In some scenarios the exposed URL in the backend service differs from the specified path in the Ingress rule. Without a rewrite any request will return 404.
If the application contains relative links it is possible to add an additional annotation `nginx.ingress.kubernetes.io/add-base-url` that will prepend a [`base` tag](https://developer.mozilla.org/en/docs/Web/HTML/Element/base) in the header of the returned HTML from the backend.
If the scheme of [`base` tag](https://developer.mozilla.org/en/docs/Web/HTML/Element/base) need to be specific, set the annotation `nginx.ingress.kubernetes.io/base-url-scheme` to the scheme such as `http` and `https`.
If the Application Root is exposed in a different path and needs to be redirected, set the annotation `nginx.ingress.kubernetes.io/app-root` to redirect requests for `/`.
The annotation `nginx.ingress.kubernetes.io/affinity` enables and sets the affinity type in all Upstreams of an Ingress. This way, a request will always be directed to the same upstream server.
Please check the [affinity](../../examples/affinity/cookie/README.md) example.
#### Cookie affinity
If you use the ``cookie`` affinity type you can also specify the name of the cookie that will be used to route the requests with the annotation `nginx.ingress.kubernetes.io/session-cookie-name`. The default is to create a cookie named 'INGRESSCOOKIE'.
In case of NGINX the annotation `nginx.ingress.kubernetes.io/session-cookie-hash` defines which algorithm will be used to hash the used upstream. Default value is `md5` and possible values are `md5`, `sha1` and `index`.
!!! attention
The `index` option is not an actual hash; an in-memory index is used instead, which has less overhead.
However, with `index`, matching against a changing upstream server list is inconsistent.
So, at reload, if upstream servers have changed, index values are not guaranteed to correspond to the same server as before!
**Use `index` with caution** and only if you need to!
In NGINX this feature is implemented by the third party module [nginx-sticky-module-ng](https://bitbucket.org/nginx-goodies/nginx-sticky-module-ng). The workflow used to define which upstream server will be used is explained [here](https://bitbucket.org/nginx-goodies/nginx-sticky-module-ng/raw/08a395c66e425540982c00482f55034e1fee67b6/docs/sticky.pdf)
Is possible to add authentication adding additional annotations in the Ingress rule. The source of the authentication is a secret that contains usernames and passwords inside the key `auth`.
The name of the Secret that contains the usernames and passwords which are granted access to the `path`s defined in the Ingress rules.
This annotation also accepts the alternative form "namespace/secretName", in which case the Secret lookup is performed in the referenced namespace instead of the Ingress namespace.
NGINX exposes some flags in the [upstream configuration](http://nginx.org/en/docs/http/ngx_http_upstream_module.html#upstream) that enable the configuration of each server in the upstream. The Ingress controller allows custom `max_fails` and `fail_timeout` parameters in a global context using `upstream-max-fails` and `upstream-fail-timeout` in the NGINX ConfigMap or in a particular Ingress rule. `upstream-max-fails` defaults to 0. This means NGINX will respect the container's `readinessProbe` if it is defined. If there is no probe and no values for `upstream-max-fails` NGINX will continue to send traffic to the container.
With the default configuration NGINX will not health check your backends. Whenever the endpoints controller notices a readiness probe failure, that pod's IP will be removed from the list of endpoints. This will trigger the NGINX controller to also remove it from the upstreams.**
`nginx.ingress.kubernetes.io/upstream-max-fails`: number of unsuccessful attempts to communicate with the server that should occur in the duration set by the `upstream-fail-timeout` parameter to consider the server unavailable.
`nginx.ingress.kubernetes.io/upstream-fail-timeout`: time in seconds during which the specified number of unsuccessful attempts to communicate with the server should occur to consider the server unavailable. This is also the period of time the server will be considered unavailable.
In NGINX, backend server pools are called "[upstreams](http://nginx.org/en/docs/http/ngx_http_upstream_module.html)". Each upstream contains the endpoints for a service. An upstream is created for each service that has Ingress rules defined.
