-
Notifications
You must be signed in to change notification settings - Fork 1.3k
/
control_plane_init_mutex.go
193 lines (171 loc) · 5.72 KB
/
control_plane_init_mutex.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
/*
Copyright 2019 The Kubernetes Authors.
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 locking implements locking functionality.
package locking
import (
"context"
"encoding/json"
"fmt"
"github.com/go-logr/logr"
"github.com/pkg/errors"
corev1 "k8s.io/api/core/v1"
apierrors "k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"sigs.k8s.io/controller-runtime/pkg/client"
clusterv1 "sigs.k8s.io/cluster-api/api/v1beta1"
)
const semaphoreInformationKey = "lock-information"
// ControlPlaneInitMutex uses a ConfigMap to synchronize cluster initialization.
type ControlPlaneInitMutex struct {
log logr.Logger
client client.Client
}
// NewControlPlaneInitMutex returns a lock that can be held by a control plane node before init.
func NewControlPlaneInitMutex(log logr.Logger, client client.Client) *ControlPlaneInitMutex {
return &ControlPlaneInitMutex{
log: log,
client: client,
}
}
// Lock allows a control plane node to be the first and only node to run kubeadm init.
func (c *ControlPlaneInitMutex) Lock(ctx context.Context, cluster *clusterv1.Cluster, machine *clusterv1.Machine) bool {
sema := newSemaphore()
cmName := configMapName(cluster.Name)
log := c.log.WithValues("namespace", cluster.Namespace, "cluster-name", cluster.Name, "configmap-name", cmName, "machine-name", machine.Name)
err := c.client.Get(ctx, client.ObjectKey{
Namespace: cluster.Namespace,
Name: cmName,
}, sema.ConfigMap)
switch {
case apierrors.IsNotFound(err):
break
case err != nil:
log.Error(err, "Failed to acquire lock")
return false
default: // Successfully found an existing config map.
info, err := sema.information()
if err != nil {
log.Error(err, "Failed to get information about the existing lock")
return false
}
// The machine requesting the lock is the machine that created the lock, therefore the lock is acquired.
if info.MachineName == machine.Name {
return true
}
// If the machine that created the lock can not be found unlock the mutex.
if err := c.client.Get(ctx, client.ObjectKey{
Namespace: cluster.Namespace,
Name: info.MachineName,
}, &clusterv1.Machine{}); err != nil {
log.Error(err, "Failed to get machine holding ControlPlane lock")
if apierrors.IsNotFound(err) {
c.Unlock(ctx, cluster)
}
}
log.Info("Waiting on another machine to initialize", "init-machine", info.MachineName)
return false
}
// Adds owner reference, namespace and name
sema.setMetadata(cluster)
// Adds the additional information
if err := sema.setInformation(&information{MachineName: machine.Name}); err != nil {
log.Error(err, "Failed to acquire lock while setting semaphore information")
return false
}
log.Info("Attempting to acquire the lock")
err = c.client.Create(ctx, sema.ConfigMap)
switch {
case apierrors.IsAlreadyExists(err):
log.Info("Cannot acquire the lock. The lock has been acquired by someone else")
return false
case err != nil:
log.Error(err, "Error acquiring the lock")
return false
default:
return true
}
}
// Unlock releases the lock.
func (c *ControlPlaneInitMutex) Unlock(ctx context.Context, cluster *clusterv1.Cluster) bool {
sema := newSemaphore()
cmName := configMapName(cluster.Name)
log := c.log.WithValues("namespace", cluster.Namespace, "cluster-name", cluster.Name, "configmap-name", cmName)
log.Info("Checking for lock")
err := c.client.Get(ctx, client.ObjectKey{
Namespace: cluster.Namespace,
Name: cmName,
}, sema.ConfigMap)
switch {
case apierrors.IsNotFound(err):
log.Info("Control plane init lock not found, it may have been released already")
return true
case err != nil:
log.Error(err, "Error unlocking the control plane init lock")
return false
default:
// Delete the config map semaphore if there is no error fetching it
if err := c.client.Delete(ctx, sema.ConfigMap); err != nil {
if apierrors.IsNotFound(err) {
return true
}
log.Error(err, "Error deleting the config map underlying the control plane init lock")
return false
}
return true
}
}
type information struct {
MachineName string `json:"machineName"`
}
type semaphore struct {
*corev1.ConfigMap
}
func newSemaphore() *semaphore {
return &semaphore{&corev1.ConfigMap{}}
}
func configMapName(clusterName string) string {
return fmt.Sprintf("%s-lock", clusterName)
}
func (s semaphore) information() (*information, error) {
li := &information{}
if err := json.Unmarshal([]byte(s.Data[semaphoreInformationKey]), li); err != nil {
return nil, errors.Wrap(err, "failed to unmarshal semaphore information")
}
return li, nil
}
func (s semaphore) setInformation(information *information) error {
b, err := json.Marshal(information)
if err != nil {
return errors.Wrap(err, "failed to marshal semaphore information")
}
s.Data = map[string]string{}
s.Data[semaphoreInformationKey] = string(b)
return nil
}
func (s *semaphore) setMetadata(cluster *clusterv1.Cluster) {
s.ObjectMeta = metav1.ObjectMeta{
Namespace: cluster.Namespace,
Name: configMapName(cluster.Name),
Labels: map[string]string{
clusterv1.ClusterLabelName: cluster.Name,
},
OwnerReferences: []metav1.OwnerReference{
{
APIVersion: cluster.APIVersion,
Kind: cluster.Kind,
Name: cluster.Name,
UID: cluster.UID,
},
},
}
}