[PATCH 5 of 5 V2] tools/xl: Remus - Network buffering cmdline switch

[Shriram Rajagopalan <rshriram@cs.ubc.ca>]

# HG changeset patch
# User Shriram Rajagopalan <rshriram@cs.ubc.ca>
# Date 1377814007 25200
# Node ID 66e6a3c645669e76e119edeed9271e6ae2a49bdb
# Parent  b8839e0b61c2e15b94a274cfddedf0814d2560de
tools/xl: Remus - Network buffering cmdline switch

Command line switch to 'xl remus' command, to enable network buffering.
Pass on this flag to libxl so that it can act accordingly.
Also update man pages to reflect the addition of a new option to
'xl remus' command.

Signed-off-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>

diff -r b8839e0b61c2 -r 66e6a3c64566 docs/man/xl.pod.1
--- a/docs/man/xl.pod.1	Thu Aug 29 14:50:01 2013 -0700
+++ b/docs/man/xl.pod.1	Thu Aug 29 15:06:47 2013 -0700
@@ -398,8 +398,7 @@ Print huge (!) amount of debug during th
 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.
+N.B: There is no support for disk buffering at the moment.
 
 B<OPTIONS>
 
@@ -418,6 +417,13 @@ Generally useful for debugging.
 
 Disable memory checkpoint compression.
 
+=item B<-n>
+
+Enable network output buffering.  The default script used to configure
+network buffering is /etc/xen/scripts/remus-netbuf-setup. If you wish to
+use a custom script, set the global variable "remus.default.netbufscript"
+in /etc/xen/xl.conf to point to your script.
+
 =item B<-s> I<sshcommand>
 
 Use <sshcommand> instead of ssh.  String will be passed to sh.
diff -r b8839e0b61c2 -r 66e6a3c64566 tools/libxl/xl.c
--- a/tools/libxl/xl.c	Thu Aug 29 14:50:01 2013 -0700
+++ b/tools/libxl/xl.c	Thu Aug 29 15:06:47 2013 -0700
@@ -46,6 +46,7 @@ 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;
 
@@ -177,6 +178,11 @@ static void parse_global_config(const ch
     if (!xlu_cfg_get_long (config, "claim_mode", &l, 0))
         claim_mode = l;
 
+    if (!xlu_cfg_get_string (config, "remus.default.netbufscript", &buf, 0)) {
+        free(default_remus_netbufscript);
+        default_remus_netbufscript = strdup(buf);
+    }
+
     xlu_cfg_destroy(config);
 }
 
diff -r b8839e0b61c2 -r 66e6a3c64566 tools/libxl/xl.h
--- a/tools/libxl/xl.h	Thu Aug 29 14:50:01 2013 -0700
+++ b/tools/libxl/xl.h	Thu Aug 29 15:06:47 2013 -0700
@@ -152,6 +152,7 @@ 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 -r b8839e0b61c2 -r 66e6a3c64566 tools/libxl/xl_cmdimpl.c
--- a/tools/libxl/xl_cmdimpl.c	Thu Aug 29 14:50:01 2013 -0700
+++ b/tools/libxl/xl_cmdimpl.c	Thu Aug 29 15:06:47 2013 -0700
@@ -7070,8 +7070,9 @@ int main_remus(int argc, char **argv)
     r_info.interval = 200;
     r_info.blackhole = 0;
     r_info.compression = 1;
-
-    SWITCH_FOREACH_OPT(opt, "bui:s:e", NULL, "remus", 2) {
+    r_info.netbuf = 0;
+
+    SWITCH_FOREACH_OPT(opt, "buni:s:e", NULL, "remus", 2) {
     case 'i':
         r_info.interval = atoi(optarg);
         break;
@@ -7081,6 +7082,9 @@ int main_remus(int argc, char **argv)
     case 'u':
         r_info.compression = 0;
         break;
+    case 'n':
+        r_info.netbuf = 1;
+        break;
     case 's':
         ssh_command = optarg;
         break;
@@ -7092,6 +7096,11 @@ int main_remus(int argc, char **argv)
     domid = find_domain(argv[optind]);
     host = argv[optind + 1];
 
+    if (r_info.netbuf) {
+        if (default_remus_netbufscript)
+            r_info.netbufscript = strdup(default_remus_netbufscript);
+    }
+
     if (r_info.blackhole) {
         send_fd = open("/dev/null", O_RDWR, 0644);
         if (send_fd < 0) {
@@ -7126,13 +7135,10 @@ 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.
+    /* If we are here, it means remus setup/domain susppend/backup has
+     * failed. Try to resume the domain and exit gracefully.
      * TODO: Split-Brain check.
      */
-    fprintf(stderr, "remus sender: libxl_domain_suspend failed"
-            " (rc=%d)\n", rc);
-
     if (rc == ERROR_GUEST_TIMEDOUT)
         fprintf(stderr, "Failed to suspend domain at primary.\n");
     else {
diff -r b8839e0b61c2 -r 66e6a3c64566 tools/libxl/xl_cmdtable.c
--- a/tools/libxl/xl_cmdtable.c	Thu Aug 29 14:50:01 2013 -0700
+++ b/tools/libxl/xl_cmdtable.c	Thu Aug 29 15:06:47 2013 -0700
@@ -481,6 +481,7 @@ 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                      Enable network output buffering.\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"