Absolutely! You can migrate your apps using Web Deploy without overwriting existing sites/apps on the target server, and merge the contents of both servers' Default Web Site instances safely. Here are step-by-step approaches tailored to your scenario:

1. Migrate Individual Apps (Recommended for Precision) #

Instead of migrating the entire Default Web Site from the source, export and import only the specific apps you need. This minimizes the risk of conflicting with target content:

Export from Source Server #

Use the msdeploy command to export a single app under Default Web Site:

msdeploy -verb:export -source:appHostConfig="Default Web Site/YourTargetApp" -dest:package="YourTargetApp.zip"

Replace YourTargetApp with the name of the app you want to move.

Import to Target Server #

On the target server, import the package while ensuring existing content isn't deleted:

msdeploy -verb:sync -source:package="YourTargetApp.zip" -dest:appHostConfig="Default Web Site/YourTargetApp" -enableRule:DoNotDeleteRule

• The -enableRule:DoNotDeleteRule flag is critical here: it tells Web Deploy to only add or update your migrated app and leave all existing target site/apps/files untouched.
• If the app name already exists on the target, you can either rename the imported app (e.g., Default Web Site/YourTargetApp_Migrated) or use the -skip rule to avoid overwriting it (see section 2).

2. Merge Entire Default Web Site Contents (Preserve Target Existing Items) #

If you need to sync the full Default Web Site from source to target but keep the target's existing content intact, use sync with targeted skip rules:

msdeploy -verb:sync -source:appHostConfig="Default Web Site" -dest:appHostConfig="Default Web Site",computerName=TargetServerName -enableRule:DoNotDeleteRule -skip:objectName=filePath,absolutePath="C:\inetpub\wwwroot\TargetExistingAppFolder" -skip:objectName=appHostConfig,keyAttribute="applicationPath",value="Default Web Site/TargetExistingApp"

Breakdown of key flags:

• -enableRule:DoNotDeleteRule: Prevents deletion of any existing content on the target.
• -skip:objectName=filePath: Skips specific directories/files on the target you want to protect (replace the path with your actual target folder).
• -skip:objectName=appHostConfig: Skips specific existing apps on the target by their application path.

3. GUI Approach (IIS Manager) #

If you prefer a visual interface instead of command line:

• Source Server: Right-click the app under Default Web Site → Deploy → Export Application Package. Save the zip file.
• Target Server: Right-click Default Web Site → Deploy → Import Application Package. Select your zip file.
  • In the import wizard, under Select the import options, check the box for Do not delete extra files on destination (this maps to the DoNotDeleteRule).
  • If the app name already exists on the target, you can choose to skip it or rename the imported app during setup.

Critical Pre-Migration Checks #

• Backup First: Always back up the target server's Default Web Site before making changes:

  msdeploy -verb:export -source:appHostConfig="Default Web Site" -dest:package="TargetDefaultSiteBackup.zip"
  

• Validate Dependencies: Ensure the target server has matching .NET versions, IIS features, and any custom components (like certificates or third-party modules) required by your migrated apps.
• Database Sync: If your apps rely on databases, migrate those separately (e.g., SQL Server backup/restore or data sync tools) to avoid overwriting target databases.

内容的提问来源于stack exchange，提问作者Syntax Error