Configuring The Boot Stack - Cisco ASR 5000 Series Administration Manual

Software Management Operations

Configuring the Boot Stack

The boot stack consists of a prioritized listing of operating system software image-to-CLI configuration file
associations. These associations determine the software image and configuration file that gets loaded during
system startup or upon a reload/reboot. Though multiple associations can be configured, the system uses the
association with the highest priority. In the event that there is an error processing this association (for example,
one of the files cannot be located), the system attempts to use the association with the next highest priority.
Priorities range from 1 to 100, with 1 being the highest priority. The maximum number of boot stack entries
that may be configured in the boot.sys file is 10.
Boot stack information is contained in the boot.sys file, described in
120. In addition to boot stack entries, the boot.sys file contains any configuration commands required to define
the system boot method as explained in the section that follows.
System Boot Methods
The local-boot method uses software image and configuration files stored locally on the system. On system
startup or reboot, the system looks on one of its local devices or /hd-raid for the specific software image and
accompanying configuration text file. When using the local-booting method, you only need to configure boot
stack parameters.
The system can also be configured to obtain its software image from a specific external network server while
it is paired with a configuration text file that resides on the system. When using network booting, you need
to configure the following:
• Boot stack parameters, which define the files to use and in what priority to use them
• Boot interface and network parameters defining the remote management LAN interface and the methods
• Network booting delay time and optional name server parameters defining the delay period (in seconds)
Detailed information on how to configure the system to use the network booting method appears in
Booting Configuration Requirements, on page 127
Viewing the Current Boot Stack
To view the boot stack entries contained in the boot.sys file run the Exec mode show boot command.
Important
The examples below shows the command output for a local booting configuration. Notice that in these examples
both the image file (operating system software) and configuration file (CLI commands) are located on the
/flash device.
to use to reach the external network server
to allow for network communications to be established, and the IP address of any Domain Name Service
(DNS) name server that may be used
Operator and inspector-level users can execute the show boot command.
Understanding the boot.sys File, on page
ASR 5500 System Administration Guide, StarOS Release 21.4
Configuring the Boot Stack
Network
125