nghttpx Ingress Controller

This is an Ingress Controller which uses nghttpx as L7 load balancer.

nghttpx ingress controller was initially created based on nginx ingress controller.

Docker images

The official Docker images are available at Docker Hub.

Requirements

• default backend 404-server

Actually, any backend web server will suffice as long as it returns some kind of error code for any requests.

If --internal-default-backend flag is given, the default backend service is not necessary. The controller configures nghttpx to act as a default backend.

Deploy the Ingress controller

Before the deploy of the Ingress controller we need a default backend:

$ kubectl create -f examples/default-backend.yaml
$ kubectl expose deployment default-http-backend --port=80 --target-port=8080 --name=default-http-backend

Load balancers are created via a Deployment or DaemonSet:

$ kubectl create -f examples/default/service-account.yaml
$ kubectl create -f examples/default/rc-default.yaml

IngressClass

This controller supports IngressClass resource. The default IngressClass controller name is "zlab.co.jp/nghttpx". It supports ingressclass.kubernetes.io/is-default-class annotation.

This controller no longer supports the deprecated kubernetes.io/ingress.class annotation.

The default behavior around IngressClass does not follow the standard rule for a historical reason. nghttpx ingress controller processes Ingress resource which does not have .spec.ingressClassName specified. It also interprets the default IngressClass in its own way. If Ingress resource does not have .spec.ingressClassName specified, but the default IngressClass does not point to nghttpx ingress controller, it does not process the resource. The standard rule is that if Ingress resource does not have .spec.ingressClassName, it should be ignored, and only process the resource which is explicitly designated to the controller via IngressClass. --require-ingress-class flag enforces this rule. Obviously, it completely changes which resources are processed by this controller. You need to set .spec.ingressClassName for all Ingress resources in your cluster. And create the default IngressClass resource to ensure that Ingress.spec.ingressClassName is defaulted properly.

networking.k8s.io/v1 Ingress

This controller only recognizes Service backend. It ignores pathType and behaves as if ImplementationSpecific is specified. Hosts in .spec.tls are also ignored.

HTTP

First we need to deploy some application to publish. To keep this simple we will use the echoheaders app that just returns information about the HTTP request as output

kubectl create deployment echoheaders --image=registry.k8s.io/echoserver:1.10

Now we expose the same application in two different services (so we can create different Ingress rules)

kubectl expose deployment echoheaders --port=80 --target-port=8080 --name=echoheaders-x
kubectl expose deployment echoheaders --port=80 --target-port=8080 --name=echoheaders-y

Next we create a couple of Ingress rules

kubectl create -f examples/ingress.yaml

we check that ingress rules are defined:

$ kubectl get ing
NAME      HOSTS                     ADDRESS         PORTS   AGE
echomap   foo.bar.com,bar.baz.com   192.168.0.1     80      1m11s

Check nghttpx it is running with the defined Ingress rules:

$ LBIP=$(kubectl get node `kubectl get po -l name=nghttpx-ingress-lb --namespace=kube-system --template '{{range .items}}{{.spec.nodeName}}{{end}}'` --template '{{range $i, $n := .status.addresses}}{{if eq $n.type "ExternalIP"}}{{$n.address}}{{end}}{{end}}')
$ curl $LBIP/foo -H 'Host: foo.bar.com'

The above command might not work properly. In that case, check out Ingress resource's .Status.LoadBalancer.Ingress field. nghttpx Ingress controller periodically (30 - 60 seconds) writes its IP address there.

TLS

You can secure an Ingress by specifying a secret that contains a TLS private key and certificate. Currently the Ingress only supports a single TLS port, 443, and assumes TLS termination. This controller supports SNI. The TLS secret must contain keys named tls.crt and tls.key that contain the certificate and private key to use for TLS:

apiVersion: v1
data:
  tls.crt: <base64 encoded cert>
  tls.key: <base64 encoded key>
kind: Secret
metadata:
  name: testsecret
  namespace: default
type: kubernetes.io/tls

You can create this kind of secret using kubectl create secret tls subcommand.

