案例需求

我们期望开发一个Operator，能够实现如下效果：

  • 定义一个名为 Memcached 的 CR
    • 编写Controller具有调谐 Memcached 的能力
      • Memcached Spec中有一个Size，Controller 将不允许创建的Memcached实例 超过Size
      • Controller 还要负责更新资源的 Status

开发项目

  • 创建一个项目Project

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    [root@master memcached-operator]# mkdir $GOPATH/memcached-operator
    [root@master memcached-operator]# cd $GOPATH/memcached-operator
    [root@master memcached-operator]# kubebuilder init --domain=graham924.com --repo=graham924.com/memcached-operator
    INFO Writing kustomize manifests for you to edit...
    INFO Writing scaffold for you to edit...
    INFO Get controller runtime:
    $ go get sigs.k8s.io/controller-runtime@v0.17.0
    INFO Update dependencies:
    $ go mod tidy
    Next: define a resource with:
    $ kubebuilder create api

  • 创建一个API

  • 这里 kubebuilder create api时，使用 deploy-image等 参数，直接就完成了全部代码的生成

deploy-image插件

  • 这里我们在使用 kubebuilder create api 时，将使用 deploy-image 的 plugin，帮我们自动生成一些代码。完整命令如下：
    1
    kubebuilder create api --group cache --version v1alpha1 --kind Memcached --image=memcached:1.4.36-alpine --image-container-command="memcached,-m=64,-o,modern,-v" --image-container-port="11211" --run-as-user="1001" --plugins="deploy-image/v1-alpha" --make=false
    参数解释：
  • kubebuilder create api：这是 Kubebuilder 工具的命令，用于创建一个新的 API 资源。
  • –group cache：指定新创建的 API 资源所属的 API 组，这里指定为 “cache”。
  • –version v1alpha1：指定新创建的 API 资源的版本号，这里指定为 “v1alpha1”。
  • –kind Memcached：指定新创建的资源的种类（Kind），这里指定为 “Memcached”，即自定义资源的类型为 Memcached。
  • –image=memcached:1.4.36-alpine：指定用于部署的镜像名称及版本，这里指定为 “memcached:1.4.36-alpine”。
  • –image-container-command=”memcached,-m=64,-o,modern,-v”：指定容器的启动命令，这里设置为在容器中运行 memcached 服务，并指定了一些参数如内存限制、存储模式等。
  • –image-container-port=”11211”：指定容器监听的端口号，这里指定为 “11211”，通常是 memcached 服务的默认端口。
  • –run-as-user=”1001”：指定容器运行时的用户 ID，这里指定为 “1001”。
  • –plugins=”deploy-image/v1-alpha”：指定要使用的插件，这里指定为部署镜像的插件 “deploy-image/v1-alpha”，用于将镜像部署到目标环境中。
  • –make=false：表示不立即构建二进制文件。当设置为 false 时，Kubebuilder 不会自动为你构建 Go 二进制文件，而是生成代码结构以供你自己构建。
    kubebuilder create api 时，使用 deploy-image plugin，会帮我们额外生成什么？
  • controllers/*_controller.go (脚手架controller的reconcile调谐逻辑框架)
  • controllers/*_controller_test.go (scaffold the tests for the controller)
  • controllers/*_suite_test.go (scaffold/update the suite of tests)
  • api//*_types.go (scaffold the specs for the new api)
  • config/samples/*_.yaml (scaffold default values for its CR)
  • main.go (update to add controller setup)
  • config/manager/manager.yaml (update with envvar to store the image)

创建API实践演示

  • 创建API

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    [root@master memcached-operator]# kubebuilder create api --group cache --version v1alpha1 --kind Memcached --image=memcached:1.4.36-alpine --image-container-command="memcached,-m=64,-o,modern,-v" --image-container-port="11211" --run-as-user="1001" --plugins="deploy-image/v1-alpha" --make=false
    INFO updating scaffold with deploy-image/v1alpha1 plugin...
    INFO Writing scaffold for you to edit...
    INFO Writing scaffold for you to edit...
    INFO api/v1alpha1/memcached_types.go
    INFO api/v1alpha1/groupversion_info.go
    INFO internal/controller/suite_test.go
    INFO internal/controller/memcached_controller.go
    INFO internal/controller/memcached_controller_test.go
    INFO Writing kustomize manifests for you to edit...
    INFO api/v1alpha1/memcached_types.go
    INFO config/samples/cache_v1alpha1_memcached.yaml
    INFO internal/controller/memcached_controller.go
    INFO creating import for % graham924.com/memcached-operator/api/v1alpha1
    INFO internal/controller/memcached_controller_test.go
    INFO creating import for % graham924.com/memcached-operator/api/v1alpha1
    INFO Update dependencies:
    $ go mod tidy
    INFO Running make:
    $ make manifests
    mkdir -p /root/zgy/project/share-code-operator-study/memcached-operator/bin
    Downloading sigs.k8s.io/controller-tools/cmd/controller-gen@v0.14.0
    /root/zgy/project/share-code-operator-study/memcached-operator/bin/controller-gen-v0.14.0 rbac:roleName=manager-role crd webhook paths="./..." output:crd:artifacts:config=config/crd/bases
    Next: check the implementation of your new API and controller. If you do changes in the API run the manifests with:
    $ make manifests

