Kubernetes Bare-Metal Install (on Packet.net)

Installing Kubernetes on bare-metal machines is dead simple, and a million times easier than installing OpenStack. The bulk of the instructions below involve setting up the bare-metal machines on packet.net.

What You’ll Get with These Instructions

One may use these instructions to create a basic Kubernetes cluster. In order to create a cluster environment equivalent to a hosted solution (GKE) or turn-key solutions (Kubernetes on AWS or GCE), you’ll need persistent volume and load-balancer support. A future post will cover how to setup persistent volume storage as a Ceph RBD cluster, and how to work around the need for external load-balancer integration by deploying a Kubernetes Ingress DaemonSet with DNS.

In the following guide, we’ll build a Kubernetes cluster with 1 master and 2 nodes.

Bare-Metal or Cloud VMs, All the Same

These instructions should also work cloud VMs, so long as the following criterial are met:

  • All machines are network reachable, without restriction
    • i.e. open iptables, open security groups
  • Root access through password-less SSH is enabled
    • i.e. configured /root/.ssh/authorized_keys

Because not many of us have multiple bare-metal machines laying around, we’ll rent them from packet.net.

Step Summary

  • Setup a Development Environment
  • Provision Bare-Metal Machines (on packet.net)
  • Configure and Run the Kubernetes contrib/ansible scripts
  • Test the Cluster by Creating a POD
  • Configure a Remote Kubernetes Client to Talk to the Cluster

Setup a Development Environment

The easiest method is to instantiate a vagrant machine with all of the necessary tools. Feel free to do this manually. The vagrant environment includes the following:

  • Docker
  • Kubectl
  • Ansible
  • Hashicorp Terraform

Fetch the vagrant machine

# Tested at dcwangmit01/vagrant-devenv - branch master, commit a6c65478
git clone git@github.com:dcwangmit01/vagrant-devenv
cd vagrant-devenv

If you are on OSX, ensure and install the host dependencies.

# Installs brew, virtualbox, etc.
make deps

Create your vagant environment

# Start ssh-agent and load your key
eval `ssh-agent`; ssh-add

# Create the vagrant machine
vagrant up

# Connect to the box
vagrant ssh

Note: From now on, do everything from within this vagrant machine.

Provision Bare-Metal Machines (on packet.net)

The contrib/ansible scripts are targeted to offical Redhat distributions including RHEL and Fedora. However, packet.net does not currently support these operating systems. Thus, we deploy Centos7 servers, which is the next-closest thing and happens to work.

If you enjoy clicking around Web UI’s, follow the manual instructions below. Otherwise, the only automated provisioning method supported by packet.net is to use Hashicorp Terraform. A CLI client does not yet exist.

Manual WebUI Instructions

  • Login to the web UI at packet.net
  • Create a project
  • Set an SSH key (which will be provisioned on new servers)
  • Create 3 servers with Centos7
  • Note the names and IPs of the newly created machines

Automated Instructions (using Terraform)

Instantiating servers via Hashicorp Terraform must happen in two steps if a “packet_project” has not yet been created.

This is because the “packet_device” (aka. bare metal machine) definitions require a “project_id” upon execution. However, one does not know the “project_id” until after the “packet_project” has been created. One might resolve this issue in the future by having the packet_device require a project_name instead of a project_id. Then we could “terraform apply” this file in one go.

See the Appendix for curl commands that will help you discover project_ids from the API.

Step 1: Create the Packet.net Project

First, create your auth token via the packet.net UI and note it down.

Create a cluster.tf, and tweak the {variables} according to your needs.

# Configure the Packet Provider
provider "packet" {
        auth_token = "{REPLACE_WITH_AUTH_TOKEN}"
}

# Create a new SSH key
#   You may have to stage an ssh key on the vagrant box,
#     or run "ssh-keygen -b 4096" to create a new key.
#   This key specified below will be auto-added to the 
#     /root/.ssh/authorized_keys of newly provisioned machines.
resource "packet_ssh_key" "{REPLACE_WITH_A_NAME_FOR_SSH_KEY}" {
    name = "{REPLACE_WITH_A_NAME_FOR_SSH_KEY}"
    public_key = "${file("/{REPLACE_WITH_PATH_TO_SSH_KEY}")}"
}

# Create a project
resource "packet_project" "{REPLACE_WITH_A_NAME_FOR_CLUSTER}" {
        name = "{REPLACE_WITH_A_NAME_FOR_CLUSTER}"
}

Run Terraform to create the project.

terraform plan -out cluster
terraform apply

Step 2: Create the Packet.net Machines

Locate your PACKET_PROJECT_ID, so that you may embed it in the cluster.tf Terraform file.

# Locate your API Key from the Web Portal https://app.packet.net/
export PACKET_AUTH={REPLACE_WITH_AUTH_TOKEN}

# Get a list of projects
curl -s -H  "X-Auth-Token: $PACKET_AUTH" https://api.packet.net/projects |python -m json.tool

# Search the output above for the PACKET_PROJECT_ID
#   and use it in the packet_device definitions below

Append to cluster.tf, and tweak the {variables} according to your needs.

