Adds a kubeadm config images pull command #63833

chuckha · 2018-05-15T01:01:40Z

This command will use crictl or docker to pull images locally.

The dockerfall back is needed because in some cases the kubelet is not
yet running so there is no CRI dockershim socket available.

Fixes kubernetes/kubeadm#812

Signed-off-by: Chuck Ha ha.chuck@gmail.com

What this PR does / why we need it:
This PR adds a command to the kubeadm config images subcommand to pull images using either crictl or docker.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes kubernetes/kubeadm#812

Special notes for your reviewer:

Release note:

Adds a `kubeadm config images pull` command to pull container images used by kubeadm.

/cc @kubernetes/sig-cluster-lifecycle-pr-reviews

timothysc · 2018-05-15T01:16:37Z

cmd/kubeadm/app/images/puller.go

+		return ip.exec.Command("sh", "-c", fmt.Sprintf("docker pull %v", image)).Run()
+	}
+
+	return ip.exec.Command(ip.crictlPath, "-r", ip.criSocket, "pull", image).Run()


Don't we need todo version magic checking to ensure that the crictl can pull for the runtimes we are endorsing? We'll need to ship a version with kubeadm that we we vet.

You are 💯% correct. We'll be addressing that in this issue kubernetes/kubeadm#811

neolit123 · 2018-05-15T01:34:59Z

cmd/kubeadm/app/cmd/config.go

+		Use:   "images",
+		Short: "Interact with container images used by kubeadm.",
+		RunE:  cmdutil.SubCmdRunE("images"),
+	}


did these two PRs overlap?
#63811

oddly, for the other one the bots are saying PR is unable to be automatically merged. Needs rebase. but github thinks there is no need for rebase.

the refactor and pull addition could have been separate commits.

Yeah, that was me basing this branch off that one. I forgot to mention that, my mistake. The refactor and the addition are in two separate commits. I just fixed the merge conflict, it should look a lot better now.

neolit123 · 2018-05-15T01:35:43Z

cmd/kubeadm/app/cmd/config.go

@@ -258,8 +324,8 @@ func (i *ListImages) Run(out io.Writer) error {
 	return nil
 }

-// AddListImagesConfigFlag adds the flags that configure kubeadm
-func AddListImagesConfigFlag(flagSet *flag.FlagSet, cfg *kubeadmapiv1alpha1.MasterConfiguration, featureGatesString *string) {
+// AddImagesCommonConfigFlags adds the flags that configure kubeadm (and affect the images kubeadm will use)


it's OK to remove the ( ) here, but keep the text in there.

fabriziopandini · 2018-05-15T16:24:48Z

cmd/kubeadm/app/cmd/config.go

+}
+
+// Puller is an interface for pulling images
+type Puller interface {


What about to move it in app/images? This more part of a re-usabe tools than a UX concern...
(Same for types that follows)

I was thinking about this as if it were an internal interface (which I should have then named it puller instead) -- not really something for reuse, but I don't see any reason why it can't live in the images package.

The ImagesPull was not designed for use elsewhere, but looking at it a bit closer, the only thing I can see that is specific to this command is the glog call.

Would you be ok if I moved the Puller interface out to the images package but kept ImagesPull internal to this package for now?

Ever if there is no real use case for reuse now, I would like to have the capability to pull a set of images implemented in the app/images package instead of in the UX

..., the only thing I can see that is specific to this command is the glog call.
I don't see this as a constraint, e.g. there are already several glog calls in phases

fabriziopandini · 2018-05-15T16:24:55Z

cmd/kubeadm/app/images/puller.go

+)
+
+// ImagePuller is a struct that can pull images and hides the implementation (crictl vs docker)
+type ImagePuller struct {


criImagePuller?

