memcached-operator-with-okt

Intro

This Operator is only usable with the Operators Karma Tools (OKT), see usage below, which relies itself on the OperatorSDK, a tool to build Kubernetes Operators.

This code just to illustrate an implementation to compare with the original Memcached Operator implemented with the OperatorSDK alone.

• Note that we de-activated the webhooks in the main.go file. Uncomment to re-activate them if you have generated the expected certificates.
• The go.mod file is updated to depend on a local clone of OKT (recommended). A replace rule is added to use OKT locally if needed. The line is commented in order to pick up OKT on Orange's Gitlab directly instead.
• Have a look of the integration of the OKT Reconciler in controller/memcached_controller.go to perform the reconciliation
• The Deployment resource files (controller/MCDeployment.go and controller/DeploymentStub.go) have been created thanks to the gen-res.sh shell script in the Controller folder.
• controller/MCDeployment.go is the file where you implement your own mutation for this resource throug 3 dedicated GO methods to customize:
  • 1-define the scope of data to put in the hash computation for change detection,
  • 2-fill initial data in the 'Expected' GO struct object (to use to update the K8S cluster),
  • 3-apply CR values in the 'Expected' object.
• The controller/DeploymentStub.go is a wrapper on a K8S Deployment resource/version. It would be shared among several Deployment resources used by this controller, if any. This file is not intended to be modified.
• The gen-res.sh shell depends on the installation of the okt-gen-res binary in your PATH. To install it, download OKT repo and install the command thanks to the Makefile. It will install the command in $HOME/bin (see OKT documentation).

Usage

Clone OKT and Memcached-with-OKT repositries

    $ cd $HOME/go/src
$ git clone https://github.com/Orange-OpenSource/Operators-Karma-Tools.git
$ git clone https://github.com/tapairmax/memcached-operator-with-okt.git

Memcached project Init

$ make generate
$ make manifests

Memcached project Local Run and example of output

$ make install run
....
2021-...Z        INFO    controllers.Memcached.ENV=dev   History: >CRChecker>ObjectsGetter>Mutator>Updater>SuccessManager>End
2021-...Z        INFO    controllers.Memcached.ENV=dev   Op: CR is succesfully picked up on Cluster      {"res": "Memcached/memcached-sample"}
2021-...Z        INFO    controllers.Memcached.ENV=dev   Op: resource registration success       {"res": "Deployment/memcached-sample"}
2021-...Z        INFO    controllers.Memcached.ENV=dev   Op: resource mutation success   {"res": "Deployment/memcached-sample"}
2021-...Z        INFO    controllers.Memcached.ENV=dev   Op: resource unchanged  {"res": "Deployment/memcached-sample"}
2021-...Z        INFO    controllers.Memcached.ENV=dev   Op: status updated      {"res": "Memcached/memcached-sample"}
2021-...Z        INFO    controllers.Memcached.ENV=dev   Consolidated requeue duration: 0 seconds
2021-...Z        INFO    controllers.Memcached.ENV=dev   1 CR is succesfully picked up on Cluster
2021-...Z        INFO    controllers.Memcached.ENV=dev   1 resource registration success
2021-...Z        INFO    controllers.Memcached.ENV=dev   1 resource mutation success
2021-...Z        INFO    controllers.Memcached.ENV=dev   1 resource unchanged
2021-...Z        INFO    controllers.Memcached.ENV=dev   1 status updated
2021-...Z        INFO    controllers.Memcached.ENV=dev   5 Ops(s)
2021-...Z        INFO    controllers.Memcached.ENV=dev   0 Error(s)

Memcached CR creation

$ vi config/samples/cache_v1alpha1_memcached.yaml
$ kubectl create -f config/samples/cache_v1alpha1_memcached.yaml

Memcached project Wait for Reconciliation success (after failure for example)

$ kubectl wait --for=condition=ReconciliationSuccess Memcached/memcached-sample

Memcached project Cleanup

$ kubectl delete -f config/samples/cache_v1alpha1_memcached.yaml
$ make undeploy

Memcached Application Lifecyle concerns thanks to a State Machine

Please see the markdown here