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README.md

Horizon Operator Example Edge Service

This is a simple example of using and creating an operator as edge service.

Preconditions for Using the Operator Example Edge Service

If you haven't done so already, you must do these steps before proceeding with the operator example:

  1. Install the Horizon management hub (exchange and agbot).

  2. Install the Horizon agent on your edge cluster and configure it to point to your Horizon exchange.

  3. As part of the management hub installation process a file called agent-install.cfg was created that contains the values for HZN_ORG_ID and the exchange and css URL values. Locate this file and set those environment variables in your shell now:

    eval export $(cat agent-install.cfg)

    Note: if for some reason you disconnected from ssh or your command line closes, run the above command again to set the required environment variables.

  4. The hzn command is inside the agent container, but you can set some aliases to make it possible to run hzn from the cluster host with the following commands:

    cat << 'END_ALIASES' >> ~/.bash_aliases
alias getagentpod='kubectl -n openhorizon-agent get pods --selector=app=agent -o jsonpath={.items[*].metadata.name}'
alias hzn='kubectl -n openhorizon-agent exec -i $(getagentpod) -- hzn'
END_ALIASES
source ~/.bash_aliases

  5. In addition to the file above, an API key associated with your Horizon instance would have been created, set the exchange user credentials, and verify them:

    export HZN_EXCHANGE_USER_AUTH=iamapikey:<horizon-API-key>
hzn exchange user list -u $HZN_EXCHANGE_USER_AUTH

  6. Choose an ID and token for your edge node, create it, and verify it:

    export HZN_EXCHANGE_NODE_AUTH="<choose-any-node-id>:<choose-any-node-token>"
hzn exchange node create -n $HZN_EXCHANGE_NODE_AUTH -u $HZN_EXCHANGE_USER_AUTH -T "<device/cluster>"
hzn exchange node confirm -n $HZN_EXCHANGE_NODE_AUTH -u $HZN_EXCHANGE_USER_AUTH

  7. If you have not done so already, unregister your node before moving on:

    hzn unregister -f

Using the Operator Example Edge Service with Deployment Policy

In the following steps you will deploy the nginx-operator to your edge cluster. This operator will then create a pod running a hello world service you can curl externally or interally.

  1. Get the required node policy file on your edge cluster host:

    wget https://raw.githubusercontent.com/open-horizon/examples/master/edge/services/nginx-operator/horizon/node.policy.json

  • Below is the node_policy.json file you obtained in the step above:

    {
  "properties": [
    { "name": "openhorizon.example", "value": "nginx-operator" }
  ],
  "constraints": [
  ]
}

  • It provides one value for properties (openhorizon.example), that will effect which services get deployed to this edge node, and states no constraints.

  1. Register your Node Policy with this policy

    hzn register -u $HZN_EXCHANGE_USER_AUTH
cat node.policy.json | hzn policy update -f-

  2. When the registration completes, use the following command to review the Node Policy:

    hzn policy list

  3. The edge device will make an agreement with one of the Horizon agreement bots (this typically takes about 15 seconds). Repeatedly query the agreements of this device until the agreement_finalized_time and agreement_execution_start_time fields are filled in:

    hzn agreement list

    • Below is the service.policy.json that was published into the Exchange when the example operator was published:

      {
    "properties": [],
    "constraints": [
        "openhorizon.arch in \"'ppc64le','amd64'\""
    ]
}

    • Below is the example deployment.policy.json that has been published into the Exchange as part of the example operator:

      {
  "mycluster/policy-ibm.nginx-operator_1.0.1": {
    "owner": "root/root",
    "label": "ibm.nginx-operator Deployment Policy",
    "description": "A super-simple sample Horizon Deployment Policy",
    "service": {
      "name": "ibm.nginx-operator",
      "org": "IBM",
      "arch": "*",
      "serviceVersions": [
        {
          "version": "1.0.1",
          "priority": {},
          "upgradePolicy": {}
        }
      ],
      "nodeHealth": {}
    },
    "constraints": [
      "openhorizon.example == nginx-operator"
    ],
    "created": "2022-05-12T23:17:04.919499Z[UTC]",
    "lastUpdated": "2022-05-12T23:17:04.919489Z[UTC]"
  }
}

  4. Verify that the nginx-operator deployment is up and running:

    kubectl get pods -n openhorizon-agent

    If everything deployed correctly you should see an output similar to the following:

    NAME                                   READY   STATUS    RESTARTS   AGE
agent-dd984ff96-jmmdl                  1/1     Running   0          1d
nginx-8699f45b-pw7dj                   1/1     Running   0          23s
nginx-operator-898999564-nnzb5         1/1     Running   0          50s

  5. Check that the service is up:

    kubectl get service -n openhorizon-agent

    If everything deployed correctly you should see an output similar to the following after around 60 seconds:

    NAME      TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)         AGE
nginx     NodePort    172.30.37.113    <none>        80:30080/TCP    45s

    If you are using an OCP edge cluster you will need to curl the service using the exposed route.

  6. Get the exposed route name:

    kubectl get route -n openhorizon-agent

    If the route was exposed correctly you should see an output similar to the following:

    NAME          HOST/PORT                                                    PATH   SERVICES   PORT   TERMINATION   WILDCARD
nginx-route   nginx-route-openhorizon-agent.apps.apollo5.cp.fyre.ibm.com          nginx      8080                 None

  7. curl the service to test if it is functioning correctly: OCP edge cluster substitute the above HOST/PORT value:

    curl nginx-route-openhorizon-agent.apps.apollo5.cp.fyre.ibm.com

    k3s or microk8s edge cluster:

    curl <external-ip-address>:30080

    If the service is running you should see following Welcome to nginx! output:

    <!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>

  8. Unregister your edge cluster:

    hzn unregister -f