Referencing this secret in an Ingress will tell the Ingress controller to secure the channel from the client to the load balancer using TLS:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: no-rules-map
spec:
  tls:
  - secretName: testsecret
  defaultBackend:
    service:
      name: s1
      port:
        number: 80

If TLS is configured for a service, and it is accessed via cleartext HTTP, those requests are redirected to HTTPS URI. If --default-tls-secret flag is used, all cleartext HTTP requests are redirected to https URI. This behaviour is configurable using path-config annotation.

TLS OCSP stapling

By default, nghttpx performs OCSP request to OCSP responder for each certificate. This requires that the controller pod is allowed to make outbound connections to the server. If there are several Ingress controllers, this method is not efficient since each controller performs OCSP request.

With --fetch-ocsp-resp-from-secret flag, the controller fetches OCSP response from TLS Secret described above. Although we have to store OCSP response to these Secrets in a separate step, and update regularly, they are shared among all controllers, and therefore it is efficient for large deployment.

Note that currently the controller has no facility to store and update OCSP response to TLS Secret. The controller just fetches OCSP response from TLS Secret.

The key for OCSP response in TLS Secret is tls.ocsp-resp by default. It can be changed by --ocsp-resp-key flag. The value of OCSP response in TLS Secret must be DER encoded.

HTTP/3 (Experimental)

In order to enable the experimental HTTP/3 feature, run the controller with --http3 flag. The controller will create and maintain a Secret, specified by --quic-keying-materials-secret flag, which contains QUIC keying materials in the same namespace as the controller Pod. The controller maintains the secret as a whole, and it should not be altered by an external tool or user. nghttpx listens on UDP port specified by --nghttpx-https-port flag.

HTTP/3 requires writing Secret and extra capabilities to load eBPF program. For writing Secret, you might need to add the following entry to ClusterRole:

kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
...
rules:
- apiGroups: [""]
  resources: ["secrets"]
  verbs: ["create", "update", "patch"]
...

Add the following capabilities to the nghttpx-ingress-controller container:

apiVersion: apps/v1
kind: DaemonSet
...
spec:
  template:
    spec:
      containers:
      - image: zlabjp/nghttpx-ingress-controller:latest
        ...
        securityContext:
          capabilities:
            add:
            - SYS_ADMIN
            - SYS_RESOURCE
        ...

If you use PodSecurityPolicy, grant these capabilities:

apiVersion: policy/v1beta1
kind: PodSecurityPolicy
...
spec:
  ...
  allowedCapabilities:
  - SYS_ADMIN
  - SYS_RESOURCE
  ...

PROXY protocol support - preserving ClientIP addresses

In case you are running nghttpx-ingress-lb behind a LoadBalancer you might to preserve the ClientIP addresses accessing your Kubernetes cluster.

As an example we are using a deployment on a Kubernetes on AWS.

In order to use all nghttpx features, especially upstream HTTP/2 forwarding and TLS SNI, the only way to deploy nghttpx-ingress-lb, is to use an AWS ELB (Classic LoadBalancer) in TCP mode and let nghttpx do the TLS-termination, because:

• AWS ELB does not handle HTTP/2 at all.
• AWS ALB does not handle upstream HTTP/2.

Therefore using an X-Forward-For header does not work, and you have to rely on the PROXY-protocol feature.

Enable PROXY-protocol on external LoadBalancer

You can enable the PROXY protocol manually on the external AWS ELB(http://docs.aws.amazon.com/elasticloadbalancing/latest/classic/enable-proxy-protocol.html), which forwards traffic to your nghttpx-ingress-lb, or you can let Kubernetes handle this for your like:

# Kubernetes LoadBalancer ELB configuration, which forwards traffic
# on ports 80 and 443 to an nghttpx-ingress-lb controller.
# Kubernetes enabled the PROXY protocol on the AWS ELB.
apiVersion: v1
kind: Service
metadata:
  annotations:
    service.beta.kubernetes.io/aws-load-balancer-proxy-protocol: '*'
  name: nghttpx-ingress
  namespace: kube-system
spec:
  selector:
    k8s-app: nghttpx-ingress-lb
  type: LoadBalancer
  ports:
  - name: http-ingress
    port: 80
  - name: tls-ingress
    port: 443

Enable PROXY-protocol on nghttpx-ingress-lb

Once the external LoadBalancer has PROXY-protocol enabled, you have to enable the PROXY-protocol on nghttpx-ingress-lb as well by specifying an additional launch-parameter of the nghttpx-ingress-lb, using --proxy-proto=true

See the examples/proxyproto subdirectory for a working deployment or use:

# Deploy nghttpx-ingress-lb behind LoadBalancer with PROXY protocol and RBAC enabled.
kubctl apply -f examples/proxyproto/

Default backend

The default backend is used when the request does not match any given rules. The default backend must be set in command-line flag of nghttpx Ingress controller unless --internal-default-backend flag is given, see below. It can be overridden by specifying Ingress.Spec.Backend. If multiple Ingress resources have .Spec.Backend, one of them is used, but it is undefined which one is used. The default backend always does not require TLS.

If --internal-default-backend is used, the controller configures nghttpx to act as a default backend. In this case, the default backend service is not necessary.

Services without selectors

nghttpx supports Services without selectors.

Logs

The access, and error log of nghttpx are written to stdout, and stderr respectively. They can be configured using accesslog-file and errorlog-file options respectively. No log file rotation is configured by default.

Ingress status

By default, nghttpx Ingress controller periodically writes the addresses of their Pods in all Ingress resource status. If multiple nghttpx Ingress controllers are running, the controller first gets all Pods with the same labels of its own, and writes all addresses in Ingress status.

If a Service is specified in --publish-service flag, external IPs, and load balancer addresses in the specified Service are written into Ingress resource instead.

Additional configurations

nghttpx supports additional configurations via Ingress Annotations.

ingress.zlab.co.jp/backend-config annotation

nghttpx-ingress-controller understands ingress.zlab.co.jp/backend-config key in Ingress .metadata.annotations to configure the particular backend. Its value is a serialized YAML or JSON dictionary. The configuration is done per service port (.spec.rules[*].http.paths[*].backend.service.port). The first key under the root dictionary is the name of service name (.spec.rules[*].http.paths[*].backend.service.name). Its value is the JSON dictionary, and its keys are service port (.spec.rules[*].http.paths[*].backend.service.port.name or .spec.rules[*].http.paths[*].backend.service.port.number if .port.name is not specified). The final value is the JSON dictionary, and can contain the following key value pairs:

• proto: Specify the application protocol used for this service port. The value is of type string, and it should be either h2, or http/1.1. Use h2 to use HTTP/2 for backend connection. This is optional, and defaults to "http/1.1".

• tls: Specify whether or not TLS is used for this service port. This is optional, and defaults to false.

• sni: Specify SNI hostname for TLS connection. This is used to validate server certificate.

• dns: Specify whether backend host name should be resolved dynamically.

• weight: Specify the weight of the backend selection. nghttpx ingress controller can aggregates multiple services under single host and path pattern. The weight specifies how frequently this service is selected compared to the other services aggregated under the same pattern. The service with weight 3 is 3 times more frequently used than the one with weight 1. Using this settings, one can send more/less traffic to a particular service. This is useful, for example, if one wants to send 80% of traffic to Service A, while remaining 20% traffic to Service B. The value must be [1, 256], inclusive.

