Container Service for Kubernetes：NGINX Ingress controller troubleshooting

Table of contents

Background information

Container Service for Kubernetes (ACK) provides the NGINX Ingress controller that is optimized based on the open source version. The NGINX Ingress controller provided by ACK is compatible with the open source version and supports all the annotations provided by the open source version. You can install the NGINX Ingress controller when you create an ACK cluster.

Ingresses can work as normal only if you deploy an NGINX Ingress controller in the cluster to parse the routing rules of the Ingresses. After the NGINX Ingress controller receives a request that matches a routing rule, the NGINX Ingress controller routes the request to a corresponding backend Service. The backend Service then forwards the request to pods. In a Kubernetes cluster, Services, Ingresses, and the NGINX Ingress controller work in the following process:

• A Service is an abstraction of a backend application that runs on a set of replicated pods.

• An Ingress contains reverse proxy rules. It controls to which Service pods HTTP or HTTPS requests are routed. For example, requests are routed to different Service pods based on the hosts and URL paths in the requests.

• The NGINX Ingress controller is a reverse proxy program that parses Ingress rules. If changes are made to the Ingress rules, the NGINX Ingress controller updates the Ingress rules accordingly. After the NGINX Ingress controller receives a request, it redirects the request to Service pods based on the Ingress rules.

The NGINX Ingress controller acquires Ingress rule changes from the API server and dynamically generates configuration files, such as nginx.conf. These configuration files are required by a load balancer, such as NGINX. Then, the NGINX Ingress controller reloads the load balancer. For example, the NGINX Ingress controller runs the nginx -s load command to reload NGINX and generates new Ingress rules.

Diagnostics procedure

1. You can perform the following steps to check whether an issue is caused by the Ingress. Make sure that the configuration of the Ingress controller is valid.

   1. Check whether you can access a specific pod from the controller pod. For more information, see the Manually access the Ingress and backend pod by using the Ingress controller pod section of this topic.

   2. Check whether the NGINX Ingress controller is properly configured. For more information, see Documentation for the NGINX Ingress controller.

2. Use the Ingress diagnostics feature to check the configurations of the Ingress and components. Then, modify the configurations as prompted. For more information, see the Use the Ingress diagnostics feature section of this topic.

3. Locate the cause of the issue and refer to the relevant solution described in the Troubleshooting section of this topic.

4. If the issue persists, perform the following steps:

   • Issues that are related to TLS certificates:

     1. Check whether the domain name is added to Web Application Firewall (WAF) in CNAME record mode or transparent proxy mode.

        • If the domain name is added to WAF, check whether the domain name has a TLS certificate.

        • If the domain name is not added to WAF, proceed to the next step.

     2. Check whether a Layer 7 listener is configured for the Server Load Balancer (SLB) instance.

        • If a Layer 7 listener is configured for the SLB instance, check whether a TLS certificate is associated with the listener.

        • If no Layer 7 listener is configured for the SLB instance, proceed to the next step.

   • If the issue is not related to TLS certificates, check the error log of the controller pod. For more information, see the Diagnose the error log of the NGINX Ingress controller pod section of this topic.

5. If the issue persists, locate the cause of the issue by capturing packets in the controller pod and the backend pod. For more information, see the Capture packets section of this topic.

6. If the issue persists, submit a ticket.

Troubleshooting

Commonly used diagnostics methods

Use the Ingress diagnostics feature

1. Log on to the ACK console. In the left-side navigation pane, click Clusters.

2. On the Clusters page, find the cluster that you want to manage and click its name. In the left-side pane, choose Inspections and Diagnostics > Diagnostics.

3. On the Diagnostics page, click Ingress diagnosis.

4. On the Ingress diagnosis page, click Diagnosis. In the Select Ingress panel, enter the URL that cannot be accessed, such as https://www.example.com. Select I know and agree and then click Create diagnosis.

   After the diagnostics is complete, you can view the diagnostics results and try to fix the issue.

Diagnose the access log of the NGINX Ingress controller pod in Simple Log Service

You can check the access log format of the NGINX Ingress controller in the nginx-configuration ConfigMap in the kube-system namespace.

$remote_addr - [$remote_addr] - $remote_user [$time_local]
    "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent" $request_length
    $request_time [$proxy_upstream_name] $upstream_addr $upstream_response_length
    $upstream_response_time $upstream_status $req_id $host [$proxy_alternative_upstream_name]

The following figure shows the page on which the access log of the NGINX Ingress controller is displayed in the Simple Log Service console. For more information, see the Step 4: View log data section of the "Collect log data from containers by using Simple Log Service" topic.

kubectl logs <controller pod name> -n <namespace> | less

42.11.**.** - [42.11.**.**]--[25/Nov/2021:11:40:30 +0800]"GET / HTTP/1.1" 200 615 "_" "curl/7.64.1" 76 0.001 [default-nginx-svc-80] 172.16.254.208:80 615 0.000 200 46b79dkahflhakjhdhfkah**** 47.11.**.**[]
42.11.**.** - [42.11.**.**]--[25/Nov/2021:11:40:31 +0800]"GET / HTTP/1.1" 200 615 "_" "curl/7.64.1" 76 0.001 [default-nginx-svc-80] 172.16.254.208:80 615 0.000 200 fadgrerthflhakjhdhfkah**** 47.11.**.**[]

Diagnose the error log of the NGINX Ingress controller pod

You can diagnose the error log of the NGINX Ingress controller pod to narrow down the scope of troubleshooting. The error log of the Ingress controller pod includes the following types:

• The log that records errors of the Ingress controller. Typically, this type of error log is generated due to invalid Ingress configurations. You can run the following command to query this type of error log:

  kubectl logs <controller pod name> -n <namespace> | grep -E ^[WE]

  Note

  During the initialization of an Ingress controller, a few warning events may be generated. For example, if you do not specify the kubeconfig file or IngressClass resource, warning events are generated. These events do not affect the Ingress controller and can be ignored.

• The log that records errors of the NGINX application. Typically, this type of error log is generated due to failed requests. You can run the following command to query this type of error log:

  kubectl logs <controller pod name> -n <namespace> | grep error

Manually access the Ingress and backend pod by using the Ingress controller pod

1. Run the following command to log on to the Ingress controller pod:

   kubectl exec <controller pod name> -n <namespace> -it -- bash

2. The Ingress controller pod is preinstalled with curl and OpenSSL, which allow you to test network connectivity and verify certificates.

   • Run the following command to test the network connectivity between the Ingress and the backend pod:

     # Replace your.domain.com with the actual domain name of the Ingress. 
     curl -H "Host: your.domain.com" http://127.0.**.**/ # for http
     curl --resolve your.domain.com:443:127.0.0.1 https://127.0.0.1/ # for https

   • Run the following command to verify the certificate:

     openssl s_client -servername your.domain.com -connect 127.0.0.1:443

   • Test access to the backend pod.

     Note

     An Ingress controller directly connects to the IP address of the backend pod instead of by using a ClusterIP Service.

     1. Run the following kubectl command to query the IP address of the backend pod:

        kubectl get pod -n <namespace> <pod name> -o wide

        Expected output:

        NAME                      READY    STATUS    RESTARTS   AGE    IP            NODE                        NOMINATED NODE    READINESS GATES
        nginx-dp-7f5fcc7f-****    1/1      Running   0          23h    10.71.0.146   cn-beijing.192.168.**.**    <none>            <none>

        The output shows that the IP address of the backend pod is 10.71.0.146.

     2. To test the network connectivity between the Ingress controller pod and the backend pod, run the following command to connect to the IP address by using the Ingress controller pod:

        curl http://<your pod ip>:<port>/path

Capture packets

If you cannot identify the issue, capture and diagnose packets.

1. Check whether the issue is related to the Ingress controller pod or the application pod. If no sufficient information is available, capture packets for both the Ingress controller pod and the application pod.

