Talos Manager

App built to help bootstrap and manage Talos Linux servers on Hetzner.

Approach

Based on bootstrapping nodes via the talos.config kernel parameter (https://www.talos.dev/latest/reference/kernel/#talosconfig). This can be applied inside the Grub config of a Talos installation image. By writing the image to disk with dd and then mounting the boot partition we can inject the parameter into its grub/grub.cfg.

Example of passing a URL into the talos.config parameter:

talos.config=https://talos-manager.example.com/config?uuid=${uuid}

Deploying

Feel free to deploy the application using our published container images at https://hub.docker.com/r/reclaimthestack/talos-manager/tags

Apart from deploying the application you'll also need to deploy a Postgres database and configure some ENV variables. Follow the SSH key and Heroku deployment instructions and apply the same ENV variables in whatever environment you're deploying on.

Creating an SSH key and upload to Hetzner

Talos Manager will bootstrap servers by putting servers into Rescue Mode and then running commands on the servers via SSH. We need an SSH key configured for this.

Note: Due to Ruby's net-ssh library not being compatible with OpenSSL3 private keys we need to make sure we generate the private key in PEM format.

ssh-keygen -m PEM -t rsa -P "" -f ~/.ssh/talos-manager.pem -C talos-manager

Now add the public key (cat ~/.ssh/talos-manager.pem.pub) with the name talos-manager at:

• Hetzner Robot at https://robot.hetzner.com/key/index -> New key
• Hetzner Cloud at https://console.hetzner.cloud/ -> Select Project -> Security -> Add SSH Key

Deploying on Heroku

First we'll create a Heroku application where we can deploy Talos Manager. For Postgres we'll use the crunchy-postgres:hobby-1 costing $30/month. This plan provides continuous data protection and point in time recovery. If you plan to manually backup your postgres database you can also consider using heroku-postgres:mini at $5/month.

heroku create --stack container --region <eu/us> --addons crunchy-postgres:hobby-1 [--team <heroku-account>] <name-of-application>

Now clone the talos-manager repository and connect it to the heroku repository.

git clone https://github.com/reclaim-the-stack/talos-manager.git
cd talos-manager
heroku git:remote -a <name-of-application>

Now we can configure the application.

# We'll start by setting some standard Rails variables
function random_string() { cat /dev/urandom | LC_ALL=C tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1; }

heroku config:set \
  RAILS_ENV=production \
  RAILS_MAX_THREADS=20 \
  SECRET_KEY_BASE=$(random_string) \
  AR_ENCRYPTION_PRIMARY_KEY=$(random_string) \
  AR_ENCRYPTION_DETERMINISTIC_KEY=$(random_string) \
  AR_ENCRYPTION_KEY_DERIVATION_SALT=$(random_string)

# Rails expects DATABASE_URL to connect to Postgres but crunchy uses CRUNCHY_DATABASE_URL
heroku config:set DATABASE_URL=$(heroku config:get CRUNCHY_DATABASE_URL)

# Manage Hetzner cloud API token at:
# https://console.hetzner.cloud -> Project -> Security -> API Tokens
# If you're not planning to use Hetzner cloud servers you can skip this part.
heroku config:set HETZNER_CLOUD_API_TOKEN=<hetzner-cloud-api-token>

# Manage Hetzner webservice API credentials at:
# https://robot.hetzner.com/preferences/index -> Webservice and app settings
# If you're not planning to use dedicated servers you can skip this part.
heroku config:set HETZNER_WEBSERVICE_USER=<username> HETZNER_WEBSERVICE_PASSWORD=<password>

# Note: You may want to change this to your own domain via the Heroku application settings page
heroku config:set HOST=<application-name>.herokuapp.com

# Assumes you created the SSH key for bootstrapping according to the instructions above
heroku config:set SSH_PRIVATE_KEY="$(cat ~/.ssh/talos-manager.pem)"

# Set a HTTP basic auth password to protect the app
heroku config:set BASIC_AUTH_PASSWORD=$(random_string)

Confirm that the Crunchy Postgres cluster is in ready status. This can take a few minutes after initial creation.

# If you can successfully psql to the database you're good to go
psql $(heroku config:get DATABASE_URL)

# If psql failed you can track the cluster status in the crunchy postgres dashboard
heroku addons:open crunchy-postgres

Once Postgres is ready, we're can go ahead and git push to build and deploy the application 🚀

git push heroku

Once the build has completed you should be able to access Talos Manager at <name>.herokuapp.com with the BASIC_AUTH_PASSWORD value as password.

