Deploying Machine ID on Jenkins

Jenkins is an open source automation server that is frequently used to build Continuous Integration and Continuous Delivery (CI/CD) pipelines.

In this guide, we will demonstrate how to migrate existing Jenkins pipelines to utilize Machine ID with minimal changes.

Prerequisites

You will need the following tools to use Teleport with Jenkins.

• A running Teleport cluster version 16.4.12 or above. If you want to get started with Teleport, sign up for a free trial or set up a demo environment.

• The tctl admin tool and tsh client tool.

  Visit Installation for instructions on downloading tctl and tsh.

• ssh OpenSSH tool
• Jenkins
• To check that you can connect to your Teleport cluster, sign in with tsh login, then verify that you can run tctl commands using your current credentials. For example:

  tsh login --proxy=teleport.example.com --user=[email protected]
  tctl status
  Cluster  teleport.example.com
  Version  16.4.12
  CA pin   sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678

  If you can connect to the cluster and run the tctl status command, you can use your current credentials to run subsequent tctl commands from your workstation. If you host your own Teleport cluster, you can also run tctl commands on the computer that hosts the Teleport Auth Service for full permissions.

Architecture

Before we begin, it should be noted that Jenkins is a tool that is notoriously difficult to secure. Machine ID is one part of securing your infrastructure, but it alone is not sufficient. Below we will provide some basic guidance which can help improve the security posture of your Jenkins installation.

Single-host deployments

The simplest Jenkins deployments have the controller (process that stores configuration, plugins, UI) and agents (process that executes tasks) run on the same host. This deployment model is simple to get started with, however any compromise of the jenkins user within a single pipeline can lead to the compromise of your entire CI/CD infrastructure.

Multihost deployments

A slightly more complex, but more secure deployment is running your Jenkins controllers and agents on different hosts and pinning workloads to specific agents. This is an improvement over the simple deployment because you can limit the blast radius of the compromise of a single pipeline to a subset of your CI/CD infrastructure instead of all of your infrastructure.

Best practices

We strongly encourage the use of the second deployment model whenever possible, with ephemeral hosts and IAM joining when possible. When using Machine ID with this model, create and run Machine ID bots per-host and pin particular pipelines to a worker. This will allow you to give each pipeline the minimal scope for server access, reduce the blast radius if one pipeline is compromised, and allow you to remotely audit and lock pipelines if you detect malicious behavior.

Step 1/2 Configure and start Machine ID

First, determine if you would like to create a new role for Machine ID or use an existing role. You can run tctl get roles to examine your existing roles.

In the example below, create a file called api-workers.yaml with the content below to create a new role called api-workers that will allow you to log in to Nodes with the label group: api and Linux user jenkins.

kind: "role"
version: "v3"
metadata:
  name: "api-workers"
spec:
  allow:
    logins: ["jenkins"]
    node_labels:
      "group": "api"

tctl create -f api-workers.yaml
tctl bots add jenkins --roles=api-workers

tctl create -f api-workers.yaml
tctl bots add jenkins --roles=api-workers

Machine ID allows you to use Linux Access Control Lists (ACLs) to control access to certificates on disk. You will use this to limit the access Jenkins has to the short-lived certificates Machine ID issues.

In the example that follows, you will create a Linux user called teleport to run Machine ID but short-lived certificates will be written to disk as the Linux user jenkins.

sudo adduser \    --disabled-password \    --no-create-home \    --shell=/bin/false \    --gecos "" \    teleport

Create and initialize the directories you will need using the tbot init command.

sudo tbot init \    --destination-dir=/opt/machine-id \    --bot-user=teleport \    --owner=teleport:teleport \    --reader-user=jenkins

Create the bot data directory and grant permissions to access it to the Linux user (in our example, teleport) which tbot will run as.

Make the bot directory and assign ownership to teleport user
sudo mkdir -p /var/lib/teleport/bot
sudo chown teleport:teleport /var/lib/teleport/bot
Allow teleport user to open directory
sudo chmod +x /var/lib/teleport /var/lib/teleport/bot

Next, you need to start Machine ID in the background of each Jenkins worker.

First create a configuration file for Machine ID at /etc/tbot.yaml.

version: v2
# Replace "example.teleport.sh:443" with the address of your Teleport Proxy or
# Teleport Cloud tenant.
proxy_server: "example.teleport.sh:443"
onboarding:
  join_method: "token"
  # Replace the token field with the name of the token that was output when you
  # ran `tctl bots add`.
  token: "00000000000000000000000000000000"
storage:
  type: directory
  path: /var/lib/teleport/bot
outputs:
  - type: identity
    destination:
      type: directory
      path: /opt/machine-id

Create a tbot systemd unit file

By default, tbot will run in daemon mode. However, this must then be configured as a service within the service manager on the Linux host. The service manager will start tbot on boot and ensure it is restarted if it fails. For this guide, systemd will be demonstrated but tbot should be compatible with all common alternatives.

Use tbot install systemd to generate a systemd service file:

tbot install systemd \   --write \   --config /etc/tbot.yaml \   --user teleport \   --group teleport \   --anonymous-telemetry

Ensure that you replace:

• teleport with the name of Linux user you wish to run tbot as.
• /etc/tbot.yaml with the path to the configuration file you have created.

You can omit --write to print the systemd service file to the console instead of writing it to disk.

--anonymous-telemetry enables the submission of anonymous usage telemetry. This helps us shape the future development of tbot. You can disable this by omitting this.

Next, enable the service so that it will start on boot and then start the service:

sudo systemctl daemon-reload
sudo systemctl enable tbot
sudo systemctl start tbot

Check the service has started successfully:

sudo systemctl status tbot

Step 2/2. Update and run Jenkins pipelines

Using Machine ID within a Jenkins pipeline is now a one-line change. For example, if you want to run the hostname command on a remote host, add the following to your Jenkins pipeline.

steps {
  sh "ssh -F /opt/machine-id/ssh_config [email protected] hostname"
}

You are all set. You have provided Jenkins with short-lived certificates tied to a machine identity that can be rotated, audited, and controlled with all the familiar Teleport access controls.

Next steps

More information about TELEPORT_ANONYMOUS_TELEMETRY.