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kube.go
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kube.go
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// Copyright (c) 2016, M Bogus.
// This source file is part of the KUBE-AMQP-AUTOSCALE open source project
// Licensed under Apache License v2.0
// See LICENSE file for license information
package main
import (
"fmt"
"io/ioutil"
"log"
v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
restclient "k8s.io/client-go/rest"
certutil "k8s.io/client-go/util/cert"
"github.com/prometheus/client_golang/prometheus"
"k8s.io/client-go/kubernetes"
)
const (
deploymentKind = "Deployment"
replicationControllerKind = "ReplicationController"
replicaSetKind = "ReplicaSet"
)
var (
scalingEvents = prometheus.NewCounterVec(
prometheus.CounterOpts{
Namespace: namespace,
Name: "scaling_events_total",
Help: "Count of scaling events by resource kind.",
},
[]string{"kind", "name"},
)
)
type apiContext struct {
URL string
User string
Passwd string
TokenFile string
CAFile string
Insecure bool
Bounds *scaleBounds
clientConf *restclient.Config
}
func scale(kind string, ns string, name string, newSize int32, ctx *apiContext) error {
c, err := ctx.client()
if err != nil {
return err
}
return scaleKind(c, kind, ns, name, newSize, ctx.Bounds)
}
func scaleKind(c *kubernetes.Clientset, kind string, ns string, name string, newSize int32, b *scaleBounds) error {
switch kind {
case replicaSetKind:
return scaleReplicaSets(c, ns, name, newSize, b)
case deploymentKind:
return scaleDeployments(c, ns, name, newSize, b)
}
return fmt.Errorf("No scaler has been implemented for '%s'", kind)
}
func scaleDeployments(c *kubernetes.Clientset, ns string, name string, newSize int32, b *scaleBounds) error {
deployment, err := c.AppsV1().Deployments(ns).Get(name, v1.GetOptions{})
if err != nil {
return err
}
replicas := b.newSize(*deployment.Spec.Replicas, newSize)
if replicas != *deployment.Spec.Replicas {
log.Printf("Scaling deployment '%s' from %d to %d replicas", name, *deployment.Spec.Replicas, replicas)
scalingEvents.With(prometheus.Labels{"kind": "Deployment", "name": name}).Inc()
deployment.Spec.Replicas = &replicas
_, err = c.AppsV1().Deployments(ns).Update(deployment)
if err != nil {
return err
}
}
return nil
}
func scaleReplicaSets(c *kubernetes.Clientset, ns string, name string, newSize int32, b *scaleBounds) error {
pod, err := c.AppsV1().ReplicaSets(ns).Get(name, v1.GetOptions{})
if err != nil {
return err
}
replicas := b.newSize(*pod.Spec.Replicas, newSize)
if replicas != *pod.Spec.Replicas {
log.Printf("Scaling replica set '%s' from %d to %d replicas", name, *pod.Spec.Replicas, replicas)
scalingEvents.With(prometheus.Labels{"kind": "ReplicaSet", "name": name}).Inc()
pod.Spec.Replicas = &replicas
_, err = c.AppsV1().ReplicaSets(ns).Update(pod)
if err != nil {
return err
}
}
return nil
}
func (ctx *apiContext) client() (*kubernetes.Clientset, error) {
if ctx.clientConf == nil {
conf, err := apiConfig(ctx.URL, ctx.User, ctx.Passwd, ctx.TokenFile, ctx.CAFile, ctx.Insecure)
if err != nil {
return nil, err
}
ctx.clientConf = conf
}
return kubernetes.NewForConfig(ctx.clientConf)
}
func apiConfig(apiURL string,
apiUser string,
apiPasswd string,
apiTokenFile string,
apiCAFile string,
apiInsecure bool) (*restclient.Config, error) {
if len(apiURL) == 0 {
return nil, fmt.Errorf("API URL must be defined")
}
cfg := &restclient.Config{
Host: apiURL,
}
if apiInsecure {
cfg.Insecure = apiInsecure
}
if len(apiUser) > 0 && len(apiPasswd) > 0 {
cfg.Username = apiUser
cfg.Password = apiPasswd
}
if len(apiTokenFile) > 0 {
token, err := ioutil.ReadFile(apiTokenFile)
if err != nil {
return nil, err
}
cfg.BearerToken = string(token)
}
if len(apiCAFile) > 0 {
tlsClientConfig := restclient.TLSClientConfig{}
if _, err := certutil.NewPool(apiCAFile); err != nil {
log.Printf("Expected to load root CA config from '%s', but got err: %v", apiCAFile, err)
} else {
tlsClientConfig.CAFile = apiCAFile
cfg.TLSClientConfig = tlsClientConfig
}
}
return cfg, nil
}
type scaleBounds struct {
Min int
Max int
IncreaseLimit int
DecreaseLimit int
}
func (sb *scaleBounds) newSize(size, newSize int32) int32 {
if size == newSize {
return newSize
}
replicas := newSize
if newSize < size {
if sb.DecreaseLimit > 0 {
replicas = max(size-int32(sb.DecreaseLimit), newSize)
}
} else {
if sb.IncreaseLimit > 0 {
replicas = min(size+int32(sb.IncreaseLimit), newSize)
}
}
replicas = max(replicas, int32(sb.Min))
replicas = min(replicas, int32(sb.Max))
return replicas
}
func min(x, y int32) int32 {
if x < y {
return x
}
return y
}
func max(x, y int32) int32 {
if x < y {
return y
}
return x
}