From 67a31eeb667f48fe5be0d312b96dead863b3c93e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicolas=20Mass=C3=A9?= <nicolas.masse@itix.fr>
Date: Fri, 24 Apr 2020 16:23:11 +0200
Subject: [PATCH] new article about operators

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+---
+title: "Install Kubernetes operators in OpenShift using only the CLI"
+date: 2020-04-24T00:00:00+02:00
+opensource: 
+- OpenShift
+---
+
+OpenShift 4 went all-in on Kubernetes operators: they are used for installation of the platform itself but also to install databases, middlewares, etc.
+There are more and more operators available on the [Operator Hub](https://operatorhub.io/).
+Most software now provide an operator and describe how to use it.
+
+Nevertheless, almost every software documentation I read so far, includes the steps to install the operator using the nice GUI of OpenShift 4.
+But since my OpenShift environments are provisioned by a playbook, I want to be able to install operators using the CLI only!
+
+The [OpenShift official documentation](https://docs.openshift.com/container-platform/4.3/operators/olm-adding-operators-to-cluster.html#olm-installing-operator-from-operatorhub-using-cli_olm-adding-operators-to-a-cluster) covers this part but I did not find it very clear.
+So, this article tries to make it clearer: **how to install Kubernetes operators in OpenShift using only the CLI**.
+
+## Discover the available operators from the CLI
+
+Discover the operators available on your platform.
+
+```sh
+oc get packagemanifests -n openshift-marketplace --sort-by=.metadata.name
+```
+
+This should give you a very long list of operators.
+You can filter it to retain only the ones you need.
+
+For instance, to discover the operators required to install Red Hat Service Mesh / Istio:
+
+```
+$ oc get packagemanifests -n openshift-marketplace |egrep -i '(elastic|jaeger|kiali|service.*mesh)'
+elasticsearch-operator                       Red Hat Operators     47h
+jaeger-product                               Red Hat Operators     47h
+jaeger                                       Community Operators   47h
+kiali                                        Community Operators   47h
+kiali-ossm                                   Red Hat Operators     47h
+servicemeshoperator                          Red Hat Operators     47h
+```
+
+The second column is the display name of the operator source.
+Later in the procedure, we will need the identifier of the operator source.
+
+Query it programmatically for a specific operator using the following command.
+
+```sh
+oc get packagemanifests -n openshift-marketplace -o jsonpath='{.status.catalogSource}{"\n"}' elasticsearch-operator
+```
+
+In the rest of this article, we will install Elastic Search using the **elasticsearch-operator** coming from the **redhat-operators** source using the CLI.
+
+Query the available channels for this operator using the follwing command.
+
+```sh
+oc get packagemanifest -o jsonpath='{range .status.channels[*]}{.name}{"\n"}{end}{"\n"}' -n openshift-marketplace elasticsearch-operator
+```
+
+When this article was written, the Elastic Search operator had four channels:
+
+```
+4.2
+4.2-s390x
+4.3
+preview
+```
+
+In the rest of this article we will install version 4.3 using the CLI.
+
+Finally discover whether the operator can be installed cluster-wide or in a single namespace.
+
+```sh
+oc get packagemanifest -o jsonpath='{range .status.channels[*]}{.name}{" => cluster-wide: "}{.currentCSVDesc.installModes[?(@.type=="AllNamespaces")].supported}{"\n"}{end}{"\n"}' -n openshift-marketplace elasticsearch-operator
+```
+
+You will discover that the Elastic Search operator can be installed cluster-wide for all of its four channels.
+
+```
+4.2 => cluster-wide: true
+4.2-s390x => cluster-wide: true
+4.3 => cluster-wide: true
+preview => cluster-wide: true
+```
+
+The rest of the procedure varies slightly depending if the operator supports cluster-wide installation or not.
+
+## Install an operator cluster-wide using the CLI
+
+To install an operator cluster-wide using the CLI, create a Subscription object in the **openshift-operators** namespace.
+
+```sh
+oc apply -f - <<EOF
+apiVersion: operators.coreos.com/v1alpha1
+kind: Subscription
+metadata:
+  name: elasticsearch-operator
+  namespace: openshift-operators
+spec:
+  channel: "4.3"
+  name: elasticsearch-operator
+  source: redhat-operators
+  sourceNamespace: openshift-marketplace
+EOF
+```
+
+The outstanding fields of the Subscription object are:
+
+* **metadata.name**: name of your subscription. *free choice*
+* **metadata.namespace**: for a cluster-wide installation, the value is fixed: *openshift-operators*
+* **spec.channel**: the channel to install (see above the output of the *oc get packagemanifest* command)
+* **spec.name**: the name of the operator to install
+* **spec.source**: the id of the operator source (currently there are three operator sources: *certified-operators*, *community-operators* and *redhat-operators*)
+* **spec.sourceNamespace**: fixed value (*openshift-marketplace*)
+
+Ensure the Elastic Search operator has been deployed successfully in the **openshift-operators** namespace.
