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Microsoft SQL Server QuickStart

This tutorial will show you how to use KubeDB to run a Microsoft SQL Server database.

lifecycle

Note: The yaml files used in this tutorial are stored in docs/examples/mssqlserver/quickstart/ folder in GitHub repository kubedb/docs.

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 operator in your cluster following the steps here and make sure install with helm command including --set global.featureGates.MSSQLServer=true to ensure MSSQLServer crd installation.

StorageClass is required to run KubeDB. Check the available StorageClass in cluster.

$ kubectl get storageclasses
NAME                 PROVISIONER             RECLAIMPOLICY   VOLUMEBINDINGMODE      ALLOWVOLUMEEXPANSION   AGE
standard (default)   rancher.io/local-path   Delete          WaitForFirstConsumer   false                  5d20h

To keep things isolated, this tutorial uses a separate namespace called demo throughout this tutorial.
```
$ kubectl create ns demo
namespace/demo created
```

Find Available Microsoft SQL Server Versions

When you have installed KubeDB, it has created MSSQLServerVersion crd for all supported Microsoft SQL Server versions. Check it by using the kubectl get mssqlserverversions. You can also use msversion shorthand instead of mssqlserverversions.

$ kubectl get mssqlserverversions
NAME        VERSION   DB_IMAGE                                                DEPRECATED   AGE
2022-cu12   2022      mcr.microsoft.com/mssql/server:2022-CU12-ubuntu-22.04                2d3h

Create Microsoft SQL Server database

KubeDB implements a MSSQLServer CRD to define the specification of a Microsoft SQL Server database. Below is the MSSQLServer object created in this tutorial.

apiVersion: kubedb.com/v1alpha2
kind: MSSQLServer
metadata:
  name: mssqlserver-quickstart
  namespace: demo
spec:
  version: "2022-cu12"
  replicas: 1
  storageType: Durable
  tls:
    issuerRef:
      name: mssqlserver-issuer
      kind: Issuer
      apiGroup: "cert-manager.io"
    clientTLS: false
  storage:
    storageClassName: "standard"
    accessModes:
      - ReadWriteOnce
    resources:
      requests:
        storage: 1Gi
  deletionPolicy: WipeOut

$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.8.21/docs/examples/mssqlserver/quickstart/mssqlserver-quickstart.yaml
mssqlserver.kubedb.com/mssqlserver-quickstart created

Here,

spec.version is the name of the MSSQLServerVersion CR where the docker images are specified. In this tutorial, a MSSQLServer 2022-cu12 database is going to be created.
spec.storageType specifies the type of storage that will be used for MSSQLServer database. It can be Durable or Ephemeral. Default value of this field is Durable. If Ephemeral is used then KubeDB will create MSSQLServer database using EmptyDir volume. In this case, you don’t have to specify spec.storage field. This is useful for testing purposes.
spec.tls specifies the TLS/SSL configurations. The KubeDB operator supports TLS management by using the cert-manager. Here tls.clientTLS: false means tls will not be enabled for SQL Server but the Issuer will be used to configure tls enabled wal-g proxy-server which is required for SQL Server backup operation.
spec.storage specifies the StorageClass of PVC dynamically allocated to store data for this database. This storage spec will be passed to the PetSet created by KubeDB operator to run database pods. You can specify any StorageClass available in your cluster with appropriate resource requests.
spec.deletionPolicy gives flexibility whether to nullify(reject) the delete operation of MSSQLServer CR or which resources KubeDB should keep or delete when you delete MSSQLServer CR. If admission webhook is enabled, It prevents users from deleting the database as long as the spec.deletionPolicy is set to DoNotTerminate. Learn details of all DeletionPolicy here

Note: spec.storage section is used to create PVC for database pod. It will create PVC with storage size specified in storage.resources.requests field. Don’t specify limits here. PVC does not get resized automatically.

KubeDB operator watches for MSSQLServer objects using Kubernetes api. When a MSSQLServer object is created, KubeDB operator will create a new PetSet and a Service with the matching MSSQLServer object name. KubeDB operator will also create a governing service for PetSets with the name <MSSQLServerName>-pods, if one is not already present.

