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Install rancher on k3os
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rancher-on-k3os.md

Rancher cluster on k3os

Goal

Install rancher on k3os with centralized datastore on mysql cluster.

Environment

  • Host: Ubuntu 18.04.4 Desktop (32gb ram 4 cpu)
  • Virtualisation: kvm/qemu (virtual machine manager)
  • Local network: 192.168.0.0/16
    • Gateway: 192.168.0.1
    • Nameserver: 192.168.254.254
  • Local domain: vc.lan
    • dns.vc.lan: 192.168.254.254
    • db1.vc.lan: 192.168.5.1
    • db2.vc.lan: 192.168.5.2
    • rancher.vc.lan: 192.168.5.5
    • rancher1.vc.lan: 192.168.8.1
    • rancher2.vc.lan: 192.168.8.2

In my environment I have created a pdns-recursor on 1 virtual machine to service the vc.lan domain.

  • dns.vc.lan (1gb ram 1vcpu 4gb disk)

Create database server(s)

https://rancher.com/docs/rancher/v2.x/en/installation/k8s-install/create-nodes-lb/

In my environment I have created a mysql cluster (ubuntu 18 with mysql) on 2 virtual machines.

  • db1.vc.lan (1gb ram 2vcpu 4gb disk) (master)
  • db2.vc.lan (1gb ram 2vcpu 4gb disk) (slave)

Database uri: mysql://rancher:rancherpass@tcp(db1.vc.lan:3306)/rancher

Create loadbalancer

https://rancher.com/docs/rancher/v2.x/en/installation/options/nginx/

In my environment I have created a loadbalancer (ubuntu 18 with nginx) on 1 virtual machine.

  • rancher.vc.lan (1gb ram 2vcpu 4gb disk)

/etc/nginx/nginx.conf

user www-data;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
        worker_connections 768;
}

http {
        sendfile on;
        tcp_nopush on;
        tcp_nodelay on;
        keepalive_timeout 65;
        types_hash_max_size 2048;
        include /etc/nginx/mime.types;
        default_type application/octet-stream;
        ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
        ssl_prefer_server_ciphers on;
        access_log /var/log/nginx/access.log;
        error_log /var/log/nginx/error.log;
        gzip on;
        include /etc/nginx/conf.d/*.conf;
        include /etc/nginx/sites-enabled/*;
}

stream {
    upstream rancher_servers_http {
        least_conn;
        server 192.168.20.1:80 max_fails=3 fail_timeout=5s;
        server 192.168.20.2:80 max_fails=3 fail_timeout=5s;
    }

    server {
        listen 80;
        proxy_pass rancher_servers_http;
    }

    upstream rancher_servers_https {
        least_conn;
        server 192.168.20.1:443 max_fails=3 fail_timeout=5s;
        server 192.168.20.2:443 max_fails=3 fail_timeout=5s;
    }

    server {
        listen     443;
        proxy_pass rancher_servers_https;
    }
}

Basicly the default nginx.conf with the stream definition added.

Modify default website on loadbalancer

/etc/nginx/sites-enabled/default

server {
        listen 8080 default_server;
        listen [::]:8080 default_server;
        root /var/www/html;
...
...
}

Create cloud-config files on the default website of the loadbalancer

/var/www/html/rancher1.yml

#cloud-config
hostname: rancher1
ssh_authorized_keys:
  - ssh-rsa [AUTHORIZED_KEY]

write_files:
- enconding: ""
  content: |-
    #!/bin/bash
    write_log () {
        local message="${1}"
        logger -t "run-cmd" "${message}"
        echo "${message}"
    }
    write_log "Getting the service using eth0..."
    ETH0=$(connmanctl services | awk '{ print $3 }' | while read -r s1; do connmanctl services $s1 | grep -q "eth0" && echo "$s1"; done)
    write_log "Device eth0 is configured using: ${ETH0}"
    write_log "Setting up manual net config..."
    connmanctl config $ETH0 --ipv4 manual 192.168.8.1 255.255.0.0 192.168.0.1 --nameservers 192.168.254.254 --domains vc.lan
    write_log "Network setup done."
  owner: root:root
  path: /etc/run-cmd.sh
  permissions: '0755'
run_cmd:
- "/etc/run-cmd.sh"

k3os:
  dns_nameservers:
    - 192.168.254.254
  ntp_servers:
    - 0.nl.pool.ntp.org
    - 1.nl.pool.ntp.org
  k3s_args:
    - server
    - "--datastore-endpoint=mysql://rancher:rancherpass@tcp(db1.vc.lan:3306)/rancher"

/var/www/html/rancher2.yml

#cloud-config
hostname: rancher2
ssh_authorized_keys:
  - ssh-rsa [AUTHORIZED_KEY]

write_files:
- enconding: ""
  content: |-
    #!/bin/bash
    write_log () {
        local message="${1}"
        logger -t "run-cmd" "${message}"
        echo "${message}"
    }
    write_log "Getting the service using eth0..."
    ETH0=$(connmanctl services | awk '{ print $3 }' | while read -r s1; do connmanctl services $s1 | grep -q "eth0" && echo "$s1"; done)
    write_log "Device eth0 is configured using: ${ETH0}"
    write_log "Setting up manual net config..."
    connmanctl config $ETH0 --ipv4 manual 192.168.8.2 255.255.0.0 192.168.0.1 --nameservers 192.168.254.254 --domains vc.lan
    write_log "Network setup done."
  owner: root:root
  path: /etc/run-cmd.sh
  permissions: '0755'
run_cmd:
- "/etc/run-cmd.sh"

k3os:
  dns_nameservers:
    - 192.168.254.254
  ntp_servers:
    - 0.nl.pool.ntp.org
    - 1.nl.pool.ntp.org
  k3s_args:
    - server
    - "--datastore-endpoint=mysql://rancher:rancherpass@tcp(db1.vc.lan:3306)/rancher"