  • 生成后的目录如下：

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    51
    52
    53
    54
    55
    56
    57
    58
    59
    60
    61
    62
    63
    [root@master memcached-operator]# tree
    .
    ├── api
    │   └── v1alpha1
    │       ├── groupversion_info.go
    │       └── memcached_types.go
    ├── bin
    │   └── controller-gen-v0.14.0
    ├── cmd
    │   └── main.go
    ├── config
    │   ├── crd
    │   │   ├── bases
    │   │   │   └── cache.graham924.com_memcacheds.yaml
    │   │   ├── kustomization.yaml
    │   │   └── kustomizeconfig.yaml
    │   ├── default
    │   │   ├── kustomization.yaml
    │   │   ├── manager_auth_proxy_patch.yaml
    │   │   └── manager_config_patch.yaml
    │   ├── manager
    │   │   ├── kustomization.yaml
    │   │   └── manager.yaml
    │   ├── prometheus
    │   │   ├── kustomization.yaml
    │   │   └── monitor.yaml
    │   ├── rbac
    │   │   ├── auth_proxy_client_clusterrole.yaml
    │   │   ├── auth_proxy_role_binding.yaml
    │   │   ├── auth_proxy_role.yaml
    │   │   ├── auth_proxy_service.yaml
    │   │   ├── kustomization.yaml
    │   │   ├── leader_election_role_binding.yaml
    │   │   ├── leader_election_role.yaml
    │   │   ├── memcached_editor_role.yaml
    │   │   ├── memcached_viewer_role.yaml
    │   │   ├── role_binding.yaml
    │   │   ├── role.yaml
    │   │   └── service_account.yaml
    │   └── samples
    │       ├── cache_v1alpha1_memcached.yaml
    │       └── kustomization.yaml
    ├── Dockerfile
    ├── go.mod
    ├── go.sum
    ├── hack
    │   └── boilerplate.go.txt
    ├── internal
    │   └── controller
    │       ├── memcached_controller.go
    │       ├── memcached_controller_test.go
    │       └── suite_test.go
    ├── Makefile
    ├── PROJECT
    ├── README.md
    └── test
        ├── e2e
        │   ├── e2e_suite_test.go
        │   └── e2e_test.go
        └── utils
            └── utils.go

    18 directories, 41 files

查看CR的 types.go

因为我们使用了 deploy-image 插件，所以 api/v1alpha1/memcached_types.go 的 Spec、Status 中，会默认生成几个字段

  • Spec 字段
    • Size：使用 +kubebuilder:validation 标记 设置Size的值在1~3之间。
    • ContainerPort：容器Port
  • Status 字段
    • Conditions：描述资源的状态信息
      1
      2
      3
      4
      5
      6
      7
      8
      9
      10
      11
      12
      13
      14
      15
      16
      17
      18
      19
      20
      21
      22
      23
      24
      25
      26
      27
      28
      29
      30
      31
      32
      ......
      // MemcachedSpec defines the desired state of Memcached
      type MemcachedSpec struct {
              // INSERT ADDITIONAL SPEC FIELDS - desired state of cluster
              // Important: Run "make" to regenerate code after modifying this file

              // Size defines the number of Memcached instances
              // The following markers will use OpenAPI v3 schema to validate the value
              // More info: https://book.kubebuilder.io/reference/markers/crd-validation.html
              // +kubebuilder:validation:Minimum=1
              // +kubebuilder:validation:Maximum=3
              // +kubebuilder:validation:ExclusiveMaximum=false
              Size int32 `json:"size,omitempty"`

              // Port defines the port that will be used to init the container with the image
              ContainerPort int32 `json:"containerPort,omitempty"`
      }

      // MemcachedStatus defines the observed state of Memcached
      type MemcachedStatus struct {
              // Represents the observations of a Memcached's current state.
              // Memcached.status.conditions.type are: "Available", "Progressing", and "Degraded"
              // Memcached.status.conditions.status are one of True, False, Unknown.
              // Memcached.status.conditions.reason the 	value should be a CamelCase string and producers of specific
              // condition types may define expected values and meanings for this field, and whether the values
              // are considered a guaranteed API.
              // Memcached.status.conditions.Message is a human readable message indicating details about the transition.
              // For further information see: https://github.com/kubernetes/community/blob/master/contributors/devel/sig-architecture/api-conventions.md#typical-status-properties

              Conditions []metav1.Condition `json:"conditions,omitempty" patchStrategy:"merge" patchMergeKey:"type" protobuf:"bytes,1,rep,name=conditions"`
      }
      ......
      kubebuilder的官方文档中，给出了各种用于配置/代码生成的标记：https://book.kubebuilder.io/reference/markers

查看CR的资源定义文件CRD

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
config/crd/bases/cache.example.com_memcacheds.yaml 文件