$ kubectl get petset -n demo mssqlserver-quickstart
NAME                     AGE
mssqlserver-quickstart   13m


$ kubectl get pvc -n demo
NAME                            STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
data-mssqlserver-quickstart-0   Bound    pvc-ccbba9d2-5556-49cd-9ce8-23c28ad56f12   1Gi        RWO            standard       15m


$ kubectl get pv -n demo
NAME                                       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                                STORAGECLASS   REASON   AGE
pvc-ccbba9d2-5556-49cd-9ce8-23c28ad56f12   1Gi        RWO            Delete           Bound    demo/data-mssqlserver-quickstart-0   standard                15m


kubectl get service -n demo
NAME                          TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)    AGE
mssqlserver-quickstart        ClusterIP   10.96.128.61   <none>        1433/TCP   15m
mssqlserver-quickstart-pods   ClusterIP   None           <none>        1433/TCP   15m

KubeDB operator sets the status.phase to Ready once the database is successfully created and is able to accept client connections. Run the following command to see the modified MSSQLServer object:

$ kubectl get ms -n demo mssqlserver-quickstart -o yaml

apiVersion: kubedb.com/v1alpha2
kind: MSSQLServer
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"kubedb.com/v1alpha2","kind":"MSSQLServer","metadata":{"annotations":{},"name":"mssqlserver-quickstart","namespace":"demo"},"spec":{"deletionPolicy":"WipeOut","replicas":1,"storage":{"accessModes":["ReadWriteOnce"],"resources":{"requests":{"storage":"1Gi"}}},"storageType":"Durable","tls":{"clientTLS":false,"issuerRef":{"apiGroup":"cert-manager.io","kind":"Issuer","name":"mssqlserver-issuer"}},"version":"2022-cu12"}}      
  creationTimestamp: "2024-06-25T06:12:57Z"
  finalizers:
    - kubedb.com
  generation: 2
  name: mssqlserver-quickstart
  namespace: demo
  resourceVersion: "60663"
  uid: e0fbca5f-b699-489b-a218-4c5b35025394
spec:
  authSecret:
    name: mssqlserver-quickstart-auth
  deletionPolicy: WipeOut
  healthChecker:
    failureThreshold: 1
    periodSeconds: 10
    timeoutSeconds: 10
  podTemplate:
    controller: {}
    metadata: {}
    spec:
      containers:
        - name: mssql
          resources:
            limits:
              memory: 1536Mi
            requests:
              cpu: 500m
              memory: 1536Mi
          securityContext:
            allowPrivilegeEscalation: false
            capabilities:
              add:
                - NET_BIND_SERVICE
              drop:
                - ALL
            runAsGroup: 10001
            runAsNonRoot: true
            runAsUser: 10001
            seccompProfile:
              type: RuntimeDefault
      initContainers:
        - name: mssql-init
          resources:
            limits:
              memory: 512Mi
            requests:
              cpu: 200m
              memory: 512Mi
          securityContext:
            allowPrivilegeEscalation: false
            capabilities:
              drop:
                - ALL
            runAsGroup: 10001
            runAsNonRoot: true
            runAsUser: 10001
            seccompProfile:
              type: RuntimeDefault
      podPlacementPolicy:
        name: default
      securityContext:
        fsGroup: 10001
  replicas: 1
  storage:
    accessModes:
      - ReadWriteOnce
    resources:
      requests:
        storage: 1Gi
    storageClassName: standard
  storageType: Durable
  tls:
    certificates:
      - alias: server
        secretName: mssqlserver-quickstart-server-cert
        subject:
          organizationalUnits:
            - server
          organizations:
            - kubedb
      - alias: client
        secretName: mssqlserver-quickstart-client-cert
        subject:
          organizationalUnits:
            - client
          organizations:
            - kubedb
    clientTLS: false
    issuerRef:
      apiGroup: cert-manager.io
      kind: Issuer
      name: mssqlserver-issuer
  version: 2022-cu12
status:
  conditions:
    - lastTransitionTime: "2024-06-25T06:12:57Z"
      message: 'The KubeDB operator has started the provisioning of MSSQL: demo/mssqlserver-quickstart'
      observedGeneration: 1
      reason: DatabaseProvisioningStartedSuccessfully
      status: "True"
      type: ProvisioningStarted
    - lastTransitionTime: "2024-06-25T06:15:02Z"
      message: All replicas are ready for MSSQL demo/mssqlserver-quickstart
      observedGeneration: 2
      reason: AllReplicasReady
      status: "True"
      type: ReplicaReady
    - lastTransitionTime: "2024-06-25T06:15:13Z"
      message: database demo/mssqlserver-quickstart is accepting connection
      observedGeneration: 2
      reason: AcceptingConnection
      status: "True"
      type: AcceptingConnection
    - lastTransitionTime: "2024-06-25T06:15:13Z"
      message: database demo/mssqlserver-quickstart is ready
      observedGeneration: 2
      reason: AllReplicasReady
      status: "True"
      type: Ready
    - lastTransitionTime: "2024-06-25T06:16:04Z"
      message: 'The MSSQL: demo/mssqlserver-quickstart is successfully provisioned.'
      observedGeneration: 2
      reason: DatabaseSuccessfullyProvisioned
      status: "True"
      type: Provisioned
  phase: Ready

