Kubectl apply: Difference between revisions

From NovaOrdis Knowledge Base
Jump to navigation Jump to search
 
(3 intermediate revisions by the same user not shown)
Line 3: Line 3:
* [[Kubectl#Commands|kubectl]]
* [[Kubectl#Commands|kubectl]]
* [[kubectl create]]
* [[kubectl create]]
* [[kubectl delete]]
* [[Kubernetes_Manifests#Overview|Kubernetes Manifests]]
* [[Kubernetes_Manifests#Overview|Kubernetes Manifests]]
* [[Kubernetes_Concepts#Declarative_versus_Imperative_Approach|Declarative versus Imperative Approach]]
* [[Kubernetes_Concepts#Declarative_versus_Imperative_Approach|Declarative versus Imperative Approach]]
Line 10: Line 11:
Apply a configuration to a resource by filename or stdin:
Apply a configuration to a resource by filename or stdin:


kubectl apply -f <manifest.yaml>
<syntaxhighlight lang='bash'>
kubectl apply -f <manifest.yaml>
</syntaxhighlight>
<syntaxhighlight lang='bash'>
cat <manifest.yaml> | kubectl apply -f -
</syntaxhighlight>


cat <manifest.yaml> | kubectl apply -f -
To apply all manifests from a directory:
<syntaxhighlight lang='bash'>
kubectl apply -f ./dir
</syntaxhighlight>
 
In-line:
<syntaxhighlight lang='bash'>
cat <<EOF | kubectl -n ${namespace} apply -f -  
apiVersion: v1
kind: Service
metadata:
  name: something
  namespace: ${namespace}
spec:
  ...
EOF
</syntaxhighlight>


The command can be used to both create a new resource or update the state of an existing resource. When updating the state, the command supports [[Kubernetes Strategic Merge Patch|strategic merge patch]].
The command can be used to both create a new resource or update the state of an existing resource. When updating the state, the command supports [[Kubernetes Strategic Merge Patch|strategic merge patch]].
Line 28: Line 50:
==-f|--filename==
==-f|--filename==


The filename that contains the configuration to apply.
The filename that contains the configuration to apply. "-" means it will take stdin and apply it.


==-k|--kustomize==
==-k|--kustomize==

Latest revision as of 02:20, 26 February 2022

Internal

Overview

Apply a configuration to a resource by filename or stdin:

kubectl apply -f <manifest.yaml>
cat <manifest.yaml> | kubectl apply -f -

To apply all manifests from a directory:

kubectl apply -f ./dir

In-line:

cat <<EOF | kubectl -n ${namespace} apply -f - 
apiVersion: v1
kind: Service
metadata:
  name: something
  namespace: ${namespace}
spec:
  ...
EOF

The command can be used to both create a new resource or update the state of an existing resource. When updating the state, the command supports strategic merge patch.

Also see:

kubectl create

Namespace Handling

The resources specified by the manifest can be deployed in an arbitrary namespace with the -n <namespace> option, unless the manifest already specifies a different namespace in the metadata section. In that case, an error will ensue:

error: the namespace from the provided object "default" does not match the namespace "prometheus". You must pass '--namespace=default' to perform this operation.

Options

-f|--filename

The filename that contains the configuration to apply. "-" means it will take stdin and apply it.

-k|--kustomize

Process a kustomization directory.

-k