Use the Network-restricted Cluster
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To access services running on the remote, edge or network-restricted cluster from the Management cluster, connect to the tunnel proxy.
You can use these three methods:
If the client program supports use of a kubeconfig file, use the network-restricted cluster’s kubeconfig.
If the client program supports SOCKS5 proxies, use the proxy directly.
Otherwise, deploy a proxy server on the Management cluster.
Network-restricted Cluster Service
These sections require a service to run on the Attached or Managed network-restricted cluster.
As an example, start the following service:
service_namespace=test
service_name=webserver
service_port=8888
service_endpoint=${service_name}.${service_namespace}.svc.cluster.local:${service_port}
cat > nginx.yaml <<EOF
apiVersion: v1
kind: Namespace
metadata:
name: ${service_namespace}
---
apiVersion: apps/v1
kind: Deployment
metadata:
namespace: ${service_namespace}
name: nginx-deployment
labels:
app: nginx-deployment
spec:
replicas: 3
selector:
matchLabels:
app: nginx-app
template:
metadata:
labels:
app: nginx-app
spec:
containers:
- name: nginx
image: nginx:1.14.2
ports:
- containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
namespace: ${service_namespace}
name: ${service_name}
spec:
selector:
app: nginx-app
type: ClusterIP
ports:
- targetPort: 80
port: ${service_port}
EOF
kubectl apply -f nginx.yaml
kubectl rollout status deploy -n ${service_namespace} nginx-deployment
On the Attached or Managed cluster, a client Job can access this service using:
cat > curl.yaml <<EOF
apiVersion: batch/v1
kind: Job
metadata:
name: curl
spec:
template:
spec:
containers:
- name: curl
image: curlimages/curl:7.76.0
command: ["curl", "--silent", "--show-error", "http://${service_endpoint}"]
restartPolicy: Never
backoffLimit: 4
EOF
kubectl apply -f curl.yaml
kubectl wait --for=condition=complete job curl
podname=$(kubectl get pods --selector=job-name=curl --field-selector=status.phase=Succeeded -o jsonpath='{.items[0].metadata.name}')
kubectl logs ${podname}
The final command returns the default Nginx web page:
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
Use of kubeconfig file
This is primarily useful for running kubectl
commands on the Management cluster to monitor the network-restricted, Managed or Attached cluster.
On the Management cluster, a kubeconfig
file for the Attached or Managed cluster configured to use the tunnel proxy is available as a Secret. The Secret’s name can be identified using:
kubeconfig_secret=$(kubectl get tunnelconnector -n ${namespace} ${connector} -o jsonpath='{.status.kubeconfigRef.name}')
After setting service_namespace
and service_name
to the service resource, run this command on the Management cluster:
cat > get-service.yaml <<EOF
apiVersion: batch/v1
kind: Job
metadata:
name: get-service
spec:
template:
spec:
containers:
- name: kubectl
image: bitnami/kubectl:1.19
command: ["kubectl", "get", "service", "-n", "${service_namespace}", "${service_name}"]
env:
- name: KUBECONFIG
value: /tmp/kubeconfig/kubeconfig
volumeMounts:
- name: kubeconfig
mountPath: /tmp/kubeconfig
volumes:
- name: kubeconfig
secret:
secretName: "${kubeconfig_secret}"
restartPolicy: Never
backoffLimit: 4
EOF
kubectl apply -n ${namespace} -f get-service.yaml
kubectl wait --for=condition=complete --timeout=5m job -n ${namespace} get-service
podname=$(kubectl get pods -n ${namespace} --selector=job-name=get-service --field-selector=status.phase=Succeeded -o jsonpath='{.items[0].metadata.name}')
kubectl logs -n ${namespace} ${podname}
Direct use of SOCKS5 proxy
To use the SOCKS5 proxy directly, obtain the SOCKS5 proxy endpoint using:
proxy_service=$(kubectl get tunnelconnector -n ${namespace} ${connector} -o jsonpath='{.status.tunnelServer.serviceRef.name}')
socks_proxy=$(kubectl get service -n ${namespace} "${proxy_service}" -o jsonpath='{.spec.clusterIP}{":"}{.spec.ports[?(@.name=="proxy")].port}')
Provide the value of ${socks_proxy}
as the SOCKS5 proxy to your client.
