Install and use Cent. OS 7 or RHEL 7 as KVM virtualization host. Tweet. When thinking about virtualization, everybody immediately thinks about VMWare. And it must be said, the product they offer is very decent but also comes with a decent price. MongoDB Enterprise Install on Linux Install the official builds of MongoDB Enterprise on Linuxbased systems. Install on OS X Install the official build of MongoDB. How to install latest apache on CentOS How to configure it and do basic hardening Full tutorial covers installation and setup httpd on CentOS. This guide is based on a minimal CentOS 7 install following the idea that you only install software that you require. For those familiar with OpenSCAP, you will. If for some reason you want to pin an older version of Mono rather than updating to the latest, you can modify the Debian repository to wheezysnapshotsX. XX. X. As an alternative, its worth looking into KVM for your virtualization. As with the VMWare product range, KVM offers full virtualization and it can compete with VMWare regarding stability and performance. Virtualization terminology. To prevent things getting confused I would first like to clear out some terminology used for virtualization. For somebody working on a daily basis in virtual environments, these might be clear but can be rather confusing for others. Host the machine that hosts other system, KVM will be installed on this machine. Guest the system running on the host, also referred to as VM, Virtual Machine or domain. Hypervisor the piece of software that enables virtualization on the host. For example KVM, ESXi, Xen, This post has been completely reviewed and updated where needed on 0. Part. 1 KVM installation and preparation. KVM hypervisor and VM extensions. As mentioned earlier, KVM offers, as VMWare, full virtualization. This means that a full system, which looks like a real physical system to the guest OS, will be offered. Besides full virtualization, there is also such a thing as paravirtualization, as Xen can offer. Paravirtualization gives you higher performance but needs a modified guest OS and is basically limited to nix systems. How to Install JBoss 6 on CentOS. This post will cover installing JBoss 6. CentOS 5. x. If you are looking to install JBoss 7, please see my post here httpwww. Switch Centos Installation Guide' title='Switch Centos Installation Guide' />Installing CentOS This section provides a summary of the screens used to install CentOS. For more detailed installation instructions, it is possible to use the. News and feature lists of Linux and BSD distributions. Switch Centos Installation Guide' title='Switch Centos Installation Guide' />Full virtualization enables you to run unmodified guest systems and thus also most proprietary systems as Windows . In order to be able to use full virtualization, you either need some virtualization extensions on your CPU or use emulation. First thing to do is to check if the host machine supports VM extensions. On the x. 86 platofrom, those are either AMD V or Intels VT X. Toshiba Satellite L745 Wireless Driver. In order to check if the installed CPUs support those extensions, we need to check if the vmx for VT X or svm for AMD V flag exists in the cpuinfo output jensdkvmhostegrep cvmxsvmproccpuinfo. Switch Centos Installation Guide' title='Switch Centos Installation Guide' />When the output is 0, meaning that neither vmx or svm is found in the flags, it probably means that your CPU doesnt support those extensions and there is little you can do. When the extensions are listed, be sure to check if they are enabled in the systems BIOS since that would cause problems later on. In