CA Backup and Restore Windows PowerShell cmdlets
Author: Justin Turner, Senior Support Escalation Engineer with the Windows group
Note
This content is written by a Microsoft customer support engineer, and is intended for experienced administrators and systems architects who are looking for deeper technical explanations of features and solutions in Windows Server 2012 R2 than topics on TechNet usually provide. However, it has not undergone the same editing passes, so some of the language may seem less polished than what is typically found on TechNet.
Overview
The ADCSAdministration Windows PowerShell module was introduced in Window Server 2012. Two new cmdlets were added to this module in Window Server 2012 R2 to support the Backup and Restore of a CA.
Backup-CARoleService
Restore-CARoleService
Backup-CARoleService
ADCSAdministration Cmdlet: Backup-CARoleService
| Arguments - Bold arguments are required | Description |
|---|---|
| -Path | - String - location to save the backup - This is the only unnamed parameter - positional parameter Example: Backup-CARoleService.-Path c:\adcsbackup1 Backup-CARoleService c:\adcsbackup2 |
| -KeyOnly | - Backup the CA certificate without the database Example: Backup-CARoleService c:\adcsbackup3 -KeyOnly |
| -Password | - Specifies the password to protect CA certificates and private keys - Must be a secure string - Not valid with the -DatabaseOnly parameter Example: Backup-CARoleService c:\adcsbackup4 -Password (Read-Host -prompt "Password:" -AsSecureString) Backup-CARoleService c:\adcsbackup5 -Password (ConvertTo-SecureString "Pa55w0rd!" -AsPlainText -Force) |
| -DatabaseOnly | - Backup the database without the CA certificate Backup-CARoleService c:\adcsbackup6 -DatabaseOnly |
| -Force | 1. Allows you to overwrite the backup that pre-exists in the location specified in the -Path parameter Backup-CARoleService c:\adcsbackup1 -Force |
| -Incremental | - Perform an incremental backup Backup-CARoleService c:\adcsbackup7 -Incremental |
| -KeepLog | 1. Instructs the command to keep log files. If the switch isn't specified, log files are truncated by default except in the Incremental scenario Backup-CARoleService c:\adcsbackup7 -KeepLog |
-Password <Secure String>
If the -Password parameter is used, the supplied password must be a secure string. Use the Read-Host cmdlet to launch an interactive prompt for secure password entry, or use the ConvertTo-SecureString cmdlet to specify the password in-line.
Review the following examples
Specifying a secure string for the Password parameter using Read-Host
Backup-CARoleService c:\adcsbackup4 -Password (Read-Host -prompt "Password:" -AsSecureString)
Specifying a secure string for the Password parameter using ConvertTo-SecureString
Backup-CARoleService c:\adcsbackup5 -Password (ConvertTo-SecureString "Pa55w0rd!" -AsPlainText -Force)
Restore-CARoleService
ADCSAdministration Cmdlet: Restore-CARoleService
| Arguments - Bold arguments are required | Description |
|---|---|
| -Path | - String - location to restore backup from - This is the only unnamed parameter - positional parameter Example: Restore-CARoleService.-Path c:\adcsbackup1 -Force Restore-CARoleService c:\adcsbackup2 -Force |
| -KeyOnly | - Restore the CA certificate without the database - Must be specified if the backup was taken with the -KeyOnly option Example: Restore-CARoleService c:\adcsbackup3 -KeyOnly -Force |
| -Password | - Specifies the password of the CA certificates and private keys - Must be a secure string Example: Restore-CARoleService c:\adcsbackup4 -Password (read-host -prompt "Password:" -AsSecureString) -Force Restore-CARoleService c:\adcsbackup5 -Password (ConvertTo-SecureString "Pa55w0rd!" -AsPlainText -Force) -Force |
| -DatabaseOnly | - Restore the database without the CA certificate Restore-CARoleService c:\adcsbackup6 -DatabaseOnly |
| -Force | - Allows you to overwrite the preexisting keys - Is an optional parameter but when restoring in-place, it is likely required Restore-CARoleService c:\adcsbackup1 -Force |
Issues
A nonpassword protected backup is taken if the ConvertTo-SecureString function fails while using the Backup-CARoleService with the -Password parameter.
Common errors
| Action | Error | Comment |
|---|---|---|
| Restore-CARoleService C:\ADCSBackup | Restore-CARoleService : The process can't access the file because it's being used by another process. (Exception from HRESULT: 0x80070020) |
Stop the Active Directory Certificate Services service prior to running the Restore-CARoleService cmdlet |
| Restore-CARoleService C:\ADCSBackup | Restore-CARoleService : The directory isn't empty. (Exception from HRESULT: 0x80070091) | Use the -Force parameter to overwrite preexisting keys |
| Backup-CARoleService C:\ADCSBackup -Password (Read-Host -Prompt "Password:" -AsSecureString) -DatabaseOnly | Backup-CARoleService : Parameter set can't be resolved using the specified named parameters. | The -Password parameter is only used to password protect private keys and is therefore invalid when you aren't backing them up |
| Restore-CARoleService C:\ADCSBack15 -Password (Read-Host -Prompt "Password:" -AsSecureString) -DatabaseOnly | Restore-CARoleService : Parameter set can't be resolved using the specified named parameters. | The -Password parameter is only used to password protect private keys and is therefore invalid when you aren't restoring them |
| Restore-CARoleService C:\ADCSBack14 -Password (Read-Host -Prompt "Password:" -AsSecureString) | Restore-CARoleService : The system can't find the file specified. (Exception from HRESULT: 0x80070002) | The path specified doesn't contain a valid database backup. Perhaps the path is invalid or the backup was taken with the -KeysOnly option? |
Additional Resources
Active Directory Certificate Services Migration Guide
Backing up a CA database and private key
Restoring the CA database and configuration on the destination server
Try This: Backup the CA in your lab using Windows PowerShell
Use the commands in this lesson to backup the CA database and private key secured with a password.
Hold off on the restore of the CA at this time.