-
Notifications
You must be signed in to change notification settings - Fork 451
/
constraints.go
383 lines (336 loc) · 17.1 KB
/
constraints.go
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
// Copyright (c) 2021 SAP SE or an SAP affiliate company. All rights reserved. This file is licensed under the Apache Software License, v. 2 except as noted otherwise in the LICENSE file
//
// 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 care
import (
"context"
"fmt"
"strconv"
"strings"
"time"
gardencorev1beta1 "github.com/gardener/gardener/pkg/apis/core/v1beta1"
v1beta1constants "github.com/gardener/gardener/pkg/apis/core/v1beta1/constants"
gardencorev1beta1helper "github.com/gardener/gardener/pkg/apis/core/v1beta1/helper"
resourcesv1alpha1 "github.com/gardener/gardener/pkg/apis/resources/v1alpha1"
"github.com/gardener/gardener/pkg/operation"
"github.com/gardener/gardener/pkg/operation/botanist/component/resourcemanager"
"github.com/gardener/gardener/pkg/operation/botanist/matchers"
"github.com/gardener/gardener/pkg/operation/shoot"
"github.com/gardener/gardener/pkg/utils"
secretutils "github.com/gardener/gardener/pkg/utils/secrets"
secretsmanager "github.com/gardener/gardener/pkg/utils/secrets/manager"
"github.com/go-logr/logr"
admissionregistrationv1 "k8s.io/api/admissionregistration/v1"
corev1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/labels"
"k8s.io/apimachinery/pkg/selection"
"k8s.io/utils/clock"
"sigs.k8s.io/controller-runtime/pkg/client"
)
// WebhookMaximumTimeoutSecondsNotProblematic is the maximum timeout in seconds a webhooks on critical resources can
// have in order to not be considered as a problematic webhook by the constraints checks. Any webhook on critical
// resources with a larger timeout is considered to be problematic.
const WebhookMaximumTimeoutSecondsNotProblematic = 15
func shootHibernatedConstraints(conditions ...gardencorev1beta1.Condition) []gardencorev1beta1.Condition {
hibernationConditions := make([]gardencorev1beta1.Condition, 0, len(conditions))
for _, cond := range conditions {
hibernationConditions = append(hibernationConditions, gardencorev1beta1helper.UpdatedCondition(cond, gardencorev1beta1.ConditionTrue, "ConstraintNotChecked", "Shoot cluster has been hibernated."))
}
return hibernationConditions
}
func shootControlPlaneNotRunningConstraints(conditions ...gardencorev1beta1.Condition) []gardencorev1beta1.Condition {
constraints := make([]gardencorev1beta1.Condition, 0, len(conditions))
for _, cond := range conditions {
constraints = append(constraints, gardencorev1beta1helper.UpdatedCondition(cond, gardencorev1beta1.ConditionFalse, "ConstraintNotChecked", "Shoot control plane is not running at the moment."))
}
return constraints
}
// Constraint contains required information for shoot constraint checks.
type Constraint struct {
shoot *shoot.Shoot
seedClient client.Client
initializeShootClients ShootClientInit
shootClient client.Client
log logr.Logger
clock clock.Clock
}
// NewConstraint returns a new constraint instance.
func NewConstraint(clock clock.Clock, op *operation.Operation, shootClientInit ShootClientInit) *Constraint {
return &Constraint{
clock: clock,
shoot: op.Shoot,
seedClient: op.SeedClientSet.Client(),
initializeShootClients: shootClientInit,
log: op.Logger,
}
}
// Check checks all given constraints.
func (c *Constraint) Check(
ctx context.Context,
constraints []gardencorev1beta1.Condition,
) []gardencorev1beta1.Condition {
updatedConstraints := c.constraintsChecks(ctx, constraints)
lastOp := c.shoot.GetInfo().Status.LastOperation
lastErrors := c.shoot.GetInfo().Status.LastErrors
return PardonConditions(updatedConstraints, lastOp, lastErrors)
}
func (c *Constraint) constraintsChecks(
ctx context.Context,
constraints []gardencorev1beta1.Condition,
) []gardencorev1beta1.Condition {
if c.shoot.HibernationEnabled || c.shoot.GetInfo().Status.IsHibernated {
return shootHibernatedConstraints(constraints...)
}
var (
// required constraints (always present in .status.constraints)
hibernationPossibleConstraint, maintenancePreconditionsSatisfiedConstraint gardencorev1beta1.Condition
// optional constraints (not always present in .status.constraints)
caCertificateValiditiesAcceptableConstraint = gardencorev1beta1.Condition{Type: gardencorev1beta1.ShootCACertificateValiditiesAcceptable}
)
for _, cons := range constraints {
switch cons.Type {
case gardencorev1beta1.ShootHibernationPossible:
hibernationPossibleConstraint = cons
case gardencorev1beta1.ShootMaintenancePreconditionsSatisfied:
maintenancePreconditionsSatisfiedConstraint = cons
case gardencorev1beta1.ShootCACertificateValiditiesAcceptable:
caCertificateValiditiesAcceptableConstraint = cons
}
}
// Check constraints not depending on the shoot's kube-apiserver to be up and running
status, reason, message, errorCodes, err := c.CheckIfCACertificateValiditiesAcceptable(ctx)
if err != nil {
caCertificateValiditiesAcceptableConstraint = gardencorev1beta1helper.UpdatedConditionUnknownError(caCertificateValiditiesAcceptableConstraint, err)
} else {
caCertificateValiditiesAcceptableConstraint = gardencorev1beta1helper.UpdatedCondition(caCertificateValiditiesAcceptableConstraint, status, reason, message, errorCodes...)
}
// Now check constraints depending on the shoot's kube-apiserver to be up and running
shootClient, apiServerRunning, err := c.initializeShootClients()
if err != nil {
c.log.Error(err, "Could not initialize Shoot client for constraints check")
message := fmt.Sprintf("Could not initialize Shoot client for constraints check: %+v", err)
hibernationPossibleConstraint = gardencorev1beta1helper.UpdatedConditionUnknownErrorMessage(hibernationPossibleConstraint, message)
maintenancePreconditionsSatisfiedConstraint = gardencorev1beta1helper.UpdatedConditionUnknownErrorMessage(maintenancePreconditionsSatisfiedConstraint, message)
return filterOptionalConstraints(
[]gardencorev1beta1.Condition{hibernationPossibleConstraint, maintenancePreconditionsSatisfiedConstraint},
[]gardencorev1beta1.Condition{caCertificateValiditiesAcceptableConstraint},
)
}
if !apiServerRunning {
// don't check constraints if API server has already been deleted or has not been created yet
return filterOptionalConstraints(
shootControlPlaneNotRunningConstraints(hibernationPossibleConstraint, maintenancePreconditionsSatisfiedConstraint),
[]gardencorev1beta1.Condition{caCertificateValiditiesAcceptableConstraint},
)
}
c.shootClient = shootClient.Client()
status, reason, message, errorCodes, err = c.CheckForProblematicWebhooks(ctx)
if err != nil {
hibernationPossibleConstraint = gardencorev1beta1helper.UpdatedConditionUnknownError(hibernationPossibleConstraint, err)
maintenancePreconditionsSatisfiedConstraint = gardencorev1beta1helper.UpdatedConditionUnknownError(maintenancePreconditionsSatisfiedConstraint, err)
} else {
hibernationPossibleConstraint = gardencorev1beta1helper.UpdatedCondition(hibernationPossibleConstraint, status, reason, message, errorCodes...)
maintenancePreconditionsSatisfiedConstraint = gardencorev1beta1helper.UpdatedCondition(maintenancePreconditionsSatisfiedConstraint, status, reason, message, errorCodes...)
}
return filterOptionalConstraints(
[]gardencorev1beta1.Condition{hibernationPossibleConstraint, maintenancePreconditionsSatisfiedConstraint},
[]gardencorev1beta1.Condition{caCertificateValiditiesAcceptableConstraint},
)
}
var (
notResourceManager = utils.MustNewRequirement(v1beta1constants.LabelApp, selection.NotIn, resourcemanager.LabelValue)
notManagedByGardener = utils.MustNewRequirement(resourcesv1alpha1.ManagedBy, selection.NotIn, "gardener")
labelSelector = client.MatchingLabelsSelector{Selector: labels.NewSelector().Add(notResourceManager).Add(notManagedByGardener)}
)
func getValidatingWebhookConfigurations(ctx context.Context, client client.Client) ([]admissionregistrationv1.ValidatingWebhookConfiguration, error) {
validatingWebhookConfigs := &admissionregistrationv1.ValidatingWebhookConfigurationList{}
if err := client.List(ctx, validatingWebhookConfigs, labelSelector); err != nil {
return nil, err
}
return validatingWebhookConfigs.Items, nil
}
func getMutatingWebhookConfigurations(ctx context.Context, c client.Client) ([]admissionregistrationv1.MutatingWebhookConfiguration, error) {
mutatingWebhookConfigs := &admissionregistrationv1.MutatingWebhookConfigurationList{}
if err := c.List(ctx, mutatingWebhookConfigs, labelSelector); err != nil {
return nil, err
}
return mutatingWebhookConfigs.Items, nil
}
// CheckIfCACertificateValiditiesAcceptable checks whether there are CA certificates which are expiring in less than a
// year.
