OpenShift 4.3环境中创建基于Go的Operator

详细步骤可以参考官方文档

https://docs.openshift.com/container-platform/4.3/operators/operator_sdk/osdk-getting-started.html

我这里只是记录一些中间过程和思考。

0.环境变量

GOROOT和GOPATH分开

[root@clientvm  ~]# cat .bash_profile

# .bash_profile

# Get the aliases and functions

if [ -f ~/.bashrc ]; then

        . ~/.bashrc

fi

# User specific environment and startup programs

export GOROOT=/usr/local/go

export GOPATH=/root

export PATH=$PATH:$HOME/bin:/usr/local/bin:/usr/local/maven/bin:/usr/local/go/bin

export GUID=`hostname | awk -F. '{print $2}'`

export KUBECONFIG=/root/cluster-/auth/kubeconfig

1.项目结构

operator-sdk new memcached-operator

[root@clientvm  ~/src/github.com/example-inc]# tree memcached-operator/

memcached-operator/

├── build

│   ├── bin

│   │   ├── entrypoint

│   │   └── user_setup

│   └── Dockerfile

├── cmd

│   └── manager

│       └── main.go

├── deploy

│   ├── operator.yaml

│   ├── role_binding.yaml

│   ├── role.yaml

│   └── service_account.yaml

├── go.mod

├── go.sum

├── pkg

│   ├── apis

│   │   └── apis.go

│   └── controller

│       └── controller.go

├── tools.go

└── version

    └── version.go

 directories,  files

2.添加CRD

operator-sdk add api \

    --api-version=cache.example.com/v1alpha1 \

    --kind=Memcached

[root@clientvm  ~/src/github.com/example-inc/memcached-operator]# tree pkg

pkg

├── apis

│   ├── addtoscheme_cache_v1alpha1.go

│   ├── apis.go

│   └── cache

│       ├── group.go

│       └── v1alpha1

│           ├── doc.go

│           ├── memcached_types.go

│           ├── register.go

│           ├── zz_generated.deepcopy.go

│           └── zz_generated.openapi.go

└── controller

    └── controller.go

 directories,  files

3.添加控制器

operator-sdk add controller \

    --api-version=cache.example.com/v1alpha1 \

    --kind=Memcached

INFO[0000] Generating controller version cache.example.com/v1alpha1 for kind Memcached.
INFO[0000] Created pkg/controller/memcached/memcached_controller.go
INFO[0000] Created pkg/controller/add_memcached.go
INFO[0000] Controller generation complete.

[root@clientvm  ~/src/github.com/example-inc/memcached-operator]# tree pkg

pkg

├── apis

│   ├── addtoscheme_cache_v1alpha1.go

│   ├── apis.go

│   └── cache

│       ├── group.go

│       └── v1alpha1

│           ├── doc.go

│           ├── memcached_types.go

│           ├── register.go

│           ├── zz_generated.deepcopy.go

│           └── zz_generated.openapi.go

└── controller

    ├── add_memcached.go

    ├── controller.go

    └── memcached

        └── memcached_controller.go

 directories,  files

比较核心的就是memcached_controller.go这个文件，修改完后的参考

https://github.com/operator-framework/operator-sdk/blob/master/example/memcached-operator/memcached_controller.go.tmpl

主要是几个部分：

watch方法：自动生成的文件是watch pod, 而我们基于deployment部署，所以要修改。

err := c.Watch(&source.Kind{Type: &appsv1.Deployment{}}, &handler.EnqueueRequestForOwner{

        IsController: true,

        OwnerType:    &cachev1alpha1.Memcached{},

    })

Reconcile: 调节器，也就是根据CR的配置进行调整。

func (r *ReconcileMemcached) Reconcile(request reconcile.Request) (reconcile.Result, error)

deploymentForMemcached:决定了CR如何创建

// deploymentForMemcached returns a memcached Deployment object

func (r *ReconcileMemcached) deploymentForMemcached(m *cachev1alpha1.Memcached) *appsv1.Deployment {

    ls := labelsForMemcached(m.Name)

