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Manage KubeDB objects using CLIs
KubeDB CLI
KubeDB comes with its own cli. It is called kubedb cli. kubedb can be used to manage any KubeDB object. kubedb cli also performs various validations to improve ux. To install KubeDB cli on your workstation, follow the steps here.
How to Create objects
kubectl create creates a database CRD object in default namespace by default. Following command will create a MongoDB object as specified in mongodb.yaml.
$ kubectl create -f mongodb-demo.yaml
mongodb.kubedb.com/mongodb-demo created
You can provide namespace as a flag --namespace. Provided namespace should match with namespace specified in input file.
$ kubectl create -f mongodb-demo.yaml --namespace=kube-system
mongodb.kubedb.com/mongodb-demo
kubectl create command also considers stdin as input.
cat mongodb-demo.yaml | kubectl create -f -
How to List Objects
kubectl get command allows users to list or find any KubeDB object. To list all MongoDB objects in default namespace, run the following command:
$ kubectl get mongodb
NAME VERSION STATUS AGE
mongodb-demo 3.4-v3 Ready 13m
mongodb-dev 3.4-v3 Ready 11m
mongodb-prod 3.4-v3 Ready 11m
mongodb-qa 3.4-v3 Ready 10m
To get YAML of an object, use --output=yaml flag.
$ kubectl get mongodb mongodb-demo --output=yaml
apiVersion: kubedb.com/v1alpha2
kind: MongoDB
metadata:
creationTimestamp: "2019-02-06T10:31:04Z"
finalizers:
- kubedb.com
generation: 2
name: mongodb-demo
namespace: demo
resourceVersion: "94703"
selfLink: /apis/kubedb.com/v1alpha2/namespaces/default/mongodbs/mongodb-demo
uid: 4eaaba0e-29fa-11e9-aebf-080027875192
spec:
authSecret:
name: mongodb-demo-auth
podTemplate:
controller: {}
metadata: {}
spec:
livenessProbe:
exec:
command:
- mongo
- --eval
- db.adminCommand('ping')
failureThreshold: 3
periodSeconds: 10
successThreshold: 1
timeoutSeconds: 5
readinessProbe:
exec:
command:
- mongo
- --eval
- db.adminCommand('ping')
failureThreshold: 3
periodSeconds: 10
successThreshold: 1
timeoutSeconds: 1
resources: {}
replicas: 1
storage:
accessModes:
- ReadWriteOnce
dataSource: null
resources:
requests:
storage: 1Gi
storageClassName: standard
storageType: Durable
terminationPolicy: Halt
version: 3.4-v3
status:
observedGeneration: 2$4213139756412538772
phase: Ready
To get JSON of an object, use --output=json flag.
kubectl get mongodb mongodb-demo --output=json
To list all KubeDB objects, use following command:
$ kubectl get kubedb -o wide
NAME VERSION STATUS AGE
mg/mongodb-demo 3.4 Ready 3h
mg/mongodb-dev 3.4 Ready 3h
mg/mongodb-prod 3.4 Ready 3h
mg/mongodb-qa 3.4 Ready 3h
NAME DATABASE BUCKET STATUS AGE
snap/mongodb-demo-20170605-073557 mg/mongodb-demo gs:bucket-name Succeeded 9m
snap/snapshot-20171212-114700 mg/mongodb-demo gs:bucket-name Succeeded 1h
Flag --output=wide is used to print additional information.
List command supports short names for each object types. You can use it like kubectl get <short-name>. Below are the short name for KubeDB objects:
- MongoDB:
mg - Snapshot:
snap - DormantDatabase:
drmn
You can print labels with objects. The following command will list all Snapshots with their corresponding labels.
$ kubectl get snap --show-labels
NAME DATABASE STATUS AGE LABELS
mongodb-demo-20170605-073557 mg/mongodb-demo Succeeded 11m app.kubernetes.io/name=mongodbs.kubedb.com,app.kubernetes.io/instance=mongodb-demo
snapshot-20171212-114700 mg/mongodb-demo Succeeded 1h app.kubernetes.io/name=mongodbs.kubedb.com,app.kubernetes.io/instance=mongodb-demo
You can also filter list using --selector flag.
$ kubectl get snap --selector='app.kubernetes.io/name=mongodbs.kubedb.com' --show-labels
NAME DATABASE STATUS AGE LABELS
mongodb-demo-20171212-073557 mg/mongodb-demo Succeeded 14m app.kubernetes.io/name=mongodbs.kubedb.com,app.kubernetes.io/instance=mongodb-demo
snapshot-20171212-114700 mg/mongodb-demo Succeeded 2h app.kubernetes.io/name=mongodbs.kubedb.com,app.kubernetes.io/instance=mongodb-demo
To print only object name, run the following command:
$ kubectl get all -o name
mongodb/mongodb-demo
mongodb/mongodb-dev
mongodb/mongodb-prod
mongodb/mongodb-qa
snapshot/mongodb-demo-20170605-073557
snapshot/snapshot-20170505-114700
How to Describe Objects
kubectl dba describe command allows users to describe any KubeDB object. The following command will describe MongoDB database mongodb-demo with relevant information.
