= Testing LinuxPMI under QEMU =

== Setup ==

=== kernel ===
You need to build a kernel to test with.
[wiki:LinuxPMIKernelBuilding]

=== initrd ===
First you'll need to build an initrd. This initrd image must contain the migtorture suite.

Download busybox 1.15.2 from [http://busybox.net/downloads/busybox-1.15.2.tar.bz2] and extract it into 2.6/tools/initrd_builder/

As root, or using sudo, run mkinitrd.sh in the same directory. The script does the following;
 * Make an image
 * Formats the image ext2
 * Loopback mounts the image
 * Builds busybox using the included config and installs it to the initrd
 * Builds the migtorture suite
 * Copies a few libraries
 * Compresses the initrd

==== Node ====
{{{
./mkinitrd.sh
}}}

This will build an initrd that will start up, bring up eth0, and attempt to get an address using dhcp.

==== Server ====
{{{
./mkinitrd.sh server
}}}

This will build an initrd that will start up, bring up eth0, assign eth0 the address 192.168.168.12 (The default address that migtorture will attempt to migrate to), and start a small dhcp server that will assign addresses in the same subnet.

=== kgdb/qemu ===

to run these tests, QEMU and GDB need to be installed on your local machine.

== Running LinuxPMI under Qemu ==
Invoke qemu with at least these options:

{{{
qemu -kernel bzImage \
-initrd initrd.gz \
-append "ramdisk_size=34000 root=/dev/ram0 rw kgdbwait kgdboc=ttyS1" \
-net nic,model=e1000,macaddr=52:54:00:12:34:57 \
-net socket,mcast=230.0.0.1:1234 \
-serial stdio \
-serial pty
}}}

You'll get something like this:
{{{
char device redirected to /dev/pts/11
}}}

Important Note:  Be sure to change the macaddr argument to be different for each machine that is invoked, else things will break.

Optionally you can add a few more useful arguments.

{{{
qemu -kernel bzImage \
-initrd initrd.gz \
-append "ramdisk_size=34000 root=/dev/ram0 rw kgdbwait kgdboc=ttyS1" \
-net nic,model=e1000,macaddr=52:54:00:12:34:57 \
-net socket,mcast=230.0.0.1:1234 \
-serial stdio \
-serial pty \
-vnc :0 
}}}

== Attaching GDB ==

Run gdb on the host system. needs to be invoked with vmlinux as the argument otherwise you wont have debugging symbols.
{{{
gdb /path/to/vmlinux
}}}
connect to kgdb
{{{
gdb) target remote /dev/pts/11
}}}
You should now be connected.
{{{
gdb) continue
}}}
This will start the kernel, if you dont want to do this, remove the kgdbwait from the append argument to qemu.

== When stuff breaks ==
{{{
gdb) bt
}}}
Will display the backtrace

== KVM ==
kvm will work just as well as qemu, the only difference being you use the kvm-qemu binary instead of the qemu binary.

== migtorture ==
migtorture is fairly straight forward to use, assuming you are using the server and node initrds to automatically setup networking, you login as root with no password into a node image and run it.

{{{
migtorture
}}}

It will then start a series of tests designed to break things, either in a minor way such as a process dying, or very major such as a kernel panic.

For kernel panics or stack dumps, refer to the kgdb section above on how to obtain a backtrace.

= New testing tools =
spook has began writing some new testing tools.

Currently;
 * Harness starts
 * It forks, and exec()s forker
 * forker SIGUSR1s the parent harness
 * harness SIGUSR1s the child forker
 * forker forks
 * local forkers signal each other
 * harness checks its own /proc/$pid for /pms/where and terminates if it doesn't find it, signalling the forkers so they self-terminate.

Planned;
 * harness migrates a forker
 * pipe/signal between local harness and remote forker
 * pipe/signal between remote forker and local forker
 * harness migrates local forker
 * pipe/signal between harness and a remote forker
 * pipe/signal between the remote forkers
 * harness migrates a remote forker home
 * pipe/signal between local harness and remote forker
 * pipe/signal between remote forker and local forker
 * harness migrates the remote forker home
 * pipe/signal between harness and a forker
 * pipe/signal between the local forkers