ovn: Create the ovn dbs only if the schema file exists

OVN has been split out from openvswitch and it's code is here [1].
With the split we have changed the ovn runtime/data dirs to
/etc/ovn and /usr/share/ovn respectively.

If a user uses latest OVN (when used after the split from
openvswitch), then the extend_start.sh of ovn-nb-db-server and
ovn-sb-db-server will fail because the OVN schema files will be in different
location (new location is /usr/share/ovn/ovn-nb.ovschema and /usr/share/ovn/ovn-sb.ovschema)

The old location is - /usr/share/openvswitch/ovn-nb.ovschema and
/usr/share/openvswitch/ovn-sb.ovschema

This patch checks for the presence of the schema files in the old location before
accessing them.

For latest OVN, it is advisable to use the "ovn-ctl" script to start
and stop OVN ovsdb-servers. ovn-citl script takes care of creating the dbs
and updating the dbs if the schema is updated.

[1] - https://github.com/ovn-org/ovn
      https://github.com/openvswitch/ovs/commit/f3e24610ea18eb873dc860f1710432e9aacd27fd

Change-Id: If2bab2fac5be28ae7e1cd02de13a2de94fe17bac
Closes-bug: 1849633
Signed-off-by: Numan Siddique <nusiddiq@redhat.com>

2 files changed, 30 insertions, 4 deletions

diff --git a/docker/ovn/ovn-nb-db-server/extend_start.sh b/docker/ovn/ovn-nb-db-server/extend_start.sh
index dffc85c1f..dfaa0f12a 100644
--- a/docker/ovn/ovn-nb-db-server/extend_start.sh
+++ b/docker/ovn/ovn-nb-db-server/extend_start.sh
@@ -1,6 +1,19 @@
 #!/bin/bash
 
 mkdir -p "/run/openvswitch"
-if [[ ! -e "/var/lib/openvswitch/ovnnb.db" ]]; then
-    ovsdb-tool create "/var/lib/openvswitch/ovnnb.db" "/usr/share/openvswitch/ovn-nb.ovsschema"
+
+# Check for the presence of schema file in the old
+# location before accessing it.
+# Note: If latest OVN is used (post split from openvswitch),
+# then the new location for the schema file
+# is - /usr/share/ovn/ovn-nb.ovsschema.
+# It is advisable to use the ovn-ctl script to start
+# ovn NB db server. ovn-ctl takes care of creating the
+# db file from the schema file if the db file is not
+# present. ovn-ctl also takes care of updating the db file
+# if the schema file is updated.
+if [[ -e "/usr/share/openvswitch/ovn-nb.ovsschema" ]]; then
+    if [[ ! -e "/var/lib/openvswitch/ovnnb.db" ]]; then
+        ovsdb-tool create "/var/lib/openvswitch/ovnnb.db" "/usr/share/openvswitch/ovn-nb.ovsschema"
+    fi
 fi
diff --git a/docker/ovn/ovn-sb-db-server/extend_start.sh b/docker/ovn/ovn-sb-db-server/extend_start.sh
index 688e37a0e..782a49c37 100644
--- a/docker/ovn/ovn-sb-db-server/extend_start.sh
+++ b/docker/ovn/ovn-sb-db-server/extend_start.sh
@@ -1,6 +1,19 @@
 #!/bin/bash
 
 mkdir -p "/run/openvswitch"
-if [[ ! -e "/var/lib/openvswitch/ovnsb.db" ]]; then
-    ovsdb-tool create "/var/lib/openvswitch/ovnsb.db" "/usr/share/openvswitch/ovn-sb.ovsschema"
+
+# Check for the presence of schema file in the old
+# location before accessing it.
+# Note: If latest OVN is used (post split from openvswitch),
+# then the new location for the schema file
+# is - /usr/share/ovn/ovn-sb.ovsschema.
+# It is advisable to use the ovn-ctl script to start
+# ovn SB db server. ovn-ctl takes care of creating the
+# db file from the schema file if the db file is not
+# present. ovn-ctl also takes care of updating the db file
+# if the schema file is updated.
+if [[ -e "/usr/share/openvswitch/ovn-sb.ovsschema" ]]; then
+    if [[ ! -e "/var/lib/openvswitch/ovnsb.db" ]]; then
+        ovsdb-tool create "/var/lib/openvswitch/ovnsb.db" "/usr/share/openvswitch/ovn-sb.ovsschema"
+    fi
 fi