func (c *Constraint) CheckIfCACertificateValiditiesAcceptable(ctx context.Context) (gardencorev1beta1.ConditionStatus, string, string, []gardencorev1beta1.ErrorCode, error) {
// CA certificates are valid for 10y, so let's only consider those certificates problematic which are valid for less
// than 1y.
const minimumValidity = 24 * time.Hour * 365
secretList := &corev1.SecretList{}
if err := c.seedClient.List(ctx, secretList, client.InNamespace(c.shoot.SeedNamespace), client.MatchingLabels{
secretsmanager.LabelKeyManagedBy: secretsmanager.LabelValueSecretsManager,
secretsmanager.LabelKeyManagerIdentity: v1beta1constants.SecretManagerIdentityGardenlet,
secretsmanager.LabelKeyPersist: secretsmanager.LabelValueTrue,
}); err != nil {
return "", "", "", nil, fmt.Errorf("could not list secrets in shoot namespace in seed to check for expiring CA certificates: %w", err)
}
expiringCACertificates := make(map[string]time.Time, len(secretList.Items))
for _, secret := range secretList.Items {
if secret.Data[secretutils.DataKeyCertificateCA] == nil || secret.Data[secretutils.DataKeyPrivateKeyCA] == nil {
continue
}
validUntilUnix, err := strconv.ParseInt(secret.Labels[secretsmanager.LabelKeyValidUntilTime], 10, 64)
if err != nil {
return "", "", "", nil, fmt.Errorf("could not parse %s label from secret %q: %w", secretsmanager.LabelKeyValidUntilTime, secret.Name, err)
}
validUntil := time.Unix(validUntilUnix, 0).UTC()
if validUntil.Sub(c.clock.Now().UTC()) < minimumValidity {
expiringCACertificates[secret.Labels[secretsmanager.LabelKeyName]] = validUntil
}
}
if len(expiringCACertificates) > 0 {
var msgs []string
for name, validUntil := range expiringCACertificates {
msgs = append(msgs, fmt.Sprintf("%q (expiring at %s)", name, validUntil))
}
return gardencorev1beta1.ConditionFalse,
"ExpiringCACertificates",
fmt.Sprintf("Some CA certificates are expiring in less than %s, you should rotate them: %s", minimumValidity, strings.Join(msgs, ", ")),
nil,
nil
}
return gardencorev1beta1.ConditionTrue,
"NoExpiringCACertificates",
fmt.Sprintf("All CA certificates are still valid for at least %s.", minimumValidity),
nil,
nil
}
// CheckForProblematicWebhooks checks the Shoot for problematic webhooks which could prevent shoot worker nodes from
// joining the cluster.
func (c *Constraint) CheckForProblematicWebhooks(ctx context.Context) (gardencorev1beta1.ConditionStatus, string, string, []gardencorev1beta1.ErrorCode, error) {
validatingWebhookConfigs, err := getValidatingWebhookConfigurations(ctx, c.shootClient)
if err != nil {
return "", "", "", nil, fmt.Errorf("could not get ValidatingWebhookConfigurations of Shoot cluster to check for problematic webhooks: %w", err)
}
for _, webhookConfig := range validatingWebhookConfigs {
for _, w := range webhookConfig.Webhooks {
if IsProblematicWebhook(w.FailurePolicy, w.ObjectSelector, w.NamespaceSelector, w.Rules, w.TimeoutSeconds) {
msg := buildProblematicWebhookMessage("ValidatingWebhookConfiguration", webhookConfig.Name, w.Name, w.FailurePolicy, w.TimeoutSeconds)
return gardencorev1beta1.ConditionFalse,
"ProblematicWebhooks",
msg,
[]gardencorev1beta1.ErrorCode{gardencorev1beta1.ErrorProblematicWebhook},
nil
}
}
if wasRemediatedByGardener(webhookConfig.Annotations) {
return gardencorev1beta1.ConditionFalse,
"RemediatedWebhooks",
fmt.Sprintf("ValidatingWebhookConfiguration %q is problematic and was remediated by Gardener (please check its annotations for details).", webhookConfig.Name),
[]gardencorev1beta1.ErrorCode{gardencorev1beta1.ErrorProblematicWebhook},
nil
}
}
mutatingWebhookConfigs, err := getMutatingWebhookConfigurations(ctx, c.shootClient)
if err != nil {
return "", "", "", nil, fmt.Errorf("could not get MutatingWebhookConfigurations of Shoot cluster to check for problematic webhooks: %w", err)
}
for _, webhookConfig := range mutatingWebhookConfigs {
for _, w := range webhookConfig.Webhooks {
if IsProblematicWebhook(w.FailurePolicy, w.ObjectSelector, w.NamespaceSelector, w.Rules, w.TimeoutSeconds) {
