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* Add system:coredns ClusterRole and binding * Annotate CoreDNS for Prometheus metrics scraping * Remove kube-dns deployment, service, & service account * https://github.com/poseidon/terraform-render-bootkube/pull/71 * https://kubernetes.io/blog/2018/06/27/kubernetes-1.11-release-announcement/
382 lines
16 KiB
Markdown
382 lines
16 KiB
Markdown
# Bare-Metal
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In this tutorial, we'll network boot and provision a Kubernetes v1.11.0 cluster on bare-metal with Container Linux.
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First, we'll deploy a [Matchbox](https://github.com/coreos/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 Container Linux to disk, reboot into the disk install, and provision themselves as Kubernetes controllers or workers via Ignition.
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Controllers are provisioned to run an `etcd-member` peer and a `kubelet` service. Workers run just a `kubelet` service. A one-time [bootkube](https://github.com/kubernetes-incubator/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.
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## Requirements
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* Machines with 2GB RAM, 30GB disk, PXE-enabled NIC, IPMI
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* PXE-enabled [network boot](https://coreos.com/matchbox/docs/latest/network-setup.html) environment
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* Matchbox v0.6+ deployment with API enabled
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* Matchbox credentials `client.crt`, `client.key`, `ca.crt`
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* Terraform v0.11.x and [terraform-provider-matchbox](https://github.com/coreos/terraform-provider-matchbox) installed locally
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## Machines
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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.
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* 52:54:00:a1:9c:ae (node1)
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* 52:54:00:b2:2f:86 (node2)
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* 52:54:00:c3:61:77 (node3)
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Configure each machine to boot from the disk through IPMI or the BIOS menu.
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```
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ipmitool -H node1 -U USER -P PASS chassis bootdev disk options=persistent
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```
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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.
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!!! tip ""
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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.
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## DNS
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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).
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* node1.example.com (node1)
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* node2.example.com (node2)
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* node3.example.com (node3)
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* myk8s.example.com (node1)
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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.
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## Matchbox
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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.
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Install Matchbox on a Kubernetes cluster or dedicated server.
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* Installing on [Kubernetes](https://coreos.com/matchbox/docs/latest/deployment.html#kubernetes) (recommended)
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* Installing on a [server](https://coreos.com/matchbox/docs/latest/deployment.html#download)
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!!! tip
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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.
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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.
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[Generate TLS](https://coreos.com/matchbox/docs/latest/deployment.html#generate-tls-certificates) client credentials. Save the `ca.crt`, `client.crt`, and `client.key` where they can be referenced in Terraform configs.
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```sh
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mv ca.crt client.crt client.key ~/.config/matchbox/
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```
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Verify the matchbox read-only HTTP endpoints are accessible (port is configurable).
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```sh
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$ curl http://matchbox.example.com:8080
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matchbox
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```
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Verify your TLS client certificate and key can be used to access the Matchbox API (port is configurable).
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```sh
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$ openssl s_client -connect matchbox.example.com:8081 \
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-CAfile ~/.config/matchbox/ca.crt \
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-cert ~/.config/matchbox/client.crt \
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-key ~/.config/matchbox/client.key
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```
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## PXE Environment
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Create a iPXE-enabled network boot environment. Configure PXE clients to chainload [iPXE](http://ipxe.org/cmd) and instruct iPXE clients to chainload from your Matchbox service's `/boot.ipxe` endpoint.
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For networks already supporting iPXE clients, you can add a `default.ipxe` config.
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```ini
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# /var/www/html/ipxe/default.ipxe
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chain http://matchbox.foo:8080/boot.ipxe
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```
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For networks with Ubiquiti Routers, you can [configure the router](/topics/hardware.md#ubiquiti) itself to chainload machines to iPXE and Matchbox.
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For a small lab, you may wish to checkout the [quay.io/coreos/dnsmasq](https://quay.io/repository/coreos/dnsmasq) container image and [copy-paste examples](https://github.com/coreos/matchbox/blob/master/Documentation/network-setup.md#coreosdnsmasq).
