[This blog was syndicated from http://blog.grallandco.com]
When I was looking for a more effective way to create my cluster I asked some sysadmins which tools I should use to do it. The answer I got during OSDC was not Puppet, nor Chef, but was Ansible.
This article shows you how you can easily configure and create a Couchbase cluster deployed and many linux boxes...and the only thing you need on these boxes is an SSH Server!
Thanks to Jan-Piet Mens that was one of the person that convinced me to use Ansible and answered questions I had about Ansible.
You can watch the demonstration below, and/or look at all the details in the next paragraph.
Ansible is an open-source software that allows administrator to configure and manage many computers over SSH.
I won't go in all the details about the installation, just follow the steps documented in the Getting Started Guide. As you can see from this guide, you just need Python and few other libraries and clone Ansible project from Github. So I am expecting that you have Ansible working with your various servers on which you want to deploy Couchbase.
Also for this first scripts I am using root on my server to do all the operations. So be sure you have register the root ssh keys to your administration server, from where you are running the Ansible scripts.
Create a Couchbase Cluster
So before going into the details of the Ansible script it is interesting to explain how you create a Couchbase Cluster. So here are the 5 steps to create and configure a cluster:
Install Couchbase on each nodes of the cluster, as documented here.
Take one of the node and "initialize" the cluster, using cluster-init command.
Add the other nodes to the cluster, using server-add command.
The group [couchbase-main] group is just one of the node that will drive the installation and configuration, as you probably already know, Couchbase does not have any master... All nodes in the cluster are identical.
Now we need to execute specific taks on the "main" server:
Initialization of the cluster using the Couchbase CLI, on line 06 and 07
Then the system needs to ask all other server to join the cluster. For this the system needs to get the various IP and for each IP address execute the add-server command with the IP address. As far as I know it is not possible to get the IP address from the main playbook YAML file, so I ask the system to generate a shell script to add each node and execute the script.
I am adding the -vv parameter to allow you to see more information about what's happening during the execution of the script.
This will execute all the commands described in the playbook, and after few seconds you will have a new cluster ready to be used! You can for example open a browser and go to the Couchase Administration Console and check that your cluster is configured as expected.
As you can see it is really easy and fast to create a new cluster using Ansible.
I have also create a script to uninstall properly the cluster.. just launch