2. Log on to the nodes on which the application pod and Ingress controller pod run.

3. Run the following command on the Elastic Compute Service (ECS) instances to capture all recent packets that are received by the Ingress:

   tcpdump -i any host <IP address of the application pod or Ingress controller pod> -C 20 -W 200 -w /tmp/ingress.pcap

4. If an error is identified in the log data, stop capturing packets.

5. Diagnose the packets that are transferred during the time period in which the error occurred.

   Note

   • Packet capture does not affect your service and only causes a slight increase in the CPU utilization and disk I/O.

   • The preceding command rotates the captured packets and can generate up to 200 .pcap files, each of which is 20 MB in size.

Why am I unable to access the IP address of the LoadBalancer Service within the Kubernetes cluster?

Issue

In a Kubernetes cluster, only specific nodes can access the IP address of the LoadBalancer Service if the externalTrafficPolicy parameter is set to Local for the LoadBalancer Service.

Cause

externalTrafficPolicy: Local is set for the LoadBalancer Service. In Local mode, the IP address of the LoadBalancer Service is accessible only from pods that are provisioned on the local node that runs the LoadBalancer Service. The IP address of the LoadBalancer Service is inaccessible from pods on other nodes in the cluster. The IP address of the LoadBalancer Service enables external access to the Kubernetes cluster. If nodes or pods in the ACK cluster cannot access the IP address without using a second hop, requests do not pass through the LoadBalancer Service. As a result, the IP address of the LoadBalancer Service is considered an extended IP address of the Service that uses the LoadBalancer Service. Requests are forwarded by kube-proxy based on iptables or IP Virtual Server (IPVS).

In this scenario, if the requested pod is not provisioned on the local node, a connectivity issue occurs. The IP address of the LoadBalancer Service is accessible only if the requested pod is provisioned on the local node. For more information about external-lb, see kube-proxy adds the IP address of external-lb to the node local iptables rules.

Solution

• We recommend that you access the IP address of the LoadBalancer Service within the Kubernetes cluster by using the ClusterIP Service or the Ingress name.

  The Ingress is named nginx-ingress-lb in the kube-system namespace.

• Run the kubectl edit svc nginx-ingress-lb -n kube-system command to modify the Ingress. Set the externalTrafficPolicy parameter to Cluster for the LoadBalancer Service. After you change the setting, client IP addresses cannot be preserved.

• If the cluster uses the Terway network plug-in and the exclusive or inclusive elastic network interface (ENI) mode is enabled for the cluster, you can set the externalTrafficPolicy parameter to Cluster for the LoadBalancer Service and add the ENI annotation. The annotation adds pods that are assigned ENIs as the backend servers of the LoadBalancer Service. This way, client IP addresses can be preserved and the IP address of the LoadBalancer Service can be accessed within the cluster.

  Sample code:

  apiVersion: v1
  kind: Service
  metadata:
    annotations:
      service.beta.kubernetes.io/backend-type: eni   # Specify pods that are assigned ENIs as backend servers. 
    labels:
      app: nginx-ingress-lb
    name: nginx-ingress-lb
    namespace: kube-system
  spec:
    externalTrafficPolicy: Cluster

  For more information about Service annotations, see Add annotations to the YAML file of a Service to configure CLB instances.

Why does the Ingress controller pod fail to access the Ingress controller?

Issue

In a cluster that uses Flannel, when the Ingress controller pod accesses the Ingress controller bsaed on a domain name, an IP address of an SLB instance, or cluster IP address, some or all of the requests sent from the Ingress controller pod fail.

Cause

By default, Flannel does not allow loopback requests.

Solution

• We recommend that you create a new cluster that uses the Terway network plug-in and migrate your workloads to the new cluster.

• If you do not want to create a new cluster, you can enable hairpinMode in the configurations of Flannel. After you modify the configurations, recreate the Flannel pod to make the modification take effect.