The following example specifies HTTP/2 as backend connection for service "greeter", and service port "50051":

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: greeter
  annotations:
    ingress.zlab.co.jp/backend-config: '{"greeter": {"50051": {"proto": "h2"}}}'
spec:
  rules:
  - http:
      paths:
      - path: /helloworld.Greeter/
        pathType: ImplementationSpecific
        backend:
          service:
            name: greeter
            port:
              number: 50051

Or in YAML:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: greeter
  annotations:
    ingress.zlab.co.jp/backend-config: |
      greeter:
        50051:
          proto: h2
spec:
  rules:
  - http:
      paths:
      - path: /helloworld.Greeter/
        pathType: ImplementationSpecific
        backend:
          service:
            name: greeter
            port:
              number: 50051

The controller also understands ingress.zlab.co.jp/default-backend-config annotation. It serves default values for missing values in backend-config per field basis in the same Ingress resource. It can contain single dictionary which contains the same key/value pairs. It is useful if same set of backend-config is required for lots of services.

For example, if a pair of service, and port has the backend-config like so:

{"sni": "www.example.com"}

And the default-backend-config looks like so:

{"proto": "h2", "sni": "example.com"}

The final backend-config becomes like so:

{"proto": "h2", "sni": "www.example.com"}

A values which specified explicitly in an individual backend-config always takes precedence.

Note that Ingress allows regular expression in .spec.rules[*].http.paths[*].path, but nghttpx does not support it.

ingress.zlab.co.jp/path-config annotation

nghttpx-ingress-controller understands ingress.zlab.co.jp/path-config key in Ingress .metadata.annotations to allow additional configuration per host and path pattern. Its value is a serialized YAML or JSON dictionary. The configuration is done per host and path pattern. The key under the root dictionary is the concatenation of host and path. For example, if host is "www.example.com" and path is "/foo", its key is "www.example.com/foo". For convenience, if "www.example.com" is specified as a key, it is normalized as "www.example.com/". Its value is the dictionary and can contain the following key value pairs:

• mruby: Specify mruby script which is invoked when the given pattern is selected. For mruby script, see nghttpx manual page

• affinity: Specify session affinity method. Specifying ip enables client IP based session affinity. Specifying cookie enables cookie-based session affinity. Specifying none or omitting this key disables session affinity.

  If cookie is specified, additional configuration is required. See affinityCookieName, affinityCookiePath, and affinityCookieSecure fields.

• affinityCookieName: Specify a name of cookie to use. This is required field if cookie is set in affinity field.

• affinityCookiePath: Specify a path of cookie path. This is optional, and if not set, cookie path is not set.

• affinityCookieSecure: Specify whether Secure attribute of cookie is added, or not. Omitting this field, specifying empty string, or specifying "auto" sets Secure attribute if client connection is TLS encrypted. If "yes" is specified, Secure attribute is always added. If "no" is specified, Secure attribute is always omitted.

• affinityCookieStickiness: Specify the stickiness of session cookie. If loose is given, which is default, the affinity might break if an existing backend server is removed, or new backend server is added. If strict is given, if the designated backend server is removed, the request is forwarded to a new server as if it is a new request. However, adding new backend server does not cause breakage.

• readTimeout: Specify read timeout. If specified, it overrides global backend read timeout set by --backend-read-timeout. You can use string representation of time used in Golang (e.g., 5s, 5m)

• writeTimeout: Specify write timeout. If specified, it overrides global backend write timeout set by --backend-write-timeout. You can use string representation of time used in Golang (e.g., 5s, 5m)

• redirectIfNotTLS: Specify whether cleartext HTTP request is redirected to HTTPS if TLS is configured. This defaults to true.

• doNotForward: Do not forward a request to a backend server. It assumes that a response is generated by mruby script. .spec.rules[*].http.paths[*].backend is a required field, so a placeholder service must be given (it never be accessed). Note that .spec.rules[*].http.paths[*].backend.resource does not work as a placeholder.