NGINX supports load balancing by client-server mapping based on [consistent hashing](http://nginx.org/en/docs/http/ngx_http_upstream_module.html#hash) for a given key. The key can contain text, variables or any combination thereof. This feature allows for request stickiness other than client IP or cookies. The [ketama](http://www.last.fm/user/RJ/journal/2007/04/10/392555/) consistent hashing method will be used which ensures only a few keys would be remapped to different servers on upstream group changes.
`nginx.ingress.kubernetes.io/upstream-hash-by`: the nginx variable, text value or any combination thereof to use for consistent hashing. For example `nginx.ingress.kubernetes.io/upstream-hash-by: "$request_uri"` to consistently hash upstream requests by the current request URI.
This is similar to (https://github.com/kubernetes/ingress-nginx/blob/master/docs/user-guide/nginx-configuration/configmap.md#load-balance) but configures load balancing algorithm per ingress.
>Note that `nginx.ingress.kubernetes.io/upstream-hash-by` takes preference over this. If this and `nginx.ingress.kubernetes.io/upstream-hash-by` are not set then we fallback to using globally configured load balancing algorithm.
This configuration setting allows you to control the value for host in the following statement: `proxy_set_header Host $host`, which forms part of the location block. This is useful if you need to call the upstream server by something other than `$host`.
The name of the Secret that contains the full Certificate Authority chain `ca.crt` that is enabled to authenticate against this Ingress.
This annotation also accepts the alternative form "namespace/secretName", in which case the Secret lookup is performed in the referenced namespace instead of the Ingress namespace.
Cloudflare only allows Authenticated Origin Pulls and is required to use their own certificate: [https://blog.cloudflare.com/protecting-the-origin-with-tls-authenticated-origin-pulls/](https://blog.cloudflare.com/protecting-the-origin-with-tls-authenticated-origin-pulls/)
Only Authenticated Origin Pulls are allowed and can be configured by following their tutorial: [https://support.cloudflare.com/hc/en-us/articles/204494148-Setting-up-NGINX-to-use-TLS-Authenticated-Origin-Pulls](https://support.cloudflare.com/hc/en-us/articles/204494148-Setting-up-NGINX-to-use-TLS-Authenticated-Origin-Pulls)
This is a global configuration for the ingress controller. In some cases could be required to return a custom content or format. In this scenario we can use the annotation `nginx.ingress.kubernetes.io/default-backend: <svc name>` to specify a custom default backend.
For more information please see [https://enable-cors.org](https://enable-cors.org/server_nginx.html) as well as this [example](../../examples/cors/README.md).
To use an existing service that provides authentication the Ingress rule can be annotated with `nginx.ingress.kubernetes.io/auth-url` to indicate the URL where the HTTP request should be sent.
*`nginx.ingress.kubernetes.io/limit-connections`: number of concurrent connections allowed from a single IP address.
*`nginx.ingress.kubernetes.io/limit-rps`: number of connections that may be accepted from a given IP each second.
*`nginx.ingress.kubernetes.io/limit-rpm`: number of connections that may be accepted from a given IP each minute.
*`nginx.ingress.kubernetes.io/limit-rate-after`: sets the initial amount after which the further transmission of a response to a client will be rate limited.
*`nginx.ingress.kubernetes.io/limit-rate`: rate of request that accepted from a client each second.
You can specify the client IP source ranges to be excluded from rate-limiting through the `nginx.ingress.kubernetes.io/limit-whitelist` annotation. The value is a comma separated list of CIDRs.
The annotation `nginx.ingress.kubernetes.io/limit-rate`, `nginx.ingress.kubernetes.io/limit-rate-after` define a limit the rate of response transmission to a client. The rate is specified in bytes per second. The zero value disables rate limiting. The limit is set per a request, and so if a client simultaneously opens two connections, the overall rate will be twice as much as the specified limit.
To configure this setting globally for all Ingress rules, the `limit-rate-after` and `limit-rate` value may be set in the [NGINX ConfigMap][configmap]. if you set the value in ingress annotation will cover global setting.
