Introduction

Operators framework is the new way to manage complex applications on top of Kubernetes. They embed operational knowledge about applications and manage all the lifecycle from installation, upgrade, monitoring, and even autopilot according to a capability model.

OpenShift 4 is making use of operators, and it offers a way to install operators from a hub called OperatorHub in the web console:

Today, we are going to build a customized operator registry to handle pre-existing operators, configure OpenShift to show these operators, and allow them to install them from the web console catalog.

Perquisites

To accomplish this lab, you will need: OpenShift 4.5+ cluster, operator-sdk, oc CLI, and a Docker v2_2 schema registry (in our case, we will be using quay.io). 

Some commands evolve regarding the CLI versions; please keep in mind to use the following versions, or to update the commands:

$ operator-sdk version operator-sdk version: "v0.18.2", commit: "f059b5e17447b0bbcef50846859519340c17ffad", kubernetes version: "v1.18.2", go version: "go1.14.4 darwin/amd64"
$ oc get clusterversion NAME      VERSION   AVAILABLE   PROGRESSING   SINCE   STATUS version   4.5.5     True        False         3h25m   Cluster version is 4.5.5

Procedure

Build opm CLI:

$ git clone https://github.com/operator-framework/operator-registry.git
$ cd operator-registry && make build

 

Create quay.io repos:

On quay.io, create one repository for the operator memcached-operator, the bundle memcached-bundle, and another for the operator registry operator-registry.

Get an existing operator, build it, and push it:

To build a custom operator, you can use operator-sdk and follow the official documentation. In our case, we will be using an existing one:

 

$ git clone https://github.com/operator-framework/operator-sdk-samples.git
$ cd operator-sdk-samples/ansible/memcached-operator/
$ operator-sdk build quay.io/saberkan/memcached-operator:latest
$ docker push quay.io/saberkan/memcached-operator:latest

 

Replace image in operator deployment:

$ sed -i'.original' -e 's/REPLACE_IMAGE/quay\.io\/saberkan\/memcached-operator\:latest/g' deploy/operator.yaml

 

Generate custom service version:

$ operator-sdk generate csv --csv-version 1.0.0 --interactive=true
INFO[0000] Generating CSV manifest version 1.0.0
Display name for the operator (required):
> memcached-operator
Description for the operator (required):
> memcached-operator
Provider's name for the operator (required):
> saberkan
Any relevant URL for the provider name (optional):
>
Comma-separated list of keywords for your operator (required):
> memcached
Comma-separated list of maintainers and their emails (e.g. 'name1:email1, name2:email2') (required):
> saberkan:salahddine.aberkan@gmail.com
INFO[0024] CSV manifest generated successfully

 

Build and publish the operator bundle:

$ operator-sdk bundle create --generate-only
$ docker build -f bundle.Dockerfile -t quay.io/saberkan/memcached-bundle:1.0.0 .
$ docker push quay.io/saberkan/memcached-bundle:1.0.0

 

Check bundle is valid:

$ ./operator-registry/bin/opm alpha bundle validate --tag quay.io/saberkan/memcached-bundle:1.0.0 --image-builder docker

 

Add the bundle into the registry image and publish it:

$ ./operator-registry/bin/opm index add --bundles quay.io/saberkan/memcached-bundle:1.0.0 --tag quay.io/saberkan/operator-registry:0.1-RC --build-tool docker
$ docker push quay.io/saberkan/operator-registry:0.1-RC

 

Configure Catalog Source on OpenShift:

$ cat << EOF | oc create -f -
apiVersion: operators.coreos.com/v1alpha1
kind: CatalogSource
metadata:
 name: saberkan-catalog-source
 namespace: openshift-marketplace
spec:
 displayName: saberkan-catalog-source
 image: 'quay.io/saberkan/operator-registry:0.1-RC'
 publisher: saberkan
 sourceType: grpc
EOF

 

Check catalog source is ready:

$ oc describe CatalogSource saberkan-catalog-source -n openshift-marketplace | grep 'Last Observed State'

 

Create namespace where to install the operator:

$ oc new-project saberkan

 

Install the operator from web console into the created namespace:

The installation can be also triggered with a subscription manifest. But we are doing it from the web console for a demo purpose:

Check operator installed (after few moments):

$ oc get csv memcached-operator.v1.0.0

NAME                        DISPLAY              VERSION   REPLACES   PHASE

memcached-operator.v1.0.0   memcached-operator   1.0.0                Succeeded

 

Categories

How-tos, Operator Framework, Operators, OpenShift 4.5

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