Controlling deletion with finalizers

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Kubernetes - - — , , , . , , kubectl delete



, delete



Kubernetes , .

:

• .
• - .
• propagationPolicy
  
  
  
  , .
• , .

ConfigMaps kubectl. , , .

delete

Kubernetes , , . kubectl



: create



, get



, patch



delete



.

kubectl delete



:

$ kubectl create configmap mymap
configmap/mymap created
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

$ kubectl get configmap/mymap
NAME    DATA   AGE
mymap   0      12s
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

$ kubectl delete configmap/mymap
configmap "mymap" deleted
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

$ kubectl get configmap/mymap
Error from server (NotFound): configmaps "mymap" not found
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

$



, . , kubectl create configmap mymap



, configmap mymap



. get



, . configmap. get



, HTTP 404, configmap .

delete



:

delete

, , -.

, Kubernetes - , .

— , , . , . , . , , . , .

, :

• kubernetes.io/pv-protection
  
  
  
  
• kubernetes.io/pvc-protection
  
  
  
  

. .

configmap , :

$ cat <<EOF | kubectl create -f -
apiVersion: v1
kind: ConfigMap
metadata:
  name: mymap
  finalizers:
  - kubernetes
EOF
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

configmap , kubernetes



. configmap «», . configmap:

$ kubectl delete configmap/mymap &
configmap "mymap" deleted
jobs
[1]+  Running kubectl delete configmap/mymap
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

Kubernetes , , , , . . get



, , deletionTimestamp



.

$ kubectl get configmap/mymap -o yaml
apiVersion: v1
kind: ConfigMap
metadata:
  creationTimestamp: "2020-10-22T21:30:18Z"
  deletionGracePeriodSeconds: 0
  deletionTimestamp: "2020-10-22T21:30:34Z"
  finalizers:
  - kubernetes
  name: mymap
  namespace: default
  resourceVersion: "311456"
  selfLink: /api/v1/namespaces/default/configmaps/mymap
  uid: 93a37fed-23e3-45e8-b6ee-b2521db81638
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

, , . , Kubernetes , , read-only. , — . , , .

patch



. , . get



configmap, .

$ kubectl patch configmap/mymap \
    --type json \
    --patch='[ { "op": "remove", "path": "/metadata/finalizers" } ]'
configmap/mymap patched
[1]+  Done  kubectl delete configmap/mymap

$ kubectl get configmap/mymap -o yaml
Error from server (NotFound): configmaps "mymap" not found
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

:

, , Kubectl. , Kubernetes .

(owner references) . , , , .

, . UID. UID. replica set, . deploy stateful set, replica set pod .

, . , . configmap , :

$ cat <<EOF | kubectl create -f -
apiVersion: v1
kind: ConfigMap
metadata:
  name: mymap-parent
EOF

$ export CM_UID=$(kubectl get configmap mymap-parent -o jsonpath="{.metadata.uid}")

$ cat <<EOF | kubectl create -f -
apiVersion: v1
kind: ConfigMap
metadata:
  name: mymap-child
  ownerReferences:
  - apiVersion: v1
    kind: ConfigMap
    name: mymap-parent
    uid: $CM_UID
EOF
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

, , :

$ kubectl get configmap
NAME           DATA   AGE
mymap-child    0      12m4s
mymap-parent   0      12m4s

$ kubectl delete configmap/mymap-child
configmap "mymap-child" deleted

$ kubectl get configmap
NAME           DATA   AGE
mymap-parent   0      12m10s
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

configmap . , , , get



configmap, , configmap :

$ kubectl get configmap
NAME           DATA   AGE
mymap-child    0      10m2s
mymap-parent   0      10m2s

$ kubectl delete configmap/mymap-parent
configmap "mymap-parent" deleted

$ kubectl get configmap
No resources found in default namespace.
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

, , . cascade



. cascade true



, --cascade=false kubectl delete



, , .

, . , --cascade=false, :

$ kubectl get configmap
NAME           DATA   AGE
mymap-child    0      13m8s
mymap-parent   0      13m8s

$ kubectl delete --cascade=false configmap/mymap-parent
configmap "mymap-parent" deleted

$ kubectl get configmap
NAME          DATA   AGE
mymap-child   0      13m21s
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

--cascade API, . API curl (propagation policy):

$ kubectl proxy --port=8080 &
Starting to serve on 127.0.0.1:8080

$ curl -X DELETE \
  localhost:8080/api/v1/namespaces/default/configmaps/mymap-parent \
  -d '{ "kind":"DeleteOptions", "apiVersion":"v1", "propagationPolicy":"Background" }' \
  -H "Content-Type: application/json"
{
  "kind": "Status",
  "apiVersion": "v1",
  "metadata": {},
  "status": "Success",
  "details": { ... }
}
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

kubectl — API. , API , curl



URL, delete



.

:

• Foreground
  
  
  
  : ( ).
• Background
  
  
  
  : ( ).
• Orphan
  
  
  
  : .

, , . , . , , .

: , - , , , finalize



. , :

$ cat <<EOF | curl -X PUT \
  localhost:8080/api/v1/namespaces/test/finalize \
  -H "Content-Type: application/json" \
  --data-binary @-
{
  "kind": "Namespace",
  "apiVersion": "v1",
  "metadata": {
    "name": "test"
  },
  "spec": {
    "finalizers": null
  }
}
EOF
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

, , , Kubernetes . , , .

, Kubernetes, . , , . , . , , API . , Kubernetes, -.

: