Book Image

OpenStack Cloud Computing Cookbook - Fourth Edition

By : Kevin Jackson, Cody Bunch, Egle Sigler, James Denton
Book Image

OpenStack Cloud Computing Cookbook - Fourth Edition

By: Kevin Jackson, Cody Bunch, Egle Sigler, James Denton

Overview of this book

This is the fourth edition of the industry-acclaimed OpenStack Cloud Computing Cookbook, created by four recognized OpenStack experts. It has now been updated to work with the latest OpenStack builds, using tools and processes based on their collective and vast OpenStack experience. OpenStack Open Source Cloud software is one of the most used cloud infrastructures to support a wide variety of use cases, from software development to big data analysis. It is developed by a thriving community of individual developers from around the globe and backed by most of the leading players in the cloud space today. We make it simple to implement, massively scalable, and able to store a large pool of data and networking resources. OpenStack has a strong ecosystem that helps you provision your cloud storage needs. Add OpenStack's enterprise features to reduce the cost of your business. This book will begin by showing you the steps to build up an OpenStack private cloud environment using Ansible. You'll then discover the uses of cloud services such as the identity service, image service, and compute service. You'll dive into Neutron, the OpenStack Networking service, and get your hands dirty with configuring networks, routers, load balancers, and more. You’ll then gather more expert knowledge on OpenStack cloud computing by managing your cloud's security and migration. After that, we delve into OpenStack Object storage and you’ll see how to manage servers and work with objects, cluster, and storage functionalities. Finally, you will learn about OpenStack dashboard, Ansible, Keystone, and other interesting topics.
Table of Contents (15 chapters)
OpenStack Cloud Computing Cookbook Fourth Edition
Contributors
Preface
Another Book You May Enjoy
Index

Troubleshooting the installation


Ansible is a tool, written by people, that runs playbooks, written by people, to configure systems that would ordinarily be manually performed by people, and as such, errors can occur. The end result is only as good as the input.

Typical failures either occur quickly, such as connection problems, and will be relatively self-evident, or after long running jobs that may be as a result of load or network timeouts. In any case, the OpenStack-Ansible playbooks provide an efficient mechanism to rerun playbooks without having to repeat the tasks it has already completed.

On failure, Ansible produces a file in /root (as we're running these playbooks as root) called the playbook name, with the file extension of .retry. This file simply lists the hosts that had failed so this can be referenced when running the playbook again. This targets the single or small group of hosts, which is far more efficient than a large cluster of machines that successfully completed.

How to do it...

We will step through a problem that caused one of the playbooks to fail.

Note the failed playbook and then invoke it again with the following steps:

  1. Ensure that you're in the playbooks directory as follows:

    cd /opt/openstack-ansible/playbooks
    
  2. Now rerun that Playbook, but specify the retry file:

    ansible-openstack setup-openstack.yml --retry /root/setup-openstack.retry
    
  3. In most situations, this will be enough to rectify the situation, however, OpenStack-Ansible has been written to be idempotent—meaning that the whole playbook can be run again, only modifying what it needs to. Therefore, you can run the Playbook again without specifying the retry file.

Should there be a failure at this first stage, execute the following:

  1. First remove the generated inventory files:

    rm -f /etc/openstack_deploy/openstack_inventory.json
    rm -f /etc/openstack_deploy/openstack_hostnames_ips.yml
    
  2. Now rerun the setup-hosts.yml playbook:

    cd /opt/openstack-ansible/playbooks
    openstack-ansible setup-hosts.yml
    

In some situations, it might be applicable to destroy the installation and begin again. As each service gets installed in LXC containers, it is very easy to wipe an installation and start from the beginning. To do so, carry out the following steps:

  1. We first destroy all of the containers in the environment:

    cd /opt/openstack-ansible/playbooks
    openstack-ansible lxc-containers-destroy.yml
    

    You will be asked to confirm this action. Follow the ons-screen prompts.

  2. We recommend you to uninstall the following package to avoid any conflicts with the future running of the playbooks, and also clear out any remnants of containers on each host:

    ansible hosts -m shell -a "pip uninstall -y appdirs"
    
  3. Finally, remove the inventory information:

    rm -f /etc/openstack_deploy/openstack_inventory.json 
    /etc/openstack_deploy/openstack_hostnames_ips.yml
    

How it works…

Ansible is not perfect and so are computers. Sometimes failures occur in the environment due to SSH timeouts, or some other transient failure. Also, despite Ansible trying its best to retry the execution of a playbook, the result might be a failure. Failure in Ansible is quite obvious—it is usually predicated by outputs of red text on the screen. In most cases, rerunning the offending playbook may get over some transient problems. Each playbook runs a specific task, and Ansible will state which task has failed. Troubleshooting why that particular task had failed will eventually lead to a good outcome. Worst case, you can reset your installation from the beginning.