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APPLIES TO: SQL Server (Linux only) Azure SQL Database Azure Synapse Analytics (SQL DW) Parallel Data Warehouse

This article explains how to configure and use the mssql-server-linux container image with Docker.

For other deployment scenarios, see:

This image consists of SQL Server running on Linux based on Ubuntu 16.04. It can be used with the Docker Engine 1.8+ on Linux or on Docker for Mac/Windows.

Note

This article specifically focuses on using the mssql-server-linux image. The Windows image is not covered, but you can learn more about it on the mssql-server-windows Docker Hub page.

Important

Before choosing to run a SQL Server container for production use cases, please review our support policy for SQL Server Containers to ensure that you are running on a supported configuration.

This 6-minute video provides an introduction into running SQL Server on containers:

Pull and run the container image

To pull and run the Docker container images for SQL Server 2017 and SQL Server 2019, follow the prerequisites and steps in the following quickstart:

This configuration article provides additional usage scenarios in the following sections.

Run RHEL-based container images

The documentation for SQL Server Linux container images points to Ubuntu-based containers. Beginning with SQL Server 2019, you can use containers based on Red Hat Enterprise Linux (RHEL). Change the container repository from mcr.microsoft.com/mssql/server:2019-GA-ubuntu-16.04 to mcr.microsoft.com/mssql/rhel/server:2019-CU1-rhel-8 in all of your docker commands.

For example, the following command pulls the Cumulative Update 1 for SQL Server 2019 container that uses RHEL 8:

Run production container images

The quickstart in the previous section runs the free Developer edition of SQL Server from Docker Hub. Most of the information still applies if you want to run production container images, such as Enterprise, Standard, or Web editions. However, there are a few differences that are outlined here.

You can only use SQL Server in a production environment if you have a valid license. You can obtain a free SQL Server Express production license here. SQL Server Standard and Enterprise Edition licenses are available through Microsoft Volume Licensing.
The Developer container image can be configured to run the production editions as well. Use the following steps to run production editions:

Review the requirements and run procedures in the quickstart. You must specify your production edition with the MSSQL_PID environment variable. The following example shows how to run the latest SQL Server 2017 container image for the Enterprise Edition:

Important

By passing the value Y to the environment variable ACCEPT_EULA and an edition value to MSSQL_PID, you are expressing that you have a valid and existing license for the edition and version of SQL Server that you intend to use. You also agree that your use of SQL Server software running in a Docker container image will be governed by the terms of your SQL Server license.

Note

For a full list of possible values for MSSQL_PID, see Configure SQL Server settings with environment variables on Linux.

Connect and query

You can connect and query SQL Server in a container from either outside the container or from within the container. The following sections explain both scenarios.

Tools outside the container

You can connect to the SQL Server instance on your Docker machine from any external Linux, Windows, or macOS tool that supports SQL connections. Some common tools include:

The following example uses sqlcmd to connect to SQL Server running in a Docker container. The IP address in the connection string is the IP address of the host machine that is running the container.

If you mapped a host port that was not the default 1433, add that port to the connection string. For example, if you specified -p 1400:1433 in your docker run command, then connect by explicitly specify port 1400.

Tools inside the container

Starting with SQL Server 2017, the SQL Server command-line tools are included in the container image. If you attach to the image with an interactive command-prompt, you can run the tools locally.

Use the docker exec -it command to start an interactive bash shell inside your running container. In the following example e69e056c702d is the container ID.
Tip
You don't always have to specify the entire container id. You only have to specify enough characters to uniquely identify it. So in this example, it might be enough to use e6 or e69 rather than the full id.
Once inside the container, connect locally with sqlcmd. Note that sqlcmd is not in the path by default, so you have to specify the full path.
When finished with sqlcmd, type exit.
When finished with the interactive command-prompt, type exit. Your container continues to run after you exit the interactive bash shell.

Run multiple SQL Server containers

Docker provides a way to run multiple SQL Server containers on the same host machine. Use this approach for scenarios that require multiple instances of SQL Server on the same host. Each container must expose itself on a different port.

