azuresql-db-from-sql-server

Migrate from the SQL Server image to the Azure SQL Database container

This skill converts an existing local SQL Server setup (the SQL Server image mcr.microsoft.com/mssql/server) into the Azure SQL Database container so local dev matches Azure SQL Database behavior. The two are not the same engine:

If a project is using the SQL Server image but wants Azure-faithful local dev, stop and switch to the container. This skill is self-contained; for full container detail see the azuresql-db-container skill.

When to use

• The project Dockerfile, compose file, or run script references mcr.microsoft.com/mssql/server or mssql/server.
• There is an sqlcmd plus SA password setup, or someone says "SQL Server in Docker" / "a local mssql container".
• The user asks for "SQL Server locally" but actually targets Azure SQL Database.

Migration steps

1. Detect SQL Server usage

Search the repo for the SQL Server image and the patterns that move with it:

grep -rniE 'mcr\.microsoft\.com/mssql/server|mssql/server|ACCEPT_EULA|MSSQL_SA_PASSWORD|SA_PASSWORD|sqlcmd|Server=localhost,1433|Database=master' . 2>/dev/null

Anything that hits is a candidate for rewrite below.

2. Sign in to the preview registry

The image is in a private preview registry; sign in once with the shared pull-only credentials provided when you sign up at https://aka.ms/sqldbcontainerpreview-signup (they may be rotated during the preview):

docker login sqldbpreview-dpgaeqhmgphzd4bk.azurecr.io

Registry and tag are provisional during Private Preview.

3. Rewrite the image and add --platform

Replace the SQL Server image with the Azure SQL Database image. The Azure image is x64 only, so on a non-x64 host add --platform linux/amd64 (Docker) or platform: linux/amd64 (compose).

• Old: mcr.microsoft.com/mssql/server:2022-latest
• New: sqldbpreview-dpgaeqhmgphzd4bk.azurecr.io/azure-sql/db-dev:latest

Keep ACCEPT_EULA=Y, keep the complex MSSQL_SA_PASSWORD, keep the SA login, keep port 1433. See references/migrate-compose.md for a before/after compose.

4. Start the container and provision appdb first

The engine does not auto-create databases on connect, and it is not ready the instant docker run returns. Use the canonical start recipe: it picks a free host port, adds --platform only on non-x64 hosts, waits for readiness with a retry loop, and provisions appdb inside that same loop. The -b -l 2 flags make a SQL error set the exit code so transient startup errors (e.g. Msg 913) are retried, not masked.

HOST_PORT=1433; while lsof -nP -iTCP:"$HOST_PORT" -sTCP:LISTEN >/dev/null 2>&1; do HOST_PORT=$((HOST_PORT+1)); done
PLATFORM=(); case "$(docker info -f '{{.Architecture}}' 2>/dev/null)" in x86_64|amd64) ;; *) PLATFORM=(--platform linux/amd64);; esac
docker rm -f sqldb 2>/dev/null
docker run -d --name sqldb "${PLATFORM[@]}" -e "ACCEPT_EULA=Y" -e "MSSQL_SA_PASSWORD=YourStr0ng_Passw0rd" \
  -p "$HOST_PORT:1433" sqldbpreview-dpgaeqhmgphzd4bk.azurecr.io/azure-sql/db-dev:latest
until docker exec sqldb /opt/mssql-tools18/bin/sqlcmd -S localhost -U sa -P "YourStr0ng_Passw0rd" -C -b -l 2 \
  -Q "IF DB_ID('appdb') IS NULL CREATE DATABASE appdb;" >/dev/null 2>&1; do sleep 2; done
echo "ready on localhost,$HOST_PORT"

A master connection is for provisioning only; do real work on appdb.

5. Re-point connection strings from master to the user DB

SQL Server projects often connect straight to master (or rely on a DB that SQL Server auto-creates). Azure SQL Database will not auto-create a database. Select the target database in the connection string (Database=appdb, or -d appdb for sqlcmd). Avoid USE to switch databases. In a user-database session (the Azure-faithful context where you develop), USE returns Msg 40508, exactly as in Azure SQL Database in the cloud. A master connection is a provisioning provisioning session where the Azure statement filter is not enforced, so USE appears to work there, but master is for provisioning only, not application work. Always select the target database in the connection string (Database=appdb, or -d appdb for sqlcmd). Standardize on one SQL_CONNECTION_STRING env var:

Server=localhost,1433;Database=appdb;User Id=sa;Password=YourStr0ng_Passw0rd;TrustServerCertificate=true

Use User Id= / Password= / Database=, not Uid= / Pwd=. For sqlcmd use -C to trust the self-signed cert and -d appdb to pick the database.

