[Qemu-devel] [PATCH COLO-Frame v6 14/31] COLO failover: Introduce a new command to trigger a failover

[zhanghailiang]

We leave users to use whatever heartbeat solution they want, if the heartbeat
is lost, or other errors they detect, they can use command
'colo_lost_heartbeat' to tell COLO to do failover, COLO will do operations
accordingly.

For example,
If send the command to PVM, Primary will exit COLO mode, and takeover,
if to Secondary, Secondary will do failover work and at last takeover server.

Cc: Luiz Capitulino <address@hidden>
Cc: Eric Blake <address@hidden>
Cc: Markus Armbruster <address@hidden>
Signed-off-by: zhanghailiang <address@hidden>
Signed-off-by: Li Zhijian <address@hidden>
Signed-off-by: Lai Jiangshan <address@hidden>
Signed-off-by: Yang Hongyang <address@hidden>
---
 hmp-commands.hx                        | 15 ++++++++++++
 hmp.c                                  |  8 +++++++
 hmp.h                                  |  1 +
 include/migration/migration-colo.h     |  4 ++++
 include/migration/migration-failover.h | 20 ++++++++++++++++
 migration/Makefile.objs                |  2 +-
 migration/colo-comm.c                  | 11 +++++++++
 migration/colo-failover.c              | 43 ++++++++++++++++++++++++++++++++++
 migration/colo.c                       |  1 +
 qapi-schema.json                       | 25 ++++++++++++++++++++
 qmp-commands.hx                        | 19 +++++++++++++++
 stubs/migration-colo.c                 |  8 +++++++
 12 files changed, 156 insertions(+), 1 deletion(-)
 create mode 100644 include/migration/migration-failover.h
 create mode 100644 migration/colo-failover.c

diff --git a/hmp-commands.hx b/hmp-commands.hx
index d3b7932..ed487a6 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1006,6 +1006,21 @@ Set the parameter @var{parameter} for migration.
 ETEXI
 
     {
+        .name       = "colo_lost_heartbeat",
+        .args_type  = "",
+        .params     = "",
+        .help       = "Tell COLO that heartbeat is lost,\n\t\t\t"
+                      "a failover or takeover is needed.",
+        .mhandler.cmd = hmp_colo_lost_heartbeat,
+    },
+
+STEXI
address@hidden colo_lost_heartbeat
address@hidden colo_lost_heartbeat
+Tell COLO that heartbeat is lost, a failover or takeover is needed.
+ETEXI
+
+    {
         .name       = "client_migrate_info",
         .args_type  = 
"protocol:s,hostname:s,port:i?,tls-port:i?,cert-subject:s?",
         .params     = "protocol hostname port tls-port cert-subject",
diff --git a/hmp.c b/hmp.c
index 23abc7d..8e25d5a 100644
--- a/hmp.c
+++ b/hmp.c
@@ -1271,6 +1271,14 @@ void hmp_client_migrate_info(Monitor *mon, const QDict 
*qdict)
     hmp_handle_error(mon, &err);
 }
 
+void hmp_colo_lost_heartbeat(Monitor *mon, const QDict *qdict)
+{
+    Error *err = NULL;
+
+    qmp_colo_lost_heartbeat(&err);
+    hmp_handle_error(mon, &err);
+}
+
 void hmp_set_password(Monitor *mon, const QDict *qdict)
 {
     const char *protocol  = qdict_get_str(qdict, "protocol");
diff --git a/hmp.h b/hmp.h
index 0cf4f2a..c36c99c 100644
--- a/hmp.h
+++ b/hmp.h
@@ -68,6 +68,7 @@ void hmp_migrate_set_capability(Monitor *mon, const QDict 
*qdict);
 void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict);
 void hmp_migrate_set_cache_size(Monitor *mon, const QDict *qdict);
 void hmp_client_migrate_info(Monitor *mon, const QDict *qdict);
+void hmp_colo_lost_heartbeat(Monitor *mon, const QDict *qdict);
 void hmp_set_password(Monitor *mon, const QDict *qdict);
 void hmp_expire_password(Monitor *mon, const QDict *qdict);
 void hmp_eject(Monitor *mon, const QDict *qdict);
diff --git a/include/migration/migration-colo.h 
b/include/migration/migration-colo.h
index c03c391..f9c09f3 100644
--- a/include/migration/migration-colo.h
+++ b/include/migration/migration-colo.h
@@ -17,6 +17,7 @@
 #include "migration/migration.h"
 #include "block/coroutine.h"
 #include "qemu/thread.h"
+#include "qemu/main-loop.h"
 
 bool colo_supported(void);
 void colo_info_mig_init(void);
@@ -35,6 +36,9 @@ bool loadvm_enable_colo(void);
 void loadvm_exit_colo(void);
 void *colo_process_incoming_checkpoints(void *opaque);
 bool loadvm_in_colo_state(void);
+
+int get_colo_mode(void);
+
 /* ram cache */
 int create_and_init_ram_cache(void);
 void colo_flush_ram_cache(void);
diff --git a/include/migration/migration-failover.h 
b/include/migration/migration-failover.h
new file mode 100644
index 0000000..a8767fc
--- /dev/null
+++ b/include/migration/migration-failover.h
@@ -0,0 +1,20 @@
+/*
+ *  COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO)
+ *  (a.k.a. Fault Tolerance or Continuous Replication)
+ *
+ * Copyright (c) 2015 HUAWEI TECHNOLOGIES CO.,LTD.
+ * Copyright (c) 2015 FUJITSU LIMITED
+ * Copyright (c) 2015 Intel Corporation
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later.  See the COPYING file in the top-level directory.
+ */
+
+#ifndef MIGRATION_FAILOVER_H
+#define MIGRATION_FAILOVER_H
+
+#include "qemu-common.h"
+
+void failover_request_set(void);
+
+#endif
diff --git a/migration/Makefile.objs b/migration/Makefile.objs
index cb7bd30..50d8392 100644
--- a/migration/Makefile.objs
+++ b/migration/Makefile.objs
@@ -1,6 +1,6 @@
 common-obj-y += migration.o tcp.o
-common-obj-$(CONFIG_COLO) += colo.o
 common-obj-y += colo-comm.o
+common-obj-$(CONFIG_COLO) += colo.o colo-failover.o
 common-obj-y += vmstate.o
 common-obj-y += qemu-file.o qemu-file-buf.o qemu-file-unix.o qemu-file-stdio.o
 common-obj-y += xbzrle.o
diff --git a/migration/colo-comm.c b/migration/colo-comm.c
index f8be027..6973215 100644
--- a/migration/colo-comm.c
+++ b/migration/colo-comm.c
@@ -16,6 +16,17 @@
 