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Read about the [many ways](https://coreos.com/matchbox/docs/latest/network-setup.html) to setup a compliant iPXE-enabled network. There is quite a bit of flexibility:
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* Continue using existing DHCP, TFTP, or DNS services
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* Configure specific machines, subnets, or architectures to chainload from Matchbox
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* Place Matchbox behind a menu entry (timeout and default to Matchbox)
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!!! note ""
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TFTP chainloading to modern boot firmware, like iPXE, avoids issues with old NICs and allows faster transfer protocols like HTTP to be used.
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## Terraform Setup
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Install [Terraform](https://www.terraform.io/downloads.html) v0.11.x on your system.
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```sh
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$ terraform version
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Terraform v0.11.1
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```
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Add the [terraform-provider-matchbox](https://github.com/coreos/terraform-provider-matchbox) plugin binary for your system.
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```sh
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wget https://github.com/coreos/terraform-provider-matchbox/releases/download/v0.2.2/terraform-provider-matchbox-v0.2.2-linux-amd64.tar.gz
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tar xzf terraform-provider-matchbox-v0.2.2-linux-amd64.tar.gz
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sudo mv terraform-provider-matchbox-v0.2.2-linux-amd64/terraform-provider-matchbox /usr/local/bin/
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```
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Add the plugin to your `~/.terraformrc`.
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```
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providers {
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matchbox = "/usr/local/bin/terraform-provider-matchbox"
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}
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```
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Read [concepts](../architecture/concepts.md) to learn about Terraform, modules, and organizing resources. Change to your infrastructure repository (e.g. `infra`).
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```
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cd infra/clusters
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```
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## Provider
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Configure the Matchbox provider to use your Matchbox API endpoint and client certificate in a `providers.tf` file.
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```tf
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provider "matchbox" {
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endpoint = "matchbox.example.com:8081"
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client_cert = "${file("~/.config/matchbox/client.crt")}"
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client_key = "${file("~/.config/matchbox/client.key")}"
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ca = "${file("~/.config/matchbox/ca.crt")}"
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}
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provider "local" {
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version = "~> 1.0"
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alias = "default"
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}
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provider "null" {
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version = "~> 1.0"
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alias = "default"
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}
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provider "template" {
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version = "~> 1.0"
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alias = "default"
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}
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provider "tls" {
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version = "~> 1.0"
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alias = "default"
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}
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```
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## Cluster
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Define a Kubernetes cluster using the module `bare-metal/container-linux/kubernetes`.
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```tf
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module "bare-metal-mercury" {
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source = "git::https://github.com/poseidon/typhoon//bare-metal/container-linux/kubernetes?ref=v1.11.0"
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providers = {
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local = "local.default"
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null = "null.default"
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template = "template.default"
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tls = "tls.default"
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}
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# bare-metal
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cluster_name = "mercury"
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matchbox_http_endpoint = "http://matchbox.example.com"
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os_channel = "coreos-stable"
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os_version = "1632.3.0"
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# configuration
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k8s_domain_name = "node1.example.com"
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ssh_authorized_key = "ssh-rsa AAAAB3Nz..."
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asset_dir = "/home/user/.secrets/clusters/mercury"
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# machines
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controller_names = ["node1"]
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controller_macs = ["52:54:00:a1:9c:ae"]
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controller_domains = ["node1.example.com"]
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worker_names = [
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"node2",
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"node3",
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]
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worker_macs = [
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"52:54:00:b2:2f:86",
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"52:54:00:c3:61:77",
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]
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worker_domains = [
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"node2.example.com",
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"node3.example.com",
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]
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}
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```
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Reference the [variables docs](#variables) or the [variables.tf](https://github.com/poseidon/typhoon/blob/master/bare-metal/container-linux/kubernetes/variables.tf) source.
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## ssh-agent
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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`.
