Merge lp:~corey.bryant/curtin/trunk into lp:~curtin-dev/curtin/trunk

[Corey Bryant]

Add kexec support and a minor update to example launch command

Sample usage: curtin install --set "power_state/mode=kexec" ...

[Scott Moser (smoser)]

Corey,
  Thanks for the merge request.

 * The 'opt_map' fix seems reasonable. Not the way I had thoght of implementing it, but that should be fine.
   The other option is to just not bother rebooting, but have curtin call 'kexec' itself.
   As I'm thinking... maybe that would be better. As if you reboot, kexec-tools will load the kernel by reading /boot/grub (or attempt to) in its root filesystem. However, we want to load the one that is in the *installed* OS's filesystem.

 * when you use subp, best to not run through 'sh' unless necessary. Ie:
   - util.subp(args=['sh', '-c', 'apt-get install kexec-tools -qy'])
   + util.subp(args=['apt-get', 'install', '-qy', 'kexec-tools'])

 * I generally prefer long format arguments to programs as they're more self documenting:
   + util.subp(args=['apt-get', 'install', '--quiet', '--assume-yes', 'kexec-tools'])

Thanks!

[Corey Bryant (corey.bryant)]

> Corey,
> Thanks for the merge request.
>

Thanks for reviewing!

> * The 'opt_map' fix seems reasonable. Not the way I had thoght of
> implementing it, but that should be fine.
> The other option is to just not bother rebooting, but have curtin call
> 'kexec' itself.

The reason I took the reboot approach is because I wanted to make sure proper
shutdown occurred before exec'ing the new kernel. From the looks of it you might
be able to get the same result by calling kexec directly without an option parameter.
But I don't think a simple 'kexec -e' does proper shutdown. I'll look into it.

> As I'm thinking... maybe that would be better. As if you reboot, kexec-
> tools will load the kernel by reading /boot/grub (or attempt to) in its root
> filesystem. However, we want to load the one that is in the *installed* OS's
> filesystem.

I think you're right. I'm currently running kexec-load in the root fs and it's
looking at the wrong /boot dir. Another approach is to run kexec-load while
chroot'ed into /tmp/.../target. Then it should look at the right /boot dir.

Which takes me to a somewhat related question that I haven't figured out. When
I use launch with a normal non-kexec reboot, and it reboots into the new OS, the
grub menu is not the one from /tmp/.../target/boot/grub/grub.cfg. However once
booted, the new root fs is the new system (/dev/vdc) and contains the updated
grub.cfg. Shouldn't the grub menu reflect what's in
/tmp/.../target/boot/grub/grub.cfg?

>
>
> * when you use subp, best to not run through 'sh' unless necessary. Ie:
> - util.subp(args=['sh', '-c', 'apt-get install kexec-tools -qy'])
> + util.subp(args=['apt-get', 'install', '-qy', 'kexec-tools'])

Ok

>
> * I generally prefer long format arguments to programs as they're more self
> documenting:
> + util.subp(args=['apt-get', 'install', '--quiet', '--assume-yes', 'kexec-
> tools'])

Yep, makes sense.

>
>
> Thanks!

[lp:~corey.bryant/curtin/trunk]

98. By Scott Moser on 2014-02-27

curthooks: always update grub linux default entry

Previously we only modified GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub
if there were new kernel command line parameters found.

The images that were built from cloud images would have baked into them
'console=ttyS0'. The result was serial console output even if the user
didn't request it (or didn't have a serial console).

99. By Scott Moser on 2014-03-12

write_files: avoid writing a file if no path is given

if the user provides an entry in 'write_files' that did not have a 'path'
then this would warn, and then stack trace. better to just warn.

100. By Scott Moser on 2014-03-12

write_files: read 'permissions' or 'perms' to specify mode

cloud-init uses 'permissions' for the permission key in a write_files
input. this just makes it more forgiving.

101. By Scott Moser on 2014-03-12

decode_perms: fix error if permissions was not an int

isinstance(thing, None) is not valid, and that was throwing
an error, causing us down the return default path.

102. By Scott Moser on 2014-03-14

support source as a local tar file (not only a url)

103. By Scott Moser on 2014-03-24

partition: default to 'mbr' format

this will probably have to change with UEFI support, but for now, partition
default to 'mbr'

104. By Corey Bryant on 2014-03-24

curtin/commands/install.py: Add kexec support

This allows for a faster alternative to the existing reboot power_state mode.
Sample usage: curtin install --set "kexec/mode=on"

Unmerged revisions

=== modified file 'curtin/commands/install.py'
--- curtin/commands/install.py	2013-09-19 21:01:27 +0000
+++ curtin/commands/install.py	2014-02-14 15:32:12 +0000
@@ -19,6 +19,7 @@
 import json
 import os
 import re
+import shlex
 import shutil
 import tempfile
 
@@ -158,6 +159,61 @@
 
     return (['sh', '-c', shcmd, 'curtin-poweroff', delay] + args)
 
+def apply_kexec(kexec, target):
+    # load kexec kernel from target directory, similar to /etc/init.d/kexec-load
+    # kexec:
+    #  mode: on
+    if kexec is None or kexec.get("mode") != "on":
+        return False
+
+    if not isinstance(kexec, dict):
+        raise TypeError("kexec is not a dict.")
+
+    util.subp(args=['apt-get', 'install', 'kexec-tools', '--assume-yes',
+                    '--quiet'])
+
+    with open(target + "/boot/grub/grub.cfg", "r") as fp:
+        default = 0
+        menu_lines = []
+
+        # get the default grub boot entry number and menu entry line numbers
+        for line_num, line in enumerate(fp, 1):
+            if re.search(r"set default=\"[0-9]+\"", line):
+                default = int(re.sub(r"[^0-9]", '', line))
+            if re.match(r"menuentry", line):
+                menu_lines.append(line_num)
+
+        if not menu_lines:
+            LOG.error("grub config file does not have a menuentry\n")
+            return False
+
+        # get the begin and end line numbers for default menuentry section
+        begin = menu_lines[default]
+        if begin != menu_lines[-1]:
+            end = menu_lines[default + 1] - 1
+        else:
+            end = line_num
+
+        fp.seek(0)
+        lines=fp.readlines()
+        kernel = append = initrd = ""
+
+        for i in range(begin, end):
+            if 'vmlinuz' in lines[i]:
+                split_line = shlex.split(lines[i])
+                kernel = target + split_line[1]
+                append = "--append=" + ' '.join(split_line[2:])
+            if 'initrd' in lines[i]:
+                split_line = shlex.split(lines[i])
+                initrd = "--initrd=" + target + split_line[1]
+
+        if not kernel:
+            LOG.error("grub config file does not have a kernel\n")
+            return False
+
+        LOG.debug("kexec -l %s %s %s" % (kernel, append, initrd))
+        util.subp(args=['kexec', '-l', kernel, append, initrd])
+        return True
 
 def cmd_install(args):
     cfg = CONFIG_BUILTIN
@@ -191,6 +247,10 @@
                 stage = Stage(name, cfg.get(commands_name, {}), env)
                 stage.run()
 
+        if apply_kexec(cfg.get('kexec'), workingd.target):
+            cfg['power_state'] = {'mode': 'reboot', 'delay': 'now',
+                                  'message': "'rebooting with kexec'"}
+
     finally:
         for d in ('sys', 'dev', 'proc'):
             util.do_umount(os.path.join(workingd.target, d))