---
tags: DevOps
title: deploy mongodb sharded cluster on k8s
---
# deploy mongodb sharded cluster on k8s
### Create Namespace
:::spoiler namespace config file

kind: Namespace
apiVersion: v1
metadata:
  name: mongodb
  labels:
    kubernetes.io/metadata.name: mongodb
    name: mongodb
spec:
  finalizers:
    - kubernetes

:::
### Config Server :
:::spoiler config server headless-service and statefulset and volume claim .yaml config

apiVersion: v1
kind: Service
metadata:
  name: mongodb-configdb-headless-service
  namespace: mongodb
  labels:
    name: mongodb-configdb
spec:
  ports:
  - port: 27019
    targetPort: 27019
  clusterIP: None
  selector:
    role: mongodb-configdb
---
apiVersion: apps/v1  #change this version based on master version
kind: StatefulSet
metadata:
  name: mongodb-configdb
  namespace: mongodb
spec:
  selector:
    matchLabels:
      role: mongodb-configdb # has to match .spec.template.metadata.labels
  serviceName: mongodb-configdb-headless-service
  replicas: 1
  template:
    metadata:
      labels:
        role: mongodb-configdb
        tier: configdb
    spec:
      affinity:
        podAntiAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
          - weight: 100
            podAffinityTerm:
              labelSelector:
                matchExpressions:
                - key: tier
                  operator: In
                  values:
                  - configdb
              topologyKey: kubernetes.io/hostname
      terminationGracePeriodSeconds: 10
      containers:
        - name: mongodb-configdb-container
          image: mongo
          command:
            - "mongod"
            - "--port"
            - "27019"
            - "--dbpath"
            - "/mongo-disk"
            - "--bind_ip"
            - "0.0.0.0"
            - "--configsvr"
            - "--replSet"
            - rs0
          resources:
            requests:
              cpu: 50m
              memory: 100Mi
          ports:
            - containerPort: 27019
          volumeMounts:
            - name: mongodb-configdb-persistent-storage-claim
              mountPath: /mongo-disk
  volumeClaimTemplates:
  - metadata:
      name: mongodb-configdb-persistent-storage-claim
      annotations:
        volume.beta.kubernetes.io/storage-class: microk8s-hostpath
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 5Gi

:::

### Sharded Server:
:::spoiler sharded server headless-service and statefulset and volume claim config

apiVersion: v1
kind: Service
metadata:
  name: mongodb-shardX-headless-service
  namespace: mongodb
  labels:
    name: mongodb-shardX
spec:
  ports:
  - port: 27017
    targetPort: 27017
  clusterIP: None
  selector:
    role: mongodb-shardX
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mongodb-shardX
  namespace: mongodb
spec:
  selector:
    matchLabels:
      role: mongodb-shardX # has to match .spec.template.metadata.labels
  serviceName: mongodb-shardX-headless-service
  replicas: 1
  template:
    metadata:
      labels:
        role: mongodb-shardX
        tier: maindb
        replicaset: ShardX
    spec:
      affinity:
        podAntiAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
          - weight: 100
            podAffinityTerm:
              labelSelector:
                matchExpressions:
                - key: replicaset
                  operator: In
                  values:
                  - ShardX
              topologyKey: kubernetes.io/hostname
      terminationGracePeriodSeconds: 10
      containers:
        - name: mongodb-shardX-container
          image: mongo
          command:
            - "mongod"
            - "--port"
            - "27017"
            - "--bind_ip"
            - "0.0.0.0"
            - "--replSet"
            - "ShardX"
            - "--dbpath"
            - "/mongo-disk"
          resources:
            requests:
              cpu: 50m
              memory: 100Mi
          ports:
            - containerPort: 27017
          volumeMounts:
            - name: mongo-shardX-persistent-storage-claim
              mountPath: /mongo-disk
  volumeClaimTemplates:
  - metadata:
      name: mongo-shardX-persistent-storage-claim
      annotations:
        volume.beta.kubernetes.io/storage-class: microk8s-hostpath
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 5Gi

:::
:::spoiler command after copy above config

# replace the series number to your current sharded server number
sed -e "s/shardX/shard1/g; s/ShardX/Shard1/g" mongodb-maindb-service-stateful.yaml

:::
### Mongos(Mongo Sharded Utils) Deployment
:::spoiler mongos deployment yaml config file

apiVersion: apps/v1
kind: Deployment
metadata:
  name: mongos
  namespace: mongodb
spec:
  replicas: 2
  selector:
    matchLabels:
      role: mongos
      tier: routers
  template:
    metadata:
      labels:
        role: mongos
        tier: routers
    spec:
      affinity:
        podAntiAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
          - weight: 100
            podAffinityTerm:
              labelSelector:
                matchExpressions:
                - key: tier
                  operator: In
                  values:
                  - routers
              topologyKey: kubernetes.io/hostname
      terminationGracePeriodSeconds: 10
      containers:
        - name: mongos-container
          image: mongo
          command:
            - "mongos"
            - "--port"
            - "27017"
            - "--bind_ip"
            - "0.0.0.0"
            - "--configdb"
            - conf/mongodb-configdb-headless-service.mongodb.svc.cluster.local:27019
          resources:
            requests:
              cpu: 50m
              memory: 100Mi
          ports:
            - containerPort: 27017

:::
### Configure Sharding
:::spoiler configure bash file(you can also run in dashboard's pod terminal)

echo "Replicaset Init mongodb-shard1-0 "
kubectl exec --namespace=mongodb mongodb-shard1-0 -c mongodb-shard1-container -- mongo --port 27017 --eval "rs.initiate({_id: \"Shard1\", version: 1, members: [ {_id: 0, host: \"mongodb-shard1-0.mongodb-shard1-headless-service.mongodb.svc.cluster.local:27017\"} ] });"
echo "Replicaset Init mongodb-shard2-0 "  
kubectl exec --namespace=mongodb mongodb-shard2-0 -c mongodb-shard2-container -- mongo --port 27017 --eval "rs.initiate({_id: \"Shard2\", version: 1, members: [ {_id: 0, host: \"mongodb-shard2-0.mongodb-shard2-headless-service.mongodb.svc.cluster.local:27017\"} ] });"

:::
:::spoiler

echo "Adding Shard 1 : Shard1 "
kubectl exec --namespace=mongodb $(kubectl get pod -l "tier=routers" -o jsonpath='{.items[0].metadata.name}' --namespace=mongodb ) -c mongos-container -- mongosh --port 27017 --eval "sh.addShard(\"Shard1/mongodb-shard1-0.mongodb-shard1-headless-service.mongodb.svc.cluster.local:27017\");"
echo "Adding Shard 2 : Shard2 "
kubectl exec --namespace=mongodb $(kubectl get pod -l "tier=routers" -o jsonpath='{.items[0].metadata.name}' --namespace=mongodb ) -c mongos-container -- mongosh --port 27017 --eval "sh.addShard(\"Shard2/mongodb-shard2-0.mongodb-shard2-headless-service.mongodb.svc.cluster.local:27017\");"

:::

### reference
- https://medium.com/google-cloud/sharded-mongodb-in-kubernetes-statefulsets-on-gke-ba08c7c0c0b0