Friday, December 25, 2015

A Simple but Complete Guide for OpenStack Trove

This post illustrates the framework and some details that help learners get started with OpenStack and its database service Trove. I started to study OpenStack and its Trove project five months ago from scratch. If I can do it, you can also do it. I appreciate the guidance I have received in every way, especially my teammates whom I have worked closely with every weekday. 

Trove is database-as-a-service project on OpenStack, which can help users save the cost on database infrastructure and eliminate administrative tasks like deployment, configurations, and backups, and so on. To understand its benefit, image that you need a database server for your business. Traditionally, you have to set up an infrastructure first, install database package, configure it, and maintain it, which cost lots of money and time. With OpenStack Trove, what you do is just to open an account, execute some commands or click some tabs to launch a database server, and only pay for what you use.

Before we start this exciting journey, I would like to highlight the following documentation and reference. 
  • OpenStack Documentation, where you can find installation guide, admin user guide, end user guide, and command line reference. That will cover almost all tasks performed on OpenStack and its service components. Reading the documentation carefully can always help us avoid some naive mistakes and save us much time.
  • OpenStack Trove, where you can find comprehensive details about Trove. 
The following steps can help you deploy OpenStack Trove and then operate it from scratch. 

1. Set up an OpenStack environment and add identity service (Keystone), image service (Glance), computer service (Nova), dashboard (Horizon), networking service (Neutron or Nova-network) and block storage service (Cinder). 

This can be done by following OpenStack Installation Guide, which can be found in OpenStack documentation. Be sure to choose the right version of the installation guide for your operating system (Ubuntu 14.04, Red Hat Enterprise Linux 7, CentOS 7, openSUSE 13.2, and SUSE Linux Enterprise Server 12)  and the version of OpenStack (Juno, Kilo, and Liberty) you want to deploy. 

2. Add database as service (Trove) on OpenStack.    

This part is not provided in the official installation documentation. For Ubuntu users, follow the steps and commands provided in my earlier post. For other Linux operating system users, I guess it will still be a good way to follow steps in that post and change commands correspondingly. 

3. Obtain or build a Trove guest image. 

This is the first step to use Trove. There are currently 3 ways. 

  • Download a pre-built guest image from here. This method is DevStack based.
  • Build a guest image using OpenStack Trove tools (Disk Image Builder, redstack). I tried these two tools on DevStack and my OpenStack, respectively. Using these two tools, I got a working image on DevStack, but failed to get a working image on my OpenStack. Back to the time I tried, probably there was some bug related to their DevStack dependency. By the working image, I mean that a working image can be used to launch a Trove instance successfully with active status. I am not sure whether they work well now or not. After struggling with the tools for one month, I came up with a customized way.  
  • Build a guest image using customized way. The way I used can be found in this post. I got a working image by performing those steps. That post also provides some insights on how the image works.
For more details about the first two ways, see this post

4. Add the Trove guest image to the datastore. 

The image we get from the above is just a QCOW2 file. In order to tell Trove where it is and let Trove use it, we must add it to Trove datastore, by performing step 2-6 in the database service chapter of OpenStack Administration Guide.  

5. Launch a Trove instance. 

This can be done either through dashboard or Trove command line client. For the latter, refer to "trove create" command in OpenStack Command Line Reference

6. Debug. 

There are some common errors that OpenStack Trove users can encounter. Just to name some.
  • Status goes to "Error" shortly after the creation. 
  • Status is stuck at "Build" and goest to "ERROR" after reaching the timeout values. 
  • No host is assigned.
To figure out the reason, the starting point should always be trove logs, including trove-api.log, trove-taskmanager.log, and trove-conductor.log, which by default are in the directory /var/log/trove on the trove controller node, and also trove-guestagent.log, which by default are in the directory /var/log/trove/ on the guest. 

With the insights log files provide, google and ask openstack are good places that can help target the errors. 

Good luck and enjoy! 

1 comment:

  1. Nice blog... Trove seem good and if all works well then it is really helpful for me to use. Recently I am looking for openstack with esxi


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