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Using Custom Configuration File
KubeDB supports providing custom configuration for MongoDB. This tutorial will show you how to use KubeDB to run a MongoDB database with custom configuration.
Before You Begin
At first, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using kind.
Now, install KubeDB cli on your workstation and KubeDB operator in your cluster following the steps here.
To keep things isolated, this tutorial uses a separate namespace called
demo
throughout this tutorial. Run the following command to prepare your cluster for this tutorial:$ kubectl create ns demo namespace/demo created
Note: The yaml files used in this tutorial are stored in docs/examples/mongodb folder in GitHub repository kubedb/docs.
Overview
MongoDB allows to configure database via configuration file. The default configuration file for MongoDB deployed by KubeDB
can be found in /data/configdb/mongod.conf
. When MongoDB starts, it will look for custom configuration file in /configdb-readonly/mongod.conf
. If configuration file exist, this custom configuration will overwrite the existing default one.
To learn available configuration option of MongoDB see Configuration File Options.
At first, you have to create a config file named mongod.conf
. Then you have to put this file into a volume. You have to specify this volume in spec.configSecret
section while creating MongoDB crd. KubeDB will mount this volume into /configdb-readonly/
directory of the database pod.
In this tutorial, we will configure net.maxIncomingConnections (default value: 65536) via a custom config file. We will use configMap as volume source.
Custom Configuration
At first, 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, create a configMap with this configuration file.
$ kubectl create configmap -n demo mg-configuration --from-file=./mongod.conf
configmap/mg-configuration created
Verify the config map has the configuration file.
$ kubectl get configmap -n demo mg-configuration -o yaml
apiVersion: v1
data:
mongod.conf: |+
net:
maxIncomingConnections: 10000
kind: ConfigMap
metadata:
creationTimestamp: "2019-02-06T10:03:45Z"
name: mg-configuration
namespace: demo
resourceVersion: "91905"
selfLink: /api/v1/namespaces/demo/configmaps/mg-configuration
uid: 7da0467c-29f6-11e9-aebf-080027875192
Now, create MongoDB crd specifying spec.configSecret
field.
apiVersion: kubedb.com/v1alpha2
kind: MongoDB
metadata:
name: mgo-custom-config
namespace: demo
spec:
version: "3.4-v3"
storageType: Durable
storage:
storageClassName: "standard"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
configSecret:
name: mg-configuration
$ kubectl create -f https://github.com/kubedb/docs/raw/v2021.01.26/docs/examples/mongodb/configuration/demo-1.yaml
mongodb.kubedb.com/mgo-custom-config created
Now, wait a few minutes. KubeDB operator will create necessary PVC, statefulset, services, secret etc. If everything goes well, we will see that a pod with the name mgo-custom-config-0
has been created.
Check that the statefulset’s pod is running
$ kubectl get pod -n demo mgo-custom-config-0
NAME READY STATUS RESTARTS AGE
mgo-custom-config-0 1/1 Running 0 1m
Now, we will check if the database has started with the custom configuration we have provided.
Now, you can connect to this database through mongo-shell. In this tutorial, we are connecting to the MongoDB server from inside the pod.
$ kubectl get secrets -n demo mgo-custom-config-auth -o jsonpath='{.data.\username}' | base64 -d
root
$ kubectl get secrets -n demo mgo-custom-config-auth -o jsonpath='{.data.\password}' | base64 -d
ErialNojWParBFoP
$ kubectl exec -it mgo-custom-config-0 -n demo sh
> mongo admin
> db.auth("root","ErialNojWParBFoP")
1
> db._adminCommand( {getCmdLineOpts: 1})
{
"argv" : [
"mongod",
"--dbpath=/data/db",
"--auth",
"--bind_ip=0.0.0.0",
"--port=27017",
"--config=/data/configdb/mongod.conf"
],
"parsed" : {
"config" : "/data/configdb/mongod.conf",
"net" : {
"bindIp" : "0.0.0.0",
"maxIncomingConnections" : 10000,
"port" : 27017
},
"security" : {
"authorization" : "enabled"
},
"storage" : {
"dbPath" : "/data/db"
}
},
"ok" : 1
}
> exit
bye
As we can see from the configuration of running mongodb, the value of maxIncomingConnections
has been set to 10000 successfully.
Cleaning up
To cleanup the Kubernetes resources created by this tutorial, run:
kubectl patch -n demo mg/mgo-custom-config -p '{"spec":{"terminationPolicy":"WipeOut"}}' --type="merge"
kubectl delete -n demo mg/mgo-custom-config
kubectl patch -n demo drmn/mgo-custom-config -p '{"spec":{"wipeOut":true}}' --type="merge"
kubectl delete -n demo drmn/mgo-custom-config
kubectl delete -n demo configmap mg-configuration
kubectl delete ns demo
Next Steps
- Backup and Restore MongoDB databases using Stash.
- Initialize MongoDB with Script.
- Monitor your MongoDB database with KubeDB using out-of-the-box Prometheus operator.
- Monitor your MongoDB database with KubeDB using out-of-the-box builtin-Prometheus.
- Use private Docker registry to deploy MongoDB with KubeDB.
- Use kubedb cli to manage databases like kubectl for Kubernetes.
- Detail concepts of MongoDB object.
- Detail concepts of MongoDBVersion object.
- Want to hack on KubeDB? Check our contribution guidelines.