Server provisioning is nothing but installs the Linux or UNIX like operating systems automatically. One can install actual operating systems, device drivers, data, and make a server ready for network operation without any user input. Typically you select a server from a pool of available servers, load the operating systems (such as RHEL, Fedora, FreeBSD, Debian), and finally customize storage, network (IP, gateway, bounding etc), drivers, applications, users, ssh keys and more. Using the following tools, you can perform automated unattended operating system installation, configuration, set virtual machines and much more. The following software can be used to install a lot (say thousands) of Linux and UNIX systems at the same time.
By default vSphere does not provide client for Linux or OS X. You need to use Windows system to manage your VMware ESX server. However, it does provides vSphere Web Access which allows you to organize and share virtual machines using web browser. If you try to access vSphere Web Access you may get an error which read as follows:
503 Service Unavailable
You can fix this problem as follows.
Virtualization is the latest buzz word. You may wonder computers are getting cheaper every day, why should I care and why should I use virtualization? Virtualization is a broad term that refers to the abstraction of computer resources such as:
- Platform Virtualization
- Resource Virtualization
- Storage Virtualization
- Network Virtualization
- Desktop Virtualization
This article describes why you need virtualization and list commonly used FOSS and proprietary Linux virtualization software.
Red Hat issued an update version of Linux operating system core called kernel that plugs various security holes for RHEL 5.x. This update has been rated as having important security impact. All users are advised to upgrade kernel package.
You can easily list all running Virtual machines from a Linux shell prompt without accessing GUI. This is useful to scripts or to get status for any VM.
Xen is one of the leading Virtualization software. You can use Xen virtualization to implement HA clusters. However, there are few issues you must be aware of while handling failures in a high-availability environment. This article explains configuration options using Xen:
The idea of using virtual machines to build high available clusters is not new. Some software companies claim that virtualization is the answer to your HA problems, off course that’s not true. Yes, you can reduce downtime by migrating virtual machines to another physical machine for maintenance purposes or when you think hardware is about to fail, but if an application crashes you still need to make sure another application instance takes over the service. And by the time your hardware fails, it’s usually already too late to initiate the migration.
So, for each and every application you still need to look at whether you want to have it constantly available, if you can afford the application to be down for some time, or if your users won’t mind having to relogin when one server fails.
=> Using Xen for High Availability Clusters [onlamp.com]
Virtualization is the process of abstracting computing resources such that multiple operating system and application images can share a single physical server, bringing significant cost-of-ownership and manageability benefits. Through its Oracle VM product, Oracle offers scalable, low-cost server virtualization for heterogeneous applications.
Oracle VM is free server virtualization software that fully supports both Oracle and non-Oracle applications, and is three times more efficient than other server virtualization products.
Continue reading “Download of the day: Oracle VM”
Vmware server comes with the nifty vmware-cmd utility. It allows an administrator to perform various operations on a virtual machine from Linux command line / shell prompt such as:
=> Stop / Start VM
=> Get VM status
=> Setup variables
=> Powerdown VM and much more
Task: Lists the virtual machines on the local server
You can list all servers and config file, enter:
# vmware-cmd -l
/nas/vms/Ubuntu/Ubuntu.vmx /nas/vms/FreeBSD/FreeBSD.vmx /nas/vms/OpenBSD/OpenBSD.vmx /nas/vms/Debian4/Debian4.vmx /nas/vms/CentOS5/CentOS5.vmx
Turn on VM / Power up VPS
Just pas start option to vmware-cmd,
# vmware-cmd /nas/vms/FreeBSD/FreeBSD.vmx start
To stop VM/VPS, enter:
# vmware-cmd /nas/vms/FreeBSD/FreeBSD.vmx stop
To reset VM/VPS, enter:
# vmware-cmd /nas/vms/FreeBSD/FreeBSD.vmx reset
To suspend VM/VPS, enter:
# vmware-cmd /nas/vms/FreeBSD/FreeBSD.vmx suspend
Find out if OpenBSD VM is on or off:
# vmware-cmd /disk2.vmware/vms/OpenBSD/OpenBSD.vmx getstate
getstate() = off
vmware-cmd offers other options, please consult VMWARE documentation for more information.
/dev/shm is nothing but implementation of traditional shared memory concept. It is an efficient means of passing data between programs. One program will create a memory portion, which other processes (if permitted) can access. This will result into speeding up things on Linux.