New to KubeDB? Please start here.
Reconfigure MongoDB Standalone Database
This guide will show you how to use KubeDB Ops-manager operator to reconfigure a MongoDB standalone database.
Before You Begin
At first, you need to have a Kubernetes cluster, and the
kubectlcommand-line tool must be configured to communicate with your cluster.Install
KubeDBProvisioner and Ops-manager operator in your cluster following the steps here.You should be familiar with the following
KubeDBconcepts:
To keep everything isolated, we are going to use a separate namespace called demo throughout this tutorial.
$ kubectl create ns demo
namespace/demo created
Note: YAML files used in this tutorial are stored in docs/examples/mongodb directory of kubedb/docs repository.
Now, we are going to deploy a MongoDB standalone using a supported version by KubeDB operator. Then we are going to apply MongoDBOpsRequest to reconfigure its configuration.
Prepare MongoDB Standalone Database
Now, we are going to deploy a MongoDB standalone database with version 4.4.26.
Deploy MongoDB standalone
At first, we will create mongod.conf file containing required configuration settings.
$ cat mongod.conf
net:
maxIncomingConnections: 10000
Here, maxIncomingConnections is set to 10000, whereas the default value is 65536.
Now, we will create a secret with this configuration file.
$ kubectl create secret generic -n demo mg-custom-config --from-file=./mongod.conf
secret/mg-custom-config created
In this section, we are going to create a MongoDB object specifying spec.configSecret field to apply this custom configuration. Below is the YAML of the MongoDB CR that we are going to create,
apiVersion: kubedb.com/v1
kind: MongoDB
metadata:
name: mg-standalone
namespace: demo
spec:
version: "4.4.26"
storageType: Durable
storage:
storageClassName: "standard"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
configSecret:
name: mg-custom-config
Let’s create the MongoDB CR we have shown above,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.12.18/docs/examples/mongodb/reconfigure/mg-standalone-config.yaml
mongodb.kubedb.com/mg-standalone created
Now, wait until mg-standalone has status Ready. i.e,
$ kubectl get mg -n demo
NAME VERSION STATUS AGE
mg-standalone 4.4.26 Ready 23s
Now, we will check if the database has started with the custom configuration we have provided.
First we need to get the username and password to connect to a mongodb instance,
$ kubectl get secrets -n demo mg-standalone-auth -o jsonpath='{.data.\username}' | base64 -d
root
$ kubectl get secrets -n demo mg-standalone-auth -o jsonpath='{.data.\password}' | base64 -d
m6lXjZugrC4VEpB8
Now let’s connect to a mongodb instance and run a mongodb internal command to check the configuration we have provided.
$ kubectl exec -n demo mg-standalone-0 -- mongo admin -u root -p m6lXjZugrC4VEpB8 --eval "db._adminCommand( {getCmdLineOpts: 1})" --quiet
{
"argv" : [
"mongod",
"--dbpath=/data/db",
"--auth",
"--ipv6",
"--bind_ip_all",
"--port=27017",
"--tlsMode=disabled",
"--config=/data/configdb/mongod.conf"
],
"parsed" : {
"config" : "/data/configdb/mongod.conf",
"net" : {
"bindIp" : "*",
"ipv6" : true,
"maxIncomingConnections" : 10000,
"port" : 27017,
"tls" : {
"mode" : "disabled"
}
},
"security" : {
"authorization" : "enabled"
},
"storage" : {
"dbPath" : "/data/db"
}
},
"ok" : 1
}
As we can see from the configuration of running mongodb, the value of maxIncomingConnections has been set to 10000.
Reconfigure using new secret
Now we will reconfigure this database to set maxIncomingConnections to 20000.
Now, we will edit the mongod.conf file containing required configuration settings.
$ cat mongod.conf
net:
maxIncomingConnections: 20000
Then, we will create a new secret with this configuration file.