  1. Run the following command to modify the configurations of Flannel:

     kubectl edit cm kube-flannel-cfg -n kube-system

  2. In the cni-conf.json file that is returned, add "hairpinMode": true in the delegate field.

     Sample code:

     cni-conf.json: |
         {
           "name": "cb0",
           "cniVersion":"0.3.1",
           "type": "flannel",
           "delegate": {
             "isDefaultGateway": true,
             "hairpinMode": true
           }
         }

  3. Run the following command to delete the previous Flannel pod and recreate the Flannel pod:

     kubectl delete pod -n kube-system -l app=flannel   

Why is the default TLS certificate or the previous TLS certificate used after I add a TLS certificate to the cluster or change the TLS certificate?

Issue

You added a Secret to the cluster or modified a Secret in the cluster, and updated the Secret name in the secretName field in the Ingress. When you access the cluster, the default certificate (Kubernetes Ingress Controller Fake Certificate) or the previous certificate is used.

Cause

• The certificate is not returned by the Ingress controller in the cluster.

• The certificate is invalid and the Ingress controller cannot load the certificate.

• The certificate is returned by the Ingress controller based on the Server Name Indication (SNI) field. The SNI field may not be sent as a part of the TLS handshake.

Solution

• Use one of the following methods to check whether the SNI field is sent as a part of the TLS handshake:

  • Update your browser to a version that supports SNI.

  • When you run the openssl s_client command to check whether the certificate is in use, specify the -servername parameter.

  • When you run curl commands, add hosts or use the --resolve parameter to map the domain name instead of using the IP address and host request header.

• Make sure that no TLS certificate is specified when you connect the website to WAF in CNAME record mode or transparent proxy mode, or no TLS certificate is associated with the Layer 7 listener of the SLB instance. The TLS certificate must be returned by the Ingress controller in the cluster.

• Go to the Container Intelligence Service console and diagnose the Ingress. In the diagnostics report, check whether the configurations of the Ingress are valid and whether the log data shows errors. For more information, see the Use the Ingress diagnostics feature section of this topic.

• Run the following command to view the error log of the Ingress controller pod and troubleshoot the issue based on the log data.

  kubectl logs <ingress pod name> -n <pod namespace> | grep -E ^[EW]

Why am I unable to access gRPC Services that are exposed by an Ingress?

Issue

You cannot access gRPC Services that are exposed by an Ingress.

Cause

• You do not set annotations in the Ingress to specify the backend protocol.

• gRPC Services can be accessed only over Transport Layer Security (TLS).

Solution

• Set the following annotation in the Ingress: nginx.ingress.kubernetes.io/backend-protocol:"GRPC".

• Make sure that clients use HTTPS ports to send requests and the traffic is encrypted by using TLS.

Why am I unable to access backend HTTPS services?

Issue

• You fail to access backend HTTPS services based on the Ingress.

• A 400 error code may be returned and the following error message may be reported: The plain HTTP request was sent to HTTPS port.

Cause

The Ingress controller sends HTTP requests to the backend pods. This is the default setting.

Solution

Set the following annotation in the Ingress: nginx.ingress.kubernetes.io/backend-protocol:"HTTPS".

Why does the Ingress controller pod fail to preserve client IP addresses?

Issue

The Ingress controller pod fails to preserve client IP addresses. The node IP address, 100.XX.XX.XX, or other addresses are displayed.

Cause

• The externalTrafficPolicy parameter is set to Cluster for the Service that is associated with the Ingress.

• A Layer 7 proxy is used by the SLB instance.

• Your website is connected to WAF in CNAME record mode or transparent proxy mode.

Solution

• If the externalTrafficPolicy parameter is set to Cluster for the Service and a Layer 4 SLB instance is used, perform the following steps:

  Set the externalTrafficPolicy parameter to Local. However, you may fail to access the IP address of the LoadBalancer Service within the cluster. For more information, see the Why am I unable to access the IP address of the LoadBalancer Service within the Kubernetes cluster?