[root@master memcached-operator]# cat config/crd/bases/cache.graham924.com_memcacheds.yaml
---
apiVersion: apiextensions.k8s.io/v1
kind: CustomResourceDefinition
metadata:
  annotations:
    controller-gen.kubebuilder.io/version: v0.14.0
  name: memcacheds.cache.graham924.com
spec:
  group: cache.graham924.com
  names:
    kind: Memcached
    listKind: MemcachedList
    plural: memcacheds
    singular: memcached
  scope: Namespaced
  versions:
  - name: v1alpha1
    schema:
      openAPIV3Schema:
        description: Memcached is the Schema for the memcacheds API
        properties:
          apiVersion:
            description: |-
              APIVersion defines the versioned schema of this representation of an object.
              Servers should convert recognized schemas to the latest internal value, and
              may reject unrecognized values.
              More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#resources
            type: string
          kind:
            description: |-
              Kind is a string value representing the REST resource this object represents.
              Servers may infer this from the endpoint the client submits requests to.
              Cannot be updated.
              In CamelCase.
              More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kinds
            type: string
          metadata:
            type: object
          spec:
            description: MemcachedSpec defines the desired state of Memcached
            properties:
              containerPort:
                description: Port defines the port that will be used to init the container
                  with the image
                format: int32
                type: integer
              size:
                description: |-
                  Size defines the number of Memcached instances
                  The following markers will use OpenAPI v3 schema to validate the value
                  More info: https://book.kubebuilder.io/reference/markers/crd-validation.html
                format: int32
                maximum: 3
                minimum: 1
                type: integer
            type: object
          status:
            description: MemcachedStatus defines the observed state of Memcached
            properties:
              conditions:
                items:
                  description: "Condition contains details for one aspect of the current
                    state of this API Resource.\n---\nThis struct is intended for
                    direct use as an array at the field path .status.conditions.  For
                    example,\n\n\n\ttype FooStatus struct{\n\t    // Represents the
                    observations of a foo's current state.\n\t    // Known .status.conditions.type
                    are: \"Available\", \"Progressing\", and \"Degraded\"\n\t    //
                    +patchMergeKey=type\n\t    // +patchStrategy=merge\n\t    // +listType=map\n\t
                    \   // +listMapKey=type\n\t    Conditions []metav1.Condition `json:\"conditions,omitempty\"
                    patchStrategy:\"merge\" patchMergeKey:\"type\" protobuf:\"bytes,1,rep,name=conditions\"`\n\n\n\t
                    \   // other fields\n\t}"
                  properties:
                    lastTransitionTime:
                      description: |-
                        lastTransitionTime is the last time the condition transitioned from one status to another.
                        This should be when the underlying condition changed.  If that is not known, then using the time when the API field changed is acceptable.
                      format: date-time
                      type: string
                    message:
                      description: |-
                        message is a human readable message indicating details about the transition.
                        This may be an empty string.
                      maxLength: 32768
                      type: string
                    observedGeneration:
                      description: |-
                        observedGeneration represents the .metadata.generation that the condition was set based upon.
                        For instance, if .metadata.generation is currently 12, but the .status.conditions[x].observedGeneration is 9, the condition is out of date
                        with respect to the current state of the instance.
                      format: int64
                      minimum: 0
                      type: integer
                    reason:
                      description: |-
                        reason contains a programmatic identifier indicating the reason for the condition's last transition.
                        Producers of specific condition types may define expected values and meanings for this field,
                        and whether the values are considered a guaranteed API.
                        The value should be a CamelCase string.
                        This field may not be empty.
                      maxLength: 1024
                      minLength: 1
                      pattern: ^[A-Za-z]([A-Za-z0-9_,:]*[A-Za-z0-9_])?$
                      type: string
                    status:
                      description: status of the condition, one of True, False, Unknown.
                      enum:
                      - "True"
                      - "False"
                      - Unknown
                      type: string
                    type:
                      description: |-
                        type of condition in CamelCase or in foo.example.com/CamelCase.
                        ---
                        Many .condition.type values are consistent across resources like Available, but because arbitrary conditions can be
                        useful (see .node.status.conditions), the ability to deconflict is important.
                        The regex it matches is (dns1123SubdomainFmt/)?(qualifiedNameFmt)
                      maxLength: 316
                      pattern: ^([a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*/)?(([A-Za-z0-9][-A-Za-z0-9_.]*)?[A-Za-z0-9])$
                      type: string
                  required:
                  - lastTransitionTime
                  - message
                  - reason
                  - status
                  - type
                  type: object
                type: array
            type: object
        type: object
    served: true
    storage: true
    subresources:
      status: {}

可以看出，+kubebuilder 标记的内容，会展示在CRD的定义文件中的，下面以Spec的内容为例，Status的内容也是一样的

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
spec:
  description: MemcachedSpec defines the desired state of Memcached
  properties:
    containerPort:
      description: Port defines the port that will be used to init the container
        with the image
      format: int32
      type: integer
    size:
      description: |-
        Size defines the number of Memcached instances
        The following markers will use OpenAPI v3 schema to validate the value
        More info: https://book.kubebuilder.io/reference/markers/crd-validation.html
      format: int32
      maximum: 3
      minimum: 1
      type: integer
  type: object

查看CR yaml示例

  • config/crd/bases/cache.example.com_memcacheds.yaml 文件
    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    apiVersion: cache.graham924.com/v1alpha1
    kind: Memcached
    metadata:
      name: memcached-sample
    spec:
      # TODO(user): edit the following value to ensure the number
      # of Pods/Instances your Operand must have on cluster
      size: 1

