summaryrefslogtreecommitdiff
path: root/cloudinit/config/cc_ubuntu_init_switch.py
blob: 5dd2690176928d0723d416750ddeaf6047f728e6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
# Copyright (C) 2014 Canonical Ltd.
#
# Author: Scott Moser <scott.moser@canonical.com>
#
# This file is part of cloud-init. See LICENSE file for license information.

"""
Ubuntu Init Switch
------------------
**Summary:** reboot system into another init.

This module provides a way for the user to boot with systemd even if the image
is set to boot with upstart. It should be run as one of the first
``cloud_init_modules``, and will switch the init system and then issue a
reboot. The next boot will come up in the target init system and no action
will be taken. This should be inert on non-ubuntu systems, and also
exit quickly.

.. note::
    best effort is made, but it's possible this system will break, and probably
    won't interact well with any other mechanism you've used to switch the init
    system.

**Internal name:** ``cc_ubuntu_init_switch``

**Module frequency:** once per instance

**Supported distros:** ubuntu

**Config keys**::

    init_switch:
      target: systemd (can be 'systemd' or 'upstart')
      reboot: true (reboot if a change was made, or false to not reboot)
"""

from cloudinit.distros import ubuntu
from cloudinit import log as logging
from cloudinit.settings import PER_INSTANCE
from cloudinit import util

import os
import time

frequency = PER_INSTANCE
REBOOT_CMD = ["/sbin/reboot", "--force"]

DEFAULT_CONFIG = {
    'init_switch': {'target': None, 'reboot': True}
}

SWITCH_INIT = """
#!/bin/sh
# switch_init: [upstart | systemd]

is_systemd() {
   [ "$(dpkg-divert --listpackage /sbin/init)" = "systemd-sysv" ]
}
debug() { echo "$@" 1>&2; }
fail() { echo "$@" 1>&2; exit 1; }

if [ "$1" = "systemd" ]; then
   if is_systemd; then
      debug "already systemd, nothing to do"
   else
      [ -f /lib/systemd/systemd ] || fail "no systemd available";
      dpkg-divert --package systemd-sysv --divert /sbin/init.diverted \\
          --rename /sbin/init
   fi
   [ -f /sbin/init ] || ln /lib/systemd/systemd /sbin/init
elif [ "$1" = "upstart" ]; then
   if is_systemd; then
      rm -f /sbin/init
      dpkg-divert --package systemd-sysv --rename --remove /sbin/init
   else
      debug "already upstart, nothing to do."
   fi
else
  fail "Error. expect 'upstart' or 'systemd'"
fi
"""

distros = ['ubuntu']


def handle(name, cfg, cloud, log, args):
    """Handler method activated by cloud-init."""

    if not isinstance(cloud.distro, ubuntu.Distro):
        log.debug("%s: distro is '%s', not ubuntu. returning",
                  name, cloud.distro.__class__)
        return

    cfg = util.mergemanydict([cfg, DEFAULT_CONFIG])
    target = cfg['init_switch']['target']
    reboot = cfg['init_switch']['reboot']

    if len(args) != 0:
        target = args[0]
        if len(args) > 1:
            reboot = util.is_true(args[1])

    if not target:
        log.debug("%s: target=%s. nothing to do", name, target)
        return

    if not util.which('dpkg'):
        log.warn("%s: 'dpkg' not available. Assuming not ubuntu", name)
        return

    supported = ('upstart', 'systemd')
    if target not in supported:
        log.warn("%s: target set to %s, expected one of: %s",
                 name, target, str(supported))

    if os.path.exists("/run/systemd/system"):
        current = "systemd"
    else:
        current = "upstart"

    if current == target:
        log.debug("%s: current = target = %s. nothing to do", name, target)
        return

    try:
        util.subp(['sh', '-s', target], data=SWITCH_INIT)
    except util.ProcessExecutionError as e:
        log.warn("%s: Failed to switch to init '%s'. %s", name, target, e)
        return

    if util.is_false(reboot):
        log.info("%s: switched '%s' to '%s'. reboot=false, not rebooting.",
                 name, current, target)
        return

    try:
        log.warn("%s: switched '%s' to '%s'. rebooting.",
                 name, current, target)
        logging.flushLoggers(log)
        _fire_reboot(log, wait_attempts=4, initial_sleep=4)
    except Exception as e:
        util.logexc(log, "Requested reboot did not happen!")
        raise


def _fire_reboot(log, wait_attempts=6, initial_sleep=1, backoff=2):
    util.subp(REBOOT_CMD)
    start = time.time()
    wait_time = initial_sleep
    for _i in range(0, wait_attempts):
        time.sleep(wait_time)
        wait_time *= backoff
        elapsed = time.time() - start
        log.debug("Rebooted, but still running after %s seconds", int(elapsed))
    # If we got here, not good
    elapsed = time.time() - start
    raise RuntimeError(("Reboot did not happen"
                        " after %s seconds!") % (int(elapsed)))

# vi: ts=4 expandtab