Config Patch Examples

Basic

As a baseline config we recommend:

• setting the Linux CPU governor to performance to ensure you're not missing out on performance
• setting network.hostname to interpolate the servername
• setting vm.max_map_count to 262144 (or higher) to avoid issues with eg. Elastic Search

machine:
  install:
    extraKernelArgs:
      - cpufreq.default_governor=performance
  network:
    hostname: ${hostname}
  sysctls:
    vm.max_map_count: 262144 # Increase max_map_count required by eg. elasticsearch

KubeSpan Network

This patch will enable Talos KubeSpan and also allow KubeSpan to run the pod - pod network via the advertiseKubernetesNetworks setting. This allows simplified hybrid cloud / metal node networking (eg. cloud nodes using public IP's can communicate with bare metal nodes on a private VLAN).

machine:
  network:
    kubespan:
      enabled: true
      advertiseKubernetesNetworks: true
      mtu: 1320 # should be 80 less than the underlying network, which is 1400 on Hetzner VLAN

Disk Encryption

Talos supports disk encryption based on SMBIOS UUID of each server. This provides an easy way to get encryption at rest for all your nodes.

machine:
  systemDiskEncryption:
    ephemeral:
      provider: luks2
      keys:
        - nodeID: {}
          slot: 0
    state:
      provider: luks2
      keys:
        - nodeID: {}
          slot: 0

OpenEBS LocalPV directory

If you want to use the OpenEBS LocalPV local storage provider you need to add an extra mounted directory under /var/openebs/local.

machine:
  kubelet:
    # OpenEBS LocalPV provisioner needs a directory available at /var/openebs/local
    extraMounts:
      - destination: /var/openebs/local
        options:
          - rbind
          - rshared
          - rw
        source: /var/openebs/local
        type: bind

Providing access to a private Docker registry

For real world production deployments you're likely using a private Docker registry to manage your application images. One option to support pulling images from a private registry is to do it inside of Kubernetes using the imagePullSecrets Pod resource field. But to avoid extra boilerplate in your resource YAML files it can be convenient to provide access directly on the Talos OS level instead.

For a reference on all available fields for registry config see: https://www.talos.dev/v1.3/reference/configuration/#registriesconfig

machine:
  registries:
    config:
      <registry-host>:
        auth:
          <auth-details>

Configuring private network on a Hetzner vSwitch

To ease private network configuration you can make use of the ${private_ip} and ${vlan} substitution variables. The vlan number will be picked up from your Hetzner vSwitch, provided you have associated your cluster with one.

Note: We currently do not support hybrid cloud / metal server configuration when using this approach since the patches will be applied to cloud servers as well, which can't be connected to the vSwitch.

machine:
  network:
    hostname: ${hostname}
    interfaces:
      - dhcp: true
        interface: eth0
        vlans:
          - addresses:
              - ${private_ip}/21
            mtu: 1400
            vlanId: ${vlan}

Assigning node roles and taints

Example of setting the appropriate roles and taints for compatibility with the default Reclaim the Stack platform scheduling rules. Before running, ensure you are targeting the correct kubernetes cluster either by setting the KUBECONFIG=... ENV variable or merging the cluster kubeconfig into your ~/.kube/config file.

kubectl label node worker-1 node-role.kubernetes.io/worker=
kubectl label node database-1 node-role.kubernetes.io/database=
kubectl taint node database-1 role=database:NoSchedule

Note: If you don't want to separate database workloads to specific nodes you can apply the database roles to your regular workers and skip adding the taints.

Solving invalid UUID issues

We have had some occasions where a newly rented dedicated server did not come with a properly configured SMBIOS UUID. If Talos Manager encounters a node with an invalid UUID it will raise an error during bootstrapping. To fix the issue: Login to Hetzner Robot UI. Navigate to support and get support for the server which is having issues. Send them an email in the style of:

Hi,

We have found that this server has an invalid SMBIOS UUID.

When running `dmidecode -t system` the output is:
<insert-output-of-dmidecode>

Note the pending fields + the UUID ending with 0'es.

We need to have a proper UUID since our disk encryption scheme is based on the entropy
of this UUID and with the one present here it doesn't work.

Downtime for the serving while solving this is fine, we won't be making use of the server until we get this solved.