      # TODO(user): edit the following value to ensure the container has the right port to be initialized
      containerPort: 11211

查看CR的 controller.go

因为我们使用了 deploy-image 插件，所以 internal/controller/memcached_controller.go 的 Reconcile 已经给生成了很多代码逻辑

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
/*
Copyright 2024.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package controller

import (
        "context"
        "fmt"
        "os"
        "strings"
        "time"

        appsv1 "k8s.io/api/apps/v1"
        corev1 "k8s.io/api/core/v1"
        apierrors "k8s.io/apimachinery/pkg/api/errors"
        "k8s.io/apimachinery/pkg/api/meta"
        metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
        "k8s.io/apimachinery/pkg/runtime"
        "k8s.io/apimachinery/pkg/types"
        "k8s.io/client-go/tools/record"
        ctrl "sigs.k8s.io/controller-runtime"
        "sigs.k8s.io/controller-runtime/pkg/client"
        "sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
        "sigs.k8s.io/controller-runtime/pkg/log"

        cachev1alpha1 "graham924.com/memcached-operator/api/v1alpha1"
)

const memcachedFinalizer = "cache.graham924.com/finalizer"

// Definitions to manage status conditions
const (
        // typeAvailableMemcached represents the status of the Deployment reconciliation
        typeAvailableMemcached = "Available"
        // typeDegradedMemcached represents the status used when the custom resource is deleted and the finalizer operations are must to occur.
        typeDegradedMemcached = "Degraded"
)

// MemcachedReconciler reconciles a Memcached object
type MemcachedReconciler struct {
        client.Client
        Scheme   *runtime.Scheme
        Recorder record.EventRecorder
}

// The following markers are used to generate the rules permissions (RBAC) on config/rbac using controller-gen
// when the command <make manifests> is executed.
// To know more about markers see: https://book.kubebuilder.io/reference/markers.html

//+kubebuilder:rbac:groups=cache.graham924.com,resources=memcacheds,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=cache.graham924.com,resources=memcacheds/status,verbs=get;update;patch
//+kubebuilder:rbac:groups=cache.graham924.com,resources=memcacheds/finalizers,verbs=update
//+kubebuilder:rbac:groups=core,resources=events,verbs=create;patch
//+kubebuilder:rbac:groups=apps,resources=deployments,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=core,resources=pods,verbs=get;list;watch

// Reconcile is part of the main kubernetes reconciliation loop which aims to
// move the current state of the cluster closer to the desired state.
// It is essential for the controller's reconciliation loop to be idempotent. By following the Operator
// pattern you will create Controllers which provide a reconcile function
// responsible for synchronizing resources until the desired state is reached on the cluster.
// Breaking this recommendation goes against the design principles of controller-runtime.
// and may lead to unforeseen consequences such as resources becoming stuck and requiring manual intervention.
// For further info:
// - About Operator Pattern: https://kubernetes.io/docs/concepts/extend-kubernetes/operator/
// - About Controllers: https://kubernetes.io/docs/concepts/architecture/controller/
// - https://pkg.go.dev/sigs.k8s.io/controller-runtime@v0.17.0/pkg/reconcile
func (r *MemcachedReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
        log := log.FromContext(ctx)

        // Fetch the Memcached instance
        // The purpose is check if the Custom Resource for the Kind Memcached
        // is applied on the cluster if not we return nil to stop the reconciliation
        memcached := &cachev1alpha1.Memcached{}
        err := r.Get(ctx, req.NamespacedName, memcached)
        if err != nil {
                if apierrors.IsNotFound(err) {
                        // If the custom resource is not found then, it usually means that it was deleted or not created
                        // In this way, we will stop the reconciliation
                        log.Info("memcached resource not found. Ignoring since object must be deleted")
                        return ctrl.Result{}, nil
                }
                // Error reading the object - requeue the request.
                log.Error(err, "Failed to get memcached")
                return ctrl.Result{}, err
        }

        // Let's just set the status as Unknown when no status are available
        if memcached.Status.Conditions == nil || len(memcached.Status.Conditions) == 0 {
                meta.SetStatusCondition(&memcached.Status.Conditions, metav1.Condition{Type: typeAvailableMemcached, Status: metav1.ConditionUnknown, Reason: "Reconciling", Message: "Starting reconciliation"})
                if err = r.Status().Update(ctx, memcached); err != nil {
                        log.Error(err, "Failed to update Memcached status")
                        return ctrl.Result{}, err
                }

                // Let's re-fetch the memcached Custom Resource after update the status
                // so that we have the latest state of the resource on the cluster and we will avoid
                // raise the issue "the object has been modified, please apply
                // your changes to the latest version and try again" which would re-trigger the reconciliation
                // if we try to update it again in the following operations
                if err := r.Get(ctx, req.NamespacedName, memcached); err != nil {
                        log.Error(err, "Failed to re-fetch memcached")
                        return ctrl.Result{}, err
                }
        }