Connect with MSSQLServer database

KubeDB operator has created a new Secret called mssqlserver-quickstart-auth (format: {mssqlserver-object-name}-auth) for storing the sa password for mssqlserver. This secret contains a username key which contains the username for MSSQLServer SA and a password key which contains the password for MSSQLServer SA user.

If you want to use an existing secret please specify that when creating the MSSQLServer object using spec.authSecret.name. While creating this secret manually, make sure the secret contains these two keys containing data username and password and also make sure of using sa as value of username and a strong password for the sa user. For more details see here.

Now, we need username and password to connect to this database from kubectl exec command. In this example mssqlserver-quickstart-auth secret holds username and password

$ kubectl get secret -n demo mssqlserver-quickstart-auth -o jsonpath='{.data.\username}' | base64 -d
sa

$ kubectl get secret -n demo mssqlserver-quickstart-auth -o jsonpath='{.data.\password}' | base64 -d
axgXHj4oRIVQ1ocK

We can exec into the pod mysql-quickstart-0 using the following command:

kubectl exec -it -n demo mssqlserver-quickstart-0 -- bash
Defaulted container "mssql" out of: mssql, mssql-init (init)
mssql@mssqlserver-quickstart-0:/$

We can connect to the database using sqlcmd utility, the ODBC-based sqlcmd, available with SQL Server or the Microsoft Command Line Utilities, and part of the mssql-tools package on Linux. To determine the version you have installed, run the following statement at the command line:

mssql@mssqlserver-quickstart-0:/$ /opt/mssql-tools/bin/sqlcmd "-?"
Microsoft (R) SQL Server Command Line Tool
Version 17.10.0001.1 Linux
Copyright (C) 2017 Microsoft Corporation. All rights reserved.

usage: sqlcmd            [-U login id]          [-P password]
  [-S server or Dsn if -D is provided] 
  [-H hostname]          [-E trusted connection]
  [-N Encrypt Connection][-C Trust Server Certificate]
  [-d use database name] [-l login timeout]     [-t query timeout]
  [-h headers]           [-s colseparator]      [-w screen width]
  [-a packetsize]        [-e echo input]        [-I Enable Quoted Identifiers]
  [-c cmdend]
  [-q "cmdline query"]   [-Q "cmdline query" and exit]
  [-m errorlevel]        [-V severitylevel]     [-W remove trailing spaces]
  [-u unicode output]    [-r[0|1] msgs to stderr]
  [-i inputfile]         [-o outputfile]
  [-k[1|2] remove[replace] control characters]
  [-y variable length type display width]
  [-Y fixed length type display width]
  [-p[1] print statistics[colon format]]
  [-R use client regional setting]
  [-K application intent]
  [-M multisubnet failover]
  [-b On error batch abort]
  [-D Dsn flag, indicate -S is Dsn] 
  [-X[1] disable commands, startup script, environment variables [and exit]]
  [-x disable variable substitution]
  [-g enable column encryption]
  [-G use Azure Active Directory for authentication]
  [-? show syntax summary]

