ovsdb: Introduce experimental support for clustered databases.

This commit adds support for OVSDB clustering via Raft.  Please read
ovsdb(7) for information on how to set up a clustered database.  It is
simple and boils down to running "ovsdb-tool create-cluster" on one server
and "ovsdb-tool join-cluster" on each of the others and then starting
ovsdb-server in the usual way on all of them.

One you have a clustered database, you configure ovn-controller and
ovn-northd to use it by pointing them to all of the servers, e.g. where
previously you might have said "tcp:1.2.3.4" was the database server,
now you say that it is "tcp:1.2.3.4,tcp:5.6.7.8,tcp:9.10.11.12".

This also adds support for database clustering to ovs-sandbox.

Acked-by: Justin Pettit <jpettit@ovn.org>
Tested-by: aginwala <aginwala@asu.edu>
Signed-off-by: Ben Pfaff <blp@ovn.org>

1 files changed, 12 insertions, 3 deletions

diff --git a/lib/smap.c b/lib/smap.c
index 6c6717c15..149b8b243 100644
--- a/lib/smap.c
+++ b/lib/smap.c
@@ -108,10 +108,19 @@ smap_add_ipv6(struct smap *smap, const char *key, struct in6_addr *addr)
 }
 
 /* Searches for 'key' in 'smap'.  If it does not already exists, adds it.
- * Otherwise, changes its value to 'value'. */
+ * Otherwise, changes its value to 'value'.  The caller retains ownership of
+ * 'value'. */
 void
 smap_replace(struct smap *smap, const char *key, const char *value)
 {
+    smap_replace_nocopy(smap, key, xstrdup(value));
+}
+
+/* Searches for 'key' in 'smap'.  If it does not already exists, adds it.
+ * Otherwise, changes its value to 'value'.  Takes ownership of 'value'. */
+void
+smap_replace_nocopy(struct smap *smap, const char *key, char *value)
+{
     size_t  key_len = strlen(key);
     size_t hash = hash_bytes(key, key_len, 0);
 
@@ -120,9 +129,9 @@ smap_replace(struct smap *smap, const char *key, const char *value)
     node = smap_find__(smap, key, key_len, hash);
     if (node) {
         free(node->value);
-        node->value = xstrdup(value);
+        node->value = value;
     } else {
-        smap_add__(smap, xmemdup0(key, key_len), xstrdup(value), hash);
+        smap_add__(smap, xmemdup0(key, key_len), value, hash);
     }
 }