        // Let's add a finalizer. Then, we can define some operations which should
        // occurs before the custom resource to be deleted.
        // More info: https://kubernetes.io/docs/concepts/overview/working-with-objects/finalizers
        if !controllerutil.ContainsFinalizer(memcached, memcachedFinalizer) {
                log.Info("Adding Finalizer for Memcached")
                if ok := controllerutil.AddFinalizer(memcached, memcachedFinalizer); !ok {
                        log.Error(err, "Failed to add finalizer into the custom resource")
                        return ctrl.Result{Requeue: true}, nil
                }

                if err = r.Update(ctx, memcached); err != nil {
                        log.Error(err, "Failed to update custom resource to add finalizer")
                        return ctrl.Result{}, err
                }
        }

        // Check if the Memcached instance is marked to be deleted, which is
        // indicated by the deletion timestamp being set.
        isMemcachedMarkedToBeDeleted := memcached.GetDeletionTimestamp() != nil
        if isMemcachedMarkedToBeDeleted {
                if controllerutil.ContainsFinalizer(memcached, memcachedFinalizer) {
                        log.Info("Performing Finalizer Operations for Memcached before delete CR")

                        // Let's add here an status "Downgrade" to define that this resource begin its process to be terminated.
                        meta.SetStatusCondition(&memcached.Status.Conditions, metav1.Condition{Type: typeDegradedMemcached,
                                Status: metav1.ConditionUnknown, Reason: "Finalizing",
                                Message: fmt.Sprintf("Performing finalizer operations for the custom resource: %s ", memcached.Name)})

                        if err := r.Status().Update(ctx, memcached); err != nil {
                                log.Error(err, "Failed to update Memcached status")
                                return ctrl.Result{}, err
                        }

                        // Perform all operations required before remove the finalizer and allow
                        // the Kubernetes API to remove the custom resource.
                        r.doFinalizerOperationsForMemcached(memcached)

                        // TODO(user): If you add operations to the doFinalizerOperationsForMemcached method
                        // then you need to ensure that all worked fine before deleting and updating the Downgrade status
                        // otherwise, you should requeue here.

                        // Re-fetch the memcached Custom Resource before update the status
                        // so that we have the latest state of the resource on the cluster and we will avoid
                        // raise the issue "the object has been modified, please apply
                        // your changes to the latest version and try again" which would re-trigger the reconciliation
                        if err := r.Get(ctx, req.NamespacedName, memcached); err != nil {
                                log.Error(err, "Failed to re-fetch memcached")
                                return ctrl.Result{}, err
                        }

                        meta.SetStatusCondition(&memcached.Status.Conditions, metav1.Condition{Type: typeDegradedMemcached,
                                Status: metav1.ConditionTrue, Reason: "Finalizing",
                                Message: fmt.Sprintf("Finalizer operations for custom resource %s name were successfully accomplished", memcached.Name)})

                        if err := r.Status().Update(ctx, memcached); err != nil {
                                log.Error(err, "Failed to update Memcached status")
                                return ctrl.Result{}, err
                        }

                        log.Info("Removing Finalizer for Memcached after successfully perform the operations")
                        if ok := controllerutil.RemoveFinalizer(memcached, memcachedFinalizer); !ok {
                                log.Error(err, "Failed to remove finalizer for Memcached")
                                return ctrl.Result{Requeue: true}, nil
                        }

                        if err := r.Update(ctx, memcached); err != nil {
                                log.Error(err, "Failed to remove finalizer for Memcached")
                                return ctrl.Result{}, err
                        }
                }
                return ctrl.Result{}, nil
        }

        // Check if the deployment already exists, if not create a new one
        found := &appsv1.Deployment{}
        err = r.Get(ctx, types.NamespacedName{Name: memcached.Name, Namespace: memcached.Namespace}, found)
        if err != nil && apierrors.IsNotFound(err) {
                // Define a new deployment
                dep, err := r.deploymentForMemcached(memcached)
                if err != nil {
                        log.Error(err, "Failed to define new Deployment resource for Memcached")

                        // The following implementation will update the status
                        meta.SetStatusCondition(&memcached.Status.Conditions, metav1.Condition{Type: typeAvailableMemcached,
                                Status: metav1.ConditionFalse, Reason: "Reconciling",
                                Message: fmt.Sprintf("Failed to create Deployment for the custom resource (%s): (%s)", memcached.Name, err)})

                        if err := r.Status().Update(ctx, memcached); err != nil {
                                log.Error(err, "Failed to update Memcached status")
                                return ctrl.Result{}, err
                        }

                        return ctrl.Result{}, err
                }

                log.Info("Creating a new Deployment",
                        "Deployment.Namespace", dep.Namespace, "Deployment.Name", dep.Name)
                if err = r.Create(ctx, dep); err != nil {
                        log.Error(err, "Failed to create new Deployment",
                                "Deployment.Namespace", dep.Namespace, "Deployment.Name", dep.Name)
                        return ctrl.Result{}, err
                }

                // Deployment created successfully
                // We will requeue the reconciliation so that we can ensure the state
                // and move forward for the next operations
                return ctrl.Result{RequeueAfter: time.Minute}, nil
        } else if err != nil {
                log.Error(err, "Failed to get Deployment")
                // Let's return the error for the reconciliation be re-trigged again
                return ctrl.Result{}, err
        }