The following example creates two SQL Server 2017 containers and maps them to ports 1401 and 1402 on the host machine.

The following example creates two SQL Server 2019 containers and maps them to ports 1401 and 1402 on the host machine.

Now there are two instances of SQL Server running in separate containers. Clients can connect to each SQL Server instance by using the IP address of the Docker host and the port number for the container.

Create a customized container

It is possible to create your own Dockerfile to create a customized SQL Server container. For more information, see a demo that combines SQL Server and a Node application. If you do create your own Dockerfile, be aware of the foreground process, because this process controls the life of the container. If it exits, the container will shutdown. For example, if you want to run a script and start SQL Server, make sure that the SQL Server process is the right-most command. All other commands are run in the background. The following command illustrates this inside a Dockerfile:

If you reversed the commands in the previous example, the container would shutdown when the do-my-sql-commands.sh script completes.

Persist your data

Your SQL Server configuration changes and database files are persisted in the container even if you restart the container with docker stop and docker start. However, if you remove the container with docker rm, everything in the container is deleted, including SQL Server and your databases. The following section explains how to use data volumes to persist your database files even if the associated containers are deleted.

Important

For SQL Server, it is critical that you understand data persistence in Docker. In addition to the discussion in this section, see Docker's documentation on how to manage data in Docker containers.

Mount a host directory as data volume

The first option is to mount a directory on your host as a data volume in your container. To do that, use the docker run command with the -v <host directory>:/var/opt/mssql flag. This allows the data to be restored between container executions.

This technique also enables you to share and view the files on the host outside of Docker.

Important

Host volume mapping for Docker on Windows does not currently support mapping the complete /var/opt/mssql directory. However, you can map a subdirectory, such as /var/opt/mssql/data to your host machine.

Important

Host volume mapping for Docker on Mac with the SQL Server on Linux image is not supported at this time. Use data volume containers instead. This restriction is specific to the /var/opt/mssql directory. Reading from a mounted directory works fine. For example, you can mount a host directory using -v on Mac and restore a backup from a .bak file that resides on the host.

Use data volume containers

The second option is to use a data volume container. You can create a data volume container by specifying a volume name instead of a host directory with the -v parameter. The following example creates a shared data volume named sqlvolume.

Note

This technique for implicitly creating a data volume in the run command does not work with older versions of Docker. In that case, use the explicit steps outlined in the Docker documentation, Creating and mounting a data volume container.

Even if you stop and remove this container, the data volume persists. You can view it with the docker volume ls command.

If you then create another container with the same volume name, the new container uses the same SQL Server data contained in the volume.

To remove a data volume container, use the docker volume rm command.

Warning

If you delete the data volume container, any SQL Server data in the container is permanently deleted.

Backup and restore

In addition to these container techniques, you can also use standard SQL Server backup and restore techniques. You can use backup files to protect your data or to move the data to another SQL Server instance. For more information, see Backup and restore SQL Server databases on Linux.

Warning

If you do create backups, make sure to create or copy the backup files outside of the container. Otherwise, if the container is removed, the backup files are also deleted.

Execute commands in a container

If you have a running container, you can execute commands within the container from a host terminal.

To get the container ID run:

To start a bash terminal in the container run:

Now you can run commands as though you are running them at the terminal inside the container. When finished, type exit. This exits in the interactive command session, but your container continues to run.

Copy files from a container

To copy a file out of the container, use the following command:

Example:

Copy files into a container

To copy a file into the container, use the following command:

Example:

Configure the timezone

To run SQL Server in a Linux container with a specific timezone, configure the TZ environment variable. To find the right timezone value, run the tzselect command from a Linux bash prompt:

After selecting the timezone, tzselect displays output similar to the following:

You can use this information to set the same environment variable in your Linux container. The following example shows how to run SQL Server in a container in the Americas/Los_Angeles timezone:

Run a specific SQL Server container image

There are scenarios where you might not want to use the latest SQL Server container image. To run a specific SQL Server container image, use the following steps:

Identify the Docker tag for the release you want to use. To view the available tags, see the mssql-server-linux Docker hub page.
Pull the SQL Server container image with the tag. For example, to pull the RC1 image, replace <image_tag> in the following command with rc1.
To run a new container with that image, specify the tag name in the docker run command. In the following command, replace <image_tag> with the version you want to run.

