If you want to play with Rancher you have several options, as outlined in the documentation. There are quick starts for the major public cloud providers (using Terraform), you can install it on a Linux host by using the Rancher container or you can do it on your own. We’ll be doing it step by step, as I believe that gives most information on how things actually work. We’ll start with one node and then extend the Kubernetes cluster to three nodes and you’ll notice that this is actually quite easy and convenient using Rancher.

I’ve created three Debian 10 EC2 instances:

We’ll start with the first one, and once it is ready, bring it to the latest release:

[email protected]:~$ sudo apt update && sudo apt dist-upgrade -y && sudo systemctl reboot

Once it is back, lets give it a more meaningful hostname:

[email protected]:~$ sudo hostnamectl set-hostname rancher1
[email protected]:~$ sudo bash
sudo: unable to resolve host rancher1: Name or service not known
[email protected]:/home/admin$ echo "10.0.1.168 rancher1 rancher1.it.dbi-services.com" >> /etc/hosts
[email protected]:/home/admin$ exit
exit

As Rancher depends on Docker, we need to install a supported version of Docker. Range provides a script for this, which does all the work:

[email protected]:~$ sudo curl https://releases.rancher.com/install-docker/19.03.sh | sh
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 17251  100 17251    0     0   561k      0 --:--:-- --:--:-- --:--:--  561k
+ sudo -E sh -c apt-get update
Hit:1 http://security.debian.org/debian-security buster/updates InRelease
Hit:2 http://cdn-aws.deb.debian.org/debian buster InRelease
Hit:3 http://cdn-aws.deb.debian.org/debian buster-updates InRelease
Hit:4 http://cdn-aws.deb.debian.org/debian buster-backports InRelease
Reading package lists... Done
...
+ sudo -E sh -c docker version
Client: Docker Engine - Community
 Version:           19.03.15
 API version:       1.40
 Go version:        go1.13.15
 Git commit:        99e3ed8919
 Built:             Sat Jan 30 03:17:05 2021
 OS/Arch:           linux/amd64
 Experimental:      false

Server: Docker Engine - Community
 Engine:
  Version:          19.03.15
  API version:      1.40 (minimum version 1.12)
  Go version:       go1.13.15
  Git commit:       99e3ed8919
  Built:            Sat Jan 30 03:15:34 2021
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.4.3
  GitCommit:        269548fa27e0089a8b8278fc4fc781d7f65a939b
 runc:
  Version:          1.0.0-rc92
  GitCommit:        ff819c7e9184c13b7c2607fe6c30ae19403a7aff
 docker-init:
  Version:          0.18.0
  GitCommit:        fec3683

If you would like to use Docker as a non-root user, you should now consider
adding your user to the "docker" group with something like:

  sudo usermod -aG docker admin

Remember that you will have to log out and back in for this to take effect!

WARNING: Adding a user to the "docker" group will grant the ability to run
         containers which can be used to obtain root privileges on the
         docker host.
         Refer to https://docs.docker.com/engine/security/security/#docker-daemon-attack-surface
         for more information.

We’ll be using the Rancher Kubernetes Engine (RKE) and to get that onto the system, Rancher provides a single binary. Before proceeding with that, we need a user, configure sudo (for convenience), and create the ssh keys:

[email protected]:~$ sudo groupadd rancher
[email protected]:~$ sudo useradd -g rancher -G docker -m -s /bin/bash rancher
[email protected]:~$ sudo passwd rancher
New password: 
Retype new password: 
passwd: password updated successfully
[email protected]:~$ sudo bash
[email protected]:/home/admin$ echo "rancher ALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers
[email protected]:/home/admin$ su - rancher
[email protected]:~$ ssh-keygen 
Generating public/private rsa key pair.
Enter file in which to save the key (/home/rancher/.ssh/id_rsa): 
Created directory '/home/rancher/.ssh'.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/rancher/.ssh/id_rsa.
Your public key has been saved in /home/rancher/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:gHzFXkMttTw8dks64+1zEpt3Oef6TWs/pKoiYDDruIk [email protected]
The key's randomart image is:
+---[RSA 2048]----+
|       ....o.    |
|   . . .. +o..   |
|    o o. . oB o  |
| o   . ..  . * . |
|  +     S   + .  |
| . o       . +.. |
|o . .       . ++o|
|oo   . .     o=*B|
|E.    . ..... [email protected]|
+----[SHA256]-----+
[email protected]:~$ cat .ssh/id_rsa.pub >> .ssh/authorized_keys
[email protected]:~$ ssh [email protected]
Linux rancher1 4.19.0-14-cloud-amd64 #1 SMP Debian 4.19.171-2 (2021-01-30) x86_64

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.