This annotation allows to return a permanent redirect instead of sending data to the upstream. For example `nginx.ingress.kubernetes.io/permanent-redirect: https://www.google.com` would redirect everything to Google.
This annotation allows you to modify the status code used for permanent redirects. For example `nginx.ingress.kubernetes.io/permanent-redirect-code: '308'` would return your permanent-redirect with a 308.
If you want to validate the upstream against a specific certificate, you can create a secret with it and reference the secret with the annotation `nginx.ingress.kubernetes.io/secure-verify-ca-secret`.
By default the NGINX ingress controller uses a list of all endpoints (Pod IP/port) in the NGINX upstream configuration.
The `nginx.ingress.kubernetes.io/service-upstream` annotation disables that behavior and instead uses a single upstream in NGINX, the service's Cluster IP and port.
This can be desirable for things like zero-downtime deployments as it reduces the need to reload NGINX configuration when Pods come up and down. See issue [#257](https://github.com/kubernetes/ingress-nginx/issues/257).
With the annotations `nginx.ingress.kubernetes.io/proxy-redirect-from` and `nginx.ingress.kubernetes.io/proxy-redirect-to` it is possible to
set the text that should be changed in the `Location` and `Refresh` header fields of a proxied server response (http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_redirect)
Setting "off" or "default" in the annotation `nginx.ingress.kubernetes.io/proxy-redirect-from` disables `nginx.ingress.kubernetes.io/proxy-redirect-to`,
otherwise, both annotations must be used in unison. Note that each annotation must be a string without spaces.
For NGINX, an 413 error will be returned to the client when the size in a request exceeds the maximum allowed size of the client request body. This size can be configured by the parameter [`client_max_body_size`](http://nginx.org/en/docs/http/ngx_http_core_module.html#client_max_body_size).
Sets a text that [should be changed in the domain attribute](http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_cookie_domain) of the "Set-Cookie" header fields of a proxied server response.
To configure this setting globally for all Ingress rules, the `proxy-cookie-domain` value may be set in the [NGINX ConfigMap][configmap].
Sets the size of the buffer [`proxy_buffer_size`](http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffer_size) used for reading the first part of the response received from the proxied server.
By default proxy buffer size is set as "4k"
To configure this setting globally, set `proxy-buffer-size` in [NGINX ConfigMap][configmap]. To use custom values in an Ingress rule, define this annotation:
The other possible values for `nginx.ingress.kubernetes.io/lua-resty-waf` are `inactive` and `simulate`.
In `inactive` mode WAF won't do anything, whereas in `simulate` mode it will log a warning message if there's a matching WAF rule for given request. This is useful to debug a rule and eliminate possible false positives before fully deploying it.
`lua-resty-waf` comes with predefined set of rules [https://github.com/p0pr0ck5/lua-resty-waf/tree/84b4f40362500dd0cb98b9e71b5875cb1a40f1ad/rules](https://github.com/p0pr0ck5/lua-resty-waf/tree/84b4f40362500dd0cb98b9e71b5875cb1a40f1ad/rules) that covers ModSecurity CRS.
It is also possible to configure custom WAF rules per ingress using the `nginx.ingress.kubernetes.io/lua-resty-waf-extra-rules` annotation. For an example the following snippet will configure a WAF rule to deny requests with query string value that contains word `foo`:
- Deploy Telegraf as a sidecar proxy to the Ingress controller configured to listen UDP with the [socket listener input](https://github.com/influxdata/telegraf/tree/release-1.6/plugins/inputs/socket_listener) and to write using
anyone of the [outputs plugins](https://github.com/influxdata/telegraf/tree/release-1.7/plugins/outputs) like InfluxDB, Apache Kafka,
Prometheus, etc.. (recommended)
It's important to remember that there's no DNS resolver at this stage so you will have to configure
an ip address to `nginx.ingress.kubernetes.io/influxdb-host`. If you deploy Influx or Telegraf as sidecar (another container in the same pod) this becomes straightforward since you can directly use `127.0.0.1`.
