# TLS/HTTPS ## TLS Secrets Anytime we reference a TLS secret, we mean a PEM-encoded X.509, RSA (2048) secret. !!! warning Ensure that the certificate order is leaf->intermediate->root, otherwise the controller will not be able to import the certificate, and you'll see this error in the logs ```W1012 09:15:45.920000 6 backend_ssl.go:46] Error obtaining X.509 certificate: unexpected error creating SSL Cert: certificate and private key does not have a matching public key: tls: private key does not match public key``` You can generate a self-signed certificate and private key with: ```bash $ openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout ${KEY_FILE} -out ${CERT_FILE} -subj "/CN=${HOST}/O=${HOST}" -addext "subjectAltName = DNS:${HOST}" ``` Then create the secret in the cluster via: ```bash kubectl create secret tls ${CERT_NAME} --key ${KEY_FILE} --cert ${CERT_FILE} ``` The resulting secret will be of type `kubernetes.io/tls`. ## Host names Ensure that the relevant [ingress rules specify a matching host name](https://kubernetes.io/docs/concepts/services-networking/ingress/#tls). ## Default SSL Certificate NGINX provides the option to configure a server as a catch-all with [server_name](https://nginx.org/en/docs/http/server_names.html) for requests that do not match any of the configured server names. This configuration works out-of-the-box for HTTP traffic. For HTTPS, a certificate is naturally required. For this reason the Ingress controller provides the flag `--default-ssl-certificate`. The secret referred to by this flag contains the default certificate to be used when accessing the catch-all server. If this flag is not provided NGINX will use a self-signed certificate. For instance, if you have a TLS secret `foo-tls` in the `default` namespace, add `--default-ssl-certificate=default/foo-tls` in the `nginx-controller` deployment. The default certificate will also be used for ingress `tls:` sections that do not have a `secretName` option. To force redirects for Ingresses that do not specify a TLS-block at all, take a look at `force-ssl-redirect` in [ConfigMap][ConfigMap]. ## SSL Passthrough The [`--enable-ssl-passthrough`](cli-arguments.md) flag enables the SSL Passthrough feature, which is disabled by default. This is required to enable passthrough backends in Ingress objects. !!! warning This feature is implemented by intercepting **all traffic** on the configured HTTPS port (default: 443) and handing it over to a local TCP proxy. This bypasses NGINX completely and introduces a non-negligible performance penalty. SSL Passthrough leverages [SNI][SNI] and reads the virtual domain from the TLS negotiation, which requires compatible clients. After a connection has been accepted by the TLS listener, it is handled by the controller itself and piped back and forth between the backend and the client. If there is no hostname matching the requested host name, the request is handed over to NGINX on the configured passthrough proxy port (default: 442), which proxies the request to the default backend. !!! note Unlike HTTP backends, traffic to Passthrough backends is sent to the *clusterIP* of the backing Service instead of individual Endpoints. ## HTTP Strict Transport Security HTTP Strict Transport Security (HSTS) is an opt-in security enhancement specified through the use of a special response header. Once a supported browser receives this header that browser will prevent any communications from being sent over HTTP to the specified domain and will instead send all communications over HTTPS. HSTS is enabled by default. To disable this behavior use `hsts: "false"` in the configuration [ConfigMap][ConfigMap]. ## Server-side HTTPS enforcement through redirect By default the controller redirects HTTP clients to the HTTPS port 443 using a 308 Permanent Redirect response if TLS is enabled for that Ingress. This can be disabled globally using `ssl-redirect: "false"` in the NGINX [config map][ConfigMap], or per-Ingress with the `nginx.ingress.kubernetes.io/ssl-redirect: "false"` annotation in the particular resource. !!! tip When using SSL offloading outside of cluster (e.g. AWS ELB) it may be useful to enforce a redirect to HTTPS even when there is no TLS certificate available. This can be achieved by using the `nginx.ingress.kubernetes.io/force-ssl-redirect: "true"` annotation in the particular resource. ## Automated Certificate Management with cert-manager [cert-manager] automatically requests missing or expired certificates from a range of [supported issuers][cert-manager-issuer-config] (including [Let's Encrypt]) by monitoring ingress resources. To set up cert-manager you should take a look at this [full example][full-cert-manager-example]. To enable it for an ingress resource you have to deploy cert-manager, configure a certificate issuer update the manifest: ```yaml apiVersion: networking.k8s.io/v1 kind: Ingress metadata: name: ingress-demo annotations: cert-manager.io/issuer: "letsencrypt-staging" # Replace this with a production issuer once you've tested it [..] spec: tls: - hosts: - ingress-demo.example.com secretName: ingress-demo-tls [...] ``` ## Default TLS Version and Ciphers To provide the most secure baseline configuration possible, ingress-nginx defaults to using TLS 1.2 and 1.3 only, with a [secure set of TLS ciphers][ssl-ciphers]. ### Legacy TLS The default configuration, though secure, does not support some older browsers and operating systems. For instance, TLS 1.1+ is only enabled by default from Android 5.0 on. At the time of writing, May 2018, [approximately 15% of Android devices](https://developer.android.com/about/dashboards/#Platform) are not compatible with ingress-nginx's default configuration. To change this default behavior, use a [ConfigMap][ConfigMap]. A sample ConfigMap fragment to allow these older clients to connect could look something like the following (generated using the Mozilla SSL Configuration Generator)[mozilla-ssl-config-old]: ``` kind: ConfigMap apiVersion: v1 metadata: name: nginx-config data: ssl-ciphers: "ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES256-SHA256:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:DES-CBC3-SHA" ssl-protocols: "TLSv1 TLSv1.1 TLSv1.2 TLSv1.3" ``` [Let's Encrypt]:https://letsencrypt.org [ConfigMap]: ./nginx-configuration/configmap.md [ssl-ciphers]: ./nginx-configuration/configmap.md#ssl-ciphers [SNI]: https://en.wikipedia.org/wiki/Server_Name_Indication [mozilla-ssl-config-old]: https://ssl-config.mozilla.org/#server=nginx&config=old [cert-manager]: https://github.com/jetstack/cert-manager/ [full-cert-manager-example]:https://cert-manager.io/docs/tutorials/acme/nginx-ingress/ [cert-manager-issuer-config]:https://cert-manager.io/docs/configuration/