How to customize the log entries of the nginx-ingress-controller pod

• Rancher v2.x

• We are trying to figure out an issue, and it requires us to know what HOST was used by a client to connect to our Kubernetes cluster.
• We want to have our custom log-format eg : "$status $request $remote_addr - $remote_user [$time_local]" for our rke2-ingress-nginx-controller pod. 

• The default log format for the "ingress-controller-log" is below.  Refer to the official doc here for more details on the parameters. 

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

• If you want to modify the default log format, you can use any one of the methods below : 

Method 1):  Using Configmap (Quick method)

• Editing the configmap is the easiest and quickest option; however, it is not recommended to make lasting changes since the ConfigMap edits aren't persistent across upgrades.
• Follow the steps below to edit the "rke2-ingress-nginx-controller" configmap and modify the "log-format-upstream" as required.
• (Optional) The configuration should reload automatically. If auto-reload works, restart is optional; otherwise, perform a rollout restart of the "rke2-ingress-nginx-controller" daemonset. 

a) Take backup: 

 #kubectl get cm -n kube-system rke2-ingress-nginx-controller -o yaml >> rke2-ingress-nginx-controller_backup.yaml

b) modify or add "log-format-upstream" : 

 #kubectl edit cm -n kube-system rke2-ingress-nginx-controller -o yaml

c) Verfiy changes : 

 #kubectl get cm -n kube-system rke2-ingress-nginx-controller -o yaml  | grep -i data -A2
 data:
  allow-snippet-annotations: "false"
  log-format-upstream: $status $request $remote_addr - $remote_user [$time_local]
  
d) (Optional) Rollout restart : 

# kubectl rollout restart ds rke2-ingress-nginx-controller -n kube-system

Method B) : Using HelmChartConfig 

•  Making the changes using "HelmChartConfig" is recommended since the changes will be persisted during the upgrade. 
  
  

A) Take the backup of "rke2-ingress-nginx" helmchartconfigs : 

#kubectl get helmchartconfigs.helm.cattle.io rke2-ingress-nginx -n kube-system -o yaml > rke2-ingress-nginx_helmchartconfig_backup.yaml

B) Edit and add "log-format-upstream" to the rke2-ingress-nginx helmchartconfigs : 

#kubectl edit helmchartconfigs.helm.cattle.io rke2-ingress-nginx -n kube-system -o yaml 

spec:
  valuesContent: |-
    controller:
      config:
        log-level: info
        error-log-level: info
        log-format-upstream: $status $request $remote_addr - $remote_user [$time_local

Validate the changes on log: 

- Access your application and monitor the logs of rke2-ingress-nginx-controller pods to validate the changes : 

Eg : kubectl logs rke2-ingress-nginx-controller-vbrtk -n kube-system -f

200 GET /apple HTTP/1.1 3.0.101.163 - - [16/Aug/2025:15:21:21 +0000]