$ kubectl dba describe mg mongodb-demo
Name: mongodb-demo
Namespace: default
CreationTimestamp: Wed, 06 Feb 2019 16:31:04 +0600
Labels: <none>
Annotations: <none>
Replicas: 1 total
Status: Ready
StorageType: Durable
Volume:
StorageClass: standard
Capacity: 1Gi
Access Modes: RWO
StatefulSet:
Name: mongodb-demo
CreationTimestamp: Wed, 06 Feb 2019 16:31:05 +0600
Labels: app.kubernetes.io/name=mongodbs.kubedb.com
app.kubernetes.io/instance=mongodb-demo
Annotations: <none>
Replicas: 824639727120 desired | 1 total
Pods Status: 1 Running / 0 Waiting / 0 Succeeded / 0 Failed
Service:
Name: mongodb-demo
Labels: app.kubernetes.io/name=mongodbs.kubedb.com
app.kubernetes.io/instance=mongodb-demo
Annotations: <none>
Type: ClusterIP
IP: 10.96.245.200
Port: db 27017/TCP
TargetPort: db/TCP
Endpoints: 172.17.0.8:27017
Service:
Name: mongodb-demo-gvr
Labels: app.kubernetes.io/name=mongodbs.kubedb.com
app.kubernetes.io/instance=mongodb-demo
Annotations: service.alpha.kubernetes.io/tolerate-unready-endpoints=true
Type: ClusterIP
IP: None
Port: db 27017/TCP
TargetPort: 27017/TCP
Endpoints: 172.17.0.8:27017
Database Secret:
Name: mongodb-demo-auth
Labels: app.kubernetes.io/name=mongodbs.kubedb.com
app.kubernetes.io/instance=mongodb-demo
Annotations: <none>
Type: Opaque
Data
====
password: 16 bytes
username: 4 bytes
No Snapshots.
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Successful 2m KubeDB operator Successfully created Service
Normal Successful 2m KubeDB operator Successfully created StatefulSet
Normal Successful 2m KubeDB operator Successfully created MongoDB
Normal Successful 2m KubeDB operator Successfully created appbinding
Normal Successful 2m KubeDB operator Successfully patched StatefulSet
Normal Successful 2m KubeDB operator Successfully patched MongoDB
kubectl dba describe command provides following basic information about a MongoDB database.
- StatefulSet
- Storage (Persistent Volume)
- Service
- Secret (If available)
- Snapshots (If any)
- Monitoring system (If available)
To hide events on KubeDB object, use flag --show-events=false
To describe all MongoDB objects in default namespace, use following command
kubectl dba describe mg
To describe all MongoDB objects from every namespace, provide --all-namespaces flag.
kubectl dba describe mg --all-namespaces
To describe all KubeDB objects from every namespace, use the following command:
kubectl dba describe all --all-namespaces
You can also describe KubeDb objects with matching labels. The following command will describe all MongoDB objects with specified labels from every namespace.
kubectl dba describe mg --all-namespaces --selector='group=dev'
To learn about various options of describe command, please visit here.
Edit Restrictions
Various fields of a KubeDb object can’t be edited using edit command. The following fields are restricted from updates for all KubeDB objects:
- apiVersion
- kind
- metadata.name
- metadata.namespace
If StatefulSets exists for a MongoDB database, following fields can’t be modified as well.
- spec.ReplicaSet
- spec.authSecret
- spec.init
- spec.storageType
- spec.storage
- spec.podTemplate.spec.nodeSelector
For DormantDatabase, spec.origin can’t be edited using kubectl edit
How to Delete Objects
kubectl delete command will delete an object in default namespace by default unless namespace is provided. The following command will delete a MongoDB mongodb-dev in default namespace
$ kubectl delete mongodb mongodb-dev
mongodb.kubedb.com "mongodb-dev" deleted
You can also use YAML files to delete objects. The following command will delete a mongodb using the type and name specified in mongodb.yaml.
$ kubectl delete -f mongodb-demo.yaml
mongodb.kubedb.com "mongodb-dev" deleted
kubectl delete command also takes input from stdin.
cat mongodb-demo.yaml | kubectl delete -f -
To delete database with matching labels, use --selector flag. The following command will delete mongodb with label mongodb.app.kubernetes.io/instance=mongodb-demo.
kubectl delete mongodb -l mongodb.app.kubernetes.io/instance=mongodb-demo
Using Kubectl
You can use Kubectl with KubeDB objects like any other CRDs. Below are some common examples of using Kubectl with KubeDB objects.
# Create objects
$ kubectl create -f
# List objects
$ kubectl get mongodb
$ kubectl get mongodb.kubedb.com
# Delete objects
$ kubectl delete mongodb <name>
Next Steps
- Learn how to use KubeDB to run a MongoDB database here.
- Want to hack on KubeDB? Check our contribution guidelines.