consul/agent/proxycfg/snapshot.go

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package proxycfg
import (
"context"
"github.com/hashicorp/consul/agent/structs"
"github.com/mitchellh/copystructure"
)
type configSnapshotConnectProxy struct {
Leaf *structs.IssuedCert
DiscoveryChain map[string]*structs.CompiledDiscoveryChain // this is keyed by the Upstream.Identifier(), not the chain name
WatchedUpstreams map[string]map[string]context.CancelFunc
WatchedUpstreamEndpoints map[string]map[string]structs.CheckServiceNodes
connect: fix failover through a mesh gateway to a remote datacenter (#6259) Failover is pushed entirely down to the data plane by creating envoy clusters and putting each successive destination in a different load assignment priority band. For example this shows that normally requests go to 1.2.3.4:8080 but when that fails they go to 6.7.8.9:8080: - name: foo load_assignment: cluster_name: foo policy: overprovisioning_factor: 100000 endpoints: - priority: 0 lb_endpoints: - endpoint: address: socket_address: address: 1.2.3.4 port_value: 8080 - priority: 1 lb_endpoints: - endpoint: address: socket_address: address: 6.7.8.9 port_value: 8080 Mesh gateways route requests based solely on the SNI header tacked onto the TLS layer. Envoy currently only lets you configure the outbound SNI header at the cluster layer. If you try to failover through a mesh gateway you ideally would configure the SNI value per endpoint, but that's not possible in envoy today. This PR introduces a simpler way around the problem for now: 1. We identify any target of failover that will use mesh gateway mode local or remote and then further isolate any resolver node in the compiled discovery chain that has a failover destination set to one of those targets. 2. For each of these resolvers we will perform a small measurement of comparative healths of the endpoints that come back from the health API for the set of primary target and serial failover targets. We walk the list of targets in order and if any endpoint is healthy we return that target, otherwise we move on to the next target. 3. The CDS and EDS endpoints both perform the measurements in (2) for the affected resolver nodes. 4. For CDS this measurement selects which TLS SNI field to use for the cluster (note the cluster is always going to be named for the primary target) 5. For EDS this measurement selects which set of endpoints will populate the cluster. Priority tiered failover is ignored. One of the big downsides to this approach to failover is that the failover detection and correction is going to be controlled by consul rather than deferring that entirely to the data plane as with the prior version. This also means that we are bound to only failover using official health signals and cannot make use of data plane signals like outlier detection to affect failover. In this specific scenario the lack of data plane signals is ok because the effectiveness is already muted by the fact that the ultimate destination endpoints will have their data plane signals scrambled when they pass through the mesh gateway wrapper anyway so we're not losing much. Another related fix is that we now use the endpoint health from the underlying service, not the health of the gateway (regardless of failover mode).
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WatchedGateways map[string]map[string]context.CancelFunc
WatchedGatewayEndpoints map[string]map[string]structs.CheckServiceNodes
WatchedServiceChecks map[string][]structs.CheckType
connect: fix failover through a mesh gateway to a remote datacenter (#6259) Failover is pushed entirely down to the data plane by creating envoy clusters and putting each successive destination in a different load assignment priority band. For example this shows that normally requests go to 1.2.3.4:8080 but when that fails they go to 6.7.8.9:8080: - name: foo load_assignment: cluster_name: foo policy: overprovisioning_factor: 100000 endpoints: - priority: 0 lb_endpoints: - endpoint: address: socket_address: address: 1.2.3.4 port_value: 8080 - priority: 1 lb_endpoints: - endpoint: address: socket_address: address: 6.7.8.9 port_value: 8080 Mesh gateways route requests based solely on the SNI header tacked onto the TLS layer. Envoy currently only lets you configure the outbound SNI header at the cluster layer. If you try to failover through a mesh gateway you ideally would configure the SNI value per endpoint, but that's not possible in envoy today. This PR introduces a simpler way around the problem for now: 1. We identify any target of failover that will use mesh gateway mode local or remote and then further isolate any resolver node in the compiled discovery chain that has a failover destination set to one of those targets. 2. For each of these resolvers we will perform a small measurement of comparative healths of the endpoints that come back from the health API for the set of primary target and serial failover targets. We walk the list of targets in order and if any endpoint is healthy we return that target, otherwise we move on to the next target. 3. The CDS and EDS endpoints both perform the measurements in (2) for the affected resolver nodes. 4. For CDS this measurement selects which TLS SNI field to use for the cluster (note the cluster is always going to be named for the primary target) 5. For EDS this measurement selects which set of endpoints will populate the cluster. Priority tiered failover is ignored. One of the big downsides to this approach to failover is that the failover detection and correction is going to be controlled by consul rather than deferring that entirely to the data plane as with the prior version. This also means that we are bound to only failover using official health signals and cannot make use of data plane signals like outlier detection to affect failover. In this specific scenario the lack of data plane signals is ok because the effectiveness is already muted by the fact that the ultimate destination endpoints will have their data plane signals scrambled when they pass through the mesh gateway wrapper anyway so we're not losing much. Another related fix is that we now use the endpoint health from the underlying service, not the health of the gateway (regardless of failover mode).
