kubernetes/pkg/kubelet/dockertools/runner.go

/*
Copyright 2015 Google Inc. 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 dockertools

import (
	"fmt"
	"os"
	"path"

	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/capabilities"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/client/record"
	kubecontainer "github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet/container"
	"github.com/fsouza/go-dockerclient"
	"github.com/golang/glog"
)

type DockerContainerRunner struct {
	Client   DockerInterface
	Recorder record.EventRecorder
}

func (r *DockerContainerRunner) RunContainer(pod *api.Pod, container *api.Container, opts *kubecontainer.RunContainerOptions) (string, error) {
	ref, err := kubecontainer.GenerateContainerRef(pod, container)
	if err != nil {
		glog.Errorf("Couldn't make a ref to pod %v, container %v: '%v'", pod.Name, container.Name, err)
	}

	dockerName := KubeletContainerName{
		PodFullName:   kubecontainer.GetPodFullName(pod),
		PodUID:        pod.UID,
		ContainerName: container.Name,
	}
	exposedPorts, portBindings := makePortsAndBindings(container)

	// TODO(vmarmol): Handle better.
	// Cap hostname at 63 chars (specification is 64bytes which is 63 chars and the null terminating char).
	const hostnameMaxLen = 63
	containerHostname := pod.Name
	if len(containerHostname) > hostnameMaxLen {
		containerHostname = containerHostname[:hostnameMaxLen]
	}
	dockerOpts := docker.CreateContainerOptions{
		Name: BuildDockerName(dockerName, container),
		Config: &docker.Config{
			Env:          opts.Envs,
			ExposedPorts: exposedPorts,
			Hostname:     containerHostname,
			Image:        container.Image,
			Memory:       container.Resources.Limits.Memory().Value(),
			CPUShares:    milliCPUToShares(container.Resources.Limits.Cpu().MilliValue()),
			WorkingDir:   container.WorkingDir,
		},
	}

	setEntrypointAndCommand(container, &dockerOpts)

	dockerContainer, err := r.Client.CreateContainer(dockerOpts)
	if err != nil {
		if ref != nil {
			r.Recorder.Eventf(ref, "failed", "Failed to create docker container with error: %v", err)
		}
		return "", err
	}

	if ref != nil {
		r.Recorder.Eventf(ref, "created", "Created with docker id %v", dockerContainer.ID)
	}

	// The reason we create and mount the log file in here (not in kubelet) is because
	// the file's location depends on the ID of the container, and we need to create and
	// mount the file before actually starting the container.
	// TODO(yifan): Consider to pull this logic out since we might need to reuse it in
	// other container runtime.
	if opts.PodContainerDir != "" && len(container.TerminationMessagePath) != 0 {
		containerLogPath := path.Join(opts.PodContainerDir, dockerContainer.ID)
		fs, err := os.Create(containerLogPath)
		if err != nil {
			// TODO: Clean up the previouly created dir? return the error?
			glog.Errorf("Error on creating termination-log file %q: %v", containerLogPath, err)
		} else {
			fs.Close() // Close immediately; we're just doing a `touch` here
			b := fmt.Sprintf("%s:%s", containerLogPath, container.TerminationMessagePath)
			opts.Binds = append(opts.Binds, b)
		}
	}

	privileged := false
	if capabilities.Get().AllowPrivileged {
		privileged = container.Privileged
	} else if container.Privileged {
		return "", fmt.Errorf("container requested privileged mode, but it is disallowed globally.")
	}

	capAdd, capDrop := makeCapabilites(container.Capabilities.Add, container.Capabilities.Drop)
	hc := &docker.HostConfig{
		PortBindings: portBindings,
		Binds:        opts.Binds,
		NetworkMode:  opts.NetMode,
		IpcMode:      opts.IpcMode,
		Privileged:   privileged,
		CapAdd:       capAdd,
		CapDrop:      capDrop,
	}
	if len(opts.DNS) > 0 {
		hc.DNS = opts.DNS
	}
	if len(opts.DNSSearch) > 0 {
		hc.DNSSearch = opts.DNSSearch
	}

	if err = r.Client.StartContainer(dockerContainer.ID, hc); err != nil {
		if ref != nil {
			r.Recorder.Eventf(ref, "failed",
				"Failed to start with docker id %v with error: %v", dockerContainer.ID, err)
		}
		return "", err
	}
	if ref != nil {
		r.Recorder.Eventf(ref, "started", "Started with docker id %v", dockerContainer.ID)
	}
	return dockerContainer.ID, nil
}

func setEntrypointAndCommand(container *api.Container, opts *docker.CreateContainerOptions) {
	if len(container.Command) != 0 {
		opts.Config.Entrypoint = container.Command
	}
	if len(container.Args) != 0 {
		opts.Config.Cmd = container.Args
	}
}