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```sh
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ssh-add ~/.ssh/id_rsa
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ssh-add -L
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```
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## Apply
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Initialize the config directory if this is the first use with Terraform.
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```sh
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terraform init
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```
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Plan the resources to be created.
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```sh
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$ terraform plan
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Plan: 55 to add, 0 to change, 0 to destroy.
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```
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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.
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```sh
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$ terraform apply
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module.bare-metal-mercury.null_resource.copy-kubeconfig.0: Provisioning with 'file'...
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module.bare-metal-mercury.null_resource.copy-etcd-secrets.0: Provisioning with 'file'...
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module.bare-metal-mercury.null_resource.copy-kubeconfig.0: Still creating... (10s elapsed)
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module.bare-metal-mercury.null_resource.copy-etcd-secrets.0: Still creating... (10s elapsed)
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...
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```
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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.
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### Power
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Power on each machine with the boot device set to `pxe` for the next boot only.
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```sh
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ipmitool -H node1.example.com -U USER -P PASS chassis bootdev pxe
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ipmitool -H node1.example.com -U USER -P PASS power on
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```
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Machines will network boot, install Container Linux to disk, reboot into the disk install, and provision themselves as controllers or workers.
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!!! tip ""
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If this is the first test of your PXE-enabled network boot environment, watch the SOL console of a machine to spot any misconfigurations.
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### Bootstrap
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Wait for the `bootkube-start` step to finish bootstrapping the Kubernetes control plane. This may take 5-15 minutes depending on your network.
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```
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module.bare-metal-mercury.null_resource.bootkube-start: Still creating... (6m10s elapsed)
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module.bare-metal-mercury.null_resource.bootkube-start: Still creating... (6m20s elapsed)
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module.bare-metal-mercury.null_resource.bootkube-start: Still creating... (6m30s elapsed)
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module.bare-metal-mercury.null_resource.bootkube-start: Still creating... (6m40s elapsed)
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module.bare-metal-mercury.null_resource.bootkube-start: Creation complete (ID: 5441741360626669024)
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Apply complete! Resources: 55 added, 0 changed, 0 destroyed.
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```
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To watch the install to disk (until machines reboot from disk), SSH to port 2222.
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```
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# before v1.11.0
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$ ssh debug@node1.example.com
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# after v1.11.0
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$ ssh -p 2222 core@node1.example.com
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```
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To watch the bootstrap process in detail, SSH to the first controller and journal the logs.
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```
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$ ssh core@node1.example.com
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$ journalctl -f -u bootkube
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bootkube[5]: Pod Status: pod-checkpointer Running
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bootkube[5]: Pod Status: kube-apiserver Running
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bootkube[5]: Pod Status: kube-scheduler Running
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bootkube[5]: Pod Status: kube-controller-manager Running
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bootkube[5]: All self-hosted control plane components successfully started
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bootkube[5]: Tearing down temporary bootstrap control plane...
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```
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## Verify
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[Install kubectl](https://coreos.com/kubernetes/docs/latest/configure-kubectl.html) on your system. Use the generated `kubeconfig` credentials to access the Kubernetes cluster and list nodes.
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```
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$ export KUBECONFIG=/home/user/.secrets/clusters/mercury/auth/kubeconfig
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$ kubectl get nodes
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NAME STATUS AGE VERSION
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node1.example.com Ready 11m v1.11.0
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node2.example.com Ready 11m v1.11.0
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node3.example.com Ready 11m v1.11.0
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```
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List the pods.
