How to enable legacy TLS versions for ingress-nginx in Rancher Kubernetes Engine (RKE) CLI and Rancher v2.x provisioned Kubernetes clusters

This document (000020076) is provided subject to the disclaimer at the end of this document.

Situation

Task

This article details how to enable TLS 1.1 on the ingress-nginx controller in Rancher Kubernetes Engine (RKE) CLI or Rancher v2.x provisioned Kubernetes clusters.

Pre-requisites

A Kubernetes cluster provisioned by the Rancher Kubernetes Engine (RKE) CLI or Rancher v2.x
For RKE provisioned clusters, you will require the RKE binary and access to the cluster configuration YAML, rkestate file and kubectl access with the kubeconfig for the cluster sourced
For Rancher v2.x provisioned clusters, you will require cluster owner or global admin permissions in Rancher

Resolution

Configuration for RKE provisioned clusters

Edit the cluster configuration YAML file to include the ssl-protocols option for the ingress, as follows:
```
  ingress:
    provider: nginx
    options:
      ssl-protocols: "TLSv1.1 TLSv1.2"
```
Apply the changes to the cluster, by invoking rke up:
```
rke up --config <cluster configuration yaml file>
```

Verify the new configuration:

for pod in $(kubectl get pods -l app=ingress-nginx -n ingress-nginx --no-headers -o name | awk -F '/' '{print $2}'); do echo -n "Checking $pod .... "; kubectl -n ingress-nginx exec "$pod" -- bash -c "cat /etc/nginx/nginx.conf | grep ssl_protocols | grep '1.1' > /dev/null 2>&1 && echo 'Good' || echo 'Bad'"; done

Configuration for Rancher provisioned clusters

Login into the Rancher UI.
Go to Global -> Clusters -> Cluster Name
From the Cluster Dashboard edit the cluster by Clicking on "⋮" then select Edit.
Click "Edit as YAML".

Include the ssl-protocols option for the ingress, as follows:

ingress:
  provider: nginx
  options:
    ssl-protocols: "TLSv1.1 TLSv1.2"

Click "Save" at the bottom of the page.
Wait for cluster to finish upgrading.
Go back to the Cluster Dashboard and click "Launch kubectl".

Run the following inside the kubectl CLI to verify the new argument:

for pod in $(kubectl get pods -l app=ingress-nginx -n ingress-nginx --no-headers -o name | awk -F '/' '{print $2}'); do echo -n "Checking $pod .... "; kubectl -n ingress-nginx exec "$pod" -- bash -c "cat /etc/nginx/nginx.conf | grep ssl_protocols | grep '1.1' > /dev/null 2>&1 && echo 'Good' || echo 'Bad'"; done

Disclaimer

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