Monday, June 30, 2014

Puppet and Oracle Enterprise Manager

Enterprises are using virtualization already for years as part of their datacenter strategy. Since recent you see that virtualization solutions are turning into private cloud solutions which enables business users even more to quickly request new systems and make full use of the benefits of cloud within the confinement of their own datacenter. A number of vendors provide both the software and the hardware to kickstart the deployment of a private cloud.

Oracle provides an engineered system in the form of the Oracle Virtual Compute Appliance which is a combination of pre-installed hardware which enables customers to get up and running in days instead of months. However, a similar solution can also be created “manually”. All software components are available separately from the OVCA. Central within the private cloud strategy from Oracle is Oracle Enterprise Manager 12C in combination with Oracle VM and Oracle Linux.

In the below diagram you can see a typical deployment of a private cloud solution based upon Oracle software.

As you can see in the above diagram Oracle Enterprise Manager plays a vital role in the Oracle private cloud architecture. Oracle positions the Oracle Enterprise Manager solution as the central monitoring and provisioning tooling for both the infrastructure components as well as application database components. Next to this Oracle Enterprise Manager is used for patching both operating system components as well as application and database components. In general Oracle positions the Oracle Enterprise Manager the central solution for your entire private cloud solution. Oracle Enterprise Manager ties in with Oracle VM Manager and enables customers to request / provision new virtual servers from an administrator role however also by using the cloud self service portals where users can create (and destroy) their own virtual servers. Before you can do so you however have to ensure that your Oracle VM Manager is connected to Oracle Enterprise Manager and that Oracle VM itself is configured. 

The initial steps to configure Oracle VM to be able to run virtual machines are outlined below and are commonly only needed once.

As you can observer quite a number of steps are needed before you will be able to create your first virtual machine. Not included in this diagram are the efforts needed to setup Oracle Enterprise Manager and combine it with Oracle VM Manager and on how to activate the self service portals that can be used by users to create a virtual machine without the need for an administrator. 

In general, when you create / provision a new virtual machine via Oracle tooling you will be making use of a template. A pre-defined template which can contain one or more virtual machines and which can potentially contain a full application or database. For this you can make use of the Oracle VM template builder or you can download pre-defined templates. The templates stored in your Oracle VM template repository can be used to provision a new virtual machine. Commonly used strategy is to use the right mix of things you put into your template and things you do configure and install using a first boot script which will be started the first time when a new virtual machine starts. even though you can do a lot in the first boot script this still will require you to potentially create and maintain a large set of templates which might differ substantially per application you would like to install or per environment it will be used in. 

In a more ideal scenario you will not be developing a large set of templates, in an ideal scenario you will only maintain one (or a very limited set of) templates and use other external tooling to ensure the correct actions are taken. Since recent Oracle has changed some of the policies and the Oracle Linux template for Oracle VM which you can download from the Oracle website is nothing more then a bare minimum installation where almost every package you might take for granted it missing. This means that there will not be a overhead of packages and services started that you do not want or need. the system will be fully your to configure. This configuration can be done by using first boot scripting which you would need to build and customize for a large part yourself or you can use external tooling for this. 

A good solution for this is to make use of puppet. This would mean that the first boot script only need to be able to install the puppet agent on the newly created virtual machine. By making use of node classification the puppet master will be able to see what the intended use of this new machine is and install packages and configure the machine accordingly.

Even though this is not a part of the Oracle best practices it is a solution for companies who do have a large set of different type of virtual machines they need to be able to provision automatically or semi automatically. By implementing puppet you will be able to keep the number of Oracle VM templates to a minimum and keep the maintenance on the template extremely limited. All changes to a certain type of virtual machine provisioning can be done by changing puppet scripts. An additional benefit is that this is seen as a non-intrusive customization to the Oracle VM way of working. This way you can stay true to the Oracle best practices and add the puppet best practices. 

As a warning, on the puppet website a number of scripts for Oracle databases and other Oracle software are available. Even though they do tend to work it is advised to be extremely contentious about using them and you should be aware that this might be harming your application and database software installation. it will be good to look at the inner workings of them before applying them in your production cloud. However, when tested and approved to be working for your needs they might be helping you to speed up deployments. 

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