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```
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$ kubectl get pods --all-namespaces
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NAMESPACE NAME READY STATUS RESTARTS AGE
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kube-system calico-node-6qp7f 2/2 Running 1 11m
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kube-system calico-node-gnjrm 2/2 Running 0 11m
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kube-system calico-node-llbgt 2/2 Running 0 11m
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kube-system coredns-1187388186-mx9rt 1/1 Running 0 11m
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kube-system kube-apiserver-7336w 1/1 Running 0 11m
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kube-system kube-controller-manager-3271970485-b9chx 1/1 Running 0 11m
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kube-system kube-controller-manager-3271970485-v30js 1/1 Running 1 11m
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kube-system kube-proxy-50sd4 1/1 Running 0 11m
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kube-system kube-proxy-bczhp 1/1 Running 0 11m
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kube-system kube-proxy-mp2fw 1/1 Running 0 11m
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kube-system kube-scheduler-3895335239-fd3l7 1/1 Running 1 11m
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kube-system kube-scheduler-3895335239-hfjv0 1/1 Running 0 11m
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kube-system pod-checkpointer-wf65d 1/1 Running 0 11m
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kube-system pod-checkpointer-wf65d-node1.example.com 1/1 Running 0 11m
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```
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## Going Further
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Learn about [maintenance](../topics/maintenance.md) and [addons](../addons/overview.md).
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!!! note
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On Container Linux clusters, install the `CLUO` addon to coordinate reboots and drains when nodes auto-update. Otherwise, updates may not be applied until the next reboot.
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## Variables
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Check the [variables.tf](https://github.com/poseidon/typhoon/blob/master/bare-metal/container-linux/kubernetes/variables.tf) source.
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### Required
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| Name | Description | Example |
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|:-----|:------------|:--------|
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| cluster_name | Unique cluster name | mercury |
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| matchbox_http_endpoint | Matchbox HTTP read-only endpoint | http://matchbox.example.com:port |
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| os_channel | Channel for a Container Linux derivative | coreos-stable, coreos-beta, coreos-alpha, flatcar-stable, flatcar-beta, flatcar-alpha |
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| os_version | Version for a Container Linux derivative to PXE and install | 1632.3.0 |
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| k8s_domain_name | FQDN resolving to the controller(s) nodes. Workers and kubectl will communicate with this endpoint | "myk8s.example.com" |
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| ssh_authorized_key | SSH public key for user 'core' | "ssh-rsa AAAAB3Nz..." |
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| asset_dir | Path to a directory where generated assets should be placed (contains secrets) | "/home/user/.secrets/clusters/mercury" |
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| controller_names | Ordered list of controller short names | ["node1"] |
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| controller_macs | Ordered list of controller identifying MAC addresses | ["52:54:00:a1:9c:ae"] |
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| controller_domains | Ordered list of controller FQDNs | ["node1.example.com"] |
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| worker_names | Ordered list of worker short names | ["node2", "node3"] |
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| worker_macs | Ordered list of worker identifying MAC addresses | ["52:54:00:b2:2f:86", "52:54:00:c3:61:77"] |
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| worker_domains | Ordered list of worker FQDNs | ["node2.example.com", "node3.example.com"] |
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### Optional
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| Name | Description | Default | Example |
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|:-----|:------------|:--------|:--------|
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| cached_install | Whether machines should PXE boot and install from the Matchbox `/assets` cache. Admin MUST have downloaded Container Linux images into the cache to use this (coreos only for now) | false | true |
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| install_disk | Disk device where Container Linux should be installed | "/dev/sda" | "/dev/sdb" |
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| networking | Choice of networking provider | "calico" | "calico" or "flannel" |
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| network_mtu | CNI interface MTU (calico-only) | 1480 | - |
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| network_ip_autodetection_method | Method to detect host IPv4 address (calico-only) | first-found | can-reach=10.0.0.1 |
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| pod_cidr | CIDR IPv4 range to assign to Kubernetes pods | "10.2.0.0/16" | "10.22.0.0/16" |
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| service_cidr | CIDR IPv4 range to assign to Kubernetes services | "10.3.0.0/16" | "10.3.0.0/24" |
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| cluster_domain_suffix | FQDN suffix for Kubernetes services answered by coredns. | "cluster.local" | "k8s.example.com" |
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| kernel_args | Additional kernel args to provide at PXE boot | [] | "kvm-intel.nested=1" |
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