White Papers

Version 2.0.0 11
7 Auto-Discovery Implementation Alternatives
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If more than one discovery method is used simultaneously, the provisioning server address acquisition
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sequence is the following:
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1. Provisioning Server Set in iDRAC settings
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2. DHCP Vendor Scope Option
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3. DNS SRV record
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4. Default Host A record
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7.1 Manually Setting the Provisioning Server
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This is not zero touch but if DHCP and DNS services are not available, or if there is a desire to skip the
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discovery process, the iDRAC can have the provisioning server set manually. This can be done in either
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the iDRAC settings page (Cntrl E on 11
th
generation servers and F2 on 12
th
generation servers) or the
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System Services/Lifecycle Controller Page (F10) during boot. For more information on manually setting
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the provisioning server see Checking iDRAC Configuration Settings (11
th
generation servers)
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7.2 Provide Provisioning Server information within DHCP scope options
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To enable the Auto-Discovery feature, the default iDRAC NIC setting out of the box is required to be
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DHCP rather than statically assigned IP address. The iDRAC sets a vendor class identifier (option 60) in
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the DHCPREQUEST message to LifecycleController. This enables DHCP servers to optionally respond
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uniquely to the iDRAC.
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There are three possible valid responses and outcomes to the DHCPREQUEST sent by the iDRAC:
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 The request times out and an IP address is unobtainable. The iDRAC retains its DHCP setting
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indefinitely with no login credentials. To change this setting, you would have to be physically
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present at the server.
2
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 The DHCP server responds, but does not provide any option 43 data. In this case the iDRAC
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attempts to locate a server using DNS (see Figure 2).
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 Option 43 data is present and includes an IP address and or hostname to use for the handshake.
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The data will have a format that can easily be set up on a Windows or Linux DHCP server. The
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sub option number for option 43 is “1” (see RFC2132) and has this format:
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(FQDN | Hostname | IP Address)[:port] [, (FQDN | Hostname | IP Address)[:port] ] [, …]
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NOTE: If the iDRAC is using a custom trusted CA to validate the provisioning provisioning server,
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the value of sub option 1 for that provisioning server must match the CN value in the provisioning
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server certificate or the TLS connection will fail. For example if the CN=provserv1.dell.com the
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sub option 1 value must also be provserv1.dell.com
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Where either the hostname or the ipaddress are provided, followed optionally by a port number.
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Examples of string values are as follows (no spaces allowed) :
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 Provisioning.dell.com:4433 (resolve using DNS, TCP port specified.)
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2
The iDRAC Configuration Utility using ctrl-E during boot up provides an opportunity for a static IP address and user
credentials to be specified. Also, local RACADM commands can be used.