initial commit oif iniit_switch

cloudinit/config/cc_ubuntu_init_switch.py

@@ -0,0 +1,120 @@
+# vi: ts=4 expandtab
+#
+#    Copyright (C) 2014 Canonical Ltd.
+#
+#    Author: Scott Moser <scott.moser@canonical.com>
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License version 3, as
+#    published by the Free Software Foundation.
+#
+#    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, see <http://www.gnu.org/licenses/>.
+
+from cloudinit.settings import PER_INSTANCE
+from cloudinit import log as logging
+from cloudinit import util
+from cloudinit.distros import ubuntu
+
+import os
+import time
+
+frequency = PER_INSTANCE
+REBOOT_CMD = ["/sbin/reboot"]
+
+DEFAULT_CONFIG = {
+    'init_switch': {'target': None}
+}
+
+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
+"""
+
+
+def handle(name, cfg, cloud, log, _args):
+
+    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']
+    if not target:
+        log.debug("%s: target=%s. nothing to do", name, target)
+        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/systemd"):
+        current = "systemd"
+    else:
+        current = "upstart"
+
+    if current == target:
+        log.debug("%s: current = target = %s. nothing to do", name, target)
+        return
+
+    try:
+        util.subp(['sh', '-c', SWITCH_INIT, '--', target])
+    except util.ProcessExecutionError as e:
+        log.warn("%s: Failed to switch to init '%s'. %s", name, target, e)
+        return
+
+    try:
+        log.warn("%s: rebooting from '%s' to '%s'", name, current, target)
+        logging.flushLoggers(log)
+        _fire_reboot(log, 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)))

config/cloud.cfg

@@ -24,6 +24,7 @@ preserve_hostname: false
 # The modules that run in the 'init' stage
 cloud_init_modules:
  - migrator
+ - ubuntu-init-switch
  - seed_random
  - bootcmd
  - write-files