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Air Gap Installation with Embedded Cluster (Beta)

This topic describes how to install applications with Embedded Cluster on a virtual machine (VM) or bare metal server with no outbound internet access.

note

Embedded Cluster installations in air gap environments is a beta feature. This feature is subject to change. To get access to this feature, reach out to Alex Parker at [email protected].

Overview​

When an air gap bundle is built for a release containing an Embedded Cluster Config, both an application air gap bundle and an Embedded Cluster air gap bundle are built. The application air gap bundle can be used for air gap installations with Replicated kURL or with Replicated KOTS in an existing cluster. The Embedded Cluster air gap bundle is used for air gap installations with Embedded Cluster.

The Embedded Cluster air gap bundle not only contains the assets normally contained in an application air gap bundle (airgap.yaml, app.tar.gz, and an images directory), but it also contains an embedded-cluster directory with the assets needed to install the infrastructure (Embedded Cluster/k0s and Helm extensions).

During installation with Embedded Cluster in air gap environments, a Docker registry is deployed to the cluster to store application images. Infrastructure images (for Embedded Cluster and Helm extensions) and the Helm charts are preloaded on each node at installation time.

Requirement​

Air gap installations are supported with Embedded Cluster version 1.3.0 or later.

Limitations and Known Issues​

Embedded Cluster installations in air gap environments have the following limitations and known issues:

  • If you pass ?airgap=true to the replicated.app endpoint but an air gap bundle is not built for the latest release, the API will not return a 404. Instead it will return the tarball without the air gap bundle (as in, with the installer and the license in it, like for online installations).

  • Images used by Helm extensions must not refer to a multi-architecture image by digest. Only x64 images are included in air gap bundles, and the digest for the x64 image will be different from the digest for the multi-architecture image, preventing the image from being discovered in the bundle. An example of a chart that does this is ingress-nginx/ingress-nginx chart. For an example of how the digests should be set to empty string to pull by tag only, see Helm Extensions in Embedded Cluster Config.

  • Images for Helm extensions are loaded directly into containerd so that they are available without internet access. But if an image used by a Helm extension has Always set as the image pull policy, Kubernetes will try to pull the image from the internet. If necessary, use the Helm values to set IfNotPresent as the image pull policy to ensure the extension works in air gap environments.

  • On the channel release history page, the links for Download air gap bundle, Copy download URL, and View bundle contents pertain to the application air gap bundle only, not the Embedded Cluster bundle.

Prerequisites​

Before you install, complete the following prerequisites:

Install​

To install with Embedded Cluster in an air gap environment:

  1. In the Vendor Portal, go the channel where the target release was promoted to build the air gap bundle. Do one of the following:

    • If the Automatically create airgap builds for newly promoted releases in this channel setting is enabled on the channel, watch for the build status to complete.
    • If automatic air gap builds are not enabled, go to the Release history page for the channel and build the air gap bundle manually.

    For more information, see Downloading Air Gap Bundles.

    note

    Errors in building either the application air gap bundle or the Embedded Cluster infrastructure will be shown if present.

  2. Go to Customers and click on the target customer. Click Install instructions > Embedded Cluster.

    Customer install instructions drop down button

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    The Embedded Cluster install instructions dialog is displayed.

    Embedded cluster install instruction dialog

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  3. (Optional) In the Embedded Cluster install instructions dialog, under Select a version, select a specific application version to install. By default, the latest version is selected.

  4. SSH onto the machine where you will install.

  5. Modify the curl command provided in the first step in the Embedded Cluster installation instructions dialog by adding the ?airgap=true query parameter to the end of the replicated.app endpoint:

    curl -f https://replicated.app/embedded/APP_SLUG/CHANNEL_SLUG?airgap=true -H "Authorization: LICENSE_ID" -o APP_SLUG-CHANNEL_SLUG.tgz

  6. On a machine with internet access, run the modified curl command to download the air gap installation assets as a .tgz.

  7. Move the downloaded .tgz to the air gapped machine where you will install.

  8. On your air gapped machine, untar the .tgz following the instructions provided in the Embedded Cluster installation instructions dialog. This will produce three files:

    • The installer
    • The license
    • The air gap bundle (APP_SLUG.airgap)

  9. Install the application with the installation command copied from the Embedded Cluster installation instructions dialog, adding --airgap-bundle flag to pass the .airgap bundle that you downloaded to the installation:

    sudo ./APP_SLUG install --license license.yaml --airgap-bundle APP_SLUG.airgap

    Where APP_SLUG is the unique application slug.

  10. When prompted, enter a password for accessing the KOTS Admin Console.

    The installation command takes a few minutes to complete. During installation, Embedded Cluster completes tasks to prepare the cluster and install KOTS in the cluster. Embedded Cluster also automatically runs a default set of host preflight checks which verify that the environment meets the requirements for the installer.

  11. When the installation command completes, go to the URL provided in the output to access the Admin Console.

    Example output:

    ✔  Host files materialized
    ? Enter an Admin Console password: ********
    ? Confirm password: ********
    ✔  Host files materialized!
    ✔  Host preflights succeeded!
    ✔  Node installation finished!
    ✔  Storage is ready!
    ✔  Embedded Cluster Operator is ready!
    ✔  Admin Console is ready!
    ✔  Additional components are ready!
    Visit the admin console to configure and install gitea-kite: http://104.155.145.60:30000

    At this point, the cluster is provisioned and the KOTS Admin Console is deployed, but the application is not yet installed.

  12. Bypass the browser TLS warning by clicking Continue to Setup.

  13. Click Advanced > Proceed.

  14. On the HTTPS page, upload your own private key and certificacte or select Self-signed.

    By default, a self-signed TLS certificate is used to secure communication between your browser and the Admin Console. You will see a warning in your browser every time you access the Admin Console unless you upload your own certificate.

  15. On the login page, enter the Admin Console password that you created during installation and click Log in.

  16. On the Nodes page, you can view details about the machine where you installed, including its node role, status, CPU, and memory. Optionally, add nodes before deploying the application. Click Continue.

  17. On the config screen, complete the fields for the application configuration options and then click Continue.

  18. 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.

    note

    If the application does not include preflight checks, you need to click Deploy then Yes, Deploy next to the target version on the Admin Console dashboard to install.

The Admin Console dashboard opens.

On the Admin Console dashboard, the application status changes from Missing to Unavailable while the application is being installed. When the installation is complete, the status changes to Ready. For example:

Admin console dashboard showing ready status

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Add Nodes to Air Gap Clusters​

You can add nodes to an air gap cluster. This involves downloading the Embedded Cluster assets to each node, copying a join command from the Admin Console, and running the join command on each node.

Prerequisites​

The Embedded Cluster binary and the air gap bundle must be present on each node you want to join to the cluster. Use the same commands as you did during installation to download and untar these assets on each node. For more information, see Install above.

note

The binary and air gap bundles on each additional node must be the same version as what is currently installed. To download a specific version of these assets, you can select a version in the Embedded Cluster install instructions dialog. For more information, see Install above.

Add Nodes​

To add nodes to a cluster after successfully installing the first node:

  1. Click the link in the install output to access the Admin Console. Proceed through the setup steps until you reach the Nodes page.

  2. Click Add node, choose one or more node roles (if present), and copy the join command.

  3. SSH onto another machine you want to join to the cluster. Run the join command on this node. For example:

    sudo ./APP_SLUG join --airgap-bundle APP_SLUG.airgap 10.128.0.32:30000 TxXboDstBAamXaPdleSK7Lid

  4. When you have finished adding all nodes, return to the Admin Console and click Continue.