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UpstreamEndpoints map[string]structs.CheckServiceNodes // DEPRECATED:see:WatchedUpstreamEndpoints
}
type configSnapshotMeshGateway struct {
WatchedServices map[string]context.CancelFunc
WatchedDatacenters map[string]context.CancelFunc
ServiceGroups map[string]structs.CheckServiceNodes
ServiceResolvers map[string]*structs.ServiceResolverConfigEntry
GatewayGroups map[string]structs.CheckServiceNodes
}
// ConfigSnapshot captures all the resulting config needed for a proxy instance.
// It is meant to be point-in-time coherent and is used to deliver the current
// config state to observers who need it to be pushed in (e.g. XDS server).
type ConfigSnapshot struct {
Kind structs.ServiceKind
Service string
ProxyID string
Address string
Port int
TaggedAddresses map[string]structs.ServiceAddress
Proxy structs.ConnectProxyConfig
Datacenter string
Roots *structs.IndexedCARoots
// connect-proxy specific
ConnectProxy configSnapshotConnectProxy
// mesh-gateway specific
MeshGateway configSnapshotMeshGateway
// Skip intentions for now as we don't push those down yet, just pre-warm them.
}
// Valid returns whether or not the snapshot has all required fields filled yet.
func (s *ConfigSnapshot) Valid() bool {
switch s.Kind {
case structs.ServiceKindConnectProxy:
// TODO(rb): sanity check discovery chain things here?
return s.Roots != nil && s.ConnectProxy.Leaf != nil
case structs.ServiceKindMeshGateway:
// TODO (mesh-gateway) - what happens if all the connect services go away
return s.Roots != nil && len(s.MeshGateway.ServiceGroups) > 0
default:
return false
}
}
// Clone makes a deep copy of the snapshot we can send to other goroutines
// without worrying that they will racily read or mutate shared maps etc.
func (s *ConfigSnapshot) Clone() (*ConfigSnapshot, error) {
snapCopy, err := copystructure.Copy(s)
if err != nil {
return nil, err
}
snap := snapCopy.(*ConfigSnapshot)
// nil these out as anything receiving one of these clones does not need them and should never "cancel" our watches
switch s.Kind {
case structs.ServiceKindConnectProxy:
snap.ConnectProxy.WatchedUpstreams = nil
connect: fix failover through a mesh gateway to a remote datacenter (#6259) Failover is pushed entirely down to the data plane by creating envoy clusters and putting each successive destination in a different load assignment priority band. For example this shows that normally requests go to 1.2.3.4:8080 but when that fails they go to 6.7.8.9:8080: - name: foo load_assignment: cluster_name: foo policy: overprovisioning_factor: 100000 endpoints: - priority: 0 lb_endpoints: - endpoint: address: socket_address: address: 1.2.3.4 port_value: 8080 - priority: 1 lb_endpoints: - endpoint: address: socket_address: address: 6.7.8.9 port_value: 8080 Mesh gateways route requests based solely on the SNI header tacked onto the TLS layer. Envoy currently only lets you configure the outbound SNI header at the cluster layer. If you try to failover through a mesh gateway you ideally would configure the SNI value per endpoint, but that's not possible in envoy today. This PR introduces a simpler way around the problem for now: 1. We identify any target of failover that will use mesh gateway mode local or remote and then further isolate any resolver node in the compiled discovery chain that has a failover destination set to one of those targets. 2. For each of these resolvers we will perform a small measurement of comparative healths of the endpoints that come back from the health API for the set of primary target and serial failover targets. We walk the list of targets in order and if any endpoint is healthy we return that target, otherwise we move on to the next target. 3. The CDS and EDS endpoints both perform the measurements in (2) for the affected resolver nodes. 4. For CDS this measurement selects which TLS SNI field to use for the cluster (note the cluster is always going to be named for the primary target) 5. For EDS this measurement selects which set of endpoints will populate the cluster. Priority tiered failover is ignored. One of the big downsides to this approach to failover is that the failover detection and correction is going to be controlled by consul rather than deferring that entirely to the data plane as with the prior version. This also means that we are bound to only failover using official health signals and cannot make use of data plane signals like outlier detection to affect failover. In this specific scenario the lack of data plane signals is ok because the effectiveness is already muted by the fact that the ultimate destination endpoints will have their data plane signals scrambled when they pass through the mesh gateway wrapper anyway so we're not losing much. Another related fix is that we now use the endpoint health from the underlying service, not the health of the gateway (regardless of failover mode).
2019-08-05 18:30:35 +00:00
snap.ConnectProxy.WatchedGateways = nil
case structs.ServiceKindMeshGateway:
snap.MeshGateway.WatchedDatacenters = nil
snap.MeshGateway.WatchedServices = nil
}
return snap, nil
}