[feature request] set job template imagePullPolicy to Always from IfNotPresent

[adamzhoul]

What would you like to be added:

imagePullPolicy: Always

now is:

openyurt/pkg/yurtctl/constants/constants.go

Line 269 in 095cc4c

imagePullPolicy: IfNotPresent

Why is this needed:

the default image is:

 docker.io/openyurt/xxxx:latest

IfNotPresent leads to never be updated while it should.

Problem I meet:

crictl  images
docker.io/openyurt/yurtctl-servant               latest               e1ec131fa6cc2       15.2MB

images left before. It’s not been build with the latest code.
I can’t remember which day I run yurtctl convert and downloaded the image.
And it contains a bug but is fixed by #490

In short：

1. duplicated code leads to bug :

2021-09-28T06:05:04.16277Z stderr F I0928 06:05:04.154963  198728 edgenode.go:263] mark openyurt-worker2 as the edge-node
2021-09-28T06:05:04.2673512Z stderr F I0928 06:05:04.266359  198728 edgenode.go:274] open the openyurt-worker2 autonomous
2021-09-28T06:05:04.3142398Z stderr F I0928 06:05:04.305542  198728 edgenode.go:281] open the openyurt-worker2 autonomous
2021-09-28T06:05:04.3908907Z stderr F F0928 06:05:04.379338  198728 edgenode.go:83] fail to convert the kubernetes node to a yurt node: Operation cannot be fulfilled on nodes "openyurt-worker2": the object has been modified; please apply your changes to the latest version and try again

2. pod exists with error. restart for ever with error

kubectl logs -f yurtctl-servant-convert-openyurt-worker2-x4fhp -n kube-system
F0928 06:44:12.296154  203920 edgenode.go:83] fail to convert the kubernetes node to a yurt node: Cannot do the convert, the worker node: openyurt-worker2 is not a Kubernetes node.

3. convert job failed. leaves pod restart forever.

PS:
locating the error log is very difficult since the job pod restarts many many times.
can we return true here?

openyurt/pkg/yurtctl/cmd/convert/edgenode.go

Lines 246 to 250 in 095cc4c

	// 3.3. check the label of EdgeNodes
	_, ok := node.Labels[projectinfo.GetEdgeWorkerLabelKey()]
	if ok {
	return fmt.Errorf("Cannot do the convert, the worker node: %s is not a Kubernetes node.", node.Name)
	}

others
/kind feature

[rambohe-ch]

@adamzhoul Thank you for raising issue.
The reason of imagePullPolicy=IfNotPresent is: pods on edge nodes can restart successfully when edge nodes can not connect public network. so we need to keep imagePullPolicy=IfNotPresent.
and iff user wants to use latest images , it's recommended to pull images manually.

[adamzhoul]

@rambohe-ch thanks for the reply.