstallations.clickhouse.altinity.com   2019-01-25T10:17:57Z
...

Check Service Account

kubectl get serviceaccounts -n kube-system

Expected result

NAME                                 SECRETS   AGE
...
clickhouse-operator                  1         27h
...

Check Cluster Role Binding

kubectl get clusterrolebinding

Expected result

NAME                                                   AGE
...
clickhouse-operator                                    31m
...

Check deployment

kubectl get deployments --namespace kube-system

Expected result

NAME                   READY   UP-TO-DATE   AVAILABLE   AGE
...
clickhouse-operator    1/1     1            1           31m
...