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Bare-Metal

Danger

Typhoon for Fedora Atomic is alpha. Expect rough edges and changes.

In this tutorial, we'll network boot and provision a Kubernetes v1.11.1 cluster on bare-metal with Fedora Atomic.

First, we'll deploy a Matchbox service and setup a network boot environment. Then, we'll declare a Kubernetes cluster using the Typhoon Terraform module and power on machines. On PXE boot, machines will install Fedora Atomic via kickstart, reboot into the disk install, and provision themselves as Kubernetes controllers or workers via cloud-init.

Controllers are provisioned to run etcd and kubelet system containers. Workers run just a kubelet system container. A one-time bootkube bootstrap schedules the apiserver, scheduler, controller-manager, and coredns on controllers and schedules kube-proxy and calico (or flannel) on every node. A generated kubeconfig provides kubectl access to the cluster.

Requirements

  • Machines with 2GB RAM, 30GB disk, PXE-enabled NIC, IPMI
  • PXE-enabled network boot environment
  • Matchbox v0.7+ deployment with API enabled
  • HTTP server for Fedora install assets and ostree repo
  • Matchbox credentials client.crt, client.key, ca.crt
  • Terraform v0.11.x and terraform-provider-matchbox installed locally

Machines

Collect a MAC address from each machine. For machines with multiple PXE-enabled NICs, pick one of the MAC addresses. MAC addresses will be used to match machines to profiles during network boot.

  • 52:54:00:a1:9c:ae (node1)
  • 52:54:00:b2:2f:86 (node2)
  • 52:54:00:c3:61:77 (node3)

Configure each machine to boot from the disk through IPMI or the BIOS menu.

ipmitool -H node1 -U USER -P PASS chassis bootdev disk options=persistent

During provisioning, you'll explicitly set the boot device to pxe for the next boot only. Machines will install (overwrite) the operating system to disk on PXE boot and reboot into the disk install.

Ask your hardware vendor to provide MACs and preconfigure IPMI, if possible. With it, you can rack new servers, terraform apply with new info, and power on machines that network boot and provision into clusters.

DNS

Create a DNS A (or AAAA) record for each node's default interface. Create a record that resolves to each controller node (or re-use the node record if there's one controller).

  • node1.example.com (node1)
  • node2.example.com (node2)
  • node3.example.com (node3)
  • myk8s.example.com (node1)

Cluster nodes will be configured to refer to the control plane and themselves by these fully qualified names and they'll be used in generated TLS certificates.

Matchbox

Matchbox is an open-source app that matches network-booted bare-metal machines (based on labels like MAC, UUID, etc.) to profiles to automate cluster provisioning.

Install Matchbox on a Kubernetes cluster or dedicated server.

Tip

Deploy Matchbox as service that can be accessed by all of your bare-metal machines globally. This provides a single endpoint to use Terraform to manage bare-metal clusters at different sites. Typhoon will never include secrets in provisioning user-data so you may even deploy matchbox publicly.

Matchbox provides a TLS client-authenticated API that clients, like Terraform, can use to manage machine matching and profiles. Think of it like a cloud provider API, but for creating bare-metal instances.

Generate TLS client credentials. Save the ca.crt, client.crt, and client.key where they can be referenced in Terraform configs.

mv ca.crt client.crt client.key ~/.config/matchbox/

Verify the matchbox read-only HTTP endpoints are accessible (port is configurable).

$ curl http://matchbox.example.com:8080
matchbox

Verify your TLS client certificate and key can be used to access the Matchbox API (port is configurable).

$ openssl s_client -connect matchbox.example.com:8081 \
  -CAfile ~/.config/matchbox/ca.crt \
  -cert ~/.config/matchbox/client.crt \
  -key ~/.config/matchbox/client.key

PXE Environment

Create a iPXE-enabled network boot environment. Configure PXE clients to chainload iPXE and instruct iPXE clients to chainload from your Matchbox service's /boot.ipxe endpoint.