For example, since curl
supports SOCKS5 proxies, the Attached or Managed service started above can be accessed from the Management cluster by adding the SOCKS5 proxy to the curl
command. After setting service_endpoint
to the service endpoint, on the Management cluster run:
cat > curl.yaml <<EOF
apiVersion: batch/v1
kind: Job
metadata:
name: curl
spec:
template:
spec:
containers:
- name: curl
image: curlimages/curl:7.76.0
command: ["curl", "--silent", "--show-error", "--socks5-hostname", "${socks_proxy}", "http://${service_endpoint}"]
restartPolicy: Never
backoffLimit: 4
EOF
kubectl apply -f curl.yaml
kubectl wait --for=condition=complete --timeout=5m job curl
podname=$(kubectl get pods --selector=job-name=curl --field-selector=status.phase=Succeeded -o jsonpath='{.items[0].metadata.name}')
kubectl logs ${podname}
The final command returns the same output as for the job on the Attached or Managed cluster, demonstrating that the job on the Management cluster accessed the service running on the Attached or Managed cluster.
Use of deployed proxy on Management cluster
To deploy a proxy on the Management cluster, obtain the SOCKS5 proxy endpoint using:
proxy_service=$(kubectl get tunnelconnector -n ${namespace} ${connector} -o jsonpath='{.status.tunnelServer.serviceRef.name}')
socks_proxy=$(kubectl get service -n ${namespace} "${proxy_service}" -o jsonpath='{.spec.clusterIP}{":"}{.spec.ports[?(@.name=="proxy")].port}')
Provide the value of ${socks_proxy}
as the SOCKS5 proxy to a proxy deployed on the Management cluster. After setting service_endpoint
to the service endpoint, on the Management cluster run:
cat > nginx-proxy.yaml <<EOF
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
name: nginx-proxy-crt
spec:
secretName: nginx-proxy-crt-secret
dnsNames:
- nginx-proxy-service.${namespace}.svc.cluster.local
issuerRef:
group: cert-manager.io
kind: ClusterIssuer
name: kubernetes-ca
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-proxy
labels:
app: nginx-proxy-deployment
spec:
replicas: 1
selector:
matchLabels:
app: nginx-proxy-app
template:
metadata:
labels:
app: nginx-proxy-app
spec:
containers:
- name: nginx-proxy
image: mesosphere/ghostunnel:v1.5.3-server-backend-proxy
args:
- "server"
- "--listen=:443"
- "--target=${service_endpoint}"
- "--cert=/etc/certs/tls.crt"
- "--key=/etc/certs/tls.key"
- "--cacert=/etc/certs/ca.crt"
- "--unsafe-target"
- "--disable-authentication"
env:
- name: ALL_PROXY
value: socks5://${socks_proxy}
ports:
- containerPort: 443
volumeMounts:
- name: certs
mountPath: /etc/certs
volumes:
- name: certs
secret:
secretName: nginx-proxy-crt-secret
---
apiVersion: v1
kind: Service
metadata:
name: nginx-proxy-service
spec:
selector:
app: nginx-proxy-app
type: ClusterIP
ports:
- targetPort: 443
port: 8765
EOF
kubectl apply -n ${namespace} -f nginx-proxy.yaml
kubectl rollout status deploy -n ${namespace} nginx-proxy
proxy_port=$(kubectl get service -n ${namespace} nginx-proxy-service -o jsonpath='{.spec.ports[0].port}')
Any client running on the Management cluster can now access the service running on the Attached or Managed cluster using the proxy service endpoint. Note in the following that the curl
job runs in the same namespace as the proxy, to provide access to the CA certificate secret.
cat > curl.yaml <<EOF
apiVersion: batch/v1
kind: Job
metadata:
name: curl
spec:
template:
spec:
containers:
- name: curl
image: curlimages/curl:7.76.0
command:
- curl
- --silent
- --show-error
- --cacert
- /etc/certs/ca.crt
- https://nginx-proxy-service.${namespace}.svc.cluster.local:${proxy_port}
volumeMounts:
- name: certs
mountPath: /etc/certs
volumes:
- name: certs
secret:
secretName: nginx-proxy-crt-secret
restartPolicy: Never
backoffLimit: 4
EOF
kubectl apply -n ${namespace} -f curl.yaml
kubectl wait --for=condition=complete --timeout=5m job -n ${namespace} curl
podname=$(kubectl get pods -n ${namespace} --selector=job-name=curl --field-selector=status.phase=Succeeded -o jsonpath='{.items[0].metadata.name}')
kubectl logs -n ${namespace} ${podname}
The final command returns the same output as the job on the Attached or Managed cluster, demonstrating that the job on the Management cluster accessed the service running on the network-restricted cluster.
Related Topic:
For information on the TunnelGateway review the API documentation (v1alpha1).