# Create a device
resource "packet_device" "kube-master-0001" {
        hostname = "kube-master-0001"
        plan = "baremetal_0"
        facility = "ewr1"
        operating_system = "centos_7"
        billing_cycle = "hourly"
        project_id = "{REPLACE_WITH_PACKET_PROJECT_ID}"
}

resource "packet_device" "kube-node-0001" {
        hostname = "kube-node-0001"
        plan = "baremetal_0"
        facility = "ewr1"
        operating_system = "centos_7"
        billing_cycle = "hourly"
        project_id = "{REPLACE_WITH_PACKET_PROJECT_ID}"
}

resource "packet_device" "kube-node-0002" {
        hostname = "kube-node-0002"
        plan = "baremetal_0"
        facility = "ewr1"
        operating_system = "centos_7"
        billing_cycle = "hourly"
        project_id = "{REPLACE_WITH_PACKET_PROJECT_ID}"
}

Run Terraform

terraform plan -out cluster
terraform apply

Note the names and IPs of the newly created machines

cat terraform.tfstate|grep -E '(hostname|network.0.address)'
# Returns something like this
# "hostname": "kube-master-0001",
# "network.0.address": "147.75.199.63",
# "hostname": "kube-node-0001",
# "network.0.address": "147.75.199.131",
# "hostname": "kube-node-0002",
# "network.0.address": "147.75.196.83",

Create an ~/.ssh/config file with the hostname to IP mappings. This allows you to refer to the machines via hostnames from your Dev box, as well as Ansible inventory definitions.

Host kube-master-0001
  User root
  Hostname {REPLACE_WITH_IP_OF_kube-master-0001}
Host kube-node-0001
  User root
  Hostname {REPLACE_WITH_IP_OF_kube-node-0001}
Host kube-node-0002
  User root
  Hostname {REPLACE_WITH_IP_OF_kube-node-0002}

Configure and Run the Kubernetes contrib/ansible Scripts

Fetch the kubernetes/contrib code

# Tested at kubernetes/contrib commit 3634e300
git clone git@github.com:kubernetes/contrib.git
cd contrib/ansible

Create an Ansible inventory file (more info in the contrib/ansible/README.md file)

# Create the inventory file from the example
cp inventory.example.single_master inventory

# Edit the inventory file and fill in the hostnames or IP addresses
emacs inventory

Example “inventory” file, which will work without modification if ~/.ssh/config is configured with host IP mappings.

# configure the master IPs
[masters]
kube-master-0001

# the following section should be the same as the [masters] above
[etcd]
kube-master-0001

# configure the node IPs
[nodes]
kube-node-0001
kube-node-0002

Test the ansible connection, and accept host-keys into your knownhosts

ansible all -u root -i inventory -m ping

Configure group_vars/all.yml to set the ansible_ssh_user to “root”

# The following will uncomment "#ansible_ssh_user: root"
sed -i 's@^#ansible_ssh_user@ansible_ssh_user@' group_vars/all.yml

Run the ansible setup script to install Kubernetes on all machines

./setup.sh

* Run this more than once until zero errors. It’s idempotent!

Test the Cluster by Creating a POD

The kubernetes master is auto-configured to talk with the cluster. Run some test commands

ssh root@kube-master-0001
kubectl cluster-info
kubectl get po,rc,svc

Create a POD, and test that it is running

# Start a POD
kubectl run echoheaders --image=gcr.io/google_containers/echoserver:1.3 --port=8080
# Find the pod ID
kubectl get po
# Start a new bash process within the first container within the pod
kubeclt exec -it {THE_POD_ID} bash
# Make a call
curl localhost:8080
# Exit with {ctrl-d}

Configure a Remote Kubernetes Client to Talk to the Cluster

Now that the kubernetes cluster has been setup, you may use “kubectl” directly after ssh’ing to the master. However, it would be nice to use “kubectl” from the vagrant dev environment.

# Copy the kube/config from the master to your dev machine
scp root@kube-master-0001:/etc/kubernetes/kubectl.kubeconfig ~/.kube/config.pkt

# Rename the context-name to be "pkt-east"
sed -i 's@kubectl-to-cluster.local@pkt-east@' ~/.kube/config.pkt

# Set the search/merge path for KUBECONFIG
export KUBECONFIG=~/.kube/config.pkt:~/.kube/config

# Verify the context by looking at ~/.kube/config.pkt
less ~/.kube/config.pkt

# Set the context
kubectl config use-context pkt-east

# Verify the context
kubectl config current-context

# Run a some commands to verify that it all works
kubectl get svc,rc,po
  • Now you have a working kubernetes cluster on Packet.net
    • Excluding persistent storage and load-balancing

Appendix

Curl Commands

# Locate your API Key from the Web Portal https://app.packet.net/
export PACKET_AUTH={REPLACE_WITH_API_KEY}

# Get a list of projects
curl -s -H  "X-Auth-Token: $PACKET_AUTH" https://api.packet.net/projects |python -m json.tool |less

# Get a list of plans (aka flavors)
curl -s -H  "X-Auth-Token: $PACKET_AUTH" https://api.packet.net/plans |python -m json.tool|less

# Get a list of facilities
curl -s -H  "X-Auth-Token: $PACKET_AUTH" https://api.packet.net/facilities |python -m json.tool|less

# Get a list of operating systems
curl -s -H  "X-Auth-Token: $PACKET_AUTH" https://api.packet.net/operating-systems |python -m json.tool|less

Example Settings

# Plan IDs
baremetal_0 baremetal_1

# Facilities
sjc1 ewr1

# Operating Systems
centos_7