For networks already supporting iPXE clients, you can add a default.ipxe config.

# /var/www/html/ipxe/default.ipxe
chain http://matchbox.foo:8080/boot.ipxe

For networks with Ubiquiti Routers, you can configure the router itself to chainload machines to iPXE and Matchbox.

For a small lab, you may wish to checkout the quay.io/coreos/dnsmasq container image and copy-paste examples.

Read about the many ways to setup a compliant iPXE-enabled network. There is quite a bit of flexibility:

  • Continue using existing DHCP, TFTP, or DNS services
  • Configure specific machines, subnets, or architectures to chainload from Matchbox
  • Place Matchbox behind a menu entry (timeout and default to Matchbox)

TFTP chainloading to modern boot firmware, like iPXE, avoids issues with old NICs and allows faster transfer protocols like HTTP to be used.

Atomic Assets

Fedora Atomic network installations require a local mirror of assets. Configure an HTTP server to serve the Atomic install tree and ostree repo.

sudo dnf install -y httpd
sudo firewall-cmd --permenant --add-port=80/tcp
sudo systemctl enable httpd --now

Download the Fedora Atomic ISO which contains install files and add them to the serve directory.

sudo mount -o loop,ro Fedora-AtomicHost-ostree-*.iso /mnt
sudo mkdir -p /var/www/html/fedora/28
sudo cp -av /mnt/* /var/www/html/fedora/28/
sudo umount /mnt

Checkout the fedora-atomic ostree manifest repo.

git clone https://pagure.io/fedora-atomic.git && cd fedora-atomic
git checkout f28

Compose an ostree repo from RPM sources.

mkdir repo
ostree init --repo=repo --mode=archive
sudo dnf install rpm-ostree
sudo rpm-ostree compose tree --repo=repo fedora-atomic-host.json

Serve the ostree repo as well.

sudo cp -r repo /var/www/html/fedora/28/
tree /var/www/html/fedora/28/
├── images
│   ├── pxeboot
│       ├── initrd.img
│       └── vmlinuz
├── isolinux/
├── repo/

Verify vmlinuz, initrd.img, and repo are accessible from the HTTP server (i.e. atomic_assets_endpoint).

curl http://example.com/fedora/28/

Note

It is possible to use the Matchbox /assets cache as an HTTP server.

Terraform Setup

Install Terraform v0.11.x on your system.

$ terraform version
Terraform v0.11.7

Add the terraform-provider-matchbox plugin binary for your system.

wget https://github.com/coreos/terraform-provider-matchbox/releases/download/v0.2.2/terraform-provider-matchbox-v0.2.2-linux-amd64.tar.gz
tar xzf terraform-provider-matchbox-v0.2.2-linux-amd64.tar.gz
sudo mv terraform-provider-matchbox-v0.2.2-linux-amd64/terraform-provider-matchbox /usr/local/bin/

Add the plugin to your ~/.terraformrc.

providers {
  matchbox = "/usr/local/bin/terraform-provider-matchbox"
}

Read concepts to learn about Terraform, modules, and organizing resources. Change to your infrastructure repository (e.g. infra).

cd infra/clusters

Provider

Configure the Matchbox provider to use your Matchbox API endpoint and client certificate in a providers.tf file.

provider "matchbox" {
  endpoint    = "matchbox.example.com:8081"
  client_cert = "${file("~/.config/matchbox/client.crt")}"
  client_key  = "${file("~/.config/matchbox/client.key")}"
  ca          = "${file("~/.config/matchbox/ca.crt")}"
}

provider "local" {
  version = "~> 1.0"
  alias = "default"
}

provider "null" {
  version = "~> 1.0"
  alias = "default"
}

provider "template" {
  version = "~> 1.0"
  alias = "default"
}

provider "tls" {
  version = "~> 1.0"
  alias = "default"
}

Cluster

Define a Kubernetes cluster using the module bare-metal/fedora-atomic/kubernetes.

