Wait for a CRD type to deploy before deploying resources that use the type

[ringerc]

Presently, when kubectl is used to apply a large manifest that defines new custom resource definitions (CRDs) as well as resources that use the new resource kind, conditions can cause the deployment to fail. Assuming you're using kubectl apply -f - and an external kustomize you might see an error like:

unable to recognize "STDIN": no matches for kind "Alertmanager" in version "monitoring.coreos.com/v1"

(the exact resource "kind" and api "version" will vary depending on what you're deplying).

This appears to be a race between the k8s cluster applying the new CRD types and kustomize sending requests that use the new types, but there's no indication of that in the command's output. It's confusing for new users, and it's a hassle operationally since deployments will fail then work when re-tried. This is something the kubectl tool could help users with.

The --server-side option does not help, as the same race occurs then. And --wait=true only affects resource removal, not creation.

This can often be reproduced with a kind cluster, though it varies since it's a race. For example:

kind create cluster
git clone -b v0.8.0 https://github.com/prometheus-operator/kube-prometheus
kubectl apply -k kube-prometheus/

... which will often fail with:

daemonset.apps/node-exporter created
unable to recognize "kube-prometheus/": no matches for kind "Alertmanager" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "Prometheus" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "PrometheusRule" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "PrometheusRule" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "PrometheusRule" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "PrometheusRule" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "PrometheusRule" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "PrometheusRule" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "PrometheusRule" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "ServiceMonitor" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "ServiceMonitor" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "ServiceMonitor" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "ServiceMonitor" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "ServiceMonitor" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "ServiceMonitor" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "ServiceMonitor" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "ServiceMonitor" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "ServiceMonitor" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "ServiceMonitor" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "ServiceMonitor" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "ServiceMonitor" in version "monitoring.coreos.com/v1"
unable to recognize "kube-prometheus/": no matches for kind "ServiceMonitor" in version "monitoring.coreos.com/v1"

but when the same command is repeated, it will succeed:

daemonset.apps/node-exporter unchanged
alertmanager.monitoring.coreos.com/main created
prometheus.monitoring.coreos.com/k8s created
prometheusrule.monitoring.coreos.com/alertmanager-main-rules created
prometheusrule.monitoring.coreos.com/kube-prometheus-rules created
...

There doesn't seem to be any (obvious) kubectl flag to impose a delay between requests, wait for a new resource to become visible before continuing, or retry a request if it fails because of a server-side error indicating something was missing.

The error message is confusing for new users and definitely does not help. A wording change and some context would help a lot. I raised that separately: #1118

[k8s-ci-robot]

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[ringerc]

See related issue discussing retries: kubernetes/kubernetes#5762 (comment)

The server does not issue HTTP status code 429 here, presumably because it doesn't know there's a pending deployment that will create this resource.

[ringerc]

See related issue in kube-prometheus - but note that this is far from specific to kube-prometheus, it can affect anything where races exist between resource creation and resource use

prometheus-operator/prometheus-operator#1866

[ringerc]

A workaround is to use kfilt to deploy the CRDs first, then wait for them to become visible, then deploy the rest:

kustomize build somedir | kfilt -i kind=CustomResourceDefinition | kubectl apply -f -
kustomize build somedir | kfilt -i kind=CustomResourceDefinition | kubectl wait --for condition=established --timeout=60s -f -
kustomize build somedir | kubectl apply -f - 

[ringerc]

See also

• crd-install hook possible race condition  helm/helm#4925
• Improve Establishing logic for CRDs by implementing Installing status to prevent race conditions kubernetes#62725

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/lifecycle stale

[eddiezane]

Wait for a CRD type to deploy before deploying resources that use the type

This isn't something that we would implement for kubectl but we will investigate which part of apply can provide a better error. We'll handle that in #1118.

/close

[k8s-ci-robot]

@eddiezane: Closing this issue.

In response to this:

Wait for a CRD type to deploy before deploying resources that use the type

This isn't something that we would implement for kubectl but we will investigate which part of apply can provide a better error. We'll handle that in #1118.

/close

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