        // The CRD API is defining that the Memcached type, have a MemcachedSpec.Size field
        // to set the quantity of Deployment instances is the desired state on the cluster.
        // Therefore, the following code will ensure the Deployment size is the same as defined
        // via the Size spec of the Custom Resource which we are reconciling.
        size := memcached.Spec.Size
        if *found.Spec.Replicas != size {
                found.Spec.Replicas = &size
                if err = r.Update(ctx, found); err != nil {
                        log.Error(err, "Failed to update Deployment",
                                "Deployment.Namespace", found.Namespace, "Deployment.Name", found.Name)

                        // Re-fetch the memcached Custom Resource before update the status
                        // so that we have the latest state of the resource on the cluster and we will avoid
                        // raise the issue "the object has been modified, please apply
                        // your changes to the latest version and try again" which would re-trigger the reconciliation
                        if err := r.Get(ctx, req.NamespacedName, memcached); err != nil {
                                log.Error(err, "Failed to re-fetch memcached")
                                return ctrl.Result{}, err
                        }

                        // The following implementation will update the status
                        meta.SetStatusCondition(&memcached.Status.Conditions, metav1.Condition{Type: typeAvailableMemcached,
                                Status: metav1.ConditionFalse, Reason: "Resizing",
                                Message: fmt.Sprintf("Failed to update the size for the custom resource (%s): (%s)", memcached.Name, err)})

                        if err := r.Status().Update(ctx, memcached); err != nil {
                                log.Error(err, "Failed to update Memcached status")
                                return ctrl.Result{}, err
                        }

                        return ctrl.Result{}, err
                }

                // Now, that we update the size we want to requeue the reconciliation
                // so that we can ensure that we have the latest state of the resource before
                // update. Also, it will help ensure the desired state on the cluster
                return ctrl.Result{Requeue: true}, nil
        }

        // The following implementation will update the status
        meta.SetStatusCondition(&memcached.Status.Conditions, metav1.Condition{Type: typeAvailableMemcached,
                Status: metav1.ConditionTrue, Reason: "Reconciling",
                Message: fmt.Sprintf("Deployment for custom resource (%s) with %d replicas created successfully", memcached.Name, size)})

        if err := r.Status().Update(ctx, memcached); err != nil {
                log.Error(err, "Failed to update Memcached status")
                return ctrl.Result{}, err
        }

        return ctrl.Result{}, nil
}

// finalizeMemcached will perform the required operations before delete the CR.
func (r *MemcachedReconciler) doFinalizerOperationsForMemcached(cr *cachev1alpha1.Memcached) {
        // TODO(user): Add the cleanup steps that the operator
        // needs to do before the CR can be deleted. Examples
        // of finalizers include performing backups and deleting
        // resources that are not owned by this CR, like a PVC.

        // Note: It is not recommended to use finalizers with the purpose of delete resources which are
        // created and managed in the reconciliation. These ones, such as the Deployment created on this reconcile,
        // are defined as depended of the custom resource. See that we use the method ctrl.SetControllerReference.
        // to set the ownerRef which means that the Deployment will be deleted by the Kubernetes API.
        // More info: https://kubernetes.io/docs/tasks/administer-cluster/use-cascading-deletion/

        // The following implementation will raise an event
        r.Recorder.Event(cr, "Warning", "Deleting",
                fmt.Sprintf("Custom Resource %s is being deleted from the namespace %s",
                        cr.Name,
                        cr.Namespace))
}

// deploymentForMemcached returns a Memcached Deployment object
func (r *MemcachedReconciler) deploymentForMemcached(
        memcached *cachev1alpha1.Memcached) (*appsv1.Deployment, error) {
        ls := labelsForMemcached(memcached.Name)
        replicas := memcached.Spec.Size

        // Get the Operand image
        image, err := imageForMemcached()
        if err != nil {
                return nil, err
        }

