Adding a wrapper around connecting to kvm console

The wrapper will connect to the console, and check in the background if
the instance is paused, unpausing it as necessary.
Signed-off-by: Stephen Shirley <diamond@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>

Makefile.am

@@ -496,6 +496,7 @@ pkglib_SCRIPTS = \
 	daemons/daemon-util \
 	tools/kvm-ifup \
 	tools/xm-console-wrapper \
+	tools/kvm-console-wrapper \
 	$(pkglib_python_scripts)
 
 nodist_pkglib_SCRIPTS = \

lib/constants.py

@@ -144,6 +144,7 @@ QUEUE_DIR = DATA_DIR + "/queue"
 DAEMON_UTIL = _autoconf.PKGLIBDIR + "/daemon-util"
 SETUP_SSH = _autoconf.TOOLSDIR + "/setup-ssh"
 KVM_IFUP = _autoconf.PKGLIBDIR + "/kvm-ifup"
+KVM_CONSOLE_WRAPPER = _autoconf.PKGLIBDIR + "/kvm-console-wrapper"
 XM_CONSOLE_WRAPPER = _autoconf.PKGLIBDIR + "/xm-console-wrapper"
 ETC_HOSTS = "/etc/hosts"
 DEFAULT_FILE_STORAGE_DIR = _autoconf.FILE_STORAGE_DIR

lib/hypervisor/hv_kvm.py

@@ -1138,7 +1138,9 @@ class KVMHypervisor(hv_base.BaseHypervisor):
 
     """
     if hvparams[constants.HV_SERIAL_CONSOLE]:
-      cmd = [constants.SOCAT_PATH,
+      cmd = [constants.KVM_CONSOLE_WRAPPER,
+             utils.ShellQuote(instance.name), constants.SOCAT_PATH,
+             utils.ShellQuote(cls._InstanceMonitor(instance.name)),
              "STDIO,%s" % cls._SocatUnixConsoleParams(),
              "UNIX-CONNECT:%s" % cls._InstanceSerial(instance.name)]
       return objects.InstanceConsole(instance=instance.name,

tools/kvm-console-wrapper

+#!/bin/bash
+
+# Copyright (C) 2011 Google Inc.
+#
+# 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; either version 2 of the License, or
+# (at your option) any later version.
+#
+# 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.
+
+INSTANCE="$1"
+SOCAT="$2"
+MONITOR="$3"
+PARAMS="$4"
+CONSOLE="$5"
+
+unpause() {
+  echo "info status" |
+    "$SOCAT" STDIO "UNIX-CONNECT:$MONITOR" 2>/dev/null |
+    grep -q '^VM status: paused' || return
+  # As there is no way to be sure when the main socat has actually connected to
+  # the instance console, sleep for a few seconds before unpausing the
+  # instance. This is a tradeoff between missing some console output if the
+  # node is overloaded and making the user wait everytime when the node isn't
+  # so busy.
+  sleep 3
+  # Send \r\n after notice as terminal is in raw mode
+  printf "Instance $INSTANCE is paused, unpausing\r\n"
+  echo "c" | "$SOCAT" STDIO "UNIX-CONNECT:$MONITOR" &>/dev/null
+}
+
+unpause &
+"$SOCAT" "$PARAMS" "$CONSOLE"