Merge pull request #235829 from hsinghjkaur/test

[PostgreSQL] - Add new article for error messages

Author: v-shils

articles/postgresql/TOC.yml

@@ -22,6 +22,8 @@
             href: migrate/how-to-migrate-single-to-flexible-portal.md
           - name: Single to Flexible server migration tool - Using CLI
             href: migrate/how-to-migrate-single-to-flexible-cli.md
+          - name: Common errors
+            href: migrate/common-errors-and-special-scenarios-fms.md
       - name: Migrate data with pg_dump and pg_restore
         href: single-server/how-to-migrate-using-dump-and-restore.md
         displayName: pg_dump, pg_restore

articles/postgresql/migrate/common-errors-and-special-scenarios-fms.md

@@ -0,0 +1,90 @@
+---
+title: "Common errors and special scenarios for PostgreSQL Single Server to Flexible using the FMS migration tool"
+description: Common errors and special scenarios for PostgreSQL Single Server to Flexible using the FMS migration tool.
+author: harmeet-singh
+ms.author: hasingh
+ms.reviewer: maghan
+ms.date: 05/01/2023
+ms.service: postgresql
+ms.topic: conceptual
+---
+
+# Common errors and special scenarios for PostgreSQL Single Server to Flexible using the FMS migration tool.
+
+This articles explains common errors and special scenarios for PostgreSQL Single Server to Flexible using the FMS migration tool. 
+
+## Custom DNS
+
+- Error message
+    Connecting to the Source DB server failed. ErrorMessage: Validation of one or more databases failed to run `select 1;` with exception 28000: The public network access on this server is disabled. Use the Private Endpoint inside your virtual network to connect to this server.
+
+- Root Cause
+
+    The VNet is, by default, not enabled for outbound connections when we use CustomDNS. Migration makes outbound calls, which cause the failure.
+
+- Mitigation/Resolution
+
+    While Microsoft is working on a fix as part of the product, customers can use one of the following mitigations to unblock:
+    Temporarily enable the public network access on the server
+    OR
+    Reach out to Microsoft, and we enable the server for outbound connections for the selected DNS addresses.
+
+## Allowlist extensions
+
+- Symptom
+    Error message appears as "Extensions plpgsql, pg_stat_statements, pg_buffercache aren't allowlisted on target server."
+
+    :::image type="content" source="media/common-errors-and-special-scenarios-fms/allow-list-extensions-common-errors-postgresql.png" alt-text="Screenshot of scenario for allow listing extensions." lightbox="media/common-errors-and-special-scenarios-fms/allow-list-extensions-common-errors-postgresql.png":::
+
+- Root Cause
+
+    The flexible server doesn't have extensions allow-listed by default and has to be manually allow-listed before migration/use.
+
+- Mitigation/Resolution
+
+    Customers need to go to the server parameters of the flexible server and allowlist all the extensions they intend to use. At least the ones mentioned in the error message should be allowed to be listed.
+
+## No pg_hba.conf entry for host
+
+- Error Message
+    Connecting to the Source DB server failed. ErrorMessage: Validation of one or more databases failed. Failed to run `select 1;` with exception 28000: no pg_hba.conf entry for host "xx.xx.xx.xx", the user "username," database "postgres," SSL on Parameter name: SourceDBServerResourceId.
+
+- Root Cause
+
+    The IP address isn't added to the firewall rules.
+
+- Mitigation/Resolution
+
+    Add IP addresses in the Firewall rules in the Networking tab of the Flex Server.
+
+    :::image type="content" source="media/common-errors-and-special-scenarios-fms/ip-addresses-common-errors-postgresql.png" alt-text="Screenshot of ip addresses." lightbox="media/common-errors-and-special-scenarios-fms/ip-addresses-common-errors-postgresql.png":::
+
+## Migration to Flex server with Burstable SKU isn't Supported
+
+- Error Message
+    Migration to Flex server with Burstable SKU isn't Supported.
+
+- Root Cause
+
+    By Design.
+
+- Mitigation/Resolution
+
+    Change the flexible server from Burstable to General Purpose or Memory Optimized by going to compute + storage tab on the left menu.
+
+## Cross-region migration isn't supported
+
+- Error Message
+    Cross-region migration isn't supported.
+
+- Root Cause
+
+    By Design.
+
+- Mitigation/Resolution
+
+    This feature is coming soon; in the meantime, only migrations within servers of the same region are supported.
+
+## Next steps
+
+- [Migration tool](concepts-single-to-flexible.md)