New to KubeDB? Please start here.
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
kubedb create creates a database CRD object in default namespace by default. Following command will create a Memcached object as specified in memcached.yaml.
$ kubedb create -f memcached-demo.yaml
memcached "memcached-demo" created
You can provide namespace as a flag --namespace. Provided namespace should match with namespace specified in input file.
$ kubedb create -f memcached-demo.yaml --namespace=kube-system
memcached "memcached-demo" created
kubedb create command also considers stdin as input.
cat memcached-demo.yaml | kubedb create -f -
To learn about various options of create command, please visit here.
How to List Objects
kubedb get command allows users to list or find any KubeDB object. To list all Memcached objects in default namespace, run the following command:
$ kubedb get memcached
NAME STATUS AGE
memcached-demo Running 5h
memcached-dev Running 4h
memcached-prod Running 30m
memcached-qa Running 2h
To get YAML of an object, use --output=yaml flag.
$ kubedb get memcached memcached-demo --output=yaml
apiVersion: kubedb.com/v1alpha1
kind: Memcached
metadata:
clusterName: ""
creationTimestamp: 2018-03-01T11:30:18Z
finalizers:
- kubedb.com
generation: 0
labels:
kubedb: cli-demo
name: memcached-demo
namespace: default
resourceVersion: "17038"
selfLink: /apis/kubedb.com/v1alpha1/namespaces/default/memcacheds/memcached-demo
uid: eb84ab44-1d43-11e8-8599-0800272b52b5
spec:
replicas: 3
resources:
limits:
cpu: 500m
memory: 128Mi
requests:
cpu: 250m
memory: 64Mi
version: "1.5.4"
status:
creationTime: 2018-03-01T11:30:18Z
phase: Running
To get JSON of an object, use --output=json flag.
$ kubedb get memcached memcached-demo --output=json
To list all KubeDB objects, use following command:
$ kubedb get all -o wide
NAME VERSION STATUS AGE
mc/memcached-demo 1.5.4 Running 3h
mc/memcached-dev 1.5.4 Running 3h
mc/memcached-prod 1.5.4 Running 3h
mc/memcached-qa 1.5.4 Running 3h
Flag --output=wide is used to print additional information.
List command supports short names for each object types. You can use it like kubedb get <short-name>. Below are the short name for KubeDB objects:
- Memcached:
mc - DormantDatabase:
drmn
You can print labels with objects. The following command will list all Memcached with their corresponding labels.
$ kubedb get mc --show-labels
NAME STATUS AGE LABELS
memcached-demo Running 2m kubedb=cli-demo
To print only object name, run the following command:
$ kubedb get all -o name
memcached/memcached-demo
memcached/memcached-dev
memcached/memcached-prod
memcached/memcached-qa
To learn about various options of get command, please visit here.
How to Describe Objects
kubedb describe command allows users to describe any KubeDB object. The following command will describe Memcached database memcached-demo with relevant information.
$ kubedb describe mc memcached-demo
Name: memcached-demo
Namespace: default
StartTimestamp: Thu, 01 Mar 2018 17:30:18 +0600
Labels: kubedb=cli-demo
Replicas: 3 total
Status: Running
Deployment:
Name: memcached-demo
Replicas: 3 current / 3 desired
CreationTimestamp: Thu, 01 Mar 2018 17:30:20 +0600
Pods Status: 3 Running / 0 Waiting / 0 Succeeded / 0 Failed
Service:
Name: memcached-demo
Type: ClusterIP
IP: 10.100.158.166
Port: db 11211/TCP
Events:
FirstSeen LastSeen Count From Type Reason Message
--------- -------- ----- ---- -------- ------ -------
2m 2m 1 Memcached operator Normal Successful Successfully created Memcached
2m 2m 1 Memcached operator Normal Successful Successfully created Deployment
2m 2m 1 Memcached operator Normal Successful Successfully created Service
kubedb describe command provides following basic information about a Memcached database.
- Deployment
- Service
- Monitoring system (If available)
To hide details about Deployment & Service, use flag --show-workload=false
To hide events on KubeDB object, use flag --show-events=false
To describe all Memcached objects in default namespace, use following command
To describe all Memcached objects from every namespace, provide --all-namespaces flag.
$ kubedb describe mc --all-namespaces
To describe all KubeDB objects from every namespace, use the following command:
$ kubedb describe all --all-namespaces
You can also describe KubeDB objects with matching labels. The following command will describe all Memcached objects with specified labels from every namespace.
$ kubedb describe mc --all-namespaces --selector='group=dev'
To learn about various options of describe command, please visit here.
How to Edit Objects
kubedb edit command allows users to directly edit any KubeDB object. It will open the editor defined by KUBEDB_EDITOR, or EDITOR environment variables, or fall back to nano.
Lets edit an existing running Memcached object to setup Monitoring. The following command will open Memcached memcached-demo in editor.
$ kubedb edit mc memcached-demo
#spec:
# monitor:
# agent: prometheus.io/builtin
memcached "memcached-demo" edited
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
- status
If Deployment exists for a Memcached database, following fields can’t be modified as well.
- spec.version
- spec.nodeSelector
For DormantDatabase, spec.origin can’t be edited using kubedb edit
To learn about various options of edit command, please visit here.
How to Delete Objects
kubedb delete command will delete an object in default namespace by default unless namespace is provided. The following command will delete a Memcached memcached-dev in default namespace
$ kubedb delete memcached memcached-dev
memcached "memcached-dev" deleted
You can also use YAML files to delete objects. The following command will delete a memcached using the type and name specified in memcached.yaml.
$ kubedb delete -f memcached-demo.yaml
memcached "memcached-dev" deleted
kubedb delete command also takes input from stdin.
cat memcached-demo.yaml | kubedb delete -f -
To delete database with matching labels, use --selector flag. The following command will delete memcached with label memcached.kubedb.com/name=memcached-demo.
$ kubedb delete memcached -l memcached.kubedb.com/name=memcached-demo
To delete all Memcached without following further steps, add flag --force
$ kubedb delete memcached -n kube-system --all --force
memcached "memcached-demo" deleted
To learn about various options of delete command, please visit here.
Using Kubectl
You can use Kubectl with KubeDB objects like any other CRDs. Below are some common examples of using Kubectl with KubeDB objects.
# List objects
$ kubectl get memcached
$ kubectl get memcached.kubedb.com
# Delete objects
$ kubectl delete memcached <name>
Next Steps
- Learn how to use KubeDB to run a Memcached database here.
- Wondering what features are coming next? Please visit here.
- Want to hack on KubeDB? Check our contribution guidelines.