        dep := &appsv1.Deployment{
                ObjectMeta: metav1.ObjectMeta{
                        Name:      memcached.Name,
                        Namespace: memcached.Namespace,
                },
                Spec: appsv1.DeploymentSpec{
                        Replicas: &replicas,
                        Selector: &metav1.LabelSelector{
                                MatchLabels: ls,
                        },
                        Template: corev1.PodTemplateSpec{
                                ObjectMeta: metav1.ObjectMeta{
                                        Labels: ls,
                                },
                                Spec: corev1.PodSpec{
                                        // TODO(user): Uncomment the following code to configure the nodeAffinity expression
                                        // according to the platforms which are supported by your solution. It is considered
                                        // best practice to support multiple architectures. build your manager image using the
                                        // makefile target docker-buildx. Also, you can use docker manifest inspect <image>
                                        // to check what are the platforms supported.
                                        // More info: https://kubernetes.io/docs/concepts/scheduling-eviction/assign-pod-node/#node-affinity
                                        //Affinity: &corev1.Affinity{
                                        //      NodeAffinity: &corev1.NodeAffinity{
                                        //              RequiredDuringSchedulingIgnoredDuringExecution: &corev1.NodeSelector{
                                        //                      NodeSelectorTerms: []corev1.NodeSelectorTerm{
                                        //                              {
                                        //                                      MatchExpressions: []corev1.NodeSelectorRequirement{
                                        //                                              {
                                        //                                                      Key:      "kubernetes.io/arch",
                                        //                                                      Operator: "In",
                                        //                                                      Values:   []string{"amd64", "arm64", "ppc64le", "s390x"},
                                        //                                              },
                                        //                                              {
                                        //                                                      Key:      "kubernetes.io/os",
                                        //                                                      Operator: "In",
                                        //                                                      Values:   []string{"linux"},
                                        //                                              },
                                        //                                      },
                                        //                              },
                                        //                      },
                                        //              },
                                        //      },
                                        //},
                                        SecurityContext: &corev1.PodSecurityContext{
                                                RunAsNonRoot: &[]bool{true}[0],
                                                // IMPORTANT: seccomProfile was introduced with Kubernetes 1.19
                                                // If you are looking for to produce solutions to be supported
                                                // on lower versions you must remove this option.
                                                SeccompProfile: &corev1.SeccompProfile{
                                                        Type: corev1.SeccompProfileTypeRuntimeDefault,
                                                },
                                        },
                                        Containers: []corev1.Container{{
                                                Image:           image,
                                                Name:            "memcached",
                                                ImagePullPolicy: corev1.PullIfNotPresent,
                                                // Ensure restrictive context for the container
                                                // More info: https://kubernetes.io/docs/concepts/security/pod-security-standards/#restricted
                                                SecurityContext: &corev1.SecurityContext{
                                                        RunAsNonRoot:             &[]bool{true}[0],
                                                        RunAsUser:                &[]int64{1001}[0],
                                                        AllowPrivilegeEscalation: &[]bool{false}[0],
                                                        Capabilities: &corev1.Capabilities{
                                                                Drop: []corev1.Capability{
                                                                        "ALL",
                                                                },
                                                        },
                                                },
                                                Ports: []corev1.ContainerPort{{
                                                        ContainerPort: memcached.Spec.ContainerPort,
                                                        Name:          "memcached",
                                                }},
                                                Command: []string{"memcached", "-m=64", "-o", "modern", "-v"},
                                        }},
                                },
                        },
                },
        }

        // Set the ownerRef for the Deployment
        // More info: https://kubernetes.io/docs/concepts/overview/working-with-objects/owners-dependents/
        if err := ctrl.SetControllerReference(memcached, dep, r.Scheme); err != nil {
                return nil, err
        }
        return dep, nil
}

// labelsForMemcached returns the labels for selecting the resources
// More info: https://kubernetes.io/docs/concepts/overview/working-with-objects/common-labels/
func labelsForMemcached(name string) map[string]string {
        var imageTag string
        image, err := imageForMemcached()
        if err == nil {
                imageTag = strings.Split(image, ":")[1]
        }
        return map[string]string{"app.kubernetes.io/name": "Memcached",
                "app.kubernetes.io/instance":   name,
                "app.kubernetes.io/version":    imageTag,
                "app.kubernetes.io/part-of":    "memcached-operator",
                "app.kubernetes.io/created-by": "controller-manager",
        }
}

// imageForMemcached gets the Operand image which is managed by this controller
// from the MEMCACHED_IMAGE environment variable defined in the config/manager/manager.yaml
func imageForMemcached() (string, error) {
        var imageEnvVar = "MEMCACHED_IMAGE"
        image, found := os.LookupEnv(imageEnvVar)
        if !found {
                return "", fmt.Errorf("Unable to find %s environment variable with the image", imageEnvVar)
        }
        return image, nil
}

// SetupWithManager sets up the controller with the Manager.
// Note that the Deployment will be also watched in order to ensure its
// desirable state on the cluster
func (r *MemcachedReconciler) SetupWithManager(mgr ctrl.Manager) error {
        return ctrl.NewControllerManagedBy(mgr).
                For(&cachev1alpha1.Memcached{}).
                Owns(&appsv1.Deployment{}).
                Complete(r)
}

controller.go 中 SetupWithManager 方法

  • SetupWithManager 方法中，已经为我们的CR创建ListWatch机制了
    1
    2
    3
    4
    5
    6
    7
    8
    9
    // SetupWithManager sets up the controller with the Manager.
    // Note that the Deployment will be also watched in order to ensure its
    // desirable state on the cluster
    func (r *MemcachedReconciler) SetupWithManager(mgr ctrl.Manager) error {
            return ctrl.NewControllerManagedBy(mgr).
                    For(&cachev1alpha1.Memcached{}).
                    Owns(&appsv1.Deployment{}).
                    Complete(r)
    }

Manager 是controller-runtime提供的组件，用于监督和管理 Controller。SetupWithManager 方法就是将 当前Controller注册到 Manager 中

controller.go 中 设置deployment 的 ownerRef

  • deploymentForMemcached 中，创建的deployment，ownerRef 已经给设置成了相应的Memcached资源
    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    // deploymentForMemcached returns a Memcached Deployment object
    func (r *MemcachedReconciler) deploymentForMemcached(
            memcached *cachev1alpha1.Memcached) (*appsv1.Deployment, error) {
            ls := labelsForMemcached(memcached.Name)
            replicas := memcached.Spec.Size
    	