    replicas := m.Spec.Size

    dep := &appsv1.Deployment{

        ObjectMeta: metav1.ObjectMeta{

            Name:      m.Name,

            Namespace: m.Namespace,

        },

        Spec: appsv1.DeploymentSpec{

            Replicas: &replicas,

            Selector: &metav1.LabelSelector{

                MatchLabels: ls,

            },

            Template: corev1.PodTemplateSpec{

                ObjectMeta: metav1.ObjectMeta{

                    Labels: ls,

                },

                Spec: corev1.PodSpec{

                    Containers: []corev1.Container{{

                        Image:   "memcached:1.4.36-alpine",

                        Name:    "memcached",

                        Command: []string{"memcached", "-m=64", "-o", "modern", "-v"},

                        Ports: []corev1.ContainerPort{{

                            ContainerPort: ,

                            Name:          "memcached",

                        }},

                    }},

                },

            },

        },

    }

    // Set Memcached instance as the owner and controller

    controllerutil.SetControllerReference(m, dep, r.scheme)

    return dep

}

这个方法在reconcil中调用，发现没有实例就自动创建。

found := &appsv1.Deployment{}

    err = r.client.Get(context.TODO(), types.NamespacedName{Name: memcached.Name, Namespace: memcached.Namespace}, found)

    if err != nil && errors.IsNotFound(err) {

        // Define a new deployment

        dep := r.deploymentForMemcached(memcached)

        reqLogger.Info("Creating a new Deployment", "Deployment.Namespace", dep.Namespace, "Deployment.Name", dep.Name)

        err = r.client.Create(context.TODO(), dep)

        if err != nil {

            reqLogger.Error(err, "Failed to create new Deployment", "Deployment.Namespace", dep.Namespace, "Deployment.Name", dep.Name)

            return reconcile.Result{}, err

        }

        // Deployment created successfully - return and requeue

        return reconcile.Result{Requeue: true}, nil

    } else if err != nil {

        reqLogger.Error(err, "Failed to get Deployment")

        return reconcile.Result{}, err

    }

4.进行下面的步骤

[root@clientvm  ~/src/github.com/example-inc/memcached-operator]# oc create     -f deploy/crds/cache.example.com_memcacheds_crd.yaml

customresourcedefinition.apiextensions.k8s.io/memcacheds.cache.example.com created

[root@clientvm  ~/src/github.com/example-inc/memcached-operator]# ls

build/    cmd/  deploy/  go.mod  go.sum  pkg/  tools.go  version/

[root@clientvm  ~/src/github.com/example-inc/memcached-operator]# operator-sdk build quay.io/example/memcached-operator:v0.0.1

INFO[] Building OCI image quay.io/example/memcached-operator:v0.0.1

Sending build context to Docker daemon  40.1 MB

Step / : FROM registry.access.redhat.com/ubi8/ubi-minimal:latest

Trying to pull repository registry.access.redhat.com/ubi8/ubi-minimal ...

latest: Pulling from registry.access.redhat.com/ubi8/ubi-minimal

03e56b46bf0b: Pull complete

3a13cc2f5d65: Pull complete

Digest: sha256:9285da611437622492f9ef4229877efe302589f1401bbd4052e9bb261b3d4387

Status: Downloaded newer image for registry.access.redhat.com/ubi8/ubi-minimal:latest

 ---> db39bd4846dc

Step / : ENV OPERATOR /usr/local/bin/memcached-operator USER_UID  USER_NAME memcached-operator

 ---> Running in 2afea6e66ac3

 ---> b57ea8f7ea83

Removing intermediate container 2afea6e66ac3

Step / : COPY build/_output/bin/memcached-operator ${OPERATOR}

 ---> 2c63ce7b17f5

Removing intermediate container e1c010812c09

Step / : COPY build/bin /usr/local/bin

 ---> 069feafcb1f1

Removing intermediate container abf95785f652

Step / : RUN /usr/local/bin/user_setup

 ---> Running in e1ef27d95dc1

+ mkdir -p /root

+ chown : /root

+ chmod ug+rwx /root

+ chmod g+rw /etc/passwd

+ rm /usr/local/bin/user_setup

 ---> a1c897de8089

Removing intermediate container e1ef27d95dc1

Step / : ENTRYPOINT /usr/local/bin/entrypoint

 ---> Running in 31bb31653349

 ---> 58f90e9fdf8b

Removing intermediate container 31bb31653349

Step / : USER ${USER_UID}

 ---> Running in 9e905642d67f

 ---> 642d5912fcd9

Removing intermediate container 9e905642d67f

Successfully built 642d5912fcd9

INFO[] Operator build complete.

这是在本地生成了Operator的镜像，然后需要tag和推到自己的镜像仓库

[root@clientvm  ~/src/github.com/example-inc/memcached-operator]# docker images

REPOSITORY                                    TAG                 IMAGE ID            CREATED             SIZE

quay.io/example/memcached-operator            v0.0.1              642d5912fcd9         seconds ago       MB

然后按照文档操作继续。。。。。。

巴特西