PUBLIC MARKS from camel with tags server & images

Many times, you want to execute a command not only on one server, but also on several servers. For example, find out * Version of kernel * Version of Apache web server * Update static html or images files on all web servers via rsync * Find out user information, server information, memory usage etc * Security/patch checking tentakel I have already covered how to execute commands on multiple Linux or UNIX servers via shell script. The disadvantage of script is commands do not run in parallel on all servers. However, several tools exist to automate this procedure in parallel. With the help of tool called tentakel, you run distributed command execution. It is a program for executing the same command on many hosts in parallel using ssh (it supports other methods too). Main advantage is you can create several sets of servers according requirements. For example webserver group, mail server group, home servers group etc. The command is executed in parallel on all servers in this group (time saving). By default, every result is printed to stdout (screen). The output format can be defined for each group.

One advantage of server virtualization is the ability to rapidly provision new production environments. Automatic virtual machine deployment can significantly speed up the time to instantiate new services or reallocate resources depending on the user needs. This article focuses on the integration of SystemImager and Xen to create a totally open source framework able to manage on-demand deployment of virtual machines, such as physical machines, using a single centralized point of management. This approach allows to strongly reduce IT costs and simplify administrative tasks for enterprise data centers, even with a complex and/or reduced set of hardware resources, exploiting the dynamic-provisioning functionalities of SystemImager and virtualization advantages of Xen.

Virtualization offers advantages that include server consolidation, isolation, rapid provisioning, and improved change management processes. Since virtualization breaks the hardware dependency and isolates virtual machines from details about the physical servers on which they are hosted, virtual images can be moved from one hosting platform to another. They can also be cloned to create more virtual machines, as desired. One of the challenges with cloning virtual images is handling operating system, network, and application specific customization. This article provides a sample framework for automating virtual image activation on new host platforms. This article, along with a previous article on Using virtual image templates to deploy WebSphere Application Server, demonstrates an automated approach for quickly and easily provisioning new WebSphere Application Server environments. The sample deployment and activation code included with this article is independent of WebSphere Application Server and can be used in conjunction with other software inside a virtual image. The specific example provided here is for WebSphere Application Server V6 in VMware or XEN virtual images, using SUSE V10 as the guest operating system. The activation techniques described in this article can be used in conjunction with IBM Tivoli® Provisioning Manager as described in Using Tivoli Provisioning Manager to deploy composite virtual appliances.