That’s it for the requirements to get started. Download the RKE binary:

[email protected]:~$ wget https://github.com/rancher/rke/releases/download/v1.1.15/rke_linux-amd64
[email protected]:~$ mv rke_linux-amd64 rke
[email protected]:~$ sudo mv rke /usr/local/bin/
[email protected]:~$ sudo chown rancher:rancher /usr/local/bin/rke
[email protected]:~$ sudo chmod 750 /usr/local/bin/rke
[email protected]:~$ rke --version
rke version v1.1.15

All you need to do, to get RKE setup on a single host is this:

[email protected]:~$ rke config
[+] Cluster Level SSH Private Key Path [~/.ssh/id_rsa]: 
[+] Number of Hosts [1]: 
[+] SSH Address of host (1) [none]: 10.0.1.168
[+] SSH Port of host (1) [22]: 
[+] SSH Private Key Path of host (10.0.1.168) [none]: 
[-] You have entered empty SSH key path, trying fetch from SSH key parameter
[+] SSH Private Key of host (10.0.1.168) [none]: 
[-] You have entered empty SSH key, defaulting to cluster level SSH key: ~/.ssh/id_rsa
[+] SSH User of host (10.0.1.168) [ubuntu]: rancher
[+] Is host (10.0.1.168) a Control Plane host (y/n)? [y]: 
[+] Is host (10.0.1.168) a Worker host (y/n)? [n]: y
[+] Is host (10.0.1.168) an etcd host (y/n)? [n]: y
[+] Override Hostname of host (10.0.1.168) [none]: 
[+] Internal IP of host (10.0.1.168) [none]: 10.0.1.168
[+] Docker socket path on host (10.0.1.168) [/var/run/docker.sock]: 
[+] Network Plugin Type (flannel, calico, weave, canal) [canal]: 
[+] Authentication Strategy [x509]: 
[+] Authorization Mode (rbac, none) [rbac]: 
[+] Kubernetes Docker image [rancher/hyperkube:v1.18.16-rancher1]: 
[+] Cluster domain [cluster.local]: 
[+] Service Cluster IP Range [10.43.0.0/16]: 
[+] Enable PodSecurityPolicy [n]: 
[+] Cluster Network CIDR [10.42.0.0/16]: 
[+] Cluster DNS Service IP [10.43.0.10]: 
[+] Add addon manifest URLs or YAML files [no]:

This creates the cluster configuration file:

[email protected]:~$ ls -la cluster.yml 
-rw-r----- 1 rancher rancher 4619 Mar  6 14:40 cluster.yml

Bring it up:

[email protected]:~$ rke up
INFO[0000] Running RKE version: v1.1.15                 
INFO[0000] Initiating Kubernetes cluster                
INFO[0000] [dialer] Setup tunnel for host [10.0.1.168]  
...
INFO[0157] [addons] Successfully saved ConfigMap for addon rke-ingress-controller to Kubernetes 
INFO[0157] [addons] Executing deploy job rke-ingress-controller 
INFO[0162] [ingress] ingress controller nginx deployed successfully 
INFO[0162] [addons] Setting up user addons              
INFO[0162] [addons] no user addons defined              
INFO[0162] Finished building Kubernetes cluster successfully

That’s it. The one node Kubernetes cluster is ready (Control Plane, worker and etcd all on one host). This is of course nothing you’d do in a serious deployment, but to get started this is fine. To talk to the Kubernetes cluster you shoud install kubectl:

[email protected]:~$ curl -LO "https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl"
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 38.3M  100 38.3M    0     0  73.9M      0 --:--:-- --:--:-- --:--:-- 73.8M

Same procedure as with the rke binary:

[email protected]:~$ ls
cluster.rkestate  cluster.yml  kube_config_cluster.yml  kubectl
[email protected]:~$ sudo mv kubectl /usr/local/bin/
[email protected]:~$ sudo chown rancher:rancher /usr/local/bin/kubectl
[email protected]:~$ sudo chmod 750 /usr/local/bin/kubectl

Use it to talk to your cluster:

[email protected]:~$ export KUBECONFIG=kube_config_cluster.yml 
[email protected]:~$ kubectl get namespace
NAME              STATUS   AGE
default           Active   6m31s
ingress-nginx     Active   5m36s
kube-node-lease   Active   6m33s
kube-public       Active   6m33s
kube-system       Active   6m33s

Done. RKE is up and running on a single node. Be aware that we did not yet install Ranger, just RKE. But also notice how easy that was: We have a Kubernetes cluster running, and all we needed to do, took around 10 minutes. In the next post we’ll extend the configuration to three nodes.

Thumbnail [60x60]
by
Daniel Westermann