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workflowpod.go
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workflowpod.go
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package controller
import (
"encoding/json"
"fmt"
"io"
"path"
"github.com/argoproj/argo/errors"
wfv1 "github.com/argoproj/argo/pkg/apis/workflow/v1alpha1"
"github.com/argoproj/argo/workflow/common"
log "github.com/sirupsen/logrus"
"github.com/valyala/fasttemplate"
apiv1 "k8s.io/api/core/v1"
apierr "k8s.io/apimachinery/pkg/api/errors"
"k8s.io/apimachinery/pkg/api/resource"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)
// Reusable k8s pod spec portions used in workflow pods
var (
// volumePodMetadata makes available the pod metadata available as a file
// to the executor's init and sidecar containers. Specifically, the template
// of the pod is stored as an annotation
volumePodMetadata = apiv1.Volume{
Name: common.PodMetadataVolumeName,
VolumeSource: apiv1.VolumeSource{
DownwardAPI: &apiv1.DownwardAPIVolumeSource{
Items: []apiv1.DownwardAPIVolumeFile{
{
Path: common.PodMetadataAnnotationsVolumePath,
FieldRef: &apiv1.ObjectFieldSelector{
APIVersion: "v1",
FieldPath: "metadata.annotations",
},
},
},
},
},
}
volumeMountPodMetadata = apiv1.VolumeMount{
Name: volumePodMetadata.Name,
MountPath: common.PodMetadataMountPath,
}
hostPathDir = apiv1.HostPathDirectory
// volumeDockerLib provides the wait container access to the minion's host docker containers
// runtime files (e.g. /var/lib/docker/container). This is used by the executor to access
// the main container's logs (and potentially storage to upload output artifacts)
volumeDockerLib = apiv1.Volume{
Name: common.DockerLibVolumeName,
VolumeSource: apiv1.VolumeSource{
HostPath: &apiv1.HostPathVolumeSource{
Path: common.DockerLibHostPath,
Type: &hostPathDir,
},
},
}
volumeMountDockerLib = apiv1.VolumeMount{
Name: volumeDockerLib.Name,
MountPath: volumeDockerLib.VolumeSource.HostPath.Path,
ReadOnly: true,
}
// volumeDockerSock provides the wait container direct access to the minion's host docker daemon.
// The primary purpose of this is to make available `docker cp` to collect an output artifact
// from a container. Alternatively, we could use `kubectl cp`, but `docker cp` avoids the extra
// hop to the kube api server.
volumeDockerSock = apiv1.Volume{
Name: common.DockerSockVolumeName,
VolumeSource: apiv1.VolumeSource{
HostPath: &apiv1.HostPathVolumeSource{
Path: "/var/run",
Type: &hostPathDir,
},
},
}
volumeMountDockerSock = apiv1.VolumeMount{
Name: volumeDockerSock.Name,
MountPath: "/var/run/docker.sock",
ReadOnly: true,
SubPath: "docker.sock",
}
// execEnvVars exposes various pod information as environment variables to the exec container
execEnvVars = []apiv1.EnvVar{
envFromField(common.EnvVarPodIP, "status.podIP"),
envFromField(common.EnvVarPodName, "metadata.name"),
envFromField(common.EnvVarNamespace, "metadata.namespace"),
}
)
// envFromField is a helper to return a EnvVar with the name and field
func envFromField(envVarName, fieldPath string) apiv1.EnvVar {
return apiv1.EnvVar{
Name: envVarName,
ValueFrom: &apiv1.EnvVarSource{
FieldRef: &apiv1.ObjectFieldSelector{
APIVersion: "v1",
FieldPath: fieldPath,
},
},
}
}
func (woc *wfOperationCtx) createWorkflowPod(nodeName string, mainCtr apiv1.Container, tmpl *wfv1.Template) (*apiv1.Pod, error) {
nodeID := woc.wf.NodeID(nodeName)
woc.log.Debugf("Creating Pod: %s (%s)", nodeName, nodeID)
tmpl = tmpl.DeepCopy()
mainCtr.Name = common.MainContainerName
pod := apiv1.Pod{
ObjectMeta: metav1.ObjectMeta{
Name: nodeID,
Labels: map[string]string{
common.LabelKeyWorkflow: woc.wf.ObjectMeta.Name, // Allows filtering by pods related to specific workflow
common.LabelKeyCompleted: "false", // Allows filtering by incomplete workflow pods
},
Annotations: map[string]string{
common.AnnotationKeyNodeName: nodeName,
},
OwnerReferences: []metav1.OwnerReference{
*metav1.NewControllerRef(woc.wf, wfv1.SchemaGroupVersionKind),
},
},
Spec: apiv1.PodSpec{
RestartPolicy: apiv1.RestartPolicyNever,
Containers: []apiv1.Container{
mainCtr,
},
Volumes: []apiv1.Volume{
volumePodMetadata,
volumeDockerLib,
volumeDockerSock,
},
ActiveDeadlineSeconds: tmpl.ActiveDeadlineSeconds,
ServiceAccountName: woc.wf.Spec.ServiceAccountName,
ImagePullSecrets: woc.wf.Spec.ImagePullSecrets,
},
}
if woc.controller.Config.InstanceID != "" {
pod.ObjectMeta.Labels[common.LabelKeyControllerInstanceID] = woc.controller.Config.InstanceID
}
if tmpl.GetType() != wfv1.TemplateTypeResource {
// we do not need the wait container for resource templates because
// argoexec runs as the main container and will perform the job of
// annotating the outputs or errors, making the wait container redundant.