Here is an example to rewrite request path to "/foo" from "/pub/foo" using mruby:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: greeter
  annotations:
    ingress.zlab.co.jp/path-config: |
      www.example.com/pub/foo:
        readTimeout: 5m
        mruby: |
          class App
            def on_req(env)
              env.req.path = "/foo"
            end
          end
          App.new
spec:
  rules:
  - host: www.example.com
    http:
      paths:
      - path: /pub/foo
        pathType: ImplementationSpecific
        backend:
          service
            name: bar
            port:
              number: 80

The controller also understands ingress.zlab.co.jp/default-path-config annotation. It serves default values for missing values in path-config per field basis in the same Ingress resource. It can contain single dictionary which contains the same key/value pairs. It is useful if same configuration is shared by lots of patterns.

A values which specified explicitly in an individual path-config always takes precedence.

Custom nghttpx configuration

Using a ConfigMap it is possible to customize the defaults in nghttpx. The content of configuration is specified under nghttpx-conf key. All nghttpx options can be used to customize behavior of nghttpx. See FILES section of nghttpx(1) manual page for the syntax of configuration file.

apiVersion: v1
kind: ConfigMap
metadata:
  name: nghttpx-ingress-lb
data:
  nghttpx-conf: |
    log-level=INFO
    accesslog-file=/dev/null

nghttpx historically strips an incoming X-Forwarded-Proto header field, and adds its own one. To change this behaviour, use the combination of no-add-x-forwarded-proto and no-strip-incoming-x-forwarded-proto. For example, in order to retain the incoming X-Forwarded-Proto header field, add no-strip-incoming-x-forwarded-proto=yes:

apiVersion: v1
kind: ConfigMap
metadata:
  name: nghttpx-ingress-lb
data:
  nghttpx-conf: |
    no-strip-incoming-x-forwarded-proto=yes

nghttpx ingress controller, by default, overrides the following default configuration:

• workers: set the number of cores that nghttpx uses.

User can override workers using ConfigMap.

Since mruby-file option takes a path to mruby script file, user has to include mruby script to the image or mount the external volume. In order to make it easier to specify mruby script, user can write mruby script under nghttpx-mruby-file-content key, like so:

apiVersion: v1
kind: ConfigMap
metadata:
  name: nghttpx-ingress-lb
data:
  nghttpx-mruby-file-content: |
    class App
      def on_req(env)
        env.req.path = "/apps#{env.req.path}"
      end
    end

    App.new

The controller saves the content, and mruby-file option which refers to the saved file is added to the configuration. Read MRUBY SCRIPTING section of nghttpx(1) manual page about mruby API.

MRUBY Scripting

In addition to the basic mrbgems included by mruby, this Ingress controller adds the following mrbgems for convenience:

• mattn/mruby-onig-regexp: This adds the regular expression support.

Troubleshooting

TBD

Debug

Using the --v flag it is possible to increase the level of logging. In particular:

• --v=2 shows details using diff about the changes in the configuration in nghttpx

I0323 04:39:16.552830       8 utils.go:90] nghttpx configuration diff /etc/nghttpx/nghttpx.conf
--- currnet
+++ new
@@ -1,7 +1,41 @@
-# A very simple nghttpx configuration file that forces nghttpx to start.
+accesslog-file=/dev/stdout
+include=/etc/nghttpx/nghttpx-backend.conf

• --v=3 shows details about the service, Ingress rule, endpoint changes and it dumps the nghttpx configuration in JSON format

Limitations

• When no TLS is configured, nghttpx still listens on port 443 for cleartext HTTP.
• TLS configuration is not bound to the specific service. In general, all proxied services are accessible via TLS.
• .spec.rules[*].http.paths[*].pathType is ignored and it is treated as if ImplementationSpecific is specified. Consult nghttpx manual to know the path matching rules.

Building from source

Build nghttpx-ingress-controller binary:

$ make controller

Build and push docker images:

$ make push

LICENSE

The MIT License (MIT)

Copyright (c) 2016  Z Lab Corporation
Copyright (c) 2017  nghttpx Ingress controller contributors

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

This repository contains the code which has the following license notice:

Copyright 2015 The Kubernetes Authors. All rights reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.