300 lines
9.8 KiB
Markdown
300 lines
9.8 KiB
Markdown
<!--
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-----------------NOTICE------------------------
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This file is referenced in code as
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https://github.com/kubernetes/ingress/blob/master/docs/troubleshooting.md
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Do not move it without providing redirects.
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-----------------------------------------------
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-->
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# Troubleshooting
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## Authentication to the Kubernetes API Server
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A number of components are involved in the authentication process and the first step is to narrow
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down the source of the problem, namely whether it is a problem with service authentication or with the kubeconfig file.
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Both authentications must work:
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```
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+-------------+ service +------------+
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| | authentication | |
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+ apiserver +<-------------------+ ingress |
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| | | controller |
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+-------------+ +------------+
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```
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__Service authentication__
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The Ingress controller needs information from apiserver. Therefore, authentication is required, which can be achieved in two different ways:
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1. _Service Account:_ This is recommended, because nothing has to be configured. The Ingress controller will use information provided by the system to communicate with the API server. See 'Service Account' section for details.
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2. _Kubeconfig file:_ In some Kubernetes environments service accounts are not available. In this case a manual configuration is required. The Ingress controller binary can be started with the `--kubeconfig` flag. The value of the flag is a path to a file specifying how to connect to the API server. Using the `--kubeconfig` does not requires the flag `--apiserver-host`.
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The format of the file is identical to `~/.kube/config` which is used by kubectl to connect to the API server. See 'kubeconfig' section for details.
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3. _Using the flag `--apiserver-host`:_ Using this flag `--apiserver-host=http://localhost:8080` it is possible to specify an unsecure api server or reach a remote kubernetes cluster using [kubectl proxy](https://kubernetes.io/docs/user-guide/kubectl/kubectl_proxy/).
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Please do not use this approach in production.
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In the diagram below you can see the full authentication flow with all options, starting with the browser
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on the lower left hand side.
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```
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Kubernetes Workstation
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+---------------------------------------------------+ +------------------+
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| | | |
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| +-----------+ apiserver +------------+ | | +------------+ |
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| | | proxy | | | | | | |
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| | apiserver | | ingress | | | | ingress | |
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| | | | controller | | | | controller | |
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| | | | | | | | | |
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| | | | | | | | | |
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| | | service account/ | | | | | | |
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| | | kubeconfig | | | | | | |
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| | +<-------------------+ | | | | | |
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| | | | | | | | | |
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| +------+----+ kubeconfig +------+-----+ | | +------+-----+ |
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| |<--------------------------------------------------------| |
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| | | |
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+---------------------------------------------------+ +------------------+
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```
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## Service Account
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If using a service account to connect to the API server, Dashboard expects the file
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`/var/run/secrets/kubernetes.io/serviceaccount/token` to be present. It provides a secret
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token that is required to authenticate with the API server.
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Verify with the following commands:
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```shell
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# start a container that contains curl
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$ kubectl run test --image=tutum/curl -- sleep 10000
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# check that container is running
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$ kubectl get pods
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NAME READY STATUS RESTARTS AGE
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test-701078429-s5kca 1/1 Running 0 16s
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# check if secret exists
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$ kubectl exec test-701078429-s5kca ls /var/run/secrets/kubernetes.io/serviceaccount/
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ca.crt
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namespace
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token
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# get service IP of master
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$ kubectl get services
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NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
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kubernetes 10.0.0.1 <none> 443/TCP 1d
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# check base connectivity from cluster inside
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$ kubectl exec test-701078429-s5kca -- curl -k https://10.0.0.1
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Unauthorized
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# connect using tokens
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$ TOKEN_VALUE=$(kubectl exec test-701078429-s5kca -- cat /var/run/secrets/kubernetes.io/serviceaccount/token)
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$ echo $TOKEN_VALUE
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eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3Mi....9A
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$ kubectl exec test-701078429-s5kca -- curl --cacert /var/run/secrets/kubernetes.io/serviceaccount/ca.crt -H "Authorization: Bearer $TOKEN_VALUE" https://10.0.0.1
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{
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"paths": [
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"/api",
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"/api/v1",
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"/apis",
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"/apis/apps",
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"/apis/apps/v1alpha1",
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"/apis/authentication.k8s.io",
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"/apis/authentication.k8s.io/v1beta1",
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"/apis/authorization.k8s.io",
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"/apis/authorization.k8s.io/v1beta1",
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"/apis/autoscaling",
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"/apis/autoscaling/v1",
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"/apis/batch",
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"/apis/batch/v1",
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"/apis/batch/v2alpha1",
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"/apis/certificates.k8s.io",
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"/apis/certificates.k8s.io/v1alpha1",
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"/apis/extensions",
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"/apis/extensions/v1beta1",
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"/apis/policy",
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"/apis/policy/v1alpha1",
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"/apis/rbac.authorization.k8s.io",
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"/apis/rbac.authorization.k8s.io/v1alpha1",
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"/apis/storage.k8s.io",
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"/apis/storage.k8s.io/v1beta1",
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"/healthz",
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"/healthz/ping",
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"/logs",
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"/metrics",
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"/swaggerapi/",
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"/ui/",
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"/version"
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]
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}
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```
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If it is not working, there are two possible reasons:
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1. The contents of the tokens are invalid. Find the secret name with `kubectl get secrets | grep service-account` and
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delete it with `kubectl delete secret <name>`. It will automatically be recreated.