• Perform the following steps if a Layer 7 proxy is used. For example, a Layer 7 SLB instance is used or your website is connected to WAF in CNAME record mode or transparent proxy mode,

  1. Make sure that the X-Forwarded-For header is enabled for the Layer 7 proxy.

  2. Add enable-real-ip: "true" to the ConfigMap of the Ingress controller. By default, the ConfigMap is named nginx-configuration and belongs to the kube-system namespace.

  3. Analyze the log data to check whether client IP addresses can be preserved.

• If a client request traverses multiple hops before it reaches the Ingress controller pod, such as the case that the request must pass through a reverse proxy before it reaches the Ingress controller pod, you can check the value of remote_addr after you set enable-real-ip to true. If the value is a client IP address, the X-Forwarded-For header is enabled to pass client IP addresses to the Ingress controller pod. If the X-Forwarded-For header is disabled, enable the X-Forwarded-For header or use other methods to add client IP addresses to requests before the requests reach the Ingress controller pod.

Why do canary release rules fail to take effect?

Issue

You set canary release rules in a cluster but the rules do not take effect.

Cause

Possible causes:

• When you add canary-* annotations, you do not set nginx.ingress.kubernetes.io/canary: "true".

• The version of the NGINX Ingress controller is earlier than 0.47.0. When you add canary-* annotations, you do not specify the domain name of your application in the host field of the Ingress rules.

Solution

• If the issue occurs due to the preceding reasons, set nginx.ingress.kubernetes.io/canary: "true" or specify the domain name of your application in the host field of the Ingress rules. For more information, see Use the NGINX Ingress controller to implement canary releases and blue-green releases.

• If none of the preceding reasons causes the issue, see the What do I do if traffic is not distributed based on canary release rules or traffic from other Ingresses is routed to the canary Service? section of this topic.

What do I do if traffic is not distributed based on canary release rules or traffic from other Ingresses is routed to the canary Service?

Issue

You configured canary release rules but traffic is not distributed based on the canary release rules, or traffic from other Ingresses is routed to the canary Service.

Cause

Canary release rules in an NGINX Ingress controller take effect on all Ingresses that are associated with the Service for which the canary release rules are created.

For more information about this issue, see An Ingress with canary will impact all ingresses with the same Service.

Solution

Canary Ingresses include Ingresses that are assigned the service-match or canary-* annotations. Before you create a canary Ingress, create two same Services that are used for canary releases, and then map the Services to the backend pods that you want to access. For more information, see Use the NGINX Ingress controller to implement canary releases and blue-green releases.

What do I do if an error "failed calling webhook" occurs when I create an Ingress?

Issue

The following error occurs when you create an Ingress: "Internal error occurred: failed calling webhook...".

Cause

When you create an Ingress, a Service is used to check whether the Ingress is valid. By default, the Service named ingress-nginx-controller-admission is used. If webhook link errors occur, such as the error that the Service or the Ingress controller is deleted, the Ingress cannot be created.

Solution

• Check whether the resource exists and works as expected based on the following webhook link: ValidatingWebhookConfiguration > Service > Pod.

• Make sure that the admission feature is enabled for the Ingress controller pod and the pod can be accessed by sending external requests outside the cluster.

• If the Ingress controller is deleted or you do not want to use the webhook feature, you can delete the ValidatingWebhookConfiguration resource.

What do I do if an error "SSL_ERROR_RX_RECORD_TOO_LONG" is returned for HTTPS requests?

Issue

One of the following errors is returned for HTTPS requests: SSL_ERROR_RX_RECORD_TOO_LONG or routines:CONNECT_CR_SRVR_HELLO:wrong version number.

Cause

HTTPS requests are distributed to a non-HTTPS port, such as an HTTP port.

Solution

Modify the configurations of the SLB instance or Service to ensure that HTTPS requests can be distributed to the proper port.

What do I do if a common HTTP status code is returned?

Issue

HTTP status codes other than 2xx and 3xx are returned, such as 502, 503, 413, and 499.