+
+```
+$ oc get pods -n openshift-operators -l name=elasticsearch-operator
+NAME                                      READY   STATUS    RESTARTS   AGE
+elasticsearch-operator-6697867687-x7r6t   1/1     Running   0          3d6h
+```
+
+## Install an operator in a namespace using the CLI
+
+To install an operator in a specific project, you need to create first an OperatorGroup in the target namespace.
+An OperatorGroup is an OLM resource that selects target namespaces in which to generate required RBAC access for all Operators in the same namespace as the OperatorGroup.
+
+Create a new project.
+
+```sh
+oc new-project my-project
+```
+
+Create an **OperatorGroup** object in your project.
+
+```sh
+oc apply -f - <<EOF
+apiVersion: operators.coreos.com/v1
+kind: OperatorGroup
+metadata:
+  name: my-project
+  namespace: my-project
+spec:
+  targetNamespaces:
+  - my-project
+EOF
+```
+
+The outstanding fields of the OperatorGroup object are:
+
+* **metadata.name**: name of your OperatorGroup. *free choice*
+* **metadata.namespace**: the namespace in which you want to deploy your operator.
+* **spec.targetNamespaces[0]**: the namespace in which you want to deploy your operator (again).
+
+Once the subscription is created, the OLM should create a CSV (ClusterServiceVersion):
+
+```
+$ oc get csv
+NAME                                         DISPLAY                  VERSION               REPLACES                                     PHASE
+elasticsearch-operator.4.3.13-202004131016   Elasticsearch Operator   4.3.13-202004131016   elasticsearch-operator.4.3.10-202003311428   Succeeded
+```
+
+If the CSV is not created, it might be because there are multiple OperatorGroup object in the namespace.
+Delete them all before recreating the one you need.
+
+You can then create the Subscription object in **your project**.
+
+```sh
+oc apply -f - <<EOF
+apiVersion: operators.coreos.com/v1alpha1
+kind: Subscription
+metadata:
+  name: elasticsearch-operator
+  namespace: my-project
+spec:
+  channel: "4.3"
+  name: elasticsearch-operator
+  source: redhat-operators
+  sourceNamespace: openshift-marketplace
+EOF
+```
+
+The meaning of each field is the same as described above in the section **Install an operator cluster-wide using the CLI**.
+
+## Use the installed operator
+
+Once installed, you will want to use the operator to perform something useful.
+All the capabilities of your newly installed operator are described in the ClusterServiceVersion (CSV) created automatically by the Operator Lifecycle Manager (OLM).
+
+```
+$ oc get csv
+NAME                                         DISPLAY                  VERSION               REPLACES                                     PHASE
+elasticsearch-operator.4.3.13-202004131016   Elasticsearch Operator   4.3.13-202004131016   elasticsearch-operator.4.3.10-202003311428   Succeeded
+```
+
+You can get details about the Custom Resource Definitions (CRD) supported by the operator or retrieve some sample CRDs.
+
+Get the CSV name of the installed Elastic Search operator.
+
+```sh
+CSV=$(oc get csv -o name |grep /elasticsearch-operator.)
+```
+
+Now you can query the CRDs enabled by your operator.
+
+```sh
+oc get $CSV -o json |jq -r '.spec.customresourcedefinitions.owned[]|.name'
+```
+
+This will return a list of fully qualified CRDs:
+
+```
+elasticsearches.logging.openshift.io
+```
+
+You can also retrieve the sample CRDs if you need some help to get started.
+
+```sh
+oc get $CSV -o json |jq -r '.metadata.annotations["alm-examples"]'
+```
+
+For example, you can create an Elastic Search instance by using the provided sample CRD.
+
+```sh
+oc get $CSV -o json |jq -r '.metadata.annotations["alm-examples"]' |jq '.[0]' |oc apply -f -
+```
+
+And then retrieve all the created objects belonging to the operator.
+
+```sh
+oc get $(oc get $CSV -o json |jq -r '[.spec.customresourcedefinitions.owned[]|.name]|join(",")')
+```
+
+## Conclusion
+
+This article explained how to install Kubernetes operators in OpenShift using only the CLI and also how to use them afterwards without having to use to the OpenShift console!