From 83ca0c42d72c4f0ea7a505ba53b692c40b8fc3e3 Mon Sep 17 00:00:00 2001 From: Murali Reddy Date: Wed, 19 Jul 2017 21:13:03 +0530 Subject: [PATCH] BGP export polices to advertise routes so that extra hop is avoided Fixes #71 --- app/controllers/network_routes_controller.go | 193 +++++++++++++------ 1 file changed, 134 insertions(+), 59 deletions(-) diff --git a/app/controllers/network_routes_controller.go b/app/controllers/network_routes_controller.go index 074a8b1932..5fe3c9d45a 100644 --- a/app/controllers/network_routes_controller.go +++ b/app/controllers/network_routes_controller.go @@ -42,6 +42,7 @@ type NetworkRoutingController struct { defaultNodeAsnNumber uint32 nodeAsnNumber uint32 globalPeerRouters []string + nodePeerRouters []string globalPeerAsnNumber uint32 bgpFullMeshMode bool } @@ -149,6 +150,11 @@ func (nrc *NetworkRoutingController) Run(stopCh <-chan struct{}, wg *sync.WaitGr glog.Errorf("Failed to advertise route: %s", err.Error()) } + err = nrc.addExportPolicies() + if err != nil { + glog.Errorf("Failed to add BGP export policies due to %s", err.Error()) + } + select { case <-stopCh: glog.Infof("Shutting down network routes controller") @@ -186,6 +192,7 @@ func (nrc *NetworkRoutingController) advertiseRoute() error { if err != nil { return err } + cidrStr := strings.Split(cidr, "/") subnet := cidrStr[0] cidrLen, err := strconv.Atoi(cidrStr[1]) @@ -201,6 +208,21 @@ func (nrc *NetworkRoutingController) advertiseRoute() error { return nil } +func (nrc *NetworkRoutingController) getClusterIps() ([]string, error) { + clusterIpList := make([]string, 0) + for _, svc := range watchers.ServiceWatcher.List() { + if svc.Spec.Type == "ClusterIP" || svc.Spec.Type == "NodePort" || svc.Spec.Type == "LoadBalancer" { + + // skip headless services + if svc.Spec.ClusterIP == "None" || svc.Spec.ClusterIP == "" { + continue + } + clusterIpList = append(clusterIpList, svc.Spec.ClusterIP) + } + } + return clusterIpList, nil +} + func (nrc *NetworkRoutingController) AdvertiseClusterIp(clusterIp string) error { attrs := []bgp.PathAttributeInterface{ @@ -215,6 +237,117 @@ func (nrc *NetworkRoutingController) AdvertiseClusterIp(clusterIp string) error return nil } +// Each node advertises its pod CIDR to the nodes with same ASN (iBGP peers) and to the global BGP peer +// or per node BGP peer. Each node ends up advertising not only pod CIDR assigned to the self but other +// routers learned to the node pod CIDR's as well to global BGP peer or per node BGP peers. external BGP +// peer will randomly (since all path have equal selection atributes) select the routes from multiple +// routes to a pod CIDR which will result in extra hop. To prevent this behaviour this methods add +// defult export policy to reject. and explicit policy is added so that each node only advertised the +// pod CIDR assigned to it. Additionally export policy is added so that a node advertises cluster IP's +// only to the external BGP peers. +func (nrc *NetworkRoutingController) addExportPolicies() error { + + cidr, err := utils.GetPodCidrFromNodeSpec(nrc.clientset, nrc.hostnameOverride) + if err != nil { + return err + } + + // creates prefix set to represent the assigned node's pod CIDR + podCidrPrefixSet, err := table.NewPrefixSet(config.PrefixSet{ + PrefixSetName: "podcidrprefixset", + PrefixList: []config.Prefix{ + config.Prefix{ + IpPrefix: cidr, + }, + }, + }) + nrc.bgpServer.AddDefinedSet(podCidrPrefixSet) + + // creates prefix set to represent all the cluster IP associated with the services + clusterIpPrefixList := make([]config.Prefix, 0) + clusterIps, _ := nrc.getClusterIps() + for _, ip := range clusterIps { + clusterIpPrefixList = append(clusterIpPrefixList, config.Prefix{IpPrefix: ip + "/32"}) + } + clusterIpPrefixSet, err := table.NewPrefixSet(config.PrefixSet{ + PrefixSetName: "clusteripprefixset", + PrefixList: clusterIpPrefixList, + }) + nrc.bgpServer.AddDefinedSet(clusterIpPrefixSet) + + statements := make([]config.Statement, 0) + + // statement