$ kubectl create secret generic -n demo new-custom-config --from-file=./mongod.conf
secret/new-custom-config created
Create MongoDBOpsRequest
Now, we will use this secret to replace the previous secret using a MongoDBOpsRequest CR. The MongoDBOpsRequest yaml is given below,
apiVersion: ops.kubedb.com/v1alpha1
kind: MongoDBOpsRequest
metadata:
name: mops-reconfigure-standalone
namespace: demo
spec:
type: Reconfigure
databaseRef:
name: mg-standalone
configuration:
standalone:
configSecret:
name: new-custom-config
readinessCriteria:
oplogMaxLagSeconds: 20
objectsCountDiffPercentage: 10
timeout: 5m
apply: IfReady
Here,
spec.databaseRef.namespecifies that we are reconfiguringmops-reconfigure-standalonedatabase.spec.typespecifies that we are performingReconfigureon our database.spec.configuration.standalone.configSecret.namespecifies the name of the new secret.- Have a look here on the respective sections to understand the
readinessCriteria,timeout&applyfields.
Let’s create the MongoDBOpsRequest CR we have shown above,
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.12.18/docs/examples/mongodb/reconfigure/mops-reconfigure-standalone.yaml
mongodbopsrequest.ops.kubedb.com/mops-reconfigure-standalone created
Verify the new configuration is working
If everything goes well, KubeDB Ops-manager operator will update the configSecret of MongoDB object.
Let’s wait for MongoDBOpsRequest to be Successful. Run the following command to watch MongoDBOpsRequest CR,
$ watch kubectl get mongodbopsrequest -n demo
Every 2.0s: kubectl get mongodbopsrequest -n demo
NAME TYPE STATUS AGE
mops-reconfigure-standalone Reconfigure Successful 10m
We can see from the above output that the MongoDBOpsRequest has succeeded. If we describe the MongoDBOpsRequest we will get an overview of the steps that were followed to reconfigure the database.
$ kubectl describe mongodbopsrequest -n demo mops-reconfigure-standalone
Name: mops-reconfigure-standalone
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: ops.kubedb.com/v1alpha1
Kind: MongoDBOpsRequest
Metadata:
Creation Timestamp: 2021-03-02T15:04:45Z
Generation: 1
Managed Fields:
API Version: ops.kubedb.com/v1alpha1
Fields Type: FieldsV1
fieldsV1:
f:metadata:
f:annotations:
.:
f:kubectl.kubernetes.io/last-applied-configuration:
f:spec:
.:
f:apply:
f:configuration:
.:
f:standalone:
.:
f:configSecret:
.:
f:name:
f:databaseRef:
.:
f:name:
f:readinessCriteria:
.:
f:objectsCountDiffPercentage:
f:oplogMaxLagSeconds:
f:timeout:
f:type:
Manager: kubectl-client-side-apply
Operation: Update
Time: 2021-03-02T15:04:45Z
API Version: ops.kubedb.com/v1alpha1
Fields Type: FieldsV1
fieldsV1:
f:spec:
f:configuration:
f:standalone:
f:podTemplate:
.:
f:controller:
f:metadata:
f:spec:
.:
f:resources:
f:status:
.:
f:conditions:
f:observedGeneration:
f:phase:
Manager: kubedb-enterprise
Operation: Update
Time: 2021-03-02T15:04:45Z
Resource Version: 125826
Self Link: /apis/ops.kubedb.com/v1alpha1/namespaces/demo/mongodbopsrequests/mops-reconfigure-standalone
UID: f63bb606-9df5-4516-9901-97dfe5b46b15
Spec:
Apply: IfReady
Configuration:
Standalone:
Config Secret:
Name: new-custom-config
Database Ref:
Name: mg-standalone
Readiness Criteria:
Objects Count Diff Percentage: 10
Oplog Max Lag Seconds: 20
Timeout: 5m
Type: Reconfigure
Status:
Conditions:
Last Transition Time: 2021-03-02T15:04:45Z
Message: MongoDB ops request is reconfiguring database
Observed Generation: 1
Reason: Reconfigure
Status: True
Type: Reconfigure
Last Transition Time: 2021-03-02T15:05:10Z
Message: Successfully Reconfigured MongoDB
Observed Generation: 1
Reason: ReconfigureStandalone
Status: True
Type: ReconfigureStandalone
Last Transition Time: 2021-03-02T15:05:10Z
Message: Successfully completed the modification process.
