Merge pull request #1458 from brendandburns/dontpull

Add the ability to turn off image pulling.

pkg/api/types.go

@@ -17,6 +17,8 @@ limitations under the License.
 package api
 
 import (
+	"strings"
+
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
 	"github.com/fsouza/go-dockerclient"
 )
@@ -181,6 +183,38 @@ type LivenessProbe struct {
 	InitialDelaySeconds int64 `yaml:"initialDelaySeconds,omitempty" json:"initialDelaySeconds,omitempty"`
 }
 
+// PullPolicy describes a policy for if/when to pull a container image
+type PullPolicy string
+
+const (
+	// Always attempt to pull the latest image.  Container will fail If the pull fails.
+	PullAlways PullPolicy = "PullAlways"
+	// Never pull an image, only use a local image.  Container will fail if the image isn't present
+	PullNever PullPolicy = "PullNever"
+	// Pull if the image isn't present on disk. Container will fail if the image isn't present and the pull fails.
+	PullIfNotPresent PullPolicy = "PullIfNotPresent"
+)
+
+func IsPullAlways(p PullPolicy) bool {
+	// Default to pull always
+	if len(p) == 0 {
+		return true
+	}
+	return pullPoliciesEqual(p, PullAlways)
+}
+
+func IsPullNever(p PullPolicy) bool {
+	return pullPoliciesEqual(p, PullNever)
+}
+
+func IsPullIfNotPresent(p PullPolicy) bool {
+	return pullPoliciesEqual(p, PullIfNotPresent)
+}
+
+func pullPoliciesEqual(p1, p2 PullPolicy) bool {
+	return strings.ToLower(string(p1)) == strings.ToLower(string(p2))
+}
+
 // Container represents a single container that is expected to be run on the host.
 type Container struct {
 	// Required: This must be a DNS_LABEL.  Each container in a pod must
@@ -203,6 +237,8 @@ type Container struct {
 	Lifecycle     *Lifecycle     `yaml:"lifecycle,omitempty" json:"lifecycle,omitempty"`
 	// Optional: Default to false.
 	Privileged bool `json:"privileged,omitempty" yaml:"privileged,omitempty"`
+	// Optional: Policy for pulling images for this container
+	ImagePullPolicy PullPolicy `json:"imagePullPolicy" yaml:"imagePullPolicy"`
 }
 
 // Handler defines a specific action that should be taken

pkg/api/v1beta1/types.go

@@ -191,6 +191,18 @@ type LivenessProbe struct {
 	InitialDelaySeconds int64 `yaml:"initialDelaySeconds,omitempty" json:"initialDelaySeconds,omitempty"`
 }
 
+// PullPolicy describes a policy for if/when to pull a container image
+type PullPolicy string
+
+const (
+	// Always attempt to pull the latest image.  Container will fail If the pull fails.
+	PullAlways PullPolicy = "PullAlways"
+	// Never pull an image, only use a local image.  Container will fail if the image isn't present
+	PullNever PullPolicy = "PullNever"
+	// Pull if the image isn't present on disk. Container will fail if the image isn't present and the pull fails.
+	PullIfNotPresent PullPolicy = "PullIfNotPresent"
+)
+
 // Container represents a single container that is expected to be run on the host.
 type Container struct {
 	// Required: This must be a DNS_LABEL.  Each container in a pod must
@@ -213,6 +225,8 @@ type Container struct {
 	Lifecycle     *Lifecycle     `yaml:"lifecycle,omitempty" json:"lifecycle,omitempty"`
 	// Optional: Default to false.
 	Privileged bool `json:"privileged,omitempty" yaml:"privileged,omitempty"`
+	// Optional: Policy for pulling images for this container
+	ImagePullPolicy PullPolicy `json:"imagePullPolicy" yaml:"imagePullPolicy"`
 }
 
 // Handler defines a specific action that should be taken

pkg/api/v1beta2/types.go

@@ -190,6 +190,18 @@ type LivenessProbe struct {
 	InitialDelaySeconds int64 `yaml:"initialDelaySeconds,omitempty" json:"initialDelaySeconds,omitempty"`
 }
 
+// PullPolicy describes a policy for if/when to pull a container image
+type PullPolicy string
+
+const (
+	// Always attempt to pull the latest image.  Container will fail If the pull fails.
+	PullAlways PullPolicy = "PullAlways"
+	// Never pull an image, only use a local image.  Container will fail if the image isn't present
+	PullNever PullPolicy = "PullNever"
+	// Pull if the image isn't present on disk. Container will fail if the image isn't present and the pull fails.
+	PullIfNotPresent PullPolicy = "PullIfNotPresent"
+)
+
 // Container represents a single container that is expected to be run on the host.
 type Container struct {
 	// Required: This must be a DNS_LABEL.  Each container in a pod must
@@ -212,6 +224,8 @@ type Container struct {
 	Lifecycle     *Lifecycle     `yaml:"lifecycle,omitempty" json:"lifecycle,omitempty"`
 	// Optional: Default to false.
 	Privileged bool `json:"privileged,omitempty" yaml:"privileged,omitempty"`
+	// Optional: Policy for pulling images for this container
+	ImagePullPolicy PullPolicy `json:"imagePullPolicy" yaml:"imagePullPolicy"`
 }
 
