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Version: Developer

Install custom root certificates in a Kasm Workspaces image

Overview​

Administrators install custom root certificates inside a Kasm image so users can access organization resources with certificates signed by an internal certificate authority (CA), or so a transparent proxy can inspect traffic and enforce policies. Installing a custom root certificate requires building a custom image. This guide builds a custom image with a root certificate installed.

Prerequisites​

  • Familiarity with building custom images.
  • The root certificate to install, in ca.crt format.
  • SSH access to a Kasm Workspaces server, or a separate build machine with access to a registry.

Build the custom image​

These steps use the open source Git repository that contains the example Dockerfiles and scripts. The example uses Firefox, and the same steps apply to the other provided images. For simplicity, the steps assume a single-server Kasm deployment. For a multi-server or distributed deployment, run these steps from a separate machine and push the image to a registry. For details, see building custom images.

  1. SSH to the Kasm Workspaces server and clone the example Git repository:

    git clone https://github.com/kasmtech/workspaces-images
    cd workspaces-images

  2. Place your certificate at ./src/ubuntu/install/certificates/ca.crt, overwriting the placeholder file. Confirm that it is named ca.crt.

  3. Edit dockerfile-kasm-firefox and uncomment the following lines by removing the # characters:

    Example - with comments character:

    ...
    # Install Custom Certificate Authority
    # COPY ./src/ubuntu/install/certificates $INST_SCRIPTS/certificates/
    # RUN bash $INST_SCRIPTS/certificates/install_ca_cert.sh && rm -rf $INST_SCRIPTS/certificates/
    ...

    Example - comments character removed:

    ...
    # Install Custom Certificate Authority
    COPY ./src/ubuntu/install/certificates $INST_SCRIPTS/certificates/
    RUN bash $INST_SCRIPTS/certificates/install_ca_cert.sh && rm -rf $INST_SCRIPTS/certificates/
    ...

  4. Build the image:

    sudo docker build -t firefox:custom -f dockerfile-kasm-firefox .

  5. Log in to the Kasm UI as an administrator and create a new Workspace that references the new Docker image. For details, see building custom images.