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2. You have a non-standard Kubernetes installation and the file containing the token
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may not be present. The API server will mount a volume containing this file, but
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only if the API server is configured to use the ServiceAccount admission controller.
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If you experience this error, verify that your API server is using the ServiceAccount
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admission controller. If you are configuring the API server by hand, you can set
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this with the `--admission-control` parameter. Please note that you should use
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other admission controllers as well. Before configuring this option, you should
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read about admission controllers.
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More information:
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* [User Guide: Service Accounts](http://kubernetes.io/docs/user-guide/service-accounts/)
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* [Cluster Administrator Guide: Managing Service Accounts](http://kubernetes.io/docs/admin/service-accounts-admin/)
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## Kubeconfig
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If you want to use a kubeconfig file for authentication, create a deployment file similar to the one below:
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*Note:* the important part is the flag `--kubeconfig=/etc/kubernetes/kubeconfig.yaml`.
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```
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kind: Service
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apiVersion: v1
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metadata:
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name: nginx-default-backend
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labels:
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k8s-addon: ingress-nginx.addons.k8s.io
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spec:
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ports:
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- port: 80
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targetPort: http
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selector:
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app: nginx-default-backend
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---
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kind: Deployment
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apiVersion: extensions/v1beta1
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metadata:
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name: nginx-default-backend
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labels:
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k8s-addon: ingress-nginx.addons.k8s.io
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spec:
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replicas: 1
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template:
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metadata:
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labels:
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k8s-addon: ingress-nginx.addons.k8s.io
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app: nginx-default-backend
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spec:
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terminationGracePeriodSeconds: 60
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containers:
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- name: default-http-backend
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image: gcr.io/google_containers/defaultbackend:1.0
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volumeMounts:
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- mountPath: /etc/kubernetes
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name: kubeconfig
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livenessProbe:
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httpGet:
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path: /healthz
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port: 8080
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scheme: HTTP
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initialDelaySeconds: 30
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timeoutSeconds: 5
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resources:
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limits:
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cpu: 10m
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memory: 20Mi
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requests:
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cpu: 10m
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memory: 20Mi
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ports:
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- name: http
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containerPort: 8080
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protocol: TCP
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---
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kind: ConfigMap
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apiVersion: v1
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metadata:
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name: ingress-nginx
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labels:
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k8s-addon: ingress-nginx.addons.k8s.io
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---
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kind: Service
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apiVersion: v1
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metadata:
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name: ingress-nginx
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labels:
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k8s-addon: ingress-nginx.addons.k8s.io
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spec:
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type: LoadBalancer
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selector:
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app: ingress-nginx
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ports:
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- name: http
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port: 80
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targetPort: http
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- name: https
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port: 443
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targetPort: https
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---
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kind: Deployment
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apiVersion: extensions/v1beta1
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metadata:
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name: ingress-nginx
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labels:
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k8s-addon: ingress-nginx.addons.k8s.io
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spec:
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replicas: 1
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template:
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metadata:
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labels:
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app: ingress-nginx
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k8s-addon: ingress-nginx.addons.k8s.io
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spec:
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terminationGracePeriodSeconds: 60
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containers:
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- image: gcr.io/google_containers/nginx-ingress-controller:0.9.0-beta.12
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name: ingress-nginx
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imagePullPolicy: Always
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ports:
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- name: http
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containerPort: 80
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protocol: TCP
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- name: https
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containerPort: 443
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protocol: TCP
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livenessProbe:
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httpGet:
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path: /healthz
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port: 10254
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scheme: HTTP
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initialDelaySeconds: 30
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timeoutSeconds: 5
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env:
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- name: POD_NAME
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valueFrom:
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fieldRef:
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fieldPath: metadata.name
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- name: POD_NAMESPACE
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valueFrom:
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fieldRef:
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fieldPath: metadata.namespace
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args:
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- /nginx-ingress-controller
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- --default-backend-service=$(POD_NAMESPACE)/nginx-default-backend
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- --configmap=$(POD_NAMESPACE)/ingress-nginx
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- --kubeconfig=/etc/kubernetes/kubeconfig.yaml
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volumes:
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- name: "kubeconfig"
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hostPath:
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path: "/etc/kubernetes/"
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```
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