 // Handler defines a specific action that should be taken

pkg/api/v1beta3/types.go

@@ -226,6 +226,18 @@ type LivenessProbe struct {
 	InitialDelaySeconds int64 `json:"initialDelaySeconds,omitempty" yaml:"initialDelaySeconds,omitempty"`
 }
 
+// PullPolicy describes a policy for if/when to pull a container image
+type PullPolicy string
+
+const (
+	// Always attempt to pull the latest image.  Container will fail If the pull fails.
+	PullAlways PullPolicy = "PullAlways"
+	// Never pull an image, only use a local image.  Container will fail if the image isn't present
+	PullNever PullPolicy = "PullNever"
+	// Pull if the image isn't present on disk. Container will fail if the image isn't present and the pull fails.
+	PullIfNotPresent PullPolicy = "PullIfNotPresent"
+)
+
 // Container represents a single container that is expected to be run on the host.
 type Container struct {
 	// Required: This must be a DNS_LABEL.  Each container in a pod must
@@ -248,6 +260,8 @@ type Container struct {
 	Lifecycle     *Lifecycle     `json:"lifecycle,omitempty" yaml:"lifecycle,omitempty"`
 	// Optional: Default to false.
 	Privileged bool `json:"privileged,omitempty" yaml:"privileged,omitempty"`
+	// Optional: Policy for pulling images for this container
+	ImagePullPolicy PullPolicy `json:"imagePullPolicy" yaml:"imagePullPolicy"`
 }
 
 // Handler defines a specific action that should be taken

pkg/kubelet/dockertools/docker.go

@@ -47,6 +47,7 @@ type DockerInterface interface {
 	CreateContainer(docker.CreateContainerOptions) (*docker.Container, error)
 	StartContainer(id string, hostConfig *docker.HostConfig) error
 	StopContainer(id string, timeout uint) error
+	InspectImage(image string) (*docker.Image, error)
 	PullImage(opts docker.PullImageOptions, auth docker.AuthConfiguration) error
 	Logs(opts docker.LogsOptions) error
 }
@@ -57,6 +58,7 @@ type DockerID string
 // DockerPuller is an abstract interface for testability.  It abstracts image pull operations.
 type DockerPuller interface {
 	Pull(image string) error
+	IsImagePresent(image string) (bool, error)
 }
 
 // dockerPuller is the default implementation of DockerPuller.
@@ -148,6 +150,24 @@ func (p throttledDockerPuller) Pull(image string) error {
 	return fmt.Errorf("pull QPS exceeded.")
 }
 
+func (p dockerPuller) IsImagePresent(name string) (bool, error) {
+	image, _ := parseImageName(name)
+	_, err := p.client.InspectImage(image)
+	if err == nil {
+		return true, nil
+	}
+	// This is super brittle, but its the best we got.
+	// TODO: Land code in the docker client to use docker.Error here instead.
+	if err.Error() == "no such image" {
+		return false, nil
+	}
+	return false, err
+}
+
+func (p throttledDockerPuller) IsImagePresent(name string) (bool, error) {
+	return p.puller.IsImagePresent(name)
+}
+
 // DockerContainers is a map of containers
 type DockerContainers map[DockerID]*docker.APIContainers
 

pkg/kubelet/dockertools/fake_docker_client.go

@@ -130,6 +130,10 @@ func (f *FakeDockerClient) PullImage(opts docker.PullImageOptions, auth docker.A
 	return f.Err
 }
 
+func (f *FakeDockerClient) InspectImage(name string) (*docker.Image, error) {
+	return nil, f.Err
+}
+
 // FakeDockerPuller is a stub implementation of DockerPuller.
 type FakeDockerPuller struct {
 	sync.Mutex
@@ -153,3 +157,7 @@ func (f *FakeDockerPuller) Pull(image string) (err error) {
 	}
 	return err
 }
+
+func (f *FakeDockerPuller) IsImagePresent(name string) (bool, error) {
+	return true, nil
+}

pkg/kubelet/kubelet.go

@@ -528,9 +528,18 @@ func (kl *Kubelet) syncPod(pod *Pod, dockerContainers dockertools.DockerContaine
 		}
 
 		glog.V(3).Infof("Container with name %s--%s--%s doesn't exist, creating %#v", podFullName, uuid, container.Name, container)
-		if err := kl.dockerPuller.Pull(container.Image); err != nil {
-			glog.Errorf("Failed to pull image %s: %v skipping pod %s container %s.", container.Image, err, podFullName, container.Name)
-			continue
+		if !api.IsPullNever(container.ImagePullPolicy) {
+			present, err := kl.dockerPuller.IsImagePresent(container.Image)
+			if err != nil {
+				glog.Errorf("Failed to inspect image: %s: %#v skipping pod %s container %s", container.Image, err, podFullName, container.Name)
+				continue
+			}
+			if api.IsPullAlways(container.ImagePullPolicy) || !present {
+				if err := kl.dockerPuller.Pull(container.Image); err != nil {
+					glog.Errorf("Failed to pull image %s: %v skipping pod %s container %s.", container.Image, err, podFullName, container.Name)
+					continue
+				}
+			}
 		}
 		// TODO(dawnchen): Check RestartPolicy.DelaySeconds before restart a container
 		containerID, err := kl.runContainer(pod, &container, podVolumes, "container:"+string(netID))