PowerShell脚本通过SSH配置iDRAC网络时变量失效问题求助

尝试通过PowerShell脚本在本地修改搭载iDRAC的服务器网络设置，单独执行命令可正常运行，但在脚本中使用变量时执行失败，报错信息如下：

ERROR: RAC947: Invalid object value specified. Make sure to specify the value depending on the type of object. For more information, see RACADM help.

怀疑是变量未被正确解析，相关脚本代码如下：

$idrac_iploopback = 169.254.0.1
$dns1 = 1.1.1.1
$dns1 = 8.8.8.8

$hosts_idrac = @{
    "HOSTNAME1" = @{"IP" = "192.168.1.200"; "MASK" = "255.255.255.0"; "GW" = "192.168.1.1"; "dns1" = $dns1; "dns2" = $dns2};
}
$idrac_ip_cust = $hosts_idrac.$servername.IP
$idrac_mask_cust = $hosts_idrac.$servername.MASK
$idrac_gw_cust = $hosts_idrac.$servername.GW
$idrac_dns1_cust = $hosts_idrac.$servername.dns1
$idrac_dns2_cust = $hosts_idrac.$servername.dns2

 #SSH connection with command input.
 ssh -o 'StrictHostKeyChecking no' root@$idrac_iploopback 'set iDRAC.IPv4.Address $($idrac_ip_cust)'
 ssh -o 'StrictHostKeyChecking no' root@$idrac_iploopback 'set iDRAC.IPv4.Netmask $($idrac_mask_cust)'
 ssh -o 'StrictHostKeyChecking no' root@$idrac_iploopback 'set iDRAC.IPv4.Gateway $($idrac_gw_cust)'
 ssh -o 'StrictHostKeyChecking no' root@$idrac_iploopback 'set iDRAC.IPv4.DHCPEnable 0'
 ssh -o 'StrictHostKeyChecking no' root@$idrac_iploopback 'set iDRAC.IPv4.DNSFromDHCP 0'
 ssh -o 'StrictHostKeyChecking no' root@$idrac_iploopback 'set iDRAC.IPv4.DNS1 $($idrac_dns1_cust)'
 ssh -o 'StrictHostKeyChecking no' root@$idrac_iploopback 'set iDRAC.IPv4.DNS2 $($idrac_dns2_cust)'

1. 核心问题：单引号字符串无法解析PowerShell变量 #

PowerShell中，单引号包裹的字符串不会展开变量，你当前ssh命令里的'set iDRAC.IPv4.Address $($idrac_ip_cust)'会直接把$($idrac_ip_cust)作为字面量传给iDRAC，而非变量对应的IP值，这是触发RAC947错误的主要原因。

解决方法：将ssh命令中的单引号改为双引号，让PowerShell解析变量后再传递给ssh：

ssh -o 'StrictHostKeyChecking no' root@$idrac_iploopback "set iDRAC.IPv4.Address $idrac_ip_cust"
ssh -o 'StrictHostKeyChecking no' root@$idrac_iploopback "set iDRAC.IPv4.Netmask $idrac_mask_cust"
ssh -o 'StrictHostKeyChecking no' root@$idrac_iploopback "set iDRAC.IPv4.Gateway $idrac_gw_cust"
# 其余命令同理修改引号

2. 修复未定义的变量问题 #

你的脚本中存在两处变量未定义/赋值错误：

• $dns2从未初始化，导致$hosts_idrac中的dns2 = $dns2值为$null，传递给iDRAC会触发无效值错误。需补充定义$dns2，比如$dns2 = 8.8.4.4。
• $servername未赋值，$hosts_idrac.$servername会返回$null，后续的$idrac_ip_cust等变量全为空值。需明确指定服务器名称，比如$servername = "HOSTNAME1"。

3. 替代实现：使用本地racadm命令（更可靠） #

如果本地安装了Dell官方的racadm工具，无需通过ssh执行命令，直接本地调用racadm更稳定，也避免字符串解析问题：

$idrac_iploopback = 169.254.0.1
$dns1 = 8.8.8.8
$dns2 = 8.8.4.4
$servername = "HOSTNAME1"

$hosts_idrac = @{
    "HOSTNAME1" = @{"IP" = "192.168.1.200"; "MASK" = "255.255.255.0"; "GW" = "192.168.1.1"; "dns1" = $dns1; "dns2" = $dns2};
}

$idrac_ip_cust = $hosts_idrac.$servername.IP
$idrac_mask_cust = $hosts_idrac.$servername.MASK
$idrac_gw_cust = $hosts_idrac.$servername.GW
$idrac_dns1_cust = $hosts_idrac.$servername.dns1
$idrac_dns2_cust = $hosts_idrac.$servername.dns2

# 使用racadm本地命令，需替换为你的iDRAC密码
racadm -r $idrac_iploopback -u root -p "your_idrac_password" set iDRAC.IPv4.Address $idrac_ip_cust
racadm -r $idrac_iploopback -u root -p "your_idrac_password" set iDRAC.IPv4.Netmask $idrac_mask_cust
racadm -r $idrac_iploopback -u root -p "your_idrac_password" set iDRAC.IPv4.Gateway $idrac_gw_cust
racadm -r $idrac_iploopback -u root -p "your_idrac_password" set iDRAC.IPv4.DHCPEnable 0
racadm -r $idrac_iploopback -u root -p "your_idrac_password" set iDRAC.IPv4.DNSFromDHCP 0
racadm -r $idrac_iploopback -u root -p "your_idrac_password" set iDRAC.IPv4.DNS1 $idrac_dns1_cust
racadm -r $idrac_iploopback -u root -p "your_idrac_password" set iDRAC.IPv4.DNS2 $idrac_dns2_cust

$idrac_iploopback = 169.254.0.1
$dns1 = 8.8.8.8
$dns2 = 8.8.4.4
$servername = "HOSTNAME1"

$hosts_idrac = @{
    "HOSTNAME1" = @{"IP" = "192.168.1.200"; "MASK" = "255.255.255.0"; "GW" = "192.168.1.1"; "dns1" = $dns1; "dns2" = $dns2};
}

$idrac_ip_cust = $hosts_idrac.$servername.IP
$idrac_mask_cust = $hosts_idrac.$servername.MASK
$idrac_gw_cust = $hosts_idrac.$servername.GW
$idrac_dns1_cust = $hosts_idrac.$servername.dns1
$idrac_dns2_cust = $hosts_idrac.$servername.dns2

# 修正引号后的SSH命令
ssh -o 'StrictHostKeyChecking no' root@$idrac_iploopback "set iDRAC.IPv4.Address $idrac_ip_cust"
ssh -o 'StrictHostKeyChecking no' root@$idrac_iploopback "set iDRAC.IPv4.Netmask $idrac_mask_cust"
ssh -o 'StrictHostKeyChecking no' root@$idrac_iploopback "set iDRAC.IPv4.Gateway $idrac_gw_cust"
ssh -o 'StrictHostKeyChecking no' root@$idrac_iploopback "set iDRAC.IPv4.DHCPEnable 0"
ssh -o 'StrictHostKeyChecking no' root@$idrac_iploopback "set iDRAC.IPv4.DNSFromDHCP 0"
ssh -o 'StrictHostKeyChecking no' root@$idrac_iploopback "set iDRAC.IPv4.DNS1 $idrac_dns1_cust"
ssh -o 'StrictHostKeyChecking no' root@$idrac_iploopback "set iDRAC.IPv4.DNS2 $idrac_dns2_cust"

内容的提问来源于stack exchange，提问作者Eddy