Add the ability to deploy installer systems

This patch adds a baserock installer script and example of the
install.conf file needed by the installer script, and a manifest
file to use it in a cluster morphology for deploying an installer
system.

The installer script (installer.py) uses the rawdisk.write extension
to deploy a baserock system to a disk. It reads from /etc/install.conf
the configuration needed to install the system, but if this
configuration is not present the installer scrpit will ask the
information needed.

2 files changed, 195 insertions, 0 deletions

diff --git a/installer/manifest b/installer/manifest
new file mode 100644
index 00000000..60ec7774
--- /dev/null
+++ b/installer/manifest
@@ -0,0 +1,4 @@
+0040755 0 0 /usr
+0040755 0 0 /usr/lib
+0040755 0 0 /usr/lib/installer
+0100755 0 0 /usr/lib/installer/installer.py
diff --git a/installer/usr/lib/installer/installer.py b/installer/usr/lib/installer/installer.py
new file mode 100755
index 00000000..d6f07658
--- /dev/null
+++ b/installer/usr/lib/installer/installer.py
@@ -0,0 +1,191 @@
+#!/usr/bin/python
+# Copyright (C) 2014 Codethink Limited
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 2 of the License.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+
+'''A Baserock installer.'''
+
+
+
+import morphlib
+import os
+import re
+import sys
+import json
+import yaml
+import subprocess
+import tempfile
+import errno
+import time
+import stat
+import traceback
+
+
+config_file = '/etc/install.conf'
+to_mount = (
+    ('/proc', 'proc', 'none'),
+    ('/sys', 'sysfs', 'none'),
+
+)
+
+def validate_install_values(disk_dest, rootfs):
+    if not is_device(disk_dest):
+       print "ERROR: Not deploying to a device"
+       raise BaseException
+    if not os.path.exists(disk_dest):
+       print "ERROR: The device %s doesn't exist." % disk_dest
+       raise BaseException
+    if not is_baserock_rootfs(rootfs):
+       print "ERROR: The rootfs %s is not a baserock rootfs." % rootfs
+       raise BaseException
+
+def is_baserock_rootfs(rootfs):
+    if os.path.isdir(os.path.join(rootfs, 'baserock')):
+        return True
+    return False
+
+def compute_install_command(rawdisk_path, deployment_config,
+                          rootfs, disk_dest):
+    fd, script = tempfile.mkstemp()
+    with os.fdopen(fd, 'w') as fp:
+        fp.write('#!/bin/sh\n')
+        fp.write('env ')
+        for name in deployment_config:
+            if deployment_config[name] is not None:
+                fp.write('%s="%s" ' % (name, deployment_config[name]))
+        fp.write("%s %s %s\n" % (rawdisk_path, rootfs, disk_dest))
+    install_system(script)
+    os.remove(script)
+
+def finish_installation(postinstallcmd):
+    os.system("sync")
+    print "Executing `%s` in 5 seconds..." % postinstallcmd
+    time.sleep(5)
+    os.system(postinstallcmd)
+
+def do_mounts(to_mount):
+    mounted = []
+    for mount_point, mount_type, source in to_mount:
+        print 'Mounting %s in %s' % (source, mount_point)
+        if not os.path.exists(mount_point):
+            os.makedirs(mount_point)
+        if mount(source, mount_point, mount_type) == 0:
+            mounted.append(mount_point)
+    return mounted
+
+def mount(partition, mount_point, fstype):
+    return subprocess.call(['mount', partition, mount_point, '-t', fstype])
+
+def do_unmounts(to_unmount):
+    for path in reversed(to_unmount):
+        print 'Unmounting %s' % path
+        try:
+            subprocess.check_call(['umount', path])
+        except subprocess.CalledProcessError as e:
+            print 'WARNING: Failed to `umount %s`' % path
+
+def check_and_read_config(config_file):
+    print "Reading configuration from %s..." % config_file
+
+    keys = ('INSTALLER_TARGET_STORAGE_DEVICE',
+            'INSTALLER_ROOTFS_TO_INSTALL')
+    try:
+        with open(config_file) as f:
+            config = yaml.load(f)
+    except IOError as e:
+        if e.errno != errno.ENOENT:
+            raise
+        print "WARNING: Configuration file '%s' not found" % config_file
+        config = {}
+
+    device, rootfs = (read_option(config, key)
+                         for key in keys)
+    postinstallcmd = read_option(config,
+                        'INSTALLER_POST_INSTALL_COMMAND',
+                        'reboot -f')
+    return device, rootfs, postinstallcmd
+
+def read_option(config, option, default_value=None):
+    try:
+        value = config[option]
+    except KeyError as e:
+        if default_value:
+            value = default_value
+        else:
+            value = raw_input("Option '%s' missing, please enter a value: "
+                                %   option)
+    print "Option '%s' with value '%s'" % (option, value)
+    return value
+
+def get_deployment_config(rootfs):
+    print "Reading deployment.meta of the system to install..."
+    try:
+        meta = open(os.path.join(rootfs, 'baserock/deployment.meta'))
+    except IOError as e:
+        if e.errno != errno.ENOENT:
+            raise
+        print "Failed to read deployment.meta, it will be empty"
+        deployment_config = {}
+    else:
+        deployment_config = json.load(meta).get('configuration', {})
+        meta.close()
+        print "################ Environment #################"
+        for key in deployment_config:
+            print "# %s: %s" % (key, deployment_config[key])
+        print "##############################################"
+    return deployment_config
+
+
+def install_system(install_script):
+    subprocess.check_call(['sh', install_script])
+
+def is_device(location):
+    try:
+        st = os.stat(location)
+        return stat.S_ISBLK(st.st_mode)
+    except OSError as e:
+        if e.errno == errno.ENOENT:
+            return False
+        raise
+
+    dev_regex = re.compile("^/dev/((sd|vd|mmcblk|hd)[a-z0-9]+)$")
+    if dev_regex.match(location):
+        return True
+    return False
+
+
+try:
+    print "Baserock installation script begins..."
+    mounted = do_mounts(to_mount)
+
+    rawdisk_path = morphlib.extensions._get_morph_extension_filename(
+                       'rawdisk', '.write')
+
+    disk_dest, rootfs, postinstallcmd = check_and_read_config(
+                                            config_file)
+    validate_install_values(disk_dest, rootfs)
+
+    deployment_config=get_deployment_config(rootfs)
+
+    compute_install_command(rawdisk_path,
+             deployment_config, rootfs, disk_dest)
+
+    do_unmounts(mounted)
+    finish_installation(postinstallcmd)
+except BaseException as e:
+    print traceback.format_exc()
+    print "Something failed, opening shell..."
+    print "Once you have finished, use `reboot -f`"
+    os.execl('/bin/sh', 'sh')