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Using Custom Configuration File
KubeDB supports providing custom configuration for MSSQLServer. This tutorial will show you how to use KubeDB to run SQL Server with custom configuration.
Before You Begin
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. Make sure install with helm command including
--set global.featureGates.MSSQLServer=true
to ensure MSSQLServer CRD installation.To configure TLS/SSL in
MSSQLServer
,KubeDB
usescert-manager
to issue certificates. So first you have to make sure that the cluster hascert-manager
installed. To installcert-manager
in your cluster following 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/mssqlserver folder in GitHub repository kubedb/docs.
Overview
SQL Server allows configuring database via configuration file. The default configuration file for SQL Server deployed by KubeDB
can be found in /var/opt/mssql/mssql.conf
. When SQL Server starts, it will look for configuration file in /var/opt/mssql/mssql.conf
. If configuration file exist, this configuration will overwrite the existing defaults.
To learn available configuration option of SQL Server see Configure SQL Server on Linux.
At first, you have to create a config file named mssql.conf
with your desired configuration. Then you have to create a secret using this file. Then specify this secret name in spec.configSecret.name
section while creating MSSQLServer CR.
KubeDB will create a secret named {mssqlserver-name}-config
with configuration file contents as the value of the key mssql.conf
and mount this secret into /var/opt/mssql/
directory of the database pod. The secret named {mssqlserver-name}-config
will contain your desired configurations with some default configurations.
In this tutorial, we will configure sql server via a custom config file.
Custom Configuration
At first, create mssql.conf
file containing required configuration settings.
$ cat mssql.conf
[network]
tlsprotocols = 1.2
forceencryption = 1
[language]
lcid = 1036
[memory]
memorylimitmb = 2304
Here we have set
- memory limit, The
memory.memorylimitmb
setting controls the amount of physical memory (in MB) available to SQL Server. The default is 80% of the physical memory, to prevent out-of-memory (OOM) conditions. The above configuration changes the memory available to SQL Server to 2.25 GB (2,304 MB). - SQL Server Locale, The language.lcid setting changes the SQL Server locale to any supported language identifier (LCID). The above example changes the locale to French (1036):
- TLS The
network.forceencryption
If 1, then SQL Server forces all connections to be encrypted. By default, this option is 0. Thenetwork.tlsprotocols
A comma-separated list of which TLS protocols are allowed by SQL Server. SQL Server always attempts to negotiate the strongest allowed protocol. If a client doesn’t support any allowed protocol, SQL Server rejects the connection attempt. For compatibility, all supported protocols are allowed by default (1.2, 1.1, 1.0). If your clients support TLS 1.2, Microsoft recommends allowing only TLS 1.2.
Now, create the secret with this configuration file.
$ kubectl create secret generic -n demo ms-custom-config --from-file=./mssql.conf
secret/ms-custom-config created
Verify the secret has the configuration file.
$ kubectl get secret -n demo ms-custom-config -oyaml
apiVersion: v1
data:
mssql.conf: W25ldHdvcmtdCnRsc3Byb3RvY29scyA9IDEuMgpmb3JjZWVuY3J5cHRpb24gPSAxCgpbbGFuZ3VhZ2VdCmxjaWQgPSAxMDM2CgpbbWVtb3J5XQptZW1vcnlsaW1pdG1iID0gMjMwNA==
kind: Secret
metadata:
creationTimestamp: "2024-10-16T06:12:28Z"
name: ms-custom-config
namespace: demo
resourceVersion: "451820"
uid: e7242e3a-d5dc-4705-a0f3-20b0ff0a59d3
type: Opaque
Now, we need to create an Issuer/ClusterIssuer which will be used to generate the certificate used for TLS configurations.