Observed Generation: 1
Reason: Successful
Status: True
Type: Successful
Observed Generation: 1
Phase: Successful
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal PauseDatabase 60s KubeDB Ops-manager operator Pausing MongoDB demo/mg-standalone
Normal PauseDatabase 60s KubeDB Ops-manager operator Successfully paused MongoDB demo/mg-standalone
Normal ReconfigureStandalone 35s KubeDB Ops-manager operator Successfully Reconfigured MongoDB
Normal ResumeDatabase 35s KubeDB Ops-manager operator Resuming MongoDB demo/mg-standalone
Normal ResumeDatabase 35s KubeDB Ops-manager operator Successfully resumed MongoDB demo/mg-standalone
Normal Successful 35s KubeDB Ops-manager operator Successfully Reconfigured Database
Now let’s connect to a mongodb instance and run a mongodb internal command to check the new configuration we have provided.
$ kubectl exec -n demo mg-standalone-0 -- mongo admin -u root -p m6lXjZugrC4VEpB8 --eval "db._adminCommand( {getCmdLineOpts: 1})" --quiet
{
"argv" : [
"mongod",
"--dbpath=/data/db",
"--auth",
"--ipv6",
"--bind_ip_all",
"--port=27017",
"--tlsMode=disabled",
"--config=/data/configdb/mongod.conf"
],
"parsed" : {
"config" : "/data/configdb/mongod.conf",
"net" : {
"bindIp" : "*",
"ipv6" : true,
"maxIncomingConnections" : 20000,
"port" : 27017,
"tls" : {
"mode" : "disabled"
}
},
"security" : {
"authorization" : "enabled"
},
"storage" : {
"dbPath" : "/data/db"
}
},
"ok" : 1
}
As we can see from the configuration of running mongodb, the value of maxIncomingConnections has been changed from 10000 to 20000. So the reconfiguration of the database is successful.
Reconfigure using apply config
Now we will reconfigure this database again to set maxIncomingConnections to 30000. This time we won’t use a new secret. We will use the applyConfig field of the MongoDBOpsRequest. This will merge the new config in the existing secret.
Create MongoDBOpsRequest
Now, we will use the new configuration in the data field in the MongoDBOpsRequest CR. The MongoDBOpsRequest yaml is given below,
apiVersion: ops.kubedb.com/v1alpha1
kind: MongoDBOpsRequest
metadata:
name: mops-reconfigure-apply-standalone
namespace: demo
spec:
type: Reconfigure
databaseRef:
name: mg-standalone
configuration:
standalone:
applyConfig:
mongod.conf: |-
net:
maxIncomingConnections: 30000
readinessCriteria:
oplogMaxLagSeconds: 20
objectsCountDiffPercentage: 10
timeout: 5m
apply: IfReady
Here,
spec.databaseRef.namespecifies that we are reconfiguringmops-reconfigure-apply-standalonedatabase.spec.typespecifies that we are performingReconfigureon our database.spec.configuration.standalone.applyConfigspecifies the new configuration that will be merged in the existing secret.
Let’s create the MongoDBOpsRequest CR we have shown above,
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.12.18/docs/examples/mongodb/reconfigure/mops-reconfigure-apply-standalone.yaml
mongodbopsrequest.ops.kubedb.com/mops-reconfigure-apply-standalone created
Verify the new configuration is working
If everything goes well, KubeDB Ops-manager operator will merge this new config with the existing configuration.
Let’s wait for MongoDBOpsRequest to be Successful. Run the following command to watch MongoDBOpsRequest CR,
$ watch kubectl get mongodbopsrequest -n demo
Every 2.0s: kubectl get mongodbopsrequest -n demo
NAME TYPE STATUS AGE
mops-reconfigure-apply-standalone Reconfigure Successful 38s
We can see from the above output that the MongoDBOpsRequest has succeeded. If we describe the MongoDBOpsRequest we will get an overview of the steps that were followed to reconfigure the database.
