Now you can start to run the kubepray playbook:
- You've already created an inventory file as inventory/mycluster/hosts.ini. Other than hosts.ini, you need to check and update global variable configuration files at inventory/mycluster/group_vars/all.yml.
- There are a lot of variables defined, but at least one variable, bootstrap_os , needs to be changed from none to your target Linux machine. If you are using RHEL/CentOS7, set bootstrap_os as centos. If you are using Ubuntu 16.04 LTS, set bootstrap_os as ubuntu as shown in the following screenshot:
You can also update other variables, such as kube_version, to change or install a Kubernetes version. For more details, read the documentation at https://github.com/kubernetes-incubator/kubespray/blob/master/docs/vars.md.
- Finally, you can execute the playbook. Use the ansible-playbook command instead of the Ansible command. Ansible-playbook runs multiple Ansible modules based on tasks and roles that are defined in the playbook.
- To run the kubespray playbook, type the ansible-playbook command with the following parameters:
//use –b (become), -i (inventory) and specify cluster.yml as playbook
$ ansible-playbook -b -i inventory/mycluster/hosts.ini cluster.yml
The ansible-playbook argument parameter is the same as the Ansible command. So, if you need to use -K (ask for the sudo password) or --become-method=su, you need to specify for ansible-playbook as well.
- It takes around 5 to 10 minutes to complete based on the machine spec and network bandwidth. But eventually you can see PLAY RECAP, as shown in the following screenshot, to see whether it has succeeded or not:
- If you see failed=0 like in the preceding screenshot, you have been successful in setting up a Kubernetes cluster. You can ssh to the Kubernetes master machine and run the /usr/local/bin/kubectl command to see the status, as shown in the following screenshot:
- The preceding screenshot shows that you have been successful in setting up the Kubernetes version 1.10.2 master and node. You can continue to use the kubectl command to configure you Kubernetes cluster in the following chapters.
- Unfortunately, if you see a failed count of more than 0, the Kubernetes cluster has probably not been set up correctly. Because failure is caused by many reasons, there is no single solution. It is recommended that you append the verbose option -v to see more detailed output from Ansible, as shown in the following code:
//use –b (become), -i (inventory) and –v (verbose)
$ ansible-playbook -v -b -i inventory/mycluster/hosts.ini cluster.yml
- If the failure is timeout, just retrying the ansible-playbook command again may solve it. Because Ansible is designed as an idempotency, if you re-perform the ansible-playbook command twice or more, Ansible still can configure correctly.
- If the failure is change target IP address after you run ansible-playbook (for example, re-using the Ansible machine to set up another Kubernetes cluster), you need to clean up the fact cache file. It is located under /tmp directory, so you just delete this file, as shown in the following screenshot:
