32 KiB
Annotations
You can add these Kubernetes annotations to specific Ingress objects to customize their behavior.
!!! tip
Annotation keys and values can only be strings.
Other types, such as boolean or numeric values must be quoted,
i.e. "true", "false", "100".
!!! note
The annotation prefix can be changed using the
--annotations-prefix command line argument,
but the default is nginx.ingress.kubernetes.io, as described in the
table below.
Rewrite
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.
Set the annotation nginx.ingress.kubernetes.io/rewrite-target to the path expected by the service.
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 in the header of the returned HTML from the backend.
If the scheme of base tag 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 /.
!!! example Please check the rewrite example.
Session Affinity
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.
The only affinity type available for NGINX is cookie.
!!! example Please check the affinity 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. The workflow used to define which upstream server will be used is explained here
Authentication
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 annotations are:
nginx.ingress.kubernetes.io/auth-type: [basic|digest]
Indicates the HTTP Authentication Type: Basic or Digest Access Authentication.
nginx.ingress.kubernetes.io/auth-secret: secretName
The name of the Secret that contains the usernames and passwords which are granted access to the paths 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.ingress.kubernetes.io/auth-realm: "realm string"
!!! example Please check the auth example.
Custom NGINX upstream checks
NGINX exposes some flags in the upstream configuration 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.
!!! tip 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.**
To use custom values in an Ingress rule define these annotations:
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". Each upstream contains the endpoints for a service. An upstream is created for each service that has Ingress rules defined.
!!! attention
All Ingress rules using the same service will use the same upstream.
Only one of the Ingress rules should define annotations to configure the upstream servers.
!!! example Please check the custom upstream check example.
Custom NGINX upstream hashing
NGINX supports load balancing by client-server mapping based on consistent hashing 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 consistent hashing method will be used which ensures only a few keys would be remapped to different servers on upstream group changes.
To enable consistent hashing for a backend:
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.
Custom NGINX load balancing
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-bytakes preference over this. If this andnginx.ingress.kubernetes.io/upstream-hash-byare not set then we fallback to using globally configured load balancing algorithm.
Custom NGINX upstream vhost
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.
Client Certificate Authentication
It is possible to enable Client Certificate Authentication using additional annotations in Ingress Rule.
The annotations are:
nginx.ingress.kubernetes.io/auth-tls-secret: secretName: The name of the Secret that contains the full Certificate Authority chainca.crtthat 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.nginx.ingress.kubernetes.io/auth-tls-verify-depth: The validation depth between the provided client certificate and the Certification Authority chain.nginx.ingress.kubernetes.io/auth-tls-verify-client: Enables verification of client certificates.nginx.ingress.kubernetes.io/auth-tls-error-page: The URL/Page that user should be redirected in case of a Certificate Authentication Errornginx.ingress.kubernetes.io/auth-tls-pass-certificate-to-upstream: Indicates if the received certificates should be passed or not to the upstream server. By default this is disabled.
!!! example Please check the client-certs example.
!!! attention TLS with Client Authentication is not possible in Cloudflare and might result in unexpected behavior.
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)
Configuration snippet
Using this annotation you can add additional configuration to the NGINX location. For example:
nginx.ingress.kubernetes.io/configuration-snippet: |
more_set_headers "Request-Id: $req_id";
Default Backend
The ingress controller requires a default backend.
This service handles the response when the service in the Ingress rule does not have endpoints.
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.
Enable CORS
To enable Cross-Origin Resource Sharing (CORS) in an Ingress rule,
add the annotation nginx.ingress.kubernetes.io/enable-cors: "true".
This will add a section in the server location enabling this functionality.
CORS can be controlled with the following annotations:
-
nginx.ingress.kubernetes.io/cors-allow-methodscontrols which methods are accepted. This is a multi-valued field, separated by ',' and accepts only letters (upper and lower case). Example:nginx.ingress.kubernetes.io/cors-allow-methods: "PUT, GET, POST, OPTIONS" -
nginx.ingress.kubernetes.io/cors-allow-headerscontrols which headers are accepted. This is a multi-valued field, separated by ',' and accepts letters, numbers, _ and -. Example:nginx.ingress.kubernetes.io/cors-allow-headers: "X-Forwarded-For, X-app123-XPTO" -
nginx.ingress.kubernetes.io/cors-allow-origincontrols what's the accepted Origin for CORS and defaults to '*'. This is a single field value, with the following format:http(s)://origin-site.comorhttp(s)://origin-site.com:portExample:nginx.ingress.kubernetes.io/cors-allow-origin: "https://origin-site.com:4443" -
nginx.ingress.kubernetes.io/cors-allow-credentialscontrols if credentials can be passed during CORS operations. Example:nginx.ingress.kubernetes.io/cors-allow-credentials: "true" -
nginx.ingress.kubernetes.io/cors-max-agecontrols how long preflight requests can be cached. Example:nginx.ingress.kubernetes.io/cors-max-age: 600
!!! note For more information please see https://enable-cors.org
Server Alias
To add Server Aliases to an Ingress rule add the annotation nginx.ingress.kubernetes.io/server-alias: "<alias>".
This will create a server with the same configuration, but a different server_name as the provided host.
!!! Note A server-alias name cannot conflict with the hostname of an existing server. If it does the server-alias annotation will be ignored. If a server-alias is created and later a new server with the same hostname is created, the new server configuration will take place over the alias configuration.
For more information please see the server_name documentation.
Server snippet
Using the annotation nginx.ingress.kubernetes.io/server-snippet it is possible to add custom configuration in the server configuration block.
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
annotations:
nginx.ingress.kubernetes.io/server-snippet: |
set $agentflag 0;
if ($http_user_agent ~* "(Mobile)" ){
set $agentflag 1;
}
if ( $agentflag = 1 ) {
return 301 https://m.example.com;
}
!!! attention This annotation can be used only once per host.
Client Body Buffer Size
Sets buffer size for reading client request body per location. In case the request body is larger than the buffer, the whole body or only its part is written to a temporary file. By default, buffer size is equal to two memory pages. This is 8K on x86, other 32-bit platforms, and x86-64. It is usually 16K on other 64-bit platforms. This annotation is applied to each location provided in the ingress rule.
!!! note The annotation value must be given in a format understood by Nginx.
!!! example
* `nginx.ingress.kubernetes.io/client-body-buffer-size: "1000"` # 1000 bytes
* `nginx.ingress.kubernetes.io/client-body-buffer-size: 1k` # 1 kilobyte
* `nginx.ingress.kubernetes.io/client-body-buffer-size: 1K` # 1 kilobyte
* `nginx.ingress.kubernetes.io/client-body-buffer-size: 1m` # 1 megabyte
* `nginx.ingress.kubernetes.io/client-body-buffer-size: 1M` # 1 megabyte
For more information please see http://nginx.org
External Authentication
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/auth-url: "URL to the authentication service"
Additionally it is possible to set:
nginx.ingress.kubernetes.io/auth-method:<Method>to specify the HTTP method to use.nginx.ingress.kubernetes.io/auth-signin:<SignIn_URL>to specify the location of the error page.nginx.ingress.kubernetes.io/auth-response-headers:<Response_Header_1, ..., Response_Header_n>to specify headers to pass to backend once authentication request completes.nginx.ingress.kubernetes.io/auth-request-redirect:<Request_Redirect_URL>to specify the X-Auth-Request-Redirect header value.
!!! example Please check the external-auth example.
Rate limiting
These annotations define a limit on the connections that can be opened by a single client IP address. This can be used to mitigate DDoS Attacks.
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.
If you specify multiple annotations in a single Ingress rule, limit-rpm, and then limit-rps takes precedence.
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. if you set the value in ingress annotation will cover global setting.
Permanent Redirect
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.
SSL Passthrough
The annotation nginx.ingress.kubernetes.io/ssl-passthrough allows to configure TLS termination in the pod and not in NGINX.
!!! attention
Using the annotation nginx.ingress.kubernetes.io/ssl-passthrough invalidates all the other available annotations.
This is because SSL Passthrough works on level 4 of the OSI stack (TCP), not on the HTTP/HTTPS level.
!!! attention
The use of this annotation requires the Proxy Protocol to be enabled in the front-end load-balancer.
For example enabling Proxy Protocol for AWS ELB is described here.
If you're using ingress-controller without load balancer then the flag
--enable-ssl-passthrough is required (by default it is disabled).
Secure backends
By default NGINX uses plain HTTP to reach the services.
Adding the annotation nginx.ingress.kubernetes.io/secure-backends: "true" in the Ingress rule changes the protocol to HTTPS.
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.
!!! attention
Note that if an invalid or non-existent secret is given,
the ingress controller will ignore the `secure-backends` annotation.
Service Upstream
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.
Known Issues
If the service-upstream annotation is specified the following things should be taken into consideration:
- Sticky Sessions will not work as only round-robin load balancing is supported.
- The
proxy_next_upstreamdirective will not have any effect meaning on error the request will not be dispatched to another upstream.
Server-side HTTPS enforcement through redirect
By default the controller redirects (308) to HTTPS if TLS is enabled for that ingress.
If you want to disable this behavior globally, you can use ssl-redirect: "false" in the NGINX config map.
To configure this feature for specific ingress resources, you can use the nginx.ingress.kubernetes.io/ssl-redirect: "false"
annotation in the particular resource.
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.
Redirect from/to www.
In some scenarios is required to redirect from www.domain.com to domain.com or vice versa.
To enable this feature use the annotation nginx.ingress.kubernetes.io/from-to-www-redirect: "true"
!!! attention
If at some point a new Ingress is created with a host equal to one of the options (like domain.com) the annotation will be omitted.
Whitelist source range
You can specify allowed client IP source ranges through the nginx.ingress.kubernetes.io/whitelist-source-range annotation.
The value is a comma separated list of CIDRs, e.g. 10.0.0.0/24,172.10.0.1.
To configure this setting globally for all Ingress rules, the whitelist-source-range value may be set in the NGINX ConfigMap.
!!! note Adding an annotation to an Ingress rule overrides any global restriction.
Custom timeouts
Using the configuration configmap it is possible to set the default global timeout for connections to the upstream servers. In some scenarios is required to have different values. To allow this we provide annotations that allows this customization:
nginx.ingress.kubernetes.io/proxy-connect-timeoutnginx.ingress.kubernetes.io/proxy-send-timeoutnginx.ingress.kubernetes.io/proxy-read-timeoutnginx.ingress.kubernetes.io/proxy-next-upstreamnginx.ingress.kubernetes.io/proxy-next-upstream-triesnginx.ingress.kubernetes.io/proxy-request-buffering
Proxy redirect
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.
Both annotations will be used in any other case. By default the value is "off".
Custom max body size
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.
To configure this setting globally for all Ingress rules, the proxy-body-size value may be set in the NGINX ConfigMap.
To use custom values in an Ingress rule define these annotation:
nginx.ingress.kubernetes.io/proxy-body-size: 8m
Proxy buffering
Enable or disable proxy buffering proxy_buffering.
By default proxy buffering is disabled in the NGINX config.
To configure this setting globally for all Ingress rules, the proxy-buffering value may be set in the NGINX ConfigMap.
To use custom values in an Ingress rule define these annotation:
nginx.ingress.kubernetes.io/proxy-buffering: "on"
SSL ciphers
Specifies the enabled ciphers.
Using this annotation will set the ssl_ciphers directive at the server level. This configuration is active for all the paths in the host.
nginx.ingress.kubernetes.io/ssl-ciphers: "ALL:!aNULL:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP"
Connection proxy header
Using this annotation will override the default connection header set by NGINX. To use custom values in an Ingress rule, define the annotation:
nginx.ingress.kubernetes.io/connection-proxy-header: "keep-alive"
Enable Access Log
Access logs are enabled by default, but in some scenarios access logs might be required to be disabled for a given ingress. To do this, use the annotation:
nginx.ingress.kubernetes.io/enable-access-log: "false"
Enable Rewrite Log
Rewrite logs are not enabled by default. In some scenarios it could be required to enable NGINX rewrite logs. Note that rewrite logs are sent to the error_log file at the notice level. To enable this feature use the annotation:
nginx.ingress.kubernetes.io/enable-rewrite-log: "true"
Lua Resty WAF
Using lua-resty-waf-* annotations we can enable and control the lua-resty-waf
Web Application Firewall per location.
Following configuration will enable the WAF for the paths defined in the corresponding ingress:
nginx.ingress.kubernetes.io/lua-resty-waf: "active"
In order to run it in debugging mode you can set nginx.ingress.kubernetes.io/lua-resty-waf-debug to "true" in addition to the above configuration.
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 that covers ModSecurity CRS.
You can use nginx.ingress.kubernetes.io/lua-resty-waf-ignore-rulesets to ignore a subset of those rulesets. For an example:
nginx.ingress.kubernetes.io/lua-resty-waf-ignore-rulesets: "41000_sqli, 42000_xss"
will ignore the two mentioned rulesets.
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:
nginx.ingress.kubernetes.io/lua-resty-waf-extra-rules: '[=[ { "access": [ { "actions": { "disrupt" : "DENY" }, "id": 10001, "msg": "my custom rule", "operator": "STR_CONTAINS", "pattern": "foo", "vars": [ { "parse": [ "values", 1 ], "type": "REQUEST_ARGS" } ] } ], "body_filter": [], "header_filter":[] } ]=]'
For details on how to write WAF rules, please refer to https://github.com/p0pr0ck5/lua-resty-waf.
gRPC backend
Since NGINX 1.13.10 it is possible to expose gRPC services natively
You only need to add the annotation nginx.ingress.kubernetes.io/grpc-backend: "true" to enable this feature.
Additionally, if the gRPC service requires TLS, add nginx.ingress.kubernetes.io/secure-backends: "true".
!!! attention This feature requires HTTP2 to work which means we need to expose this service using HTTPS. Exposing a gRPC service using HTTP is not supported.