These steps can also be used to downgrade an existing container. For example, you might want to rollback or downgrade a running container for troubleshooting or testing. To downgrade a running container, you must be using a persistence technique for the data folder. Follow the same steps outlined in the upgrade section, but specify the tag name of the older version when you run the new container.

Check the container version

If you want to know the version of SQL Server in a running docker container, run the following command to display it. Replace <Container ID or name> with the target container ID or name. Replace <YourStrong!Passw0rd> with the SQL Server password for the SA login.

You can also identify the SQL Server version and build number for a target docker container image. The following command displays the SQL Server version and build information for the mcr.microsoft.com/mssql/server:2017-latest image. It does this by running a new container with an environment variable PAL_PROGRAM_INFO=1. The resulting container instantly exits, and the docker rm command removes it.

The previous commands display version information similar to the following output:

Upgrade SQL Server in containers

To upgrade the container image with Docker, first identify the tag for the release for your upgrade. Pull this version from the registry with the docker pull command:

This updates the SQL Server image for any new containers you create, but it does not update SQL Server in any running containers. To do this, you must create a new container with the latest SQL Server container image and migrate your data to that new container.

Make sure you are using one of the data persistence techniques for your existing SQL Server container. This enables you to start a new container with the same data.
Stop the SQL Server container with the docker stop command.
Create a new SQL Server container with docker run and specify either a mapped host directory or a data volume container. Make sure to use the specific tag for your SQL Server upgrade. The new container now uses a new version of SQL Server with your existing SQL Server data.
Important
Upgrade is only supported between RC1, RC2, and GA at this time.
Verify your databases and data in the new container.
Optionally, remove the old container with docker rm.

Build and run non-root SQL Server 2017 containers

Follow the steps below to build a SQL Server 2017 container that starts up as the mssql(non-root) user.

Note

SQL Server 2019 containers automatically start up as non-root, so the following steps only apply to SQL Server 2017 containers, which start as root by default.

Download the sample dockerfile for non-root SQL Server Container and save it as dockerfile.
Run the following command in the context of the dockerfile directory to build the non-root SQL Server container:

Start the container.

Note

The --cap-add SYS_PTRACE flag is required for non-root SQL Server containers to generate dumps for troubleshooting purposes.

Check that the container is running as non-root user:

docker exec into the container.

Run whoami which will return the user running within the container.

Run container as a different non-root user on the host

To run the SQL Server container as a different non-root user, add the -u flag to the docker run command. The non-root container has the restriction that it must run as part of the root group unless a volume is mounted to '/var/opt/mssql' that the non-root user can access. The root group doesn’t grant any extra root permissions to the non-root user.

Run as a user with a UID 4000

You can start SQL Server with a custom UID. For example, the command below starts SQL Server with UID 4000:

Warning

Ensure that the SQL Server container has a named user such as 'mssql' or 'root' or SQLCMD will not be able to run within the container. You can check if the SQL Server container is running as a named user by running whoami within the container.

Run the non-root container as the root user

You can run the non-root container as the root user if required. This would also grant all file permissions automatically to the container because it is higher privilege.

Run as a user on your host machine

You can start SQL Server with an existing user on the host machine with the following command:

Run as a different user and group

You can start SQL Server with a custom user and group. In this example, the mounted volume has permissions configured for the user or group on the host machine.

Configure persistent storage permissions for non-root containers

To allow the non-root user to access DB files that are on mounted volumes, ensure that the user/group you run the container under can touch the persistent file storage.

You can get the current ownership of the database files with this command.

