Tutorial - First Steps

Part 1 of the DC/OS 101 tutorial

IMPORTANT: Tutorials are intended to give you hands-on experience working with a limited set of DC/OS features with no implied or explicit warranty of any kind. None of the information provided--including sample scripts, commands, or applications--is officially supported by Mesosphere. You should not use this information in a production environment without independent testing and validation.

Welcome to part 1 of the DC/OS 101 Tutorial.

Prerequisites

To get started with this tutorial, you should have access to a running DC/OS cluster with at least a single master node and 3 agent nodes (of which one is a public agent node). If you don’t have these requirements set up, please follow the setup instructions for various cloud providers, on-premise, or vagrant setups.

If you are unsure which option to choose, then we recommend using the AWS templates. For this tutorial, a setup with a single master node is sufficient, but for running production workloads you should have multiple master nodes.

Objective

You have access to your cluster and have already taken a first look at the GUI. You can also access the cluster from your local machine using the DC/OS CLI. By the end of this section, you will have installed the DC/OS CLI and used it to explore your cluster.

Steps

  • Install the DC/OS CLI

    • Follow the steps here or the Install CLI instruction in the lower left corner of the DC/OS GUI.
    • Make sure you are authorized to connect to your cluster by running dcos auth login. This is necessary to prevent access from unauthorized people to your cluster.
    • You can also add/invite friends and co-workers to your cluster. See user management documentation for details

  • Explore the cluster:

    • Check the running services with dcos service. Unless you already installed additional services, there should be two services running on your cluster: Marathon (basically the DC/OS init system) and metronome (basically the DC/OS cron scheduler).
    • Check the connected nodes with dcos node list. This command displays some basic information about the connected agent and master nodes in your cluster.
    • Explore the logs of the leading mesos master with dcos node log --leader. Mesos is basically the kernel of DC/OS and this tutorial explores the Mesos logs at multiple times during this tutorial.
    • To explore more CLI options, enter the dcos help command. There are also help options of the individual commands available e.g., dcos node --help. Alternatively, check the CLI documentation.

Outcome

Congratulations! You have successfully connected to your cluster using the DC/OS CLI, and started exploring some of the CLI commands. You will make further use of the CLI in the sections that follow.

Deep Dive

You have already encountered several DC/OS components (including Mesos, Marathon, or Metronome) while experimenting with the DC/OS CLI. But what other components make up DC/OS?

DC/OS components

Here are the DC/OS components that are relevant to this tutorial. A full description of all components can be found in the documentation.

  • Marathon starts and monitors DC/OS applications and services.
  • Apache Mesos is the kernel of DC/OS and responsible for low-level task maintenance.
  • Mesos DNS provides service discovery within the cluster.
  • Minuteman is the internal layer 4 load balancer.
  • Admin Router is an open source NGINX configuration that provides central authentication and proxy to DC/OS services.
  • Catalog is the package repository that holds the DC/OS services (e.g. Apache Spark or Apache Cassandra) that you can install on your cluster directly from the DC/OS GUI and CLI.