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02-compute-resources.md

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Provisioning Compute Resources

Note: You must have VirtualBox and Vagrant configured at this point

Download this github repository and cd into the vagrant folder

git clone https://github.com/mmumshad/kubernetes-the-hard-way.git

CD into vagrant directory

cd kubernetes-the-hard-way/vagrant

The Vagrantfile is configured to assume you have at least an 8 core CPU which most modern core i5, i7 and i9 do, and at least 16GB RAM. You can tune these values expecially if you have less than this by editing the Vagrantfile before the next step below and adjusting the values for RAM_SIZE and CPU_CORES accordingly.

This will not work if you have less than 8GB of RAM.

Run Vagrant up

vagrant up

This does the below:

  • Deploys 5 VMs - 2 Master, 2 Worker and 1 Loadbalancer with the name 'kubernetes-ha-* '

    This is the default settings. This can be changed at the top of the Vagrant file. If you choose to change these settings, please also update vagrant/ubuntu/vagrant/setup-hosts.sh to add the additional hosts to the /etc/hosts default before running "vagrant up".

  • Set's IP addresses in the range 192.168.56

    VM VM Name Purpose IP Forwarded Port RAM
    master-1 kubernetes-ha-master-1 Master 192.168.56.11 2711 2048
    master-2 kubernetes-ha-master-2 Master 192.168.56.12 2712 1024
    worker-1 kubernetes-ha-worker-1 Worker 192.168.56.21 2721 512
    worker-2 kubernetes-ha-worker-2 Worker 192.168.56.22 2722 1024
    loadbalancer kubernetes-ha-lb LoadBalancer 192.168.56.30 2730 1024

    These are the default settings. These can be changed in the Vagrant file

  • Add's a DNS entry to each of the nodes to access internet

    DNS: 8.8.8.8

  • Sets required kernel settings for kubernetes networking to function correctly.

See Vagrant page for details.

SSH to the nodes

There are two ways to SSH into the nodes:

1. SSH using Vagrant

From the directory you ran the vagrant up command, run vagrant ssh <vm> for example vagrant ssh master-1.

Note: Use VM field from the above table and not the VM name itself.

2. SSH Using SSH Client Tools

Use your favourite SSH Terminal tool (putty).

Use the above IP addresses. Username and password based SSH is disabled by default. Vagrant generates a private key for each of these VMs. It is placed under the .vagrant folder (in the directory you ran the vagrant up command from) at the below path for each VM:

Private Key Path: .vagrant/machines/<machine name>/virtualbox/private_key

Username/Password: vagrant/vagrant

Verify Environment

  • Ensure all VMs are up
  • Ensure VMs are assigned the above IP addresses
  • Ensure you can SSH into these VMs using the IP and private keys, or vagrant ssh
  • Ensure the VMs can ping each other

Troubleshooting Tips

Failed Provisioning

If any of the VMs failed to provision, or is not configured correct, delete the VM using the command:

vagrant destroy <vm>

Then re-provision. Only the missing VMs will be re-provisioned

vagrant up

Sometimes the delete does not delete the folder created for the VM and throws an error similar to this:

VirtualBox error:

VBoxManage.exe: error: Could not rename the directory 'D:\VirtualBox VMs\ubuntu-bionic-18.04-cloudimg-20190122_1552891552601_76806' to 'D:\VirtualBox VMs\kubernetes-ha-worker-2' to save the settings file (VERR_ALREADY_EXISTS)
VBoxManage.exe: error: Details: code E_FAIL (0x80004005), component SessionMachine, interface IMachine, callee IUnknown
VBoxManage.exe: error: Context: "SaveSettings()" at line 3105 of file VBoxManageModifyVM.cpp

In such cases delete the VM, then delete the VM folder and then re-provision, e.g.

vagrant destroy worker-2
rmdir "<path-to-vm-folder>\kubernetes-ha-worker-2
vagrant up

Provisioner gets stuck

This will most likely happen at "Waiting for machine to reboot"

  1. Hit CTRL+C
  2. Kill any running ruby process, or Vagrant will complain.
  3. Destroy the VM that got stuck: vagrant destroy <vm>
  4. Re-provision. It will pick up where it left off: vagrant up

Pausing the Environment

You do not need to complete the entire lab in one session. You may shut down and resume the environment as follows, if you need to power off your computer.

To shut down. This will gracefully shut down all the VMs in the reverse order to which they were started:

vagrant halt

To power on again:

vagrant up

Prev: Prerequisites
Next: Client tools