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Configure the backend

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Christian Hellwig edited this page Apr 12, 2021 · 5 revisions

Configure the backend

The last step is to configure our backend. The backend contains a configuration file in configs/appconfig.json. The file contains relative paths so it is important to execute the application with the repository root as working directory, as written in the ReadMe.md file.

Configure the kubernetes cluster

The config file contains a section called kubernetes with several fields that needs to be configured.

...
  "kubernetes": {
    "server": "https://192.168.80.129:51999",
    "certificate-authority": "C:\\Users\\Chris\\Documents\\GoLang\\minikube_vm\\ca.crt",
    "nginx": {
      "namespace": "kube-system",
      "tcp_config_map_name": "tcp-services",
      "deployment_name": "ingress-nginx-controller",
      "container_name": "controller"
    },
    "operators": {
      "postgres": {
        "pgo_url": "https://ingress.local:51998",
        "pgo_username": "admin",
        "pgo_password": "examplepassword",
        "pgo_version": "4.6.2",
        "pgo_ca_path": "C:\\Users\\Chris\\Documents\\GoLang\\minikube_vm\\pgo_cert.cer"
      }
    }
  },
...
Field Description Where to find? Example value
server Kubernetes address kubeconfig file https://192.168.80.129:51999
certificate-authority Kubernetes CA file path kubeconfig file /home/chris/.minikube/ca.crt
nginx.namespace Namespace of the nginx deployment kubectl get namespaces kube-system
nginx.tcp_config_map_name Name of the nginx config map for tcp settings within the nginx namespace kubectl get configmaps -n $NGINX_NAMESPACE tcp-services
nginx.deployment_name Name of the nginx deployment within the nginx namespace kubectl get deployments -n $NGINX_NAMESPACE ingress-nginx-controller
nginx.container_name Name of the container-field within the nginx deployment where the port should be added kubectl get deployments -n $NGINX_NAMESPACE $NGINX_DEPLOYMENT -o yaml controller
operators.postgres.pgo_url Address of the pgo operator kubectl get ingress -n pgo https://ingress.local:51998
operators.postgres.pgo_username Username of the pgo operator Configured with InstallPostgressOperatorIngress.sh script admin
operators.postgres.pgo_password Password of the pgo operator Configured with InstallPostgressOperatorIngress.sh script examplepassword
operators.postgres.pgo_version Version of the pgo operator Navigating to $PGO_URL/version 4.6.2
operators.postgres.pgo_ca_path Filepath to the ca certificate of the operator I.e. export by navigating to $PGO_URL/version with a browser and export with the browser tools /home/pgo/cert.cer

If you have the certifcate data within your kubeconfig file, you have to extract and base64 decode it. This can be done using the following command:

cat ~/.kube/config | grep certificate-authority-data | awk -F ': ' '{print $2}' | base64 -d > ca.crt

Configure the users

In the previous step we created a user with prefix KUB_TEMP_PREFIX user0 which results in the following kubernetes ressources:

  • A namespace called user0-namespace
  • A clusterrole called user0-role
  • A serviceaccount called user0-user
  • A clusterrolebinding called user0-clusterrolebinding

In order to add the user to the configuration we have to readout the service-account token first. The token can be printed by using the following command:

kubectl -n $KUB_TEMP_PREFIX-namespace describe secret $(kubectl -n $KUB_TEMP_PREFIX-namespace get secret | (grep $KUB_TEMP_PREFIX-user || echo "$_") | awk '{print $1}') | grep token: | awk '{print $2}'

The last step is to create an user object in the users array in the config file. The following example shows how this would look like:

...
  "users": [
    {
      "name": "user0",
      "password": "user0PlaintextPassword",
      "kubernetes_access_token": "eyJhbGciOiJSUzI1NiIsImtpZCI6Il9aV0F1RnNOSEV0VllHVWt3UmVPTFlGTWpFb1g2RHRCNzA2TVRsV2NLRlkifQ.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.DafDiqQFz1DSDQlF8XNDk20x7JCEsYWeAXYzxdVHNt5Q82ukbsYWhHvUTLP_paZO1KpfOokl-m-zjVncCaD8PltDdL-xFGqJuHZ-0qqK3S8jJEIaKNo4foXRmZA56I8UaubuulATKc-busblViQ8MfLG9R0jmWWhqkQCTKWu1duiEx2E3QCZFL7WelkAi3XoEmYhHNAALERA03ZyItA1vkbHoHbA4-e8xZDOuGogBPqFWOWO30IXftRxGm1y8UX-JCqHhhG0BIAP_Jl9NzA_lXaV18wgTPSF2wcD5HSPHhJZ3U4fnu93Ojq0iqVtkJ_9uS83Sif6tOAKYXa1HWZzeA",
      "kubernetes_namespace": "user0-namespace"
    },
...

Start the app with a config file:

To start the application with the config file we have to pass the parameters start -c configs/appconfig.json. If your config file has relative paths, then ensure you have set the correct working directory for the application.

Start the app in demo mode with a config file:

To start the application in the demo mode (without a real cluster) with the config file we have to pass the parameters demo -c configs/appconfig.json. If your config file has relative paths, then ensure you have set the correct working directory for the application.

Start the app with docker

The application can be build and executed using docker. The following commands will build and start the container:

docker build -t devoilapers-backend .
docker run --name devoilapers-backend -v /home/backendConfigDir/:/usr/src/app/configs  -p 8080:8080 devoilapers-backend

Ensure that you replace /home/backendConfigDir/ with a path to a directory which contains the configuration files. Ensure the app config file is named appconfig_docker.json. Be careful with relative paths as the working directory will be the repository root and not the configuration folder.

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