docs/scheduler/scheduler.go

68 lines
1.8 KiB
Go

package scheduler
import (
"fmt"
"sync"
"github.com/docker/libcluster/scheduler/filter"
"github.com/docker/libcluster/scheduler/strategy"
"github.com/docker/libcluster/swarm"
"github.com/samalba/dockerclient"
)
type Scheduler struct {
sync.Mutex
cluster *libcluster.Cluster
strategy strategy.PlacementStrategy
filters []filter.Filter
}
func NewScheduler(cluster *libcluster.Cluster, strategy strategy.PlacementStrategy, filters []filter.Filter) *Scheduler {
return &Scheduler{
cluster: cluster,
strategy: strategy,
filters: filters,
}
}
// Find a nice home for our container.
func (s *Scheduler) selectNodeForContainer(config *dockerclient.ContainerConfig) (*libcluster.Node, error) {
candidates := []*libcluster.Node{}
for _, node := range s.cluster.Nodes() {
candidates = append(candidates, node)
}
accepted, err := filter.ApplyFilters(s.filters, config, candidates)
if err != nil {
return nil, err
}
return s.strategy.PlaceContainer(config, accepted)
}
// Schedule a brand new container into the cluster.
func (s *Scheduler) CreateContainer(config *dockerclient.ContainerConfig, name string) (*libcluster.Container, error) {
s.Lock()
defer s.Unlock()
if config.Memory == 0 || config.CpuShares == 0 {
return nil, fmt.Errorf("Creating containers in clustering mode requires resource constraints (-c and -m) to be set")
}
node, err := s.selectNodeForContainer(config)
if err != nil {
return nil, err
}
return node.Create(config, name, true)
}
// Remove a container from the cluster. Containers should always be destroyed
// through the scheduler to guarantee atomicity.
func (s *Scheduler) RemoveContainer(container *libcluster.Container, force bool) error {
s.Lock()
defer s.Unlock()
return container.Node().Remove(container, force)
}