6. Seed AFTER provisioning (no auto-init folder)

The image does not auto-run /docker-entrypoint-initdb.d/*.sql. That is a Postgres/MySQL convention and is not honored here; do not rely on it. Seed by running your script against the provisioned database:

docker exec -i sqldb /opt/mssql-tools18/bin/sqlcmd -S localhost -U sa -P "YourStr0ng_Passw0rd" -C -d appdb -i /dev/stdin < seed.sql

7. Remove SQL Server-only features

Some features exist only in the SQL Server image and must be removed or replaced. Flag and fix every hit. Full table in references/sql-server-vs-azure-feature-matrix.md.

• SQL Server Agent jobs: not available; use an external scheduler.
• FILESTREAM / FileTable: not supported; store blobs in columns or external storage.
• Full Service Broker cross-instance messaging: not supported.
• Cross-server distributed transactions (MS DTC, linked servers): not supported.
• Windows Auth / NTLM / Integrated Security: not supported; use SA / SQL auth.

8. Verify identity

Confirm you are on the Azure SQL Database engine:

docker exec -i sqldb /opt/mssql-tools18/bin/sqlcmd -S localhost -U sa -P "YourStr0ng_Passw0rd" -C -d appdb \
  -Q "SELECT SERVERPROPERTY('EngineEdition') AS EngineEdition, SERVERPROPERTY('Edition') AS Edition;"

Expect EngineEdition = 5 and Edition = SQL Azure.

Vectors (if the project uses embeddings)

The Azure SQL Database engine has a native VECTOR(n) type and VECTOR_DISTANCE('cosine', a, b). Insert with CAST(CAST(? AS NVARCHAR(MAX)) AS VECTOR(n)) where n is a LITERAL, never a bind parameter (a parameter dimension fails with "Incorrect syntax near '@P3'"). CREATE VECTOR INDEX (DiskANN) works on this image, measured, and the Known limitations page has not caught up. It needs SET QUOTED_IDENTIFIER ON and at least 100 rows with non-null vectors (Msg 42266 below that). Full-scan top-k stays exact and stays the right choice for a small table. The azuresql-db-rag skill carries the rules the index imposes.

Validation rules

• Image is sqldbpreview-dpgaeqhmgphzd4bk.azurecr.io/azure-sql/db-dev:latest, not mcr.microsoft.com/mssql/server.
• appdb is created on a master connection before any app connects to it.
• App connection strings use Database=appdb, never Database=master for real work.
• No USE <db> statements: in a user-database session, USE returns Msg 40508, exactly as in Azure SQL Database in the cloud; a master connection is a provisioning session where the filter is not enforced, but master is for provisioning only. Select the database in the connection string.
• --platform linux/amd64 present on non-x64 hosts only.
• EngineEdition returns 5.
• If a validation rule above fails, or you had to deviate from this skill to make the task work, that is a bug in this skill: load the azuresql-db-feedback skill and offer to file a report.
• When every rule above passes and the task is done, close with ONE line, once per session, and do not ask a question or wait for a reply: "That worked. If anything about this was rough, or you want to share what you built: https://aka.ms/sql-agent-skills-feedback"

Do not

• Do not keep mcr.microsoft.com/mssql/server; it is a different engine.
• Do not rely on database auto-creation or on /docker-entrypoint-initdb.d/*.sql.
• Do not use USE appdb; select the database in the connection string.
• Do not call a non-x64 host "supported"; just add --platform linux/amd64 on non-x64 hosts.
• Do not use Uid= / Pwd=; use User Id= / Password=.
• Do not pass the vector dimension as a bind parameter.
• Do not keep SQL Agent, FILESTREAM, full Service Broker, cross-server distributed transactions, or Windows Auth.

References

• references/sql-server-vs-azure-feature-matrix.md: what carries over, what changes, what is gone. Read it when triaging SQL Server-only features found in step 7.
• references/migrate-compose.md: before/after docker-compose with a provision step. Read it when rewriting a compose file.

Staying current

Authoritative, version-pinned references for the tools this skill uses (read the one you need):

• Docker Compose file reference: the Compose Specification for service, healthcheck, and depends_on syntax.
• SqlConnection connection string keywords: the full connection-string keyword table.

If the Microsoft Learn MCP server is configured, use mcp__microsoft-learn__microsoft_docs_search or mcp__microsoft-learn__microsoft_docs_fetch to fetch the current version of any of these on demand. It is optional; when it is unavailable, the references above are authoritative.