$ kubectl describe mongodbopsrequest -n demo mops-reconfigure-apply-standalone
Name: mops-reconfigure-apply-standalone
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: ops.kubedb.com/v1alpha1
Kind: MongoDBOpsRequest
Metadata:
Creation Timestamp: 2021-03-02T15:09:12Z
Generation: 1
Managed Fields:
API Version: ops.kubedb.com/v1alpha1
Fields Type: FieldsV1
fieldsV1:
f:metadata:
f:annotations:
.:
f:kubectl.kubernetes.io/last-applied-configuration:
f:spec:
.:
f:apply:
f:configuration:
.:
f:standalone:
.:
f:applyConfig:
f:databaseRef:
.:
f:name:
f:readinessCriteria:
.:
f:objectsCountDiffPercentage:
f:oplogMaxLagSeconds:
f:timeout:
f:type:
Manager: kubectl-client-side-apply
Operation: Update
Time: 2021-03-02T15:09:12Z
API Version: ops.kubedb.com/v1alpha1
Fields Type: FieldsV1
fieldsV1:
f:spec:
f:configuration:
f:standalone:
f:podTemplate:
.:
f:controller:
f:metadata:
f:spec:
.:
f:resources:
f:status:
.:
f:conditions:
f:observedGeneration:
f:phase:
Manager: kubedb-enterprise
Operation: Update
Time: 2021-03-02T15:09:13Z
Resource Version: 126782
Self Link: /apis/ops.kubedb.com/v1alpha1/namespaces/demo/mongodbopsrequests/mops-reconfigure-apply-standalone
UID: 33eea32f-e2af-4e36-b612-c528549e3d65
Spec:
Apply: IfReady
Configuration:
Standalone:
Apply Config: net:
maxIncomingConnections: 30000
Database Ref:
Name: mg-standalone
Readiness Criteria:
Objects Count Diff Percentage: 10
Oplog Max Lag Seconds: 20
Timeout: 5m
Type: Reconfigure
Status:
Conditions:
Last Transition Time: 2021-03-02T15:09:13Z
Message: MongoDB ops request is reconfiguring database
Observed Generation: 1
Reason: Reconfigure
Status: True
Type: Reconfigure
Last Transition Time: 2021-03-02T15:09:38Z
Message: Successfully Reconfigured MongoDB
Observed Generation: 1
Reason: ReconfigureStandalone
Status: True
Type: ReconfigureStandalone
Last Transition Time: 2021-03-02T15:09:38Z
Message: Successfully completed the modification process.
Observed Generation: 1
Reason: Successful
Status: True
Type: Successful
Observed Generation: 1
Phase: Successful
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal PauseDatabase 118s KubeDB Ops-manager operator Pausing MongoDB demo/mg-standalone
Normal PauseDatabase 118s KubeDB Ops-manager operator Successfully paused MongoDB demo/mg-standalone
Normal ReconfigureStandalone 93s KubeDB Ops-manager operator Successfully Reconfigured MongoDB
Normal ResumeDatabase 93s KubeDB Ops-manager operator Resuming MongoDB demo/mg-standalone
Normal ResumeDatabase 93s KubeDB Ops-manager operator Successfully resumed MongoDB demo/mg-standalone
Normal Successful 93s KubeDB Ops-manager operator Successfully Reconfigured Database
Now let’s connect to a mongodb instance and run a mongodb internal command to check the new configuration we have provided.
$ kubectl exec -n demo mg-standalone-0 -- mongo admin -u root -p m6lXjZugrC4VEpB8 --eval "db._adminCommand( {getCmdLineOpts: 1})" --quiet
{
"argv" : [
"mongod",
"--dbpath=/data/db",
"--auth",
"--ipv6",
"--bind_ip_all",
"--port=27017",
"--tlsMode=disabled",
"--config=/data/configdb/mongod.conf"
],
"parsed" : {
"config" : "/data/configdb/mongod.conf",
"net" : {
"bindIp" : "*",
"ipv6" : true,
"maxIncomingConnections" : 30000,
"port" : 27017,
"tls" : {
"mode" : "disabled"
}
},
"security" : {
"authorization" : "enabled"
},
"storage" : {
"dbPath" : "/data/db"
}
},
"ok" : 1
}
As we can see from the configuration of running mongodb, the value of maxIncomingConnections has been changed from 20000 to 30000. So the reconfiguration of the database using the applyConfig field is successful.
Cleaning Up
To clean up the Kubernetes resources created by this tutorial, run:
kubectl delete mg -n demo mg-standalone
kubectl delete mongodbopsrequest -n demo mops-reconfigure-standalone mops-reconfigure-apply-standalone