Now, connect to the database using username and password

mssql@mssqlserver-quickstart-0:/$ /opt/mssql-tools/bin/sqlcmd -S localhost -U sa -P "axgXHj4oRIVQ1ocK"
1> select name from sys.databases
2> go
name                                                                                                                            
--------------------------------------------------------------------------------------------------------------------------------
master                                                                                                                          
tempdb                                                                                                                          
model                                                                                                                           
msdb                                                                                                                            
kubedb_system                                                                                                                   

(5 rows affected)
1>

Run the following command to see the created appbinding object:

$ kubectl get appbinding -n demo -oyaml

apiVersion: v1
items:
- apiVersion: appcatalog.appscode.com/v1alpha1
  kind: AppBinding
  metadata:
    annotations:
      kubectl.kubernetes.io/last-applied-configuration: |
        {"apiVersion":"kubedb.com/v1alpha2","kind":"MSSQLServer","metadata":{"annotations":{},"name":"mssqlserver-quickstart","namespace":"demo"},"spec":{"replicas":1,"storage":{"accessModes":["ReadWriteOnce"],"resources":{"requests":{"storage":"1Gi"}},"storageClassName":"standard"},"storageType":"Durable","deletionPolicy":"Delete","version":"2022-cu12"}}        
    creationTimestamp: "2024-05-08T06:43:45Z"
    generation: 1
    labels:
      app.kubernetes.io/component: database
      app.kubernetes.io/instance: mssqlserver-quickstart
      app.kubernetes.io/managed-by: kubedb.com
      app.kubernetes.io/name: mssqlservers.kubedb.com
    name: mssqlserver-quickstart
    namespace: demo
    ownerReferences:
    - apiVersion: kubedb.com/v1alpha2
      blockOwnerDeletion: true
      controller: true
      kind: MSSQLServer
      name: mssqlserver-quickstart
      uid: 39836735-3f08-466e-ae2f-eb483c11028d
    resourceVersion: "351872"
    uid: da0f5c83-c490-4056-b23f-c911570a8072
  spec:
    appRef:
      apiGroup: kubedb.com
      kind: MSSQLServer
      name: mssqlserver-quickstart
      namespace: demo
    clientConfig:
      service:
        name: mssqlserver-quickstart
        path: /
        port: 1433
        scheme: tcp
      url: tcp(mssqlserver-quickstart.demo.svc:1433)/
    secret:
      name: mssqlserver-quickstart-auth
    type: kubedb.com/mssqlserver
    version: "2022"
kind: List
metadata:
  resourceVersion: ""

You can use this appbinding to connect with the mssql server from external

Database DeletionPolicy

This field is used to regulate the deletion process of the related resources when MSSQLServer object is deleted. User can set the value of this field according to their needs. The available options and their use case scenario is described below:

DoNotTerminate:

When deletionPolicy is set to DoNotTerminate, KubeDB takes advantage of ValidationWebhook feature in Kubernetes 1.9.0 or later clusters to implement DoNotTerminate feature. If admission webhook is enabled, It prevents users from deleting the database as long as the spec.deletionPolicy is set to DoNotTerminate. You can see this below:

$ kubectl delete ms -n demo mssqlserver-quickstart
The MSSQLServer "mssqlserver-quickstart" is invalid: spec.deletionPolicy: Invalid value: "mssqlserver-quickstart": Can not delete as deletionPolicy is set to "DoNotTerminate"

Now, run kubectl patch -n demo ms mssqlserver-quickstart -p '{"spec":{"deletionPolicy":"Halt"}}' --type="merge" to set spec.deletionPolicy to Halt (which deletes the mssqlserver object and keeps PVC, snapshots, Secrets intact) or remove this field (which default to Delete). Then you will be able to delete/halt the database.

Learn details of all DeletionPolicy here.

Halt:

Suppose you want to reuse your database volume and credential to deploy your database in future using the same configurations. But, right now you just want to delete the database except the database volumes and credentials. In this scenario, you must set the MSSQLServer object deletionPolicy to Halt.

When the DeletionPolicy is set to halt and the MSSQLServer object is deleted, the KubeDB operator will delete the PetSet and its pods but leaves the PVCs, secrets and database backup data(snapshots) intact. You can set the deletionPolicy to halt in existing database using patch command for testing.

