Base Roll: Users Guide: 
| ||
|---|---|---|
| Prev | Chapter 7. Advanced Tasks | Next |
There are two scenarios in which you need to add extra kernel boot parameters: 1) during installation, and 2) during normal boot. For both scenarios, will use the example of adding the kernel boot parameter: "ucsd=rocks".
The boot action of a node is controlled by the Rocks command line. For example, the following lists what the nodes will do on their next PXE boot:
# rocks list host pxeboot HOST ACTION olympic: ------ compute-0-0: os |
We see that compute-0-0 will boot the "os", that is, it will boot off its local disk. Another common action is "install" which means the node will boot the installation kernel and install itself on the node's next PXE boot.
To list all the possible boot actions for a compute node, execute:
# rocks list host pxeaction compute-0-0 ACTION COMMAND ARGS install kernel vmlinuz append ks initrd=initrd.img ramdisk_size=150000 lang= devfs=nomount pxe kssendmac selinux=0 noipv6 install headless kernel vmlinuz append ks initrd=initrd.img ramdisk_size=150000 lang= devfs=nomount pxe kssendmac selinux=0 noipv6 headless vnc memtest kernel memtest ---------------------------------------------------------------------- os localboot 0 ---------------------------------------------------------------------- pxeflash kernel memdisk bigraw append initrd=pxeflash.img keeppxe rescue kernel vmlinuz append ks initrd=initrd.img ramdisk_size=150000 lang= devfs=nomount pxe kssendmac selinux=0 noipv6 rescue |
To change a node's boot action to "install", execute:
# rocks set host pxeboot compute-0-0 action="install" |
Then we see that correct boot action has been applied:
# rocks list host pxeboot HOST ACTION olympic: ------- compute-0-0: install |
Now to add or change the kernel boot parameters for the installing kernel, we'll need to add or modify an action. We'll create a new action called "install ucsd" and add our boot flag "ucsd=rocks" to the end of the kernel boot parameters:
# rocks add host pxeaction action="install ucsd" command="kernel vmlinuz \ args="append ks initrd=initrd.img ramdisk_size=150000 lang= devfs=nomount \ pxe kssendmac selinux=0 noipv6 ucsd=rocks" |
We now see that "install ucsd" is an available action:
# rocks list host pxeaction compute-0-0 ACTION COMMAND ARGS install kernel vmlinuz append ks initrd=initrd.img ramdisk_size=150000 lang= devfs=nomount pxe kssendmac selinux=0 noipv6 install headless kernel vmlinuz append ks initrd=initrd.img ramdisk_size=150000 lang= devfs=nomount pxe kssendmac selinux=0 noipv6 headless vnc install ucsd kernel vmlinuz append ks initrd=initrd.img ramdisk_size=150000 lang= devfs=nomount pxe kssendmac selinux=0 noipv6 ucsd=rocks memtest kernel memtest --------------------------------------------------------------- os localboot 0 --------------------------------------------------------------- pxeflash kernel memdisk bigraw append initrd=pxeflash.img keeppxe rescue kernel vmlinuz append ks initrd=initrd.img ramdisk_size=150000 lang= devfs=nomount pxe kssendmac selinux=0 noipv6 rescue |
We can add an action to only one node by including the node name in the "rocks add host pxeaction" command line. For example, here's how to apply the "install ucsd" action only to compute-0-0:
# rocks add host pxeaction compute-0-0 action="install ucsd" \ command="kernel vmlinuz \ args="append ks initrd=initrd.img ramdisk_size=150000 lang= devfs=nomount \ pxe kssendmac selinux=0 noipv6 ucsd=rocks" |
Also, you can override a global action by simply replacing the "args". For example, here's how to override the global "install" action:
# rocks add host pxeaction compute-0-0 action="install" \ command="kernel vmlinuz \ args="append ks initrd=initrd.img ramdisk_size=150000 lang= devfs=nomount \ pxe kssendmac selinux=0 noipv6 ucsd=rocks" |
To get the current parameters that will be appended to the default kernel boot parameters, execute:
# rocks report host bootflags rocks-168: dom0_mem=1024M compute-0-0: dom0_mem=1024M |
Then, to add our boot flag of "ucsd=rocks", execute:
# rocks set host bootflags compute-0-0 flags="dom0_mem=1024M ucsd=rocks" |
To check to make sure the flag has been added to the database, execute:
# rocks report host bootflags rocks-168: dom0_mem=1024M compute-0-0: dom0_mem=1024M ucsd=rocks |
To apply the flags to the running kernel, you'll need to reinstall the compute nodes. For example, you'll need to reinstall compute-0-0 in order to apply "ucsd=rocks" to its kernel boot parameters. After compute-0-0 is reinstalled, you can check that the new kernel boot parameters have been applied by logging into compute-0-0 and executing:
# cat /proc/cmdline ro root=LABEL=/ dom0_mem=1024M ucsd=rocks |