[Xen-devel] [PATCH v17 5/8] libxl: network buffering cmdline switch

[Yang Hongyang <yanghy@xxxxxxxxxxxxxx>]

Command line switch to 'xl remus' command.
Also update man pages to reflect the addition of a new option to
'xl remus' command.

Note: the network buffering is enabled as default. If you want to
disable it, please use -n option.

Signed-off-by: Shriram Rajagopalan <rshriram@xxxxxxxxx>
Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
Reviewed-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
---
 docs/man/xl.conf.pod.5    |  6 ++++++
 docs/man/xl.pod.1         | 11 ++++++++++-
 tools/libxl/xl.c          |  4 ++++
 tools/libxl/xl.h          |  1 +
 tools/libxl/xl_cmdimpl.c  | 28 ++++++++++++++++++++++------
 tools/libxl/xl_cmdtable.c |  3 +++
 6 files changed, 46 insertions(+), 7 deletions(-)

diff --git a/docs/man/xl.conf.pod.5 b/docs/man/xl.conf.pod.5
index 7c43bde..8ae19bb 100644
--- a/docs/man/xl.conf.pod.5
+++ b/docs/man/xl.conf.pod.5
@@ -105,6 +105,12 @@ Configures the default gateway device to set for virtual 
network devices.
 
 Default: C<None>
 
+=item B<remus.default.netbufscript="PATH">
+
+Configures the default script used by Remus to setup network buffering.
+
+Default: C</etc/xen/scripts/remus-netbuf-setup>
+
 =item B<output_format="json|sxp">
 
 Configures the default output format used by xl when printing "machine
diff --git a/docs/man/xl.pod.1 b/docs/man/xl.pod.1
index 30bd4bf..e9e4a83 100644
--- a/docs/man/xl.pod.1
+++ b/docs/man/xl.pod.1
@@ -431,7 +431,7 @@ Enable Remus HA for domain. By default B<xl> relies on ssh 
as a transport
 mechanism between the two hosts.
 
 N.B: Remus support in xl is still in experimental (proof-of-concept) phase.
-     There is no support for network or disk buffering at the moment.
+     Disk buffering support is limited to drbd disks.
 
 B<OPTIONS>
 
@@ -450,6 +450,15 @@ Generally useful for debugging.
 
 Disable memory checkpoint compression.
 
+=item B<-n>
+
+Disable network output buffering.
+
+=item B<-N> I<netbufscript>
+
+Use <netbufscript> to setup network buffering instead of the instead of
+the default (/etc/xen/scripts/remus-netbuf-setup).
+
 =item B<-s> I<sshcommand>
 
 Use <sshcommand> instead of ssh.  String will be passed to sh.
diff --git a/tools/libxl/xl.c b/tools/libxl/xl.c
index 4c5a5ee..f014306 100644
--- a/tools/libxl/xl.c
+++ b/tools/libxl/xl.c
@@ -44,6 +44,7 @@ char *default_vifscript = NULL;
 char *default_bridge = NULL;
 char *default_gatewaydev = NULL;
 char *default_vifbackend = NULL;
+char *default_remus_netbufscript = NULL;
 enum output_format default_output_format = OUTPUT_FORMAT_JSON;
 int claim_mode = 1;
 bool progress_use_cr = 0;
@@ -176,6 +177,9 @@ static void parse_global_config(const char *configfile,
     if (!xlu_cfg_get_long (config, "claim_mode", &l, 0))
         claim_mode = l;
 
+    xlu_cfg_replace_string (config, "remus.default.netbufscript",
+        &default_remus_netbufscript, 0);
+
     xlu_cfg_destroy(config);
 }
 
diff --git a/tools/libxl/xl.h b/tools/libxl/xl.h
index 10a2e66..087eb8c 100644
--- a/tools/libxl/xl.h
+++ b/tools/libxl/xl.h
@@ -170,6 +170,7 @@ extern char *default_vifscript;
 extern char *default_bridge;
 extern char *default_gatewaydev;
 extern char *default_vifbackend;
+extern char *default_remus_netbufscript;
 extern char *blkdev_start;
 
 enum output_format {
diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 68df548..b324f34 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -7175,8 +7175,9 @@ int main_remus(int argc, char **argv)
     r_info.interval = 200;
     r_info.blackhole = 0;
     r_info.compression = 1;
+    r_info.netbuf = 1;
 
-    SWITCH_FOREACH_OPT(opt, "bui:s:e", NULL, "remus", 2) {
+    SWITCH_FOREACH_OPT(opt, "buni:s:N:e", NULL, "remus", 2) {
     case 'i':
         r_info.interval = atoi(optarg);
         break;
@@ -7186,6 +7187,12 @@ int main_remus(int argc, char **argv)
     case 'u':
         r_info.compression = 0;
         break;
+    case 'n':
+        r_info.netbuf = 0;
+        break;
+    case 'N':
+        r_info.netbufscript = optarg;
+        break;
     case 's':
         ssh_command = optarg;
         break;
@@ -7197,6 +7204,9 @@ int main_remus(int argc, char **argv)
     domid = find_domain(argv[optind]);
     host = argv[optind + 1];
 
+    if (!r_info.netbufscript)
+        r_info.netbufscript = default_remus_netbufscript;
+
     if (r_info.blackhole) {
         send_fd = open("/dev/null", O_RDWR, 0644);
         if (send_fd < 0) {
@@ -7234,13 +7244,19 @@ int main_remus(int argc, char **argv)
     /* Point of no return */
     rc = libxl_domain_remus_start(ctx, &r_info, domid, send_fd, recv_fd, 0);
 
-    /* If we are here, it means backup has failed/domain suspend failed.
-     * Try to resume the domain and exit gracefully.
-     * TODO: Split-Brain check.
+    /* check if the domain exists. User may have xl destroyed the
+     * domain to force failover
      */
-    fprintf(stderr, "remus sender: libxl_domain_suspend failed"
-            " (rc=%d)\n", rc);
+    if (libxl_domain_info(ctx, 0, domid)) {
+        fprintf(stderr, "Remus: Primary domain has been destroyed.\n");
+        close(send_fd);
+        return 0;
+    }
 
+    /* If we are here, it means remus setup/domain suspend/backup has
+     * failed. Try to resume the domain and exit gracefully.
+     * TODO: Split-Brain check.
+     */
     if (rc == ERROR_GUEST_TIMEDOUT)
         fprintf(stderr, "Failed to suspend domain at primary.\n");
     else {
diff --git a/tools/libxl/xl_cmdtable.c b/tools/libxl/xl_cmdtable.c
index 4279b9f..3f7520d 100644
--- a/tools/libxl/xl_cmdtable.c
+++ b/tools/libxl/xl_cmdtable.c
@@ -487,6 +487,9 @@ struct cmd_spec cmd_table[] = {
       "-i MS                   Checkpoint domain memory every MS milliseconds 
(def. 200ms).\n"
       "-b                      Replicate memory checkpoints to /dev/null 
(blackhole)\n"
       "-u                      Disable memory checkpoint compression.\n"
+      "-n                      Disable network output buffering.\n"
+      "-N <netbufscript>       Use netbufscript to setup network buffering 
instead of the\n"
+      "                        instead of the default 
(/etc/xen/scripts/remus-netbuf-setup).\n"
       "-s <sshcommand>         Use <sshcommand> instead of ssh.  String will 
be passed\n"
       "                        to sh. If empty, run <host> instead of \n"
       "                        ssh <host> xl migrate-receive -r [-e]\n"
-- 
1.9.1


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