Why make it private? I'd also argue that the name should not reveal the implementation as this uses either docker or crictl to pull images

The initial lower case was a typo, sorry

However I'm still not fully comfortable about naming of ImagePull and ImagePuller because those confused me while reading the code. If we are keeping 'ImagePuller' because it's implementation, what about ImagePull -> ImageSetPuller or something that makes more clear it's responsibility to coordinate the pull process for a set of images

fabriziopandini

@chuckha
I suggested some refactoring for a better separation between UX and the image pull machinery.
However the PR overall is fine for me. Thanks!

chuckha · 2018-05-15T20:06:31Z

cmd/kubeadm/app/images/puller.go

+
+// Pull pulls the actual image using either crictl or docker
+func (ip *ImagePuller) Pull(image string) error {
+	if ip.crictlPath == "" {


This logic is wrong. We want to use docker if the cri socket is the default docker socket. Otherwise, use crictl

timothysc

/approve

@fabriziopandini please lgtm when you are happy with the change.

luxas

A couple of comments that need fixing, but overall this LGTM 👍. Thanks for this patch!

luxas · 2018-05-16T11:22:31Z

cmd/kubeadm/app/cmd/config.go

 	return cmd
 }

+// NewCmdConfigImagesPull returns the `config images pull` command
+func NewCmdConfigImagesPull() *cobra.Command {
+	cfg := kubeadmapiv1alpha1.MasterConfiguration{}


must use & pointer here

Is 'must' the right word here? I don't think it is unless I'm missing something.

I'm passing around the pointer everywhere else so I understand to reduce the number of &s it would make more sense to initialize it as a pointer. That being said I do agree, it's better as a pointer.

It's technically not a must, but practically. If you init it as a pointer, you don't have to remember to pass & all the time. I'm pretty sure most things break if someone somehow forgets to pass the pointer at some time. Would be super hard to debug and notice.

fair point 👍 thanks for explaining what you meant

luxas · 2018-05-16T11:23:01Z

cmd/kubeadm/app/cmd/config.go

+// NewCmdConfigImagesPull returns the `config images pull` command
+func NewCmdConfigImagesPull() *cobra.Command {
+	cfg := kubeadmapiv1alpha1.MasterConfiguration{}
+	kubeadmapiv1alpha1.SetDefaults_MasterConfiguration(&cfg)


kubeadmscheme.Scheme.Default(cfg)
where kubeadmscheme "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/scheme"

sure, seems reasonable. I need to understand this stuff better

luxas · 2018-05-16T11:24:24Z

cmd/kubeadm/app/cmd/config.go

+func (ip *ImagesPull) PullAll() error {
+	for _, image := range ip.images {
+		if err := ip.puller.Pull(image); err != nil {
+			return fmt.Errorf("failed to pull image [%v]: %v", image, err)


nit: maybe use %q instead of [%v]?

thanks for this nit, I always default to %v but will endeavor to improve my formatting strings :)

luxas · 2018-05-16T11:25:11Z

cmd/kubeadm/app/cmd/config.go

+		if err := ip.puller.Pull(image); err != nil {
+			return fmt.Errorf("failed to pull image [%v]: %v", image, err)
+		}
+		glog.Infof("[config/images/pull] Pulled %v", image)


just [images] is fine for me here. As image is a string, use %s\n (don't forget the newline)

luxas · 2018-05-16T11:25:50Z

cmd/kubeadm/app/cmd/config.go

@@ -254,12 +304,12 @@ func NewImagesList(cfgPath string, cfg *kubeadmapiv1alpha1.MasterConfiguration)
 	}, nil
 }

-// ImagesList defines the struct used for "kubeadm config images list"
+// ImagesList defines the struct used for "kubeadm images"


Why change this?

This was probably a merge conflict failing, good 👀

luxas · 2018-05-16T11:26:55Z

cmd/kubeadm/app/images/puller.go

+import (
+	"fmt"
+
+	kubeadmdefaults "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1alpha1"


kubeadmapiv1alpha1

luxas · 2018-05-16T11:27:54Z

cmd/kubeadm/app/images/puller.go

+// NewImagePuller returns a ready to go ImagePuller
+func NewImagePuller(execer utilsexec.Interface, criSocket string) (*ImagePuller, error) {
+	crictlPath, err := execer.LookPath("crictl")
+	if crictlPath == "" && err != nil {


What happens if crictlPath is "" but there isn't an error?

&& -> ||

Also wrong logic from before -- If we need crictl (our crisocket is not the default) then we fail. Otherwise it's fine that we don't have crictl available (since we use docker instead).

This command will use crictl or docker to pull images locally. The dockerfall back is needed because in some cases the kubelet is not yet running so there is no CRI dockershim socket available. Fixes kubernetes/kubeadm#812 Signed-off-by: Chuck Ha <ha.chuck@gmail.com>

luxas

/lgtm

Thanks a lot Chuck 🎉!

k8s-ci-robot · 2018-05-16T17:22:56Z

[APPROVALNOTIFIER] This PR is APPROVED

Approval requirements bypassed by manually added approval.

