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implement canary annotation and alternative backends

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Adds the ability to create alternative backends. Alternative backends enable
traffic shaping by sharing a single location but routing to different
backends depending on the TrafficShapingPolicy defined by AlternativeBackends.

When the list of upstreams and servers are retrieved, we then call
mergeAlternativeBackends which iterates through the paths of every ingress
and checks if the backend supporting the path is a AlternativeBackend. If
so, we then iterate through the map of servers and find the real backend
that the AlternativeBackend should fall under. Once found, the
AlternativeBackend is embedded in the list of VirtualBackends for the real
backend.

If no matching real backend for a AlternativeBackend is found, then the
AlternativeBackend is deleted as it cannot be backed by any server.
This commit is contained in:
Conor Landry 2018-09-18 14:05:32 -04:00
parent 5ceb723963
commit 412cd70d3a
18 changed files with 859 additions and 23 deletions
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103
internal/ingress/controller/controller.go
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@ -268,6 +268,7 @@ func (n *NGINXController) getBackendServers(ingresses []*extensions.Ingress) ([]
if host == "" {
host = defServerName
}
server := servers[host]
if server == nil {
server = servers[defServerName]
@ -300,13 +301,15 @@ func (n *NGINXController) getBackendServers(ingresses []*extensions.Ingress) ([]
}
for _, path := range rule.HTTP.Paths {
upsName := fmt.Sprintf("%v-%v-%v",
ing.Namespace,
path.Backend.ServiceName,
path.Backend.ServicePort.String())
upsName := upstreamName(ing.Namespace, path.Backend.ServiceName, path.Backend.ServicePort)
ups := upstreams[upsName]
// Backend is not referenced to by a server
if ups.NoServer {
continue
}
nginxPath := rootLocation
if path.Path != "" {
nginxPath = path.Path
@ -416,6 +419,11 @@ func (n *NGINXController) getBackendServers(ingresses []*extensions.Ingress) ([]
}
}
}
if anns.Canary.Enabled {
glog.Infof("Canary ingress %v detected. Finding eligible backends to merge into.", ing.Name)
mergeAlternativeBackends(ing, upstreams, servers)
}
}
aUpstreams := make([]*ingress.Backend, 0, len(upstreams))
@ -513,10 +521,7 @@ func (n *NGINXController) createUpstreams(data []*extensions.Ingress, du *ingres
var defBackend string
if ing.Spec.Backend != nil {
defBackend = fmt.Sprintf("%v-%v-%v",
ing.Namespace,
ing.Spec.Backend.ServiceName,
ing.Spec.Backend.ServicePort.String())
defBackend = upstreamName(ing.Namespace, ing.Spec.Backend.ServiceName, ing.Spec.Backend.ServicePort)
glog.V(3).Infof("Creating upstream %q", defBackend)
upstreams[defBackend] = newUpstream(defBackend)
@ -542,6 +547,16 @@ func (n *NGINXController) createUpstreams(data []*extensions.Ingress, du *ingres
}
}
// configure traffic shaping for canary
if anns.Canary.Enabled {
upstreams[defBackend].NoServer = true
upstreams[defBackend].TrafficShapingPolicy = ingress.TrafficShapingPolicy{
Weight: anns.Canary.Weight,
Header: anns.Canary.Header,
Cookie: anns.Canary.Cookie,
}
}
if len(upstreams[defBackend].Endpoints) == 0 {
endps, err := n.serviceEndpoints(svcKey, ing.Spec.Backend.ServicePort.String())
upstreams[defBackend].Endpoints = append(upstreams[defBackend].Endpoints, endps...)
@ -558,10 +573,7 @@ func (n *NGINXController) createUpstreams(data []*extensions.Ingress, du *ingres
}
for _, path := range rule.HTTP.Paths {
name := fmt.Sprintf("%v-%v-%v",
ing.Namespace,
path.Backend.ServiceName,
path.Backend.ServicePort.String())
name := upstreamName(ing.Namespace, path.Backend.ServiceName, path.Backend.ServicePort)
if _, ok := upstreams[name]; ok {
continue
@ -595,6 +607,16 @@ func (n *NGINXController) createUpstreams(data []*extensions.Ingress, du *ingres
}
}
// configure traffic shaping for canary
if anns.Canary.Enabled {
upstreams[name].NoServer = true
upstreams[name].TrafficShapingPolicy = ingress.TrafficShapingPolicy{
Weight: anns.Canary.Weight,
Header: anns.Canary.Header,
Cookie: anns.Canary.Cookie,
}
}
if len(upstreams[name].Endpoints) == 0 {
endp, err := n.serviceEndpoints(svcKey, path.Backend.ServicePort.String())
if err != nil {
@ -970,6 +992,63 @@ func (n *NGINXController) createServers(data []*extensions.Ingress,
return servers
}
// Compares an Ingress of a potential alternative backend's rules with each existing server and finds matching host + path pairs.
// If a match is found, we know that this server should back the alternative backend and add the alternative backend
// to a backend's alternative list.
// If no match is found, then the serverless backend is deleted.
func mergeAlternativeBackends(ing *extensions.Ingress, upstreams map[string]*ingress.Backend,
servers map[string]*ingress.Server) {
// merge catch-all alternative backends
if ing.Spec.Backend != nil {
upsName := upstreamName(ing.Namespace, ing.Spec.Backend.ServiceName, ing.Spec.Backend.ServicePort)
ups := upstreams[upsName]
defLoc := servers[defServerName].Locations[0]
glog.Infof("matching backend %v found for alternative backend %v",
upstreams[defLoc.Backend].Name, ups.Name)
upstreams[defLoc.Backend].AlternativeBackends =
append(upstreams[defLoc.Backend].AlternativeBackends, ups.Name)
}
for _, rule := range ing.Spec.Rules {
for _, path := range rule.HTTP.Paths {
upsName := upstreamName(ing.Namespace, path.Backend.ServiceName, path.Backend.ServicePort)
ups := upstreams[upsName]
merged := false
server := servers[rule.Host]
// find matching paths
for _, location := range server.Locations {
if location.Backend == defUpstreamName {
continue
}
if location.Path == path.Path && !upstreams[location.Backend].NoServer {
glog.Infof("matching backend %v found for alternative backend %v",
upstreams[location.Backend].Name, ups.Name)
upstreams[location.Backend].AlternativeBackends =
append(upstreams[location.Backend].AlternativeBackends, ups.Name)
merged = true
}
}
if !merged {
glog.Warningf("unable to find real backend for alternative backend %v. Deleting.", ups.Name)
delete(upstreams, ups.Name)
}
}
}
}
// extractTLSSecretName returns the name of the Secret containing a SSL
// certificate for the given host name, or an empty string.
func extractTLSSecretName(host string, ing *extensions.Ingress,