Rescue mode¶
Overview¶
Rescue mode is a feature that can be used to boot a ramdisk for a tenant in case the machine is otherwise inaccessible. For example, if there’s a disk failure that prevents access to another operating system, rescue mode can be used to diagnose and fix the problem.
Support in ironic-python-agent images¶
Rescue is initiated when ironic-conductor sends the finalize_rescue
command to ironic-python-agent. A user rescue is created with a password
provided as an argument to this command. DHCP is then configured to
facilitate network connectivity, thus enabling a user to login to the machine
in rescue mode.
Warning
Rescue mode exposes the contents of the ramdisk to the tenant. Ensure that any rescue image you build does not contain secrets (e.g. sensitive clean steps, proprietary firmware blobs).
The below has information about supported images that may be built to use rescue mode.
CoreOS¶
The CoreOS image supports rescue mode when used with DHCP tenant networks. You may follow the normal process for building a CoreOS ironic-python-agent image to create an image that supports rescue mode.
After the finalize_rescue command completes, DHCP will be configured on all
network interfaces, and a rescue user will be created with the specified
rescue_password.
TinyIPA¶
The TinyIPA image supports rescue mode when used with DHCP tenant networks. No special action is required to build a TinyIPA image with this support.
After the finalize_rescue command completes, DHCP will be configured on all
network interfaces, and a rescue user will be created with the specified
rescue_password.
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