waitCtr, err := woc.newWaitContainer(tmpl)
if err != nil {
return nil, err
}
pod.Spec.Containers = append(pod.Spec.Containers, *waitCtr)
}
// Add init container only if it needs input artifacts. This is also true for
// script templates (which needs to populate the script)
if len(tmpl.Inputs.Artifacts) > 0 || tmpl.GetType() == wfv1.TemplateTypeScript {
initCtr := woc.newInitContainer(tmpl)
pod.Spec.InitContainers = []apiv1.Container{initCtr}
}
woc.addSchedulingConstraints(&pod, tmpl)
err := woc.addVolumeReferences(&pod, tmpl)
if err != nil {
return nil, err
}
err = woc.addInputArtifactsVolumes(&pod, tmpl)
if err != nil {
return nil, err
}
err = woc.addArchiveLocation(&pod, tmpl)
if err != nil {
return nil, err
}
if tmpl.GetType() == wfv1.TemplateTypeScript {
addExecutorStagingVolume(&pod)
}
// addSidecars should be called after all volumes have been manipulated
// in the main container (in case sidecar requires volume mount mirroring)
err = addSidecars(&pod, tmpl)
if err != nil {
return nil, err
}
// Set the container template JSON in pod annotations, which executor
// will examine for things like artifact location/path. Also ensures
// that all variables have been resolved. Do this last, after all
// template manipulations have been performed.
tmplBytes, err := json.Marshal(tmpl)
if err != nil {
return nil, err
}
err = verifyResolvedVariables(string(tmplBytes))
if err != nil {
return nil, err
}
pod.ObjectMeta.Annotations[common.AnnotationKeyTemplate] = string(tmplBytes)
created, err := woc.controller.kubeclientset.CoreV1().Pods(woc.wf.ObjectMeta.Namespace).Create(&pod)
if err != nil {
if apierr.IsAlreadyExists(err) {
// workflow pod names are deterministic. We can get here if the
// controller fails to persist the workflow after creating the pod.
