主Ingress副本变为0后报503问题分析 #

// getDefaultUpstream 返回与默认后端关联的上游 578行
// 配置上游在错误情况下返回 HTTP 代码 503
func (n *NGINXController) getDefaultUpstream() *ingress.Backend {
    upstream := &ingress.Backend{
        Name: defUpstreamName,
    }
    svcKey := n.cfg.DefaultService

    if svcKey == "" {
        upstream.Endpoints = append(upstream.Endpoints, n.DefaultEndpoint())
        return upstream
    }
    
    // 找不到服务或服务没有有效端点时返回DefaultEndpoint
    // DefaultEndpoint通常返回503错误
    // ...
}

// nonCanaryIngressExists 只有在存在一个或多个可能合并到的ingress时才允许合并canary ingress 1544行行
func nonCanaryIngressExists(ingresses, canaryIngresses []*ingress.Ingress) bool {
    return len(ingresses)-len(canaryIngresses) > 0
}

// mergeAlternativeBackends处理 903行
if nonCanaryIngressExists(ingresses, canaryIngresses) {
    for _, canaryIng := range canaryIngresses {
        mergeAlternativeBackends(canaryIng, upstreams, servers)
    }
}

func (n *NGINXController) serviceEndpoints(svcKey, backendPort string) ([]ingress.Endpoint, error) {
    // ...
    if len(endps) == 0 {
        klog.Warningf("Service %q does not have any active Endpoint.", svcKey)
    }
    // ...
}

// getBackendServers方法内 1120行
if len(upstreams[name].Endpoints) == 0 {
    n.metricCollector.IncOrphanIngress(ing.Namespace, ing.Name, orphanMetricLabelNoEndpoint)
}

// createServers方法
for _, ing := range data {
    // ...
    if anns.Canary.Enabled {
        klog.V(2).Infof("Ingress %v is marked as Canary, ignoring", ingKey)
        continue
    }
    // ...
}

func (n *NGINXController) syncIngress(interface{}) error {
    // ...
    ings := n.store.ListIngresses()
    hosts, servers, pcfg := n.getConfiguration(ings)
    // ...
}