add db2 setup guide

Author: gilsegment

src/connections/reverse-etl/reverse-etl-source-setup-guides/db2-setup.md

@@ -0,0 +1,70 @@
+---
+title: DB2 Reverse ETL Setup
+---
+
+Set up DB2 as your Reverse ETL source.
+
+At a high level, when you set up DB2 for Reverse ETL, the configured database user must have read permissions on any tables involved in the query, and write permissions on a managed schema (`SEGMENT_REVERSE_ETL`) that Segment uses to track sync progress. Authentication is handled through username and password credentials configured in the Segment app.
+
+
+
+## Required permissions
+
+In order to run a Reverse-ETL sync in a DB2 warehouse, Segment needs the following permissions:
+
+1. **Permission to read from all tables used in the model** (i.e., the tables included in your SELECT query).
+2. **Permission to create and manage a schema** for tracking sync metadata.
+
+
+> info "Use a dedicated user for Segment"
+> It's recommended to create a dedicated DB2 user for Segment with access limited to only the relevant schemas and tables.
+
+1. Open the Db2 warehouse and navigate to  **Administration > User management**.
+2. Click **Add**.
+3. Create a new user account with *user* privileges. Make sure you save the username and password, as these are required to set up the Segment configuration in a later step.
+
+
+> info ""
+> The `SEGMENT_REVERSE_ETL` schema will be created and managed by Segment to track the status of each sync. 
+> You can also choose to create this schema yourself by running: 
+> `CREATE SCHEMA SEGMENT_REVERSE_ETL` 
+> and explicitly grant Segment privileges on it.
+
+
+
+Run the below SQL commands to grant Segment the required permissions:
+
+```sql
+-- Grant permissions to create manage objects within the SEGMENT_REVERSE_ETL schema
+GRANT CREATEIN, DROPIN ON SCHEMA SEGMENT_REVERSE_ETL TO USER <username>;
+GRANT CREATETAB ON DATABASE TO USER <username>;
+
+-- Grant read access on each table used in the model
+GRANT SELECT ON TABLE <schema_name>.<table_name> TO USER <username>;
+```
+
+
+## Set up guide
+
+To set up DB2 as your Reverse ETL source:
+
+1. Make sure your DB2 database is network-accessible from [Segment's IPs](/docs/connections/storage/warehouses/faq/#which-ips-should-i-allowlist).
+2. Open [your Segment workspace](https://app.segment.com/workspaces){:target="_blank"}.
+3. Navigate to **Connections > Sources** and select the **Reverse ETL** tab.
+4. Click **+ Add Reverse ETL source**.
+5. Select **DB2** and click **Add Source**.
+6. Enter the configuration settings for your DB2 source:
+  * Hostname: `<hostname>`
+  * Port: `<port>` (default)
+  * Database: `<db_name>`
+  * Username: `<segment_db2_user>`
+  * Password: `<password>`
+  * Schema [optional]: If not specified, Segment will use the user’s default schema
+7. Click **Test Connection** to validate the setup.
+8. If the connection is successful, click **Add source**.
+
+> warning ""
+> Segment only supports user/password authentication for DB2.
+> Ensure that your DB2 instance is configured to allow remote connections and the user has the necessary permissions.
+
+After you've successfully added your DB2 source, [add a model](/docs/connections/reverse-etl/setup/#step-2-add-a-model) and follow the rest of the steps in the Reverse ETL setup guide.