Install k3os

Download the latest k3os:

Spin up a virtual machine:

  • rancher1.vc.lan (4gb ram 2vcpu 8gb disk)

Boot the virtual machine from the k3os-amd64 iso:

  • login with the rancher user
  • install to disk sudo k3os install
  • use the cloud-config files when the installer asks for them:
    • http://rancher.vc.lan:8080/rancher1.yml
  • reboot from disk

Do the same thing for the second node. (rancher2)

Download helm

Download the helm binary to your local machine:

  • wget https://get.helm.sh/helm-v3.2.0-linux-amd64.tar.gz
  • tar -zxvf helm-v3.2.0-linux-amd64.tar.gz
  • sudo mv linux-amd64/helm /usr/local/bin

Download kubectl

Download the kubectl binary to your local machine:

  • curl -LO https://storage.googleapis.com/kubernetes-release/release/v1.18.0/bin/linux/amd64/kubectl
  • chmod +x kubectl
  • sudo mv kubectl /usr/local/bin

Note: https://kubernetes.io/docs/tasks/tools/install-kubectl/ for more info.

Download kubeconfig file

Download the kubeconfig file to your local machine:

  • scp rancher@rancher1.vc.lan:/etc/rancher/k3s/k3s.yaml ~/rancher.kubeconfig
  • chmod 0600 ~/rancher.kubeconfig

You can now admin the cluster from your local machine.

Install cert-manager

Install cert-manager on the cluster using kubectl and helm:

  • helm repo add jetstack https://charts.jetstack.io
  • helm repo update
  • kubectl --kubeconfig ~/rancher.kubeconfig create namespace cert-manager
  • kubectl --kubeconfig ~/rancher.kubeconfig apply --validate=false -f https://github.com/jetstack/cert-manager/releases/download/v0.14.3/cert-manager.crds.yaml
  • helm install cert-manager jetstack/cert-manager --namespace cert-manager --version v0.14.3 --kubeconfig ~/rancher.kubeconfig

The cert-manager webhook pod must be operational before rancher can be installed:

  • kubectl --kubeconfig ~/rancher.kubeconfig rollout status -n cert-manager deploy/cert-manager-webhook

Note: https://cert-manager.io/docs/installation/kubernetes/ for more info.

Install rancher

Install rancher on the cluster using kubectl and helm:

  • helm repo add rancher-stable https://releases.rancher.com/server-charts/stable
  • helm repo update
  • kubectl --kubeconfig ~/rancher.kubeconfig create namespace cattle-system
  • helm install rancher rancher-stable/rancher --namespace cattle-system --set hostname=rancher.vc.lan --kubeconfig ~/rancher.kubeconfig

Note: hostname=rancher.vc.lan is the hostname of the loadbalancer.

More nodes

To add more nodes (rancher3) repeat Install k3os for each additional node you want to add to the rancher cluster.

Bonus: custom cluster in rancher

  • Local domain: vc.lan
    • k8s1.vc.lan: 192.168.10.1
    • k8s2.vc.lan: 192.168.10.2

Create cloud-config files on the default website of the loadbalancer

/var/www/html/k8s1.yml

#cloud-config
hostname: k8s1
ssh_authorized_keys:
  - ssh-rsa [AUTHORIZED_KEY]

rancher:
  network:
    interfaces:
      eth0:
        address: 192.168.10.1/16
        gateway: 192.168.0.1
    dns:
      nameservers:
        - 192.168.254.254

/var/www/html/k8s2.yml

#cloud-config
hostname: k8s2
ssh_authorized_keys:
  - ssh-rsa [AUTHORIZED_KEY]

rancher:
  network:
    interfaces:
      eth0:
        address: 192.168.10.2/16
        gateway: 192.168.0.1
    dns:
      nameservers:
        - 192.168.254.254

Create a custom cluster in the rancher web interface

So easy!

Install rancheros

Download the latest rancheros:

Spin up a virtual machine:

  • k8s1.vc.lan (8gb ram 4vcpu 16gb disk)

Boot the virtual machine from the rancheros iso:

  • install to disk sudo ros install -d /dev/vda -c http://rancher.vc.lan:8080/k8s1.yml
  • reboot from disk

Deploy custom cluster managed by rancher

  • ssh rancher@k8s1.vc.lan
  • docker run -d --privileged --restart=unless-stopped --net=host -v /etc/kubernetes:/etc/kubernetes -v /var/run:/var/run rancher/rancher-agent:v2.3.6 --server https://rancher.vc.lan --token [TOKEN] --ca-checksum [CHECKSUM] --etcd --controlplane --worker

Note: The docker run command is copy/pasted from the custom cluster setup page in the rancher web interface.

Do the same thing for the second node. (k8s2)

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