Run one of the following commands if SQL Server does not have access to persisted database files.

Grant the root group r/w access to the DB files

Grant the root group permissions to the following directories so that the non-root SQL Server container has access to database files.

Set the non-root user as the owner of the files.

This can be the default non-root user, or any other non-root user you’d like to specify. In this example, we set UID 10001 as the non-root user.

Change the default file location

Add the MSSQL_DATA_DIR variable to change your data directory in your docker run command, then mount a volume to that location that your container’s user has access to.

Troubleshooting

The following sections provide troubleshooting suggestions for running SQL Server in containers.

Docker command errors

If you get errors for any docker commands, make sure that the docker service is running, and try to run with elevated permissions.

For example, on Linux, you might get the following error when running docker commands:

If you get this error on Linux, try running the same commands prefaced with sudo. If that fails, verify the docker service is running, and start it if necessary.

On Windows, verify that you are launching PowerShell or your command-prompt as an Administrator.

SQL Server container startup errors

If the SQL Server container fails to run, try the following tests:

If you get an error such as 'failed to create endpoint CONTAINER_NAME on network bridge. Error starting proxy: listen tcp 0.0.0.0:1433 bind: address already in use.', then you are attempting to map the container port 1433 to a port that is already in use. This can happen if you're running SQL Server locally on the host machine. It can also happen if you start two SQL Server containers and try to map them both to the same host port. If this happens, use the -p parameter to map the container port 1433 to a different host port. For example:

If you get an error such as 'Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get http://%2Fvar%2Frun%2Fdocker.sock/v1.30tdout=1&tail=all: dial unix /var/run/docker.sock: connect: permission denied' when trying to start a container, then add your user to the docker group in Ubuntu. Then logout and login again as this change will affect new sessions.
Check to see if there are any error messages from container.
Make sure that you meet the minimum memory and disk requirements specified in the prerequisites section of the quickstart article.
If you are using any container management software, make sure it supports container processes running as root. The sqlservr process in the container runs as root.
Review the SQL Server setup and error logs.

Enable dump captures

If the SQL Server process is failing inside the container, you should create a new container with SYS_PTRACE enabled. This adds the Linux capability to trace a process, which is necessary for creating a dump file on an exception. The dump file can be used by support to help troubleshoot the problem. The following docker run command enables this capability.

SQL Server connection failures

If you can't connect to the SQL Server instance running in your container, try the following tests:

Make sure that your SQL Server container is running by looking at the STATUS column of the docker ps -a output. If not, use docker start <Container ID> to start it.
If you mapped to a non-default host port (not 1433), make sure you are specifying the port in your connection string. You can see your port mapping in the PORTS column of the docker ps -a output. For example, the following command connects sqlcmd to a container listening on port 1401:
If you used docker run with an existing mapped data volume or data volume container, SQL Server ignores the value of MSSQL_SA_PASSWORD. Instead, the pre-configured SA user password is used from the SQL Server data in the data volume or data volume container. Verify that you are using the SA password associated with the data you're attaching to.
Review the SQL Server setup and error logs.

SQL Server Availability Groups

If you are using Docker with SQL Server Availability Groups, there are two additional requirements.

Map the port that is used for replica communication (default 5022). For example, specify -p 5022:5022 as part of your docker run command.
Explicitly set the container host name with the -h YOURHOSTNAME parameter of the docker run command. This host name is used when you configure your Availability Group. If you don't specify it with -h, it defaults to the container ID.

SQL Server setup and error logs

You can look at the SQL Server setup and error logs in /var/opt/mssql/log. If the container is not running, first start the container. Then use an interactive command-prompt to inspect the logs.

From the bash session inside your container, run the following commands:

Tip

If you mounted a host directory to /var/opt/mssql when you created your container, you can instead look in the log subdirectory on the mapped path on the host.

Next steps

Get started with SQL Server 2017 container images on Docker by going through the quickstart.

Also, see the mssql-docker GitHub repository for resources, feedback, and known issues.