module "bare-metal-mercury" {
  source = "git::https://github.com/poseidon/typhoon//bare-metal/fedora-atomic/kubernetes?ref=v1.11.1"

  providers = {
    local = "local.default"
    null = "null.default"
    template = "template.default"
    tls = "tls.default"
  }

  # bare-metal
  cluster_name           = "mercury"
  matchbox_http_endpoint = "http://matchbox.example.com"
  atomic_assets_endpoint = "http://example.com/fedora/28"

  # configuration
  k8s_domain_name    = "node1.example.com"
  ssh_authorized_key = "ssh-rsa AAAAB3Nz..."
  asset_dir          = "/home/user/.secrets/clusters/mercury"

  # machines
  controller_names   = ["node1"]
  controller_macs    = ["52:54:00:a1:9c:ae"]
  controller_domains = ["node1.example.com"]
  worker_names = [
    "node2",
    "node3",
  ]
  worker_macs = [
    "52:54:00:b2:2f:86",
    "52:54:00:c3:61:77",
  ]
  worker_domains = [
    "node2.example.com",
    "node3.example.com",
  ]
}

Reference the variables docs or the variables.tf source.

ssh-agent

Initial bootstrapping requires bootkube.service be started on one controller node. Terraform uses ssh-agent to automate this step. Add your SSH private key to ssh-agent.

ssh-add ~/.ssh/id_rsa
ssh-add -L

Apply

Initialize the config directory if this is the first use with Terraform.

terraform init

Plan the resources to be created.

$ terraform plan
Plan: 58 to add, 0 to change, 0 to destroy.

Apply the changes. Terraform will generate bootkube assets to asset_dir and create Matchbox profiles (e.g. controller, worker) and matching rules via the Matchbox API.

$ terraform apply
module.bare-metal-mercury.null_resource.copy-kubeconfig.0: Provisioning with 'file'...
module.bare-metal-mercury.null_resource.copy-etcd-secrets.0: Provisioning with 'file'...
module.bare-metal-mercury.null_resource.copy-kubeconfig.0: Still creating... (10s elapsed)
module.bare-metal-mercury.null_resource.copy-etcd-secrets.0: Still creating... (10s elapsed)
...

Apply will then loop until it can successfully copy credentials to each machine and start the one-time Kubernetes bootstrap service. Proceed to the next step while this loops.

Power

Power on each machine with the boot device set to pxe for the next boot only.

ipmitool -H node1.example.com -U USER -P PASS chassis bootdev pxe
ipmitool -H node1.example.com -U USER -P PASS power on

Machines will network boot, install Fedora Atomic to disk via kickstart, reboot into the disk install, and provision themselves as controllers or workers via cloud-init.

If this is the first test of your PXE-enabled network boot environment, watch the SOL console of a machine to spot any misconfigurations.

Bootstrap

Wait for the bootkube-start step to finish bootstrapping the Kubernetes control plane. This may take 5-15 minutes depending on your network.

module.bare-metal-mercury.null_resource.bootkube-start: Still creating... (6m10s elapsed)
module.bare-metal-mercury.null_resource.bootkube-start: Still creating... (6m20s elapsed)
module.bare-metal-mercury.null_resource.bootkube-start: Still creating... (6m30s elapsed)
module.bare-metal-mercury.null_resource.bootkube-start: Still creating... (6m40s elapsed)
module.bare-metal-mercury.null_resource.bootkube-start: Creation complete (ID: 5441741360626669024)

Apply complete! Resources: 58 added, 0 changed, 0 destroyed.

To watch the bootstrap process in detail, SSH to the first controller and journal the logs.

