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Air Gap Installation with kURL

This topic describes how to use Replicated kURL to provision an embedded cluster in a virtual machine (VM) or bare metal server and install an application in the cluster.

The procedures in this topic apply to installation environments that do not have access to the internet, known as air gap environments.

Replicated kURL is an open source project. For more information, see the kURL documentation.

About High Availability Mode​

Air gap installations can use high availability (HA) mode with the kURL installer.

A load balancer is required for high availability mode. If your vendor has chosen to use the internal load balancer with the kURL EKCO add-on, you do not need to provide your own external load balancer. An external load balancer can be preferred when clients outside the cluster need access to the cluster's Kubernetes API.

If you decide to use an external load balancer, the external load balancer must be a TCP forwarding load balancer. For more information, see Prerequisites.

The health check for an apiserver is a TCP check on the port that the kube-apiserver listens on. The default value is :6443. For more information about the kube-apiserver external load balancer, see Create load balancer for kube-apiserver in the Kubernetes documentation.

Prerequisites​

Complete the following prerequisites:

  • Ensure that your environment meets the minimum system requirements. See Minimum System Requirements in Installation Requirements.

  • Review the advanced installation options available for the kURL installer. See Advanced Options in the kURL documentation.

  • Download the .airgap bundle for the application. Ensure that you can access the downloaded bundle from the environment where you will install the application. See Downloading Air Gap Bundles.
  • Download your license file. Ensure that you can access the downloaded license file from the environment where you will install the application. See Downloading Customer Licenses.
  • Download the .tar.gz air gap bundle for the kURL installer. Ensure that you can access the downloaded bundle from the environment where you will install the application. See Download the kURL Bundle in Downloading Air Gap Bundles.
  • If you are installing in high availability mode:
    • (Optional) If you are going to use the internal load balancer, you can preconfigure it by passing | sudo bash -s ha ekco-enable-internal-load-balancer.
    • For an external load balancer, ensure that your load balancer is:
      • A TCP forwarding external load balancer.
      • Configured to distribute traffic to all healthy control plane nodes in its target list.
      • (Optional) Preconfigured by passing the load-balancer-address=HOST:PORT flag.

Install​

To install an application with kURL:

  1. In your installation environment, extract the contents of the kURL .tar.gz bundle that you downloaded:

    tar -xvzf $REPLICATED_APP.tar.gz

  2. Run one of the following commands to create the cluster and install KOTS in air gap mode:

    • For a regular installation, run:

      cat install.sh | sudo bash -s airgap

    • For high availability, run:

      cat install.sh | sudo bash -s airgap ha

  3. (High Availability Only) If you did not preconfigure a load balancer, you are prompted during the installation. Do one of the following:

    • If you are using the internal load balancer, leave the prompt blank and proceed with the installation.

    • If you are using an external load balancer, pass the load balancer address.

  4. After the installation command finishes, note the Kotsadm and Login with password (will not be shown again) fields in the output of the command. You use these to log in to the Admin Console.

    The following shows an example of the Kotsadm and Login with password (will not be shown again) fields in the output of the installation command:

            Installation
              Complete ✔

    Kotsadm: http://10.128.0.35:8800
    Login with password (will not be shown again): 3Hy8WYYid

    This password has been set for you by default. It is recommended that you change
    this password; this can be done with the following command:
    kubectl kots reset-password default

  5. Go to the address provided in the Kotsadm field in the output of the installation command. For example, Kotsadm: http://34.171.140.123:8800.

  6. On the Bypass Browser TLS warning page, review the information about how to bypass the browser TLS warning, and then click Continue to Setup.

  7. On the HTTPS page, do one of the following:

    • To use the self-signed TLS certificate only, enter the hostname (required) if you are using the identity service. If you are not using the identity service, the hostname is optional. Click Skip & continue.
    • To use a custom certificate only, enter the hostname (required) if you are using the identity service. If you are not using the identity service, the hostname is optional. Then upload a private key and SSL certificate to secure communication between your browser and the Admin Console. Click Upload & continue.

  8. Log in to the Admin Console with the password that was provided in the Login with password (will not be shown again): field in the output of the installation command.

  9. Upload your license file.

  10. Upload the .airgap application air gap bundle.

  11. On the Preflight checks page, the application-specific preflight checks run automatically. Preflight checks are conformance tests that run against the target namespace and cluster to ensure that the environment meets the minimum requirements to support the application. Click Deploy.

    note

    Replicated recommends that you address any warnings or failures, rather than dismissing them. Preflight checks help ensure that your environment meets the requirements for application deployment.

  12. (Minimal RBAC Only) If you are installing with minimal role-based access control (RBAC), KOTS recognizes if the preflight checks failed due to insufficient privileges. When this occurs, a kubectl CLI preflight command displays that lets you manually run the preflight checks. The Admin Console then automatically displays the results of the preflight checks. Click Deploy.

    kubectl CLI preflight command

    View a larger version of this image

    The Admin Console dashboard opens.

    On the Admin Console dashboard, the application status changes from Missing to Unavailable while the Deployment is being created. When the installation is complete, the status changes to Ready.

    Admin console dashboard showing ready status

    View a larger version of this image

  13. (Recommended) Change the Admin Console login password:

    1. Click the menu in the top right corner of the Admin Console, then click Change password.
    2. Enter a new password in the dialog, and click Change Password to save.

    Replicated strongly recommends that you change the password from the default provided during installation in a kURL cluster. For more information, see Changing an Admin Console Password.

  14. Add primary and secondary nodes to the cluster. You might add nodes to either meet application requirements or to support your usage of the application. See Adding Nodes to Embedded Clusters.