mirror of https://github.com/k3s-io/k3s
134 lines
4.2 KiB
Go
134 lines
4.2 KiB
Go
/*
|
|
Copyright 2014 The Kubernetes Authors All rights reserved.
|
|
|
|
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 scheduler
|
|
|
|
// Note: if you change code in this file, you might need to change code in
|
|
// contrib/mesos/pkg/scheduler/.
|
|
|
|
import (
|
|
"time"
|
|
|
|
"k8s.io/kubernetes/pkg/api"
|
|
"k8s.io/kubernetes/pkg/client/record"
|
|
"k8s.io/kubernetes/pkg/util/wait"
|
|
"k8s.io/kubernetes/plugin/pkg/scheduler/algorithm"
|
|
"k8s.io/kubernetes/plugin/pkg/scheduler/metrics"
|
|
"k8s.io/kubernetes/plugin/pkg/scheduler/schedulercache"
|
|
|
|
"github.com/golang/glog"
|
|
)
|
|
|
|
// Binder knows how to write a binding.
|
|
type Binder interface {
|
|
Bind(binding *api.Binding) error
|
|
}
|
|
|
|
// Scheduler watches for new unscheduled pods. It attempts to find
|
|
// nodes that they fit on and writes bindings back to the api server.
|
|
type Scheduler struct {
|
|
config *Config
|
|
}
|
|
|
|
type Config struct {
|
|
// It is expected that changes made via SchedulerCache will be observed
|
|
// by NodeLister and Algorithm.
|
|
SchedulerCache schedulercache.Cache
|
|
NodeLister algorithm.NodeLister
|
|
Algorithm algorithm.ScheduleAlgorithm
|
|
Binder Binder
|
|
|
|
// NextPod should be a function that blocks until the next pod
|
|
// is available. We don't use a channel for this, because scheduling
|
|
// a pod may take some amount of time and we don't want pods to get
|
|
// stale while they sit in a channel.
|
|
NextPod func() *api.Pod
|
|
|
|
// Error is called if there is an error. It is passed the pod in
|
|
// question, and the error
|
|
Error func(*api.Pod, error)
|
|
|
|
// Recorder is the EventRecorder to use
|
|
Recorder record.EventRecorder
|
|
|
|
// Close this to shut down the scheduler.
|
|
StopEverything chan struct{}
|
|
}
|
|
|
|
// New returns a new scheduler.
|
|
func New(c *Config) *Scheduler {
|
|
s := &Scheduler{
|
|
config: c,
|
|
}
|
|
metrics.Register()
|
|
return s
|
|
}
|
|
|
|
// Run begins watching and scheduling. It starts a goroutine and returns immediately.
|
|
func (s *Scheduler) Run() {
|
|
go wait.Until(s.scheduleOne, 0, s.config.StopEverything)
|
|
}
|
|
|
|
func (s *Scheduler) scheduleOne() {
|
|
pod := s.config.NextPod()
|
|
|
|
glog.V(3).Infof("Attempting to schedule: %+v", pod)
|
|
start := time.Now()
|
|
dest, err := s.config.Algorithm.Schedule(pod, s.config.NodeLister)
|
|
if err != nil {
|
|
glog.V(1).Infof("Failed to schedule: %+v", pod)
|
|
s.config.Error(pod, err)
|
|
s.config.Recorder.Eventf(pod, api.EventTypeWarning, "FailedScheduling", "%v", err)
|
|
return
|
|
}
|
|
metrics.SchedulingAlgorithmLatency.Observe(metrics.SinceInMicroseconds(start))
|
|
|
|
// Optimistically assume that the binding will succeed and send it to apiserver
|
|
// in the background.
|
|
// The only risk in this approach is that if the binding fails because of some
|
|
// reason, scheduler will be assuming that it succeeded while scheduling next
|
|
// pods, until the assumption in the internal cache expire (expiration is
|
|
// defined as "didn't read the binding via watch within a given timeout",
|
|
// timeout is currently set to 30s). However, after this timeout, the situation
|
|
// will self-repair.
|
|
assumed := *pod
|
|
assumed.Spec.NodeName = dest
|
|
s.config.SchedulerCache.AssumePod(&assumed)
|
|
|
|
go func() {
|
|
defer metrics.E2eSchedulingLatency.Observe(metrics.SinceInMicroseconds(start))
|
|
|
|
b := &api.Binding{
|
|
ObjectMeta: api.ObjectMeta{Namespace: pod.Namespace, Name: pod.Name},
|
|
Target: api.ObjectReference{
|
|
Kind: "Node",
|
|
Name: dest,
|
|
},
|
|
}
|
|
|
|
bindingStart := time.Now()
|
|
err := s.config.Binder.Bind(b)
|
|
if err != nil {
|
|
glog.V(1).Infof("Failed to bind pod: %+v", err)
|
|
s.config.Error(pod, err)
|
|
s.config.Recorder.Eventf(pod, api.EventTypeNormal, "FailedScheduling", "Binding rejected: %v", err)
|
|
return
|
|
}
|
|
metrics.BindingLatency.Observe(metrics.SinceInMicroseconds(bindingStart))
|
|
s.config.Recorder.Eventf(pod, api.EventTypeNormal, "Scheduled", "Successfully assigned %v to %v", pod.Name, dest)
|
|
}()
|
|
}
|