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User-provided configuration files

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Arc data services provide management of configuration settings and files in the system. The system generates configuration files such as mssql.conf, mssql.json, krb5.conf using the user-provided settings in the custom resource spec and some system-determined settings. The scope of what settings are supported and what changes can be made to the configuration files using the custom resource spec evolves over time. You may need to try changes in the configuration files that aren't possible through the settings on the custom resource spec.

To alleviate this problem, you can provide configuration file content for a selected set of files through a Kubernetes ConfigMap. The information in the ConfigMap effectively overrides the file content that the system would have otherwise generated. This content allows you to try some configuration settings.

For Arc SQL Managed Instance, the supported configuration files that you can override using this method are:

  • mssql.conf
  • mssql.json
  • krb5.conf

Steps to provide override configuration files

  1. Prepare the content of the configuration file

    Prepare the content of the file that you would like to provide an override for.

  2. Create a ConfigMap

    Create a ConfigMap spec to store the content of the configuration file. The key in the ConfigMap dictionary should be the name of the file, and the value should be the content.

    You can provide file overrides for multiple configuration files in one ConfigMap.

    The ConfigMap must be in the same namespace as the SQL Managed Instance.

    The following spec shows an example of how to provide an override for mssql.conf file:

    apiVersion: v1
kind: ConfigMap
metadata:
  name: sqlmifo-cm
  namespace: test
data:
  mssql.conf: "[language]\r\nlcid = 1033\r\n\r\n[licensing]\r\npid = GeneralPurpose\r\n\r\n[network]\r\nforceencryption = 0\r\ntlscert = /var/run/secrets/managed/certificates/mssql/mssql-certificate.pem\r\ntlsciphers = ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES128-SHA256:ECDHE-RSA-AES256-SHA384\r\ntlskey = /var/run/secrets/managed/certificates/mssql/mssql-privatekey.pem\r\ntlsprotocols = 1.2\r\n\r\n[sqlagent]\r\nenabled = False\r\n\r\n[telemetry]\r\ncustomerfeedback = false\r\n\r\n"

    Apply the ConfigMap in Kubernetes using kubectl apply -f <filename>.

  3. Provide the name of the ConfigMap in SQL Managed Instance spec

    In SQL Managed Instance spec, provide the name of the ConfigMap in the field spec.fileOverrideConfigMap.

    The SQL Managed Instance apiVersion must be at least v12 (released in April 2023).

    The following SQL Managed Instance spec shows an example of how to provide the name of the ConfigMap.

    apiVersion: sql.arcdata.microsoft.com/v12
kind: SqlManagedInstance
metadata:
  name: sqlmifo
  namespace: test
spec:
  fileOverrideConfigMap: sqlmifo-cm
  ...

    Apply the SQL Managed Instance spec in Kubernetes. This action leads to the delivery of the provided configuration files to Arc SQL Managed Instance container.

  4. Check that the files are downloaded in the arc-sqlmi container.

    The locations of supported files in the container are:

    • mssql.conf: /var/run/config/mssql/mssql.conf
    • mssql.json: /var/run/config/mssql/mssql.json
    • krb5.conf: /etc/krb5.conf

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