[backport] cherry-pick 988003b into release-v1.1

fix(envoy): add keep-alive time to detect sidecar disconnections (#5189)

- Defines a 60s keep-alive time after which probes will start
being sent to check if a sidecar is still connected to the
control plane
- Defines 5s interval and 5 probes after which connection
will time out

Signed-off-by: Sanya Kochhar <[email protected]>
Signed-off-by: Shalier Xia <[email protected]>

pkg/envoy/bootstrap/config.go

@@ -11,6 +11,7 @@ import (
 	xds_upstream_http "github.com/envoyproxy/go-control-plane/envoy/extensions/upstreams/http/v3"
 	"github.com/golang/protobuf/ptypes/any"
 	"google.golang.org/protobuf/types/known/anypb"
+	"google.golang.org/protobuf/types/known/wrapperspb"
 
 	"github.com/openservicemesh/osm/pkg/constants"
 	"github.com/openservicemesh/osm/pkg/envoy"
@@ -183,6 +184,13 @@ func BuildFromConfig(config Config) (*xds_bootstrap.Bootstrap, error) {
 							},
 						},
 					},
+					UpstreamConnectionOptions: &xds_cluster.UpstreamConnectionOptions{
+						TcpKeepalive: &xds_core.TcpKeepalive{
+							KeepaliveProbes:   wrapperspb.UInt32(5),
+							KeepaliveTime:     wrapperspb.UInt32(60),
+							KeepaliveInterval: wrapperspb.UInt32(5),
+						},
+					},
 				},
 			},
 		},