Goal

• Seamless development environment in Kubernetes
• Keep your local development tools, no commit or push required
• Helping local continuous development and deployment of microservice applications

Prerequisites

• telepresence
• kubectl
• k8s cluster

How to

Install Telepresence
Install telepresence on your local laptop, please follow the documentation for the installation steps. The k8s cluster for testing purposes is running on Azure Kubernetes Service. Please set context Kubernetes cluster.

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$ kubectlconfig use-context aks-playground-1
$ telepresence connect
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When we use the command telepresence connect to the Kubernetes cluster side, Telepresence will create a namespace ambassador and traffic manager deployment. On the client side, Telepresence set up DNS to enable local access to Kubernetes Cluster. So we don’t need kubectl port-forward to manually configure access to local services. When you access a remote service the DNS resolves to a specific IP
address. For more details, see the Telepresence architecture documentation

Telepresence status

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Root Daemon: Running
Version : v2.4.9 (api 3)
DNS :
 Remote IP : 10.0.0.10
 Exclude suffixes: [.arpa .com .io .net .org .ru]
 Include suffixes: []
 Timeout : 4s
 Also Proxy : (0 subnets)
 Never Proxy: (1 subnets)
User Daemon: Running
 Version : v2.4.9 (api 3)
 Ambassador Cloud : Logged out
 Status : Connected
 Kubernetes server : https://aks-playground-01-dns-d78da381.hcp.
southeastasia.azmk8s.io:443
 Kubernetes context: aks-playground-01
 Telepresence proxy: ON (networking to the cluster is enabled)
 Intercepts : 0 total
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The Telepresence daemon process creates a Virtual Network Interface (VIF) when Telepresence connects to the Kubernetes cluster

Verify from the client side, the client will get 10.0.0.10 ( kube-dns) as the DNS Server on Virtual Network Interfaces ( tel0 ). The Telepresence
DNS resolver is dynamically configured to resolve names using the namespaces of currently active intercepts.

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Link 123 (tel0)
    Current Scopes: DNS
    LLMNR setting: yes
MulticastDNS setting: no
    DNSSEC setting: no
    DNSSEC supported: no
    DNS Servers: 10.0.0.10
    DNS Domain: ~ambassador
                ~default
                ~development
                ~ingress-internal
                ~kube-node-lease
                ~kube-public
                ~kube-system
                cluster.local
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basically, we are able to resolve the service inside kubernetes cluster with the following format servicename.namespaces. for example we try to connect dataprocessingservice on development namespaces

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nslookup dataprocessingservice.development
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Create a sample deployment in Kubernetes cluster

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git clone https://github.com/datawire/edgey-corp-python.git
cd edgey-corp-python
kubectl apply -f k8s-config/edgey-corp-web-app-no-mapping.yaml -n development
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Since this scenario we will access to the ingress, create an ingress object to provide routing rules to verylargejavaservice

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spec:
rules:
- host: verylargejavaservice.development.internal
  http:
   paths:
   - backend:
       service:
         name: verylargejavaservice
        
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Verify the deployment on k8s

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kubectl get deployment,svc,ing -n development
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NAME                                  READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/dataprocessingservice 1/1     1            1           21m
deployment.apps/verylargedatastore    1/1     1            1           21m
deployment.apps/verylargejavaservice  1/1     1            1           21m
NAME                          TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)     AGE
service/dataprocessingservice ClusterIP   10.0.31.245    <none>        3000/TCP    21m
service/verylargedatastore    ClusterIP   10.0.4.75      <none>        8080/TCP    21m
service/verylargejavaservice  ClusterIP   10.0.155.58    <none>        8080/TCP    21m
NAME                                             CLASS    HOSTS                    ADDRESS   PORTS   AGE
ingress.networking.k8s.io/verylargejavaservice   <none>   verylargejavaservice.    <none>   21m
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Connection test to verylargejavaservice. below several services, such us verylargejavaservice, dataprocessingservice and verylargedatastore are running on K8s Cluster. Please ignore the wording on the symbol cloud

Intercept dataprocessingservice on that running on k8s cluster into your local environment

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$ telepresence intercept dataprocessingservice --port 3000 -n development
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Using Deployment dataprocessingservice
intercepted
    Intercept name : dataprocessingservice-development
    State : ACTIVE
    Workload kind : Deployment
    Destination : 127.0.0.1:3000
    Volume Mount Point: /tmp/telfs-2442392270
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in parallel you are working on development microservice dataprocessingservice on your laptop, once the intercept is already activated, the traffic from external toward dataprocessingservice will be routed to the local laptop

after you make changes code DEFAULT_COLOR = ‘orange’ on local development, we can see the changes when we access the service again, Traffic from verylargejaveservice will be routed to local laptop with orange color.

Reference

• https://www.getambassador.io/docs/telepresence/latest/reference/architecture
• https://github.com/datawire/edgey-corp-python.git