[ovs-dev] [PATCH] ovsdb-server: drop all connections on read/write status change

Daniel Alvarez dalvarez at redhat.com
Tue Jul 9 10:16:30 UTC 2019

Prior to this patch, only db change aware connections were dropped
on a read/write status change. However, current schema in OVN does
not allow clients to monitor whether a particular DB changes this
status. In order to accomplish this, we'd need to change the schema
and adapting ovsdb-server and existing clients.

Before tackling that, this patch is changing ovsdb-server to drop
*all* the existing connections upon a read/write status change. This
will force clients to reconnect and honor the change.

Reported-at: https://mail.openvswitch.org/pipermail/ovs-discuss/2019-July/048981.html
Signed-off-by: Daniel Alvarez <dalvarez at redhat.com>
 ovsdb/jsonrpc-server.c |  2 +-
 tests/ovn.at           | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/ovsdb/jsonrpc-server.c b/ovsdb/jsonrpc-server.c
index 4dda63a9d..ddbbc2e94 100644
--- a/ovsdb/jsonrpc-server.c
+++ b/ovsdb/jsonrpc-server.c
@@ -365,7 +365,7 @@ ovsdb_jsonrpc_server_set_read_only(struct ovsdb_jsonrpc_server *svr,
     if (svr->read_only != read_only) {
         svr->read_only = read_only;
-        ovsdb_jsonrpc_server_reconnect(svr, false,
+        ovsdb_jsonrpc_server_reconnect(svr, true,
                                                ? "making server read-only"
                                                : "making server read/write"));
diff --git a/tests/ovn.at b/tests/ovn.at
index daace1128..4da7059b3 100644
--- a/tests/ovn.at
+++ b/tests/ovn.at
@@ -14313,3 +14313,24 @@ OVN_CHECK_PACKETS([hv2/vif22-tx.pcap], [vif22.expected])
+# Run ovn-nbctl in daemon mode, change to a backup database and verify that
+# an insert operation is not allowed.
+AT_SETUP([ovn -- can't write to a backup database server instance])
+on_exit 'kill $(cat ovn-nbctl.pid)'
+export OVN_NB_DAEMON=$(ovn-nbctl --pidfile --detach)
+AT_CHECK([ovn-nbctl ls-add sw0])
+as ovn-nb
+AT_CHECK([ovs-appctl -t ovsdb-server ovsdb-server/sync-status | grep active | wc -l], [0], [1
+ovs-appctl -t ovsdb-server ovsdb-server/set-active-ovsdb-server tcp:
+ovs-appctl -t ovsdb-server ovsdb-server/connect-active-ovsdb-server
+AT_CHECK([ovs-appctl -t ovsdb-server ovsdb-server/sync-status | grep -c backup], [0], [1
+AT_CHECK([ovn-nbctl ls-add sw1], [1], [ignore],
+[ovn-nbctl: transaction error: {"details":"insert operation not allowed when database server is in read only mode","error":"not allowed"}
2.21.0 (Apple Git-120)

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