.

    Prerequesites

    You should already be familiar with containers and Docker specifically, how to use docker hub, and spin up containers.

    Helm is the package manager for Kubernetes, so you will have wanted to have used Kubernetes a little also, and understand how services and ingress controllers work. How pods are deployed, as that is what Helm pretty much does, helm manages Kubernetes deployments.

    All the configuration files and manifests for helm are written in Yaml, so you’ll want to be familiar with Yaml, and how it is constructed.

    What is Package management

    These are some package management systems for operating systems:

    Yum - Redhat Apt - debian / ubuntu Brew - OSx Chocolatey - Windows

    These package management solutions provide: - Automated installation - Version control - Automatic updates - Dependency Management - Automated removal

    Package management in kubernetes

    Deployed kubenernetes packages

    Tiller interfaces with the kubernetes api, and what makes the helm charts work.

    Example helm install

    List the helm charts that are installed:

    helm ls

    Search for helm chart

    helm search wordpress

    Install the wordpress helm chart

    helm install stable/wordpress

    View the helm chart again

    helm ls

    Remove a helm installation

    helm delete <HELM_INSTALL_NAME>

    View the installed helm charts again

    helm ls

    Install specific version of a helm chart

    helm install stable/wordpress --version 5.0.1

    Upgrade the 5.0.1 installation to the latest

    helm upgrade <HELM_INSTALL_NAME> stable/wordpress

    Now we can see that the REVISION is on 2, as we have the initial deployment and the upgrade that we just performed, we can also see that the app version is now at the latest version

    helm ls

    Dependency management

    If I want to view the dependencies I can download the chart by using helm fetch

    helm fetch stable/wordpress

    This has downloaded the chart in the form of a tar file (wordpress-5.1.3.tgz)

    But we can actually fetch the chart untarred with –untar command

    helm fetch --untar stable/wordpress

    Now if we look in the wordpress directory, and look at requirements.yaml, we can see that there is a dependency on mariadb. We can see that there is a version, a repository location for it to download that helm chart.

    Helm automatically puts these charts in /charts directory

    We can view the dependency list by running the following:

    helm dep list