Cause and solution

View the log and check whether the error is returned by the Ingress controller. For more information, see the Diagnose the access log of the NGINX Ingress controller pod in Simple Log Service section of this topic. If the error is returned by the Ingress controller, use the following solutions:

• 413 error

  • Cause: The request size exceeds the upper limit.

  • Solution: Increase the value of proxy-body-size in the ConfigMap of the Ingress controller. The default value of proxy-body-size is 1 MB for the NGINX Ingress controller of open source Kubernetes and the default value of proxy-body-size is 20 MB for the NGINX Ingress controller of ACK.

• 499 error

  • Cause: The client terminates the connection in advance. The error may not be caused by the Ingress controller or backend services.

  • Solutions:

    • If the 499 error does not occur frequently and your workloads are not affected, you can ignore the error.

    • If the 499 error occurs frequently, you must check whether the amount of time that the backend pods cost to process requests exceeds the request timeout period that is set on the client.

• 502 error

  • Cause: The Ingress controller cannot connect to backend pods.

  • Solutions:

    • The issue occurs occasionally:

      • Check whether the backend pods work as expected. If the backend pods are overloaded, add more backend pods.

      • By default, the Ingress controller sends HTTP 1.1 requests to backend services through HTTP persistent connections. Make sure that the timeout period of idle persistent connections configured for the backend pods is greater than that configured for the Ingress controller. By default, the timeout period is set to 900 seconds.

    • The issue occurs every time:

      Check whether the Service port is valid and whether the Service can be accessed from the Ingress controller pod.

    • If the issue persists, capture and analyze packets, and then submit a ticket.

• 503 error

  • Cause: The Ingress controller cannot discover the backend pods, or the Ingress controller fails to access all backend pods.

  • Solutions:

    • The issue occurs occasionally:

      • Refer to the solution for resolving the 502 error.

      • Check the status of the backend pods and configure health checks.

    • The issue occurs every time:

      Check whether the Service configuration is valid and whether the endpoint exists.

    • If you cannot locate the cause by using the preceding methods, submit a ticket.

What do I do if an error "net::ERR_HTTP2_SERVER_REFUSED_STREAM" occurs?

Issue

When you access the website, some resources cannot be loaded and one of the following errors is reported in the console: net::ERR_HTTP2_SERVER_REFUSED_STREAM and net::ERR_FAILED.

Cause

The number of concurrent HTTP/2 streams to the resource has reached the upper limit.

Solution

• We recommend that you change the value of http2-max-concurrent-streams in the ConfigMap to a greater value. The default value is 128. For more information, see http2-max-concurrent-streams.

• Disable HTTP/2 by setting use-http2 to false in the ConfigMap. For more information, see use-http2.

What do Id do if an error "The param of ServerGroupName is illegal" occurs?

Cause

ServerGroupName is generated in the following format: namespace+svcName+port. The server group name must be 2 to 128 characters in length and can contain letters, digits, periods (.), underscores (_), and hyphens (-). The name must start with a letter.

Solution

Modify the server group name in the required format.

What do I do if an error "certificate signed by unknown authority" occurs when I create an Ingress?

Cause

If multiple Ingresses are deployed in the cluster and the Ingresses use the same resources, such as Secrets, Services, or webhook configurations, the preceding error occurs because different SSL certificates are used to communicate with backend servers when webhooks are triggered.

Solution

Deploy two Ingresses and make sure that the Ingresses use different resources. For more information about the resources used by Ingresses, see the What are the system updates after I update the NGINX Ingress controller on the Add-ons page of the ACK console? section of the "Nginx Ingress FAQ" topic.

Why does the Ingress controller pod restart after it fails a health check?

Issue

The Ingress controller pod restarts after it fails a health check.

Cause

• The Ingress controller pod or the node on which the pod is deployed is overloaded. As a result, the pod failed to pass the health check.

• Kernel parameters such as tcp_tw_reuse or tcp_tw_timestamps may be configured for the cluster node on which the Ingress controller pod is deployed. This may cause health check failures.