    	......

    		if err := ctrl.SetControllerReference(memcached, dep, r.Scheme); err != nil {
                    return nil, err
            }
            return dep, nil
    }

controller.go 中 rbac 的 kubebuilder 标记

  • Reconcile 方法上方，使用 rbac 的 kubebuilder 标记，标记了当前Operator的访问权限
  • 当你修改 controller.go 里的rbac标记后，需要执行 make manifests 或 make generate 更新 config/rbac 目录下的rbac权限文件
    1
    2
    3
    4
    5
    6
    //+kubebuilder:rbac:groups=cache.graham924.com,resources=memcacheds,verbs=get;list;watch;create;update;patch;delete
    //+kubebuilder:rbac:groups=cache.graham924.com,resources=memcacheds/status,verbs=get;update;patch
    //+kubebuilder:rbac:groups=cache.graham924.com,resources=memcacheds/finalizers,verbs=update
    //+kubebuilder:rbac:groups=core,resources=events,verbs=create;patch
    //+kubebuilder:rbac:groups=apps,resources=deployments,verbs=get;list;watch;create;update;patch;delete
    //+kubebuilder:rbac:groups=core,resources=pods,verbs=get;list;watch

CRD 及 Controller 部署

安装CRD

1
2
3
4
5
[root@master memcached-operator]# make install
/root/zgy/project/share-code-operator-study/memcached-operator/bin/controller-gen-v0.14.0 rbac:roleName=manager-role crd webhook paths="./..." output:crd:artifacts:config=config/crd/bases
Downloading sigs.k8s.io/kustomize/kustomize/v5@v5.3.0
/root/zgy/project/share-code-operator-study/memcached-operator/bin/kustomize-v5.3.0 build config/crd | kubectl apply -f -
customresourcedefinition.apiextensions.k8s.io/memcacheds.cache.graham924.com created

打包Controller并上传镜像

  • cd 到 memcached-operator 的所在目录，修改 Dockerfile 文件，加上这么两句
    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    # Build the manager binary
    FROM golang:1.21 AS builder
    ARG TARGETOS
    ARG TARGETARCH

    # 就是加上这两句，设置一下go的国内代理加速
    ENV GO111MODULE=on
    ENV GOPROXY=https://goproxy.cn

    ......
  • 然后 修改Makefile 文件，在docker-build命令中，添加 –network host ，这是让我们的机器使用主机网络，能够连接外网
    1
    2
    3
    4
    5
    6
    # If you wish to build the manager image targeting other platforms you can use the --platform flag.
    # (i.e. docker build --platform linux/arm64). However, you must enable docker buildKit for it.
    # More info: https://docs.docker.com/develop/develop-images/build_enhancements/
    .PHONY: docker-build
    docker-build: ## Build docker image with the manager.
            $(CONTAINER_TOOL) build --network host -t ${IMG} .
    执行打包上传命令
    1
    make docker-build docker-push IMG=gesang321/memcached-operator:v1alpha1

部署Controller

  • 部署Controller
    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    [root@master memcached-operator]# make deploy IMG=gesang321/memcached-operator:v1alpha1
    /root/zgy/project/share-code-operator-study/memcached-operator/bin/controller-gen-v0.14.0 rbac:roleName=manager-role crd webhook paths="./..." output:crd:artifacts:config=config/crd/bases
    cd config/manager && /root/zgy/project/share-code-operator-study/memcached-operator/bin/kustomize-v5.3.0 edit set image controller=gesang321/memcached-operator:v1alpha1
    /root/zgy/project/share-code-operator-study/memcached-operator/bin/kustomize-v5.3.0 build config/default | kubectl apply -f -
    namespace/memcached-operator-system created
    customresourcedefinition.apiextensions.k8s.io/memcacheds.cache.graham924.com created
    serviceaccount/memcached-operator-controller-manager created
    role.rbac.authorization.k8s.io/memcached-operator-leader-election-role created
    clusterrole.rbac.authorization.k8s.io/memcached-operator-manager-role created
    clusterrole.rbac.authorization.k8s.io/memcached-operator-metrics-reader created
    clusterrole.rbac.authorization.k8s.io/memcached-operator-proxy-role created
    rolebinding.rbac.authorization.k8s.io/memcached-operator-leader-election-rolebinding created
    clusterrolebinding.rbac.authorization.k8s.io/memcached-operator-manager-rolebinding created
    clusterrolebinding.rbac.authorization.k8s.io/memcached-operator-proxy-rolebinding created
    service/memcached-operator-controller-manager-metrics-service created
    deployment.apps/memcached-operator-controller-manager created
  • 查看部署结果
    1
    2
    3
    4
    5
    6
    7
    [root@master memcached-operator]# kubectl get deploy -n memcached-operator-system
    NAME                                    READY   UP-TO-DATE   AVAILABLE   AGE
    memcached-operator-controller-manager   1/1     1            1           37m

    [root@master memcached-operator]# kubectl get pods -n memcached-operator-system
    NAME                                                     READY   STATUS    RESTARTS   AGE
    memcached-operator-controller-manager-6fd6c7699b-42rg4   2/2     Running   0          38m