fix: prevent hypervisor socket deletion during CAA rolling restart

During a rolling update, the old and new CAA pods share the same hostPath
(/run/peerpod/). When the old pod's ttrpc.Shutdown() calls listener.Close(),
it unlinks the socket file that the new pod already created, leaving the
shim unable to connect.

Set SetUnlinkOnClose(false) on the Unix listener so the old pod's shutdown
does not remove the socket inode. The new pod's startup already handles
cleanup via os.RemoveAll before creating a fresh socket.

Signed-off-by: Thejas N <thn@redhat.com>

Author: thejasn

src/cloud-api-adaptor/pkg/adaptor/server.go

@@ -124,6 +124,7 @@ func (s *server) Start(ctx context.Context) (err error) {
 	if err != nil {
 		return err
 	}
+	listener.(*net.UnixListener).SetUnlinkOnClose(false)
 
 	ttRPCErr := make(chan error)
 	go func() {

src/cloud-api-adaptor/pkg/adaptor/server_test.go

@@ -174,8 +174,8 @@ func testServerShutdown(t *testing.T, s Server, socketPath, dir string, serverEr
 	if err := <-serverErrCh; err != nil {
 		t.Error(err)
 	}
-	if _, err := os.Stat(socketPath); err == nil {
-		t.Errorf("Unix domain socket %s still remains\n", socketPath)
+	if _, err := os.Stat(socketPath); err != nil {
+		t.Errorf("Unix domain socket %s should remain after shutdown (SetUnlinkOnClose(false))\n", socketPath)
 	}
 	if err := os.RemoveAll(dir); err != nil {
 		t.Error(err)