Solution

• Add more Ingress controller pods and check whether the issue persists. For more information, see Deploy a high-reliability Ingress controller.

• Disable tcp_tw_reuse or set the value of the parameter to 2, disable tcp_tw_timestamps, and then check whether the issue persists.

How do I add Services that use TCP or UDP?

1. Add specific entries to the tcp-services and udp-services ConfigMaps. By default, the ConfigMaps belong to the kube-system namespace.

   The following sample code shows how to map port 8080 of example-go in the default namespace to port 9000:

   apiVersion: v1
   kind: ConfigMap
   metadata:
     name: tcp-services
     namespace: ingress-nginx
   data:
     9000: "default/example-go:8080"  # Map port 8080 to port 9000.

2. Add port 9000 to the Deployment of the NGINX Ingress controller. By default, the Deployment is named nginx-ingress-controller and belongs to the kube-system namespace.

3. Add port 9000 to the Service that is associated with the Ingress.

   View sample code

   apiVersion: v1
   kind: Service
   metadata:
     name: ingress-nginx
     namespace: ingress-nginx
     labels:
       app.kubernetes.io/name: ingress-nginx
       app.kubernetes.io/part-of: ingress-nginx
   spec:
     type: LoadBalancer
     ports:
       - name: http
         port: 80
         targetPort: 80
         protocol: TCP
       - name: https
         port: 443
         targetPort: 443
         protocol: TCP
       - name: proxied-tcp-9000
         port: 9000
         targetPort: 9000
         protocol: TCP
     selector:
       app.kubernetes.io/name: ingress-nginx
       app.kubernetes.io/part-of: ingress-nginx

   For more information about how to add Services that use TCP or UDP, see Exposing TCP or UDP services.

Why do Ingress rules fail to take effect?

Issue

After you add or modify Ingress rules, the rules do not take effect.

Cause

• The configuration of the Ingress contains errors. As a result, the Ingress failed to load the Ingress rules.

• The configurations of Ingress resources contain errors.

• The Ingress controller does not have the required permissions. As a result, the Ingress controller cannot monitor the changes made to Ingress resources.

• The previous Ingress uses a domain name specified in the server-alias field. The domain name is in conflict with that of the new Ingress. As a result, the Ingress rules are ignored.

Why does the system fail to load some web page resources or return a blank white screen when requests are redirected to the root directory?

Issue

After you set the rewrite-target annotation in the Ingress to rewrite requests, some web page resources cannot be loaded or a blank white screen is displayed when you access the backend service.

Cause

• You do not set rewrite-target in regular expressions.

• The path of the requested resource is set to the root directory.

Solution

• Check whether rewrite-target is set in regular expressions and whether capture groups are used. For more information, see Rewrite.

• Check whether requests are redirected to the expected path.

How do I fix the issue that Simple Log Service cannot parse logs as expected after ingress-nginx-controller is updated?

Issue

The ingress-nginx-controller component of versions 0.20 and 0.30 are commonly used. After you update ingress-nginx-controller from 0.20 to 0.30 on the Add-ons page of the ACK console, the Ingress dashboard does not show the actual statistics of requests to the backend servers when you perform canary releases or blue-green releases with an Ingress.

Cause

The default log format of ingress-nginx-controller 0.20 is different from that of ingress-nginx-controller 0.30. Therefore, after you update ingress-nginx-controller from 0.20 to 0.30, the Ingress dashboard may not show the actual statistics of requests to the backend servers when you perform canary releases or blue-green releases with an Ingress.

Solution

To fix the issue, perform the following steps to update the nginx-configuration ConfigMap and the configuration of k8s-nginx-ingress.