Create Issuer/ClusterIssuer
Now, we are going to create an example Issuer
that will be used throughout the duration of this tutorial. Alternatively, you can follow this cert-manager tutorial to create your own Issuer
. By following the below steps, we are going to create our desired issuer,
- Start off by generating our ca-certificates using openssl,
openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout ./ca.key -out ./ca.crt -subj "/CN=MSSQLServer/O=kubedb"
- Create a secret using the certificate files we have just generated,
$ kubectl create secret tls mssqlserver-ca --cert=ca.crt --key=ca.key --namespace=demo
secret/mssqlserver-ca created
Now, we are going to create an Issuer
using the mssqlserver-ca
secret that contains the ca-certificate we have just created. Below is the YAML of the Issuer
CR that we are going to create,
apiVersion: cert-manager.io/v1
kind: Issuer
metadata:
name: mssqlserver-ca-issuer
namespace: demo
spec:
ca:
secretName: mssqlserver-ca
Let’s create the Issuer
CR we have shown above,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.11.18/docs/examples/mssqlserver/standalone/mssqlserver-ca-issuer.yaml
issuer.cert-manager.io/mssqlserver-ca-issuer created
Now, create MSSQLServer CR specifying spec.configSecret
field.
apiVersion: kubedb.com/v1alpha2
kind: MSSQLServer
metadata:
name: mssql-custom-config
namespace: demo
spec:
version: "2022-cu12"
configSecret:
name: ms-custom-config
replicas: 1
tls:
issuerRef:
name: mssqlserver-ca-issuer
kind: Issuer
apiGroup: "cert-manager.io"
clientTLS: false
podTemplate:
spec:
containers:
- name: mssql
env:
- name: ACCEPT_EULA
value: "Y"
- name: MSSQL_PID
value: Evaluation # Change it
storageType: Durable
storage:
storageClassName: "standard"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
deletionPolicy: WipeOut
$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.11.18/docs/examples/mssqlserver/configuration/mssql-custom-config.yaml
mssqlserver.kubedb.com/mssql-custom-config created
Now, wait a few minutes. KubeDB operator will create necessary PVC, petset, services, secrets etc. If everything goes well, we will see that a pod with the name mssql-custom-config-0
has been created.
Check that the petset’s pod is running
$ kubectl get pod -n demo mssql-custom-config-0
NAME READY STATUS RESTARTS AGE
mssql-custom-config-0 1/1 Running 0 94s
Now, we will check if the database has started with the custom configuration we have provided.
Now, Let’s connect to the MSSQLServer from inside the pod.
$ kubectl get secrets -n demo mssql-custom-config-auth -o jsonpath='{.data.\username}' | base64 -d
sa
$ kubectl get secrets -n demo mssql-custom-config-auth -o jsonpath='{.data.\password}' | base64 -d
AqRe6WIuqwKXLaWc
$ kubectl exec -it mssql-custom-config-0 -n demo -c mssql -- bash
mssql@mssql-custom-config-0:/$ cat /var/opt/mssql/mssql.conf
[language]
lcid = 1036
[network]
tlsprotocols = 1.2
forceencryption = 1
[memory]
memorylimitmb = 2304
mssql@mssql-custom-config-0:/$ /opt/mssql-tools/bin/sqlcmd -S localhost -U sa -P AqRe6WIuqwKXLaWc
1> SELECT encrypt_option FROM sys.dm_exec_connections WHERE session_id = @@SPID;
2> go
encrypt_option
----------------------------------------
TRUE
(1 rows affected)
1> SELECT default_language_name FROM sys.server_principals WHERE name = 'sa';
2> go
default_language_name
-----------------------------------------------------------
Français
(1 rows affected)
1> SELECT physical_memory_kb / 1024 AS physical_memory_mb FROM sys.dm_os_sys_info;
2> go
physical_memory_mb
--------------------
2304
(1 rows affected)
1>
As we can see from the configuration of running sql server, the configuration given in the config secret has been set successfully.
Cleaning up
To clean up the Kubernetes resources created by this tutorial, run:
$ kubectl patch -n demo ms/mssql-custom-config -p '{"spec":{"deletionPolicy":"WipeOut"}}' --type="merge"
$ kubectl delete -n demo ms/mssql-custom-config
mssqlserver.kubedb.com "mssql-custom-config" deleted
$ kubectl delete -n demo secret ms-custom-config
mssqlserver.kubedb.com "mssql-custom-config" deleted
kubectl delete ns demo
Next Steps
- Backup and Restore MSSQLServer databases using KubeStash.
- Detail concepts of MSSQLServer object.
- Detail concepts of MSSQLServerVersion object.
- Want to hack on KubeDB? Check our contribution guidelines.