woc.log.Infof("Skipped pod %s (%s) creation: already exists", nodeName, nodeID)
return created, nil
}
woc.log.Infof("Failed to create pod %s (%s): %v", nodeName, nodeID, err)
return nil, errors.InternalWrapError(err)
}
woc.log.Infof("Created pod: %s (%s)", nodeName, created.Name)
return created, nil
}
func (woc *wfOperationCtx) newInitContainer(tmpl *wfv1.Template) apiv1.Container {
ctr := woc.newExecContainer(common.InitContainerName, false)
ctr.Command = []string{"argoexec"}
ctr.Args = []string{"init"}
ctr.VolumeMounts = []apiv1.VolumeMount{
volumeMountPodMetadata,
}
return *ctr
}
func (woc *wfOperationCtx) newWaitContainer(tmpl *wfv1.Template) (*apiv1.Container, error) {
ctr := woc.newExecContainer(common.WaitContainerName, false)
ctr.Command = []string{"argoexec"}
ctr.Args = []string{"wait"}
ctr.VolumeMounts = []apiv1.VolumeMount{
volumeMountPodMetadata,
volumeMountDockerLib,
volumeMountDockerSock,
}
return ctr, nil
}
func (woc *wfOperationCtx) newExecContainer(name string, privileged bool) *apiv1.Container {
exec := apiv1.Container{
Name: name,
Image: woc.controller.Config.ExecutorImage,
Env: execEnvVars,
Resources: apiv1.ResourceRequirements{
Limits: apiv1.ResourceList{
apiv1.ResourceCPU: resource.MustParse("0.5"),
apiv1.ResourceMemory: resource.MustParse("512Mi"),
},
Requests: apiv1.ResourceList{
apiv1.ResourceCPU: resource.MustParse("0.1"),
apiv1.ResourceMemory: resource.MustParse("64Mi"),
},
},
SecurityContext: &apiv1.SecurityContext{
Privileged: &privileged,
},
}
return &exec
}
// addSchedulingConstraints applies any node selectors or affinity rules to the pod, either set in the workflow or the template
func (woc *wfOperationCtx) addSchedulingConstraints(pod *apiv1.Pod, tmpl *wfv1.Template) {
// Set nodeSelector (if specified)
if len(tmpl.NodeSelector) > 0 {
pod.Spec.NodeSelector = tmpl.NodeSelector
} else if len(woc.wf.Spec.NodeSelector) > 0 {
pod.Spec.NodeSelector = woc.wf.Spec.NodeSelector
}
// Set affinity (if specified)
if tmpl.Affinity != nil {
pod.Spec.Affinity = tmpl.Affinity
} else if woc.wf.Spec.Affinity != nil {
pod.Spec.Affinity = woc.wf.Spec.Affinity
}
}
// addVolumeReferences adds any volumeMounts that a container/sidecar is referencing, to the pod.spec.volumes
// These are either specified in the workflow.spec.volumes or the workflow.spec.volumeClaimTemplate section
func (woc *wfOperationCtx) addVolumeReferences(pod *apiv1.Pod, tmpl *wfv1.Template) error {
if tmpl.Container == nil && len(tmpl.Sidecars) == 0 {
return nil
}
addVolumeRef := func(volMounts []apiv1.VolumeMount) error {
for _, volMnt := range volMounts {
vol := getVolByName(volMnt.Name, woc.wf)
if vol == nil {
return errors.Errorf(errors.CodeBadRequest, "volume '%s' not found in workflow spec", volMnt.Name)
}
found := false
for _, v := range pod.Spec.Volumes {
if v.Name == vol.Name {
found = true
break
}
}
if !found {
if pod.Spec.Volumes == nil {
pod.Spec.Volumes = make([]apiv1.Volume, 0)
}
pod.Spec.Volumes = append(pod.Spec.Volumes, *vol)
}
}
return nil
}
if tmpl.Container != nil {
err := addVolumeRef(tmpl.Container.VolumeMounts)
if err != nil {
return err
}
}
for _, sidecar := range tmpl.Sidecars {
err := addVolumeRef(sidecar.VolumeMounts)
if err != nil {
return err
}
}
return nil
}
// getVolByName is a helper to retrieve a volume by its name, either from the volumes or claims section
func getVolByName(name string, wf *wfv1.Workflow) *apiv1.Volume {
for _, vol := range wf.Spec.Volumes {
if vol.Name == name {
return &vol
}
}
for _, pvc := range wf.Status.PersistentVolumeClaims {
if pvc.Name == name {
return &pvc
}
}
return nil
}
// addInputArtifactVolumes sets up the artifacts volume to the pod to support input artifacts to containers.
// In order support input artifacts, the init container shares a emptydir volume with the main container.
// It is the responsibility of the init container to load all artifacts to the mounted emptydir location.
// (e.g. /inputs/artifacts/CODE). The shared emptydir is mapped to the user's desired location in the main
// container.
//
// It is possible that a user specifies overlapping paths of an artifact path with a volume mount,
// (e.g. user wants an external volume mounted at /src, while simultaneously wanting an input artifact
// placed at /src/some/subdirectory). When this occurs, we need to prevent the duplicate bind mounting of
// overlapping volumes, since the outer volume will not see the changes made in the artifact emptydir.