1. Update the nginx-configuration ConfigMap.

   • If you have not modified the nginx-configuration ConfigMap, copy the following content to a file named nginx-configuration.yaml and run the kubectl apply -f nginx-configuration.yaml command to deploy the file.

     apiVersion: v1
     kind: ConfigMap
     data:
       allow-backend-server-header: "true"
       enable-underscores-in-headers: "true"
       generate-request-id: "true"
       ignore-invalid-headers: "true"
       log-format-upstream: $remote_addr - [$remote_addr] - $remote_user [$time_local] "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent" $request_length $request_time [$proxy_upstream_name] $upstream_addr $upstream_response_length $upstream_response_time $upstream_status $req_id $host [$proxy_alternative_upstream_name]
       max-worker-connections: "65536"
       proxy-body-size: 20m
       proxy-connect-timeout: "10"
       reuse-port: "true"
       server-tokens: "false"
       ssl-redirect: "false"
       upstream-keepalive-timeout: "900"
       worker-cpu-affinity: auto
     metadata:
       labels:
         app: ingress-nginx
       name: nginx-configuration
       namespace: kube-system

   • If you have modified the nginx-configuration ConfigMap, run the following command to update the configuration. This ensures that your previous modifications are not overwritten.

     kubectl edit configmap nginx-configuration -n kube-system

   Append [$proxy_alternative_upstream_name] to the log-format-upstream field, save the changes, and then exit.

2. Modify the k8s-nginx-ingress configuration.

   Copy the following content to a file named k8s-nginx-ingress.yaml and run the kubectl apply -f k8s-nginx-ingress.yaml command to deploy the ingress-nginx-controller component.

   View the YAML file content

   apiVersion: log.alibabacloud.com/v1alpha1
   kind: AliyunLogConfig
   metadata:
     namespace: kube-system
     # your config name, must be unique in you k8s cluster
     name: k8s-nginx-ingress
   spec:
     # logstore name to upload log
     logstore: nginx-ingress
     # product code, only for k8s nginx ingress
     productCode: k8s-nginx-ingress
     # logtail config detail
     logtailConfig:
       inputType: plugin
       # logtail config name, should be same with [metadata.name]
       configName: k8s-nginx-ingress
       inputDetail:
         plugin:
           inputs:
           - type: service_docker_stdout
             detail:
               IncludeLabel:
                 io.kubernetes.container.name: nginx-ingress-controller
               Stderr: false
               Stdout: true
           processors:
           - type: processor_regex
             detail:
               KeepSource: false
               Keys:
               - client_ip
               - x_forward_for
               - remote_user
               - time
               - method
               - url
               - version
               - status
               - body_bytes_sent
               - http_referer
               - http_user_agent
               - request_length
               - request_time
               - proxy_upstream_name
               - upstream_addr
               - upstream_response_length
               - upstream_response_time
               - upstream_status
               - req_id
               - host
               - proxy_alternative_upstream_name
               NoKeyError: true
               NoMatchError: true
               Regex: ^(\S+)\s-\s\[([^]]+)]\s-\s(\S+)\s\[(\S+)\s\S+\s"(\w+)\s(\S+)\s([^"]+)"\s(\d+)\s(\d+)\s"([^"]*)"\s"([^"]*)"\s(\S+)\s(\S+)+\s\[([^]]*)]\s(\S+)\s(\S+)\s(\S+)\s(\S+)\s(\S+)\s*(\S*)\s*\[*([^]]*)\]*.*
               SourceKey: content

What do I do if common NGINX Ingress controller errors occur?

Issue

User "system:serviceaccount:kube-system:ingress-nginx" cannot list/get/update resource "xxx" in API group "xxx" at the cluster scope/ in the namespace "kube-system"

Cause

The NGINX Ingress controller does not have the permissions to update resources.

Solution

Issue

requeuing……nginx: configuration file xxx test failed (multiple lines)

Cause

The system failed to reload the NGINX configurations due to syntax errors in Ingress rules or the ConfigMap.

Solution

Issue

Unexpected error validating SSL certificate "xxx" for server "xxx"

Cause

A certificate configuration error occurs because the domain names associated with the certificate are different from the domain names specified in the Ingress. You can continue to use your certificate as expected when some certificate errors at the warning level occur. For example, you can continue to use your certificate even if the system prompts that the certificate does not have the SAN attribute.

Solution