msg := buildProblematicWebhookMessage("MutatingWebhookConfiguration", webhookConfig.Name, w.Name, w.FailurePolicy, w.TimeoutSeconds)
return gardencorev1beta1.ConditionFalse,
"ProblematicWebhooks",
msg,
[]gardencorev1beta1.ErrorCode{gardencorev1beta1.ErrorProblematicWebhook},
nil
}
}
if wasRemediatedByGardener(webhookConfig.Annotations) {
return gardencorev1beta1.ConditionFalse,
"RemediatedWebhooks",
fmt.Sprintf("MutatingWebhookConfiguration %q is problematic and was remediated by Gardener (please check its annotations for details).", webhookConfig.Name),
[]gardencorev1beta1.ErrorCode{gardencorev1beta1.ErrorProblematicWebhook},
nil
}
}
return gardencorev1beta1.ConditionTrue,
"NoProblematicWebhooks",
"All webhooks are properly configured.",
nil,
nil
}
func buildProblematicWebhookMessage(
kind string,
configName string,
webhookName string,
failurePolicy *admissionregistrationv1.FailurePolicyType,
timeoutSeconds *int32,
) string {
failurePolicyString := "nil"
if failurePolicy != nil {
failurePolicyString = string(*failurePolicy)
}
timeoutString := "and unset timeoutSeconds"
if timeoutSeconds != nil {
timeoutString = fmt.Sprintf("and %ds timeout", *timeoutSeconds)
}
return fmt.Sprintf("%s %q is problematic: webhook %q with failurePolicy %q %s might prevent worker nodes from properly joining the shoot cluster",
kind, configName, webhookName, failurePolicyString, timeoutString)
}
// IsProblematicWebhook checks if a single webhook of the Shoot Cluster is problematic. Problematic webhooks are
// webhooks with rules for CREATE/UPDATE/* pods or nodes and failurePolicy=Fail/nil. If the Shoot contains such a
// webhook, we can never wake up this shoot cluster again as new nodes cannot get created/ready, or our system
// component pods cannot get created/ready (because the webhook's backing pod is not yet running).
func IsProblematicWebhook(
failurePolicy *admissionregistrationv1.FailurePolicyType,
objSelector *metav1.LabelSelector,
nsSelector *metav1.LabelSelector,
rules []admissionregistrationv1.RuleWithOperations,
timeoutSeconds *int32,
) bool {
if failurePolicy != nil && *failurePolicy != admissionregistrationv1.Fail {
// in admissionregistration.k8s.io/v1 FailurePolicy is defaulted to `Fail`
// see https://github.com/kubernetes/api/blob/release-1.16/admissionregistration/v1/types.go#L195
// and https://github.com/kubernetes/api/blob/release-1.16/admissionregistration/v1/types.go#L324
// therefore, webhook with FailurePolicy==nil is also considered problematic
if timeoutSeconds != nil && *timeoutSeconds <= WebhookMaximumTimeoutSecondsNotProblematic {
// most control-plane API calls are made with a client-side timeout of 30s, so if a webhook has
// timeoutSeconds==30 the overall request might still fail although failurePolicy==Ignore, as there
// is overhead in communication with the API server and possible other webhooks.
// in admissionregistration/v1 timeoutSeconds is defaulted to 10 while in v1beta1 it's defaulted to 30.
// be restrictive here and mark all webhooks without a timeout set or timeouts > 15s as problematic to
// avoid ops effort. It's clearly documented that users should specify low timeouts, see
// https://kubernetes.io/docs/reference/access-authn-authz/extensible-admission-controllers/#timeouts
return false
}
}
for _, rule := range rules {
for _, matcher := range matchers.WebhookConstraintMatchers {
if matcher.Match(rule, objSelector, nsSelector) {
return true
}
}
}
return false
}
func wasRemediatedByGardener(annotations map[string]string) bool {
return annotations[v1beta1constants.GardenerWarning] != ""
}
func filterOptionalConstraints(required, optional []gardencorev1beta1.Condition) []gardencorev1beta1.Condition {
var out []gardencorev1beta1.Condition
out = append(out, required...)
for _, constraint := range optional {
if constraint.Status != gardencorev1beta1.ConditionTrue {
out = append(out, constraint)
}
}
return out
}