//
// To prevent overlapping bind mounts, both the controller and executor will recognize the overlap between
// the explicit volume mount and the artifact emptydir and prevent all uses of the emptydir for purposes of
// loading data. The controller will omit mounting the emptydir to the artifact path, and the executor
// will load the artifact in the in user's volume (as opposed to the emptydir)
func (woc *wfOperationCtx) addInputArtifactsVolumes(pod *apiv1.Pod, tmpl *wfv1.Template) error {
if len(tmpl.Inputs.Artifacts) == 0 {
return nil
}
artVol := apiv1.Volume{
Name: "input-artifacts",
VolumeSource: apiv1.VolumeSource{
EmptyDir: &apiv1.EmptyDirVolumeSource{},
},
}
pod.Spec.Volumes = append(pod.Spec.Volumes, artVol)
for i, initCtr := range pod.Spec.InitContainers {
if initCtr.Name == common.InitContainerName {
volMount := apiv1.VolumeMount{
Name: artVol.Name,
MountPath: common.ExecutorArtifactBaseDir,
}
initCtr.VolumeMounts = append(initCtr.VolumeMounts, volMount)
// We also add the user supplied mount paths to the init container,
// in case the executor needs to load artifacts to this volume
// instead of the artifacts volume
if tmpl.Container != nil {
for _, mnt := range tmpl.Container.VolumeMounts {
mnt.MountPath = path.Join(common.InitContainerMainFilesystemDir, mnt.MountPath)
initCtr.VolumeMounts = append(initCtr.VolumeMounts, mnt)
}
}
pod.Spec.InitContainers[i] = initCtr
break
}
}
mainCtrIndex := 0
var mainCtr *apiv1.Container
for i, ctr := range pod.Spec.Containers {
if ctr.Name == common.MainContainerName {
mainCtrIndex = i
mainCtr = &pod.Spec.Containers[i]
}
}
if mainCtr == nil {
panic("Could not find main container in pod spec")
}
// TODO: the order in which we construct the volume mounts may matter,
// especially if they are overlapping.
for _, art := range tmpl.Inputs.Artifacts {
if art.Path == "" {
return errors.Errorf(errors.CodeBadRequest, "inputs.artifacts.%s did not specify a path", art.Name)
}
overlap := common.FindOverlappingVolume(tmpl, art.Path)
if overlap != nil {
// artifact path overlaps with a mounted volume. do not mount the
// artifacts emptydir to the main container. init would have copied
// the artifact to the user's volume instead
woc.log.Debugf("skip volume mount of %s (%s): overlaps with mount %s at %s",
art.Name, art.Path, overlap.Name, overlap.MountPath)
continue
}
volMount := apiv1.VolumeMount{
Name: artVol.Name,
MountPath: art.Path,
SubPath: art.Name,
}
if mainCtr.VolumeMounts == nil {
mainCtr.VolumeMounts = make([]apiv1.VolumeMount, 0)
}
mainCtr.VolumeMounts = append(mainCtr.VolumeMounts, volMount)
}
pod.Spec.Containers[mainCtrIndex] = *mainCtr
return nil
}
// addArchiveLocation updates the template with artifact repository information configured in the controller.
// This is skipped for templates which have explicitly set an archive location in the template
func (woc *wfOperationCtx) addArchiveLocation(pod *apiv1.Pod, tmpl *wfv1.Template) error {
if tmpl.ArchiveLocation != nil {
return nil
}
tmpl.ArchiveLocation = &wfv1.ArtifactLocation{}
// artifacts are stored in using the following formula:
// <repo_key_prefix>/<worflow_name>/<node_id>/<artifact_name>.tgz
// (e.g. myworkflowartifacts/argo-wf-fhljp/argo-wf-fhljp-123291312382/src.tgz)
// TODO: will need to support more advanced organization of artifacts such as dated
// (e.g. myworkflowartifacts/2017/10/31/... )
if woc.controller.Config.ArtifactRepository.S3 != nil {
log.Debugf("Setting s3 artifact repository information")
keyPrefix := ""
if woc.controller.Config.ArtifactRepository.S3.KeyPrefix != "" {
keyPrefix = woc.controller.Config.ArtifactRepository.S3.KeyPrefix + "/"
}
artLocationKey := fmt.Sprintf("%s%s/%s", keyPrefix, woc.wf.ObjectMeta.Name, pod.ObjectMeta.Name)
tmpl.ArchiveLocation.S3 = &wfv1.S3Artifact{
S3Bucket: woc.controller.Config.ArtifactRepository.S3.S3Bucket,
Key: artLocationKey,
}
} else if woc.controller.Config.ArtifactRepository.Artifactory != nil {
log.Debugf("Setting artifactory artifact repository information")
repoURL := ""
if woc.controller.Config.ArtifactRepository.Artifactory.RepoURL != "" {
repoURL = woc.controller.Config.ArtifactRepository.Artifactory.RepoURL + "/"
}
artURL := fmt.Sprintf("%s%s/%s", repoURL, woc.wf.ObjectMeta.Name, pod.ObjectMeta.Name)
tmpl.ArchiveLocation.Artifactory = &wfv1.ArtifactoryArtifact{
ArtifactoryAuth: woc.controller.Config.ArtifactRepository.Artifactory.ArtifactoryAuth,
URL: artURL,
}
} else {
for _, art := range tmpl.Outputs.Artifacts {
if !art.HasLocation() {
log.Errorf("artifact has no location details:%#v", art)
return errors.Errorf(errors.CodeBadRequest, "controller is not configured with a default archive location")
}
}
}
return nil
}
// addExecutorStagingVolume sets up a shared staging volume between the init container
// and main container for the purpose of holding the script source code for script templates
func addExecutorStagingVolume(pod *apiv1.Pod) {
volName := "argo-staging"
stagingVol := apiv1.Volume{
Name: volName,
VolumeSource: apiv1.VolumeSource{
EmptyDir: &apiv1.EmptyDirVolumeSource{},
},
}
pod.Spec.Volumes = append(pod.Spec.Volumes, stagingVol)
for i, initCtr := range pod.Spec.InitContainers {
if initCtr.Name == common.InitContainerName {
volMount := apiv1.VolumeMount{
Name: volName,
MountPath: common.ExecutorStagingEmptyDir,
}
initCtr.VolumeMounts = append(initCtr.VolumeMounts, volMount)
pod.Spec.InitContainers[i] = initCtr
break
}
}
found := false
for i, ctr := range pod.Spec.Containers {
if ctr.Name == common.MainContainerName {
volMount := apiv1.VolumeMount{
Name: volName,
MountPath: common.ExecutorStagingEmptyDir,
}
if ctr.VolumeMounts == nil {
ctr.VolumeMounts = []apiv1.VolumeMount{volMount}
} else {
ctr.VolumeMounts = append(ctr.VolumeMounts, volMount)
}
pod.Spec.Containers[i] = ctr
found = true
break
}
}
if !found {
panic("Unable to locate main container")
}
}
// addSidecars adds all sidecars to the pod spec of the step.
// Optionally volume mounts from the main container to the sidecar
func addSidecars(pod *apiv1.Pod, tmpl *wfv1.Template) error {
if len(tmpl.Sidecars) == 0 {
return nil
}
var mainCtr *apiv1.Container
for _, ctr := range pod.Spec.Containers {
if ctr.Name != common.MainContainerName {
continue
}
mainCtr = &ctr
break
}
if mainCtr == nil {
panic("Unable to locate main container")
}
for _, sidecar := range tmpl.Sidecars {
if sidecar.MirrorVolumeMounts != nil && *sidecar.MirrorVolumeMounts {
for _, volMnt := range mainCtr.VolumeMounts {
if sidecar.VolumeMounts == nil {
sidecar.VolumeMounts = make([]apiv1.VolumeMount, 0)
}
sidecar.VolumeMounts = append(sidecar.VolumeMounts, volMnt)
}
}
pod.Spec.Containers = append(pod.Spec.Containers, sidecar.Container)
}
return nil
}
// verifyResolvedVariables is a helper to ensure all {{variables}} have been resolved
func verifyResolvedVariables(tmplStr string) error {
var unresolvedErr error
fstTmpl := fasttemplate.New(tmplStr, "{{", "}}")
fstTmpl.ExecuteFuncString(func(w io.Writer, tag string) (int, error) {
unresolvedErr = errors.Errorf(errors.CodeBadRequest, "failed to resolve {{%s}}", tag)
return 0, nil
})
return unresolvedErr
}