At first, run kubectl patch -n demo ms mssqlserver-quickstart -p '{"spec":{"deletionPolicy":"Halt"}}' --type="merge". Then delete the mssqlserver object,

$ kubectl delete ms -n demo mssqlserver-quickstart
mssqlserver.kubedb.com "mssqlserver-quickstart" deleted

Now, run the following command to get mssqlserver resources in demo namespaces,

$ kubectl get petset,svc,secret,pvc -n demo 
NAME                                 TYPE                       DATA   AGE
secret/mssqlserver-quickstart-auth   kubernetes.io/basic-auth   2      56m

NAME                                                  STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
persistentvolumeclaim/data-mssqlserver-quickstart-0   Bound    pvc-0e6a361e-9195-4d6b-8042-e90ec98d8288   1Gi        RWO            standard       4m17s

From the above output, you can see that all mssqlserver resources(PetSet, Service, etc.) are deleted except PVC and Secret. You can recreate your mssqlserver again using these resources.

You can also set the deletionPolicy to Halt(deprecated). It’s behavior same as halt and right now halt is replaced by Halt.

Delete:

If you want to delete the existing database along with the volumes used, but want to restore the database from previously taken snapshots and secrets then you might want to set the MSSQLServer object deletionPolicy to Delete. In this setting, PetSet and the volumes will be deleted. If you decide to restore the database, you can do so using the snapshots and the credentials.

When the DeletionPolicy is set to Delete and the MSSQLServer object is deleted, the KubeDB operator will delete the PetSet and its pods along with PVCs but leaves the secret and database backup data(snapshots) intact.

Suppose, we have a database with deletionPolicy set to Delete. Now, are going to delete the database using the following command:

$ kubectl delete ms -n demo mssqlserver-quickstart 
mssqlserver.kubedb.com "mssqlserver-quickstart" deleted

Now, run the following command to get all mssql resources in demo namespaces,

$ kubectl get petset,svc,secret,pvc -n demo
NAME                                 TYPE                       DATA   AGE
secret/mssqlserver-quickstart-auth   kubernetes.io/basic-auth   2      58m

From the above output, you can see that all mssqlserver resources(PetSet, Service, PVCs etc.) are deleted except Secret. You can initialize your mssqlserver using snapshots(if previously taken) and secret.

If you don’t set the deletionPolicy then the kubeDB set the DeletionPolicy to Delete by-default.

WipeOut:

You can totally delete the MSSQLServer database and relevant resources without any tracking by setting deletionPolicy to WipeOut. KubeDB operator will delete all relevant resources of this MSSQLServer database (i.e, PVCs, Secrets, Snapshots) when the deletionPolicy is set to WipeOut.

Suppose, we have a database with deletionPolicy set to WipeOut. Now, are going to delete the database using the following command:

$ kubectl delete ms -n demo mssqlserver-quickstart
mssqlserver.kubedb.com "mssqlserver-quickstart" deleted

Now, run the following command to get all mssqlserver resources in demo namespaces,

$ kubectl get petset,svc,secret,pvc -n demo
No resources found in demo namespace.

From the above output, you can see that all mssqlserver resources are deleted. there is no option to recreate/reinitialize your database if deletionPolicy is set to WipeOut.

Be careful when you set the deletionPolicy to WipeOut. Because there is no option to trace the database resources if once deleted the database.

Cleaning up

To clean up the Kubernetes resources created by this tutorial, run:

kubectl patch -n demo mssqlserver/mssqlserver-quickstart -p '{"spec":{"deletionPolicy":"WipeOut"}}' --type="merge"
kubectl delete mssqlserver -n demo mssqlserver-quickstart 


kubectl delete ns demo

Tips for Testing

If you are just testing some basic functionalities, you might want to avoid additional hassles due to some safety features that are great for production environment. You can follow these tips to avoid them.

Use storageType: Ephemeral. Databases are precious. You might not want to lose your data in your production environment if database pod fail. So, we recommend to use spec.storageType: Durable and provide storage spec in spec.storage section. For testing purpose, you can just use spec.storageType: Ephemeral. KubeDB will use emptyDir for storage. You will not require to provide spec.storage section.
Use deletionPolicy: WipeOut. It is nice to be able to delete everything created by KubeDB for a particular MSSQLServer crd when you delete the crd. For more details about deletion policy, please visit here.

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