$ ssh fedora@node1.example.com
$ journalctl -f -u bootkube
bootkube[5]:         Pod Status:        pod-checkpointer        Running
bootkube[5]:         Pod Status:          kube-apiserver        Running
bootkube[5]:         Pod Status:          kube-scheduler        Running
bootkube[5]:         Pod Status: kube-controller-manager        Running
bootkube[5]: All self-hosted control plane components successfully started
bootkube[5]: Tearing down temporary bootstrap control plane...

Verify

Install kubectl on your system. Use the generated kubeconfig credentials to access the Kubernetes cluster and list nodes.

$ export KUBECONFIG=/home/user/.secrets/clusters/mercury/auth/kubeconfig
$ kubectl get nodes
NAME                STATUS    AGE       VERSION
node1.example.com   Ready     11m       v1.11.1
node2.example.com   Ready     11m       v1.11.1
node3.example.com   Ready     11m       v1.11.1

List the pods.

$ kubectl get pods --all-namespaces
NAMESPACE     NAME                                       READY     STATUS    RESTARTS   AGE
kube-system   calico-node-6qp7f                          2/2       Running   1          11m
kube-system   calico-node-gnjrm                          2/2       Running   0          11m
kube-system   calico-node-llbgt                          2/2       Running   0          11m
kube-system   coredns-1187388186-mx9rt                   1/1       Running   0          11m
kube-system   kube-apiserver-7336w                       1/1       Running   0          11m
kube-system   kube-controller-manager-3271970485-b9chx   1/1       Running   0          11m
kube-system   kube-controller-manager-3271970485-v30js   1/1       Running   1          11m
kube-system   kube-proxy-50sd4                           1/1       Running   0          11m
kube-system   kube-proxy-bczhp                           1/1       Running   0          11m
kube-system   kube-proxy-mp2fw                           1/1       Running   0          11m
kube-system   kube-scheduler-3895335239-fd3l7            1/1       Running   1          11m
kube-system   kube-scheduler-3895335239-hfjv0            1/1       Running   0          11m
kube-system   pod-checkpointer-wf65d                     1/1       Running   0          11m
kube-system   pod-checkpointer-wf65d-node1.example.com   1/1       Running   0          11m

Going Further

Learn about maintenance and addons.

Variables

Check the variables.tf source.

Required

Name Description Example
cluster_name Unique cluster name mercury
matchbox_http_endpoint Matchbox HTTP read-only endpoint "http://matchbox.example.com:port"
atomic_assets_endpoint HTTP endpoint serving the Fedora Atomic vmlinuz, initrd.img, and ostree repo "http://example.com/fedora/28"
k8s_domain_name FQDN resolving to the controller(s) nodes. Workers and kubectl will communicate with this endpoint "myk8s.example.com"
ssh_authorized_key SSH public key for user 'fedora' "ssh-rsa AAAAB3Nz..."
asset_dir Path to a directory where generated assets should be placed (contains secrets) "/home/user/.secrets/clusters/mercury"
controller_names Ordered list of controller short names ["node1"]
controller_macs Ordered list of controller identifying MAC addresses ["52:54:00:a1:9c:ae"]
controller_domains Ordered list of controller FQDNs ["node1.example.com"]
worker_names Ordered list of worker short names ["node2", "node3"]
worker_macs Ordered list of worker identifying MAC addresses ["52:54:00:b2:2f:86", "52:54:00:c3:61:77"]
worker_domains Ordered list of worker FQDNs ["node2.example.com", "node3.example.com"]

Optional

Name Description Default Example
networking Choice of networking provider "calico" "calico" or "flannel"
network_mtu CNI interface MTU (calico-only) 1480 -
pod_cidr CIDR IPv4 range to assign to Kubernetes pods "10.2.0.0/16" "10.22.0.0/16"
service_cidr CIDR IPv4 range to assign to Kubernetes services "10.3.0.0/16" "10.3.0.0/24"
cluster_domain_suffix FQDN suffix for Kubernetes services answered by coredns. "cluster.local" "k8s.example.com"
kernel_args Additional kernel args to provide at PXE boot [] "kvm-intel.nested=1"