to represent the export policy to permit advertising node's pod CIDR + statements = append(statements, + config.Statement{ + Conditions: config.Conditions{ + MatchPrefixSet: config.MatchPrefixSet{ + PrefixSet: "podcidrprefixset", + }, + }, + Actions: config.Actions{ + RouteDisposition: config.ROUTE_DISPOSITION_ACCEPT_ROUTE, + }, + }) + + externalBgpPeers := make([]string, 0) + if len(nrc.globalPeerRouters) != 0 { + externalBgpPeers = append(externalBgpPeers, nrc.globalPeerRouters...) + } + if len(nrc.nodePeerRouters) != 0 { + externalBgpPeers = append(externalBgpPeers, nrc.nodePeerRouters...) + } + if len(externalBgpPeers) > 0 { + ns, _ := table.NewNeighborSet(config.NeighborSet{ + NeighborSetName: "externalpeerset", + NeighborInfoList: externalBgpPeers, + }) + nrc.bgpServer.AddDefinedSet(ns) + // statement to represent the export policy to permit advertising cluster IP's + // only to the global BGP peer or node specific BGP peer + statements = append(statements, config.Statement{ + Conditions: config.Conditions{ + MatchPrefixSet: config.MatchPrefixSet{ + PrefixSet: "clusteripprefixset", + }, + MatchNeighborSet: config.MatchNeighborSet{ + NeighborSet: "externalpeerset", + }, + }, + Actions: config.Actions{ + RouteDisposition: config.ROUTE_DISPOSITION_ACCEPT_ROUTE, + }, + }) + } + + definition := config.PolicyDefinition{ + Name: "kube_router", + Statements: statements, + } + + policy, err := table.NewPolicy(definition) + if err != nil { + return err + } + if err = nrc.bgpServer.AddPolicy(policy, false); err != nil { + return err + } + err = nrc.bgpServer.AddPolicyAssignment("", + table.POLICY_DIRECTION_EXPORT, + []*config.PolicyDefinition{&definition}, + table.ROUTE_TYPE_ACCEPT) + if err != nil { + return err + } + + // configure default BGP export policy to reject + pd := make([]*config.PolicyDefinition, 0) + pd = append(pd, &definition) + nrc.bgpServer.ReplacePolicyAssignment("", table.POLICY_DIRECTION_EXPORT, pd, table.ROUTE_TYPE_REJECT) + + return nil +} + func (nrc *NetworkRoutingController) injectRoute(path *table.Path) error { nexthop := path.GetNexthop() nlri := path.GetNlri() @@ -406,65 +539,6 @@ func (nrc *NetworkRoutingController) OnNodeUpdate(nodeUpdate *watchers.NodeUpdat } } -// add BGP export policy so that no learned route from the neightbour -// is exported or advertised to global or per node peer -func (nrc *NetworkRoutingController) initExportPolicies() error { - - nodes, err := nrc.clientset.Core().Nodes().List(metav1.ListOptions{}) - if err != nil { - return err - } - - nieghbors := make([]string, 0) - for _, node := range nodes.Items { - nodeIP, _ := getNodeIP(&node) - if nodeIP.String() == nrc.nodeIP.String() { - continue - } - nieghbors = append(nieghbors, nodeIP.String()) - } - - ns, err := table.NewNeighborSet(config.NeighborSet{ - NeighborSetName: clustetNieghboursSet, - NeighborInfoList: nieghbors, - }) - if err != nil { - return err - } - - err = nrc.bgpServer.AddDefinedSet(ns) - if err != nil { - return err - } - - definition := config.PolicyDefinition{ - Name: "kube_router", - Statements: []config.Statement{ - config.Statement{ - Conditions: config.Conditions{ - MatchNeighborSet: config.MatchNeighborSet{ - NeighborSet: clustetNieghboursSet, - }, - }, - Actions: config.Actions{ - RouteDisposition: config.ROUTE_DISPOSITION_REJECT_ROUTE, - }, - }, - }, - } - - policy, err := table.NewPolicy(definition) - if err != nil { - return err - } - if err = nrc.bgpServer.AddPolicy(policy, false); err != nil { - return err - } - return nrc.bgpServer.AddPolicyAssignment("", table.POLICY_DIRECTION_EXPORT, - []*config.PolicyDefinition{&definition}, - table.ROUTE_TYPE_ACCEPT) -} - func (nrc *NetworkRoutingController) startBgpServer() error { var nodeAsnNumber uint32 @@ -568,6 +642,7 @@ func (nrc *NetworkRoutingController) startBgpServer() error { } } + nrc.nodePeerRouters = nodePeerRouters glog.Infof("Successfully configured %s in ASN %v as BGP peer to the node", nodeBgpPeersAnnotation, peerAsnNo) }