 static bool colo_requested;
 
+int get_colo_mode(void)
+{
+    if (migrate_in_colo_state()) {
+        return COLO_MODE_PRIMARY;
+    } else if (loadvm_in_colo_state()) {
+        return COLO_MODE_SECONDARY;
+    } else {
+        return COLO_MODE_UNKNOWN;
+    }
+}
+
 /* save */
 static void colo_info_save(QEMUFile *f, void *opaque)
 {
diff --git a/migration/colo-failover.c b/migration/colo-failover.c
new file mode 100644
index 0000000..0f2f81f
--- /dev/null
+++ b/migration/colo-failover.c
@@ -0,0 +1,43 @@
+/*
+ * COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO)
+ * (a.k.a. Fault Tolerance or Continuous Replication)
+ *
+ * Copyright (c) 2015 HUAWEI TECHNOLOGIES CO., LTD.
+ * Copyright (c) 2015 FUJITSU LIMITED
+ * Copyright (c) 2015 Intel Corporation
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later.  See the COPYING file in the top-level directory.
+ */
+
+#include "migration/migration-colo.h"
+#include "migration/migration-failover.h"
+#include "qmp-commands.h"
+#include "qapi/qmp/qerror.h"
+
+static bool failover_request;
+
+static QEMUBH *failover_bh;
+
+static void colo_failover_bh(void *opaque)
+{
+    qemu_bh_delete(failover_bh);
+    failover_bh = NULL;
+    /*TODO: Do failover work */
+}
+
+void failover_request_set(void)
+{
+    failover_request = true;
+    failover_bh = qemu_bh_new(colo_failover_bh, NULL);
+    qemu_bh_schedule(failover_bh);
+}
+
+void qmp_colo_lost_heartbeat(Error **errp)
+{
+    if (get_colo_mode() == COLO_MODE_UNKNOWN) {
+        error_set(errp, QERR_FEATURE_DISABLED, "colo");
+        return;
+    }
+    failover_request_set();
+}
diff --git a/migration/colo.c b/migration/colo.c
index 07f677a..cc3d321 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -14,6 +14,7 @@
 #include "migration/migration-colo.h"
 #include "trace.h"
 #include "qemu/error-report.h"
+#include "migration/migration-failover.h"
 
 enum {
     COLO_CHECPOINT_READY = 0x46,
diff --git a/qapi-schema.json b/qapi-schema.json
index 88c9fd6..e5a0b1d 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -663,6 +663,31 @@
             '*tls-port': 'int', '*cert-subject': 'str' } }
 
 ##
+# @COLOMode
+#
+# The colo mode
+#
+# @unknown: unknown mode
+#
+# @primary: master side
+#
+# @secondary: slave side
+#
+# Since: 2.4
+##
+{ 'enum': 'COLOMode',
+  'data': [ 'unknown', 'primary', 'secondary'] }
+
+##
+# @colo-lost-heartbeat
+#
+# Tell qemu that heartbeat is lost, request it to do takeover working.
+#
+# Since: 2.4
+##
+{ 'command': 'colo-lost-heartbeat' }
+
+##
 # @MouseInfo:
 #
 # Information about a mouse device.
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 1db6524..74626ac 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -781,6 +781,25 @@ Example:
 EQMP
 
     {
+        .name       = "colo-lost-heartbeat",
+        .args_type  = "",
+        .mhandler.cmd_new = qmp_marshal_input_colo_lost_heartbeat,
+    },
+
+SQMP
+colo-lost-heartbeat
+--------------------
+
+Tell COLO that heartbeat is lost, a failover or takeover is needed.
+
+Example:
+
+-> { "execute": "colo-lost-heartbeat" }
+<- { "return": {} }
+
+EQMP
+
+    {
         .name       = "client_migrate_info",
         .args_type  = 
"protocol:s,hostname:s,port:i?,tls-port:i?,cert-subject:s?",
         .params     = "protocol hostname port tls-port cert-subject",
diff --git a/stubs/migration-colo.c b/stubs/migration-colo.c
index 827ee1f..23ad3aa 100644
--- a/stubs/migration-colo.c
+++ b/stubs/migration-colo.c
@@ -11,6 +11,7 @@
  */
 
 #include "migration/migration-colo.h"
+#include "qmp-commands.h"
 
 bool colo_supported(void)
 {
@@ -35,3 +36,10 @@ void *colo_process_incoming_checkpoints(void *opaque)
 {
     return NULL;
 }
+
+void qmp_colo_lost_heartbeat(Error **errp)
+{
+    error_setg(errp, "COLO is not supported, please rerun configure"
+                     " with --enable-colo option in order to support"
+                     " COLO feature");
+}
-- 
1.7.12.4