This pull-request has been approved by: chuckha, luxas, timothysc

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

~~cmd/kubeadm/OWNERS~~ [luxas,timothysc]
docs/OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

k8s-github-robot · 2018-05-16T18:21:49Z

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions here.

k8s-ci-robot requested review from smarterclayton and stealthybox May 15, 2018 01:01

k8s-ci-robot added the area/kubeadm label May 15, 2018

k8s-github-robot added the kind/old-docs label May 15, 2018

timothysc reviewed May 15, 2018

View reviewed changes

neolit123 reviewed May 15, 2018

View reviewed changes

k8s-ci-robot added the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label May 15, 2018

fabriziopandini reviewed May 15, 2018

View reviewed changes

fabriziopandini suggested changes May 15, 2018

View reviewed changes

chuckha force-pushed the image-puller branch from b8383c0 to 6005981 Compare May 15, 2018 17:27

k8s-ci-robot removed the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label May 15, 2018

chuckha commented May 15, 2018

View reviewed changes

chuckha force-pushed the image-puller branch from 6005981 to f61559d Compare May 15, 2018 21:21

timothysc approved these changes May 16, 2018

View reviewed changes

luxas reviewed May 16, 2018

View reviewed changes

luxas self-assigned this May 16, 2018

chuckha force-pushed the image-puller branch 2 times, most recently from 79aeac4 to c2d0f8b Compare May 16, 2018 15:26

k8s-ci-robot added the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label May 16, 2018

chuckha force-pushed the image-puller branch from c2d0f8b to 0edf208 Compare May 16, 2018 15:35

k8s-ci-robot removed the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label May 16, 2018

chuckha force-pushed the image-puller branch from 0edf208 to 7ecab96 Compare May 16, 2018 15:36

stealthybox mentioned this pull request May 16, 2018

how to use it without internet kubernetes/kubeadm#537

Closed

luxas approved these changes May 16, 2018

View reviewed changes

k8s-ci-robot added the lgtm "Looks good to me", indicates that a PR is ready to be merged. label May 16, 2018

luxas added the approved Indicates a PR has been approved by an approver from all required OWNERS files. label May 16, 2018

k8s-github-robot merged commit 82b355e into kubernetes:master May 16, 2018

neolit123 mentioned this pull request Jun 1, 2018

document "kubeadm config images *" kubernetes/kubeadm#880

Closed

tstromberg mentioned this pull request Mar 20, 2019

Skip "pull" command if using Kubernetes 1.10, which does not support it. kubernetes/minikube#3832

Merged

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Adds a kubeadm config images pull command #63833

Adds a kubeadm config images pull command #63833

chuckha commented May 15, 2018

timothysc May 15, 2018

chuckha May 15, 2018

neolit123 May 15, 2018

chuckha May 15, 2018

neolit123 May 15, 2018 •

edited

Loading

fabriziopandini May 15, 2018

chuckha May 15, 2018

fabriziopandini May 16, 2018

fabriziopandini May 15, 2018

chuckha May 15, 2018

fabriziopandini May 16, 2018

fabriziopandini left a comment

chuckha May 15, 2018

timothysc left a comment

luxas left a comment

luxas May 16, 2018

chuckha May 16, 2018

luxas May 16, 2018

chuckha May 16, 2018

luxas May 16, 2018

chuckha May 16, 2018

luxas May 16, 2018

chuckha May 16, 2018

luxas May 16, 2018

luxas May 16, 2018

chuckha May 16, 2018

luxas May 16, 2018

luxas May 16, 2018

neolit123 May 16, 2018

chuckha May 16, 2018

luxas left a comment

k8s-ci-robot commented May 16, 2018

k8s-github-robot commented May 16, 2018

Adds a kubeadm config images pull command #63833

Adds a kubeadm config images pull command #63833

Conversation

chuckha commented May 15, 2018

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

neolit123 May 15, 2018 • edited Loading

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

fabriziopandini left a comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

timothysc left a comment

Choose a reason for hiding this comment

luxas left a comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

luxas left a comment

Choose a reason for hiding this comment

k8s-ci-robot commented May 16, 2018

k8s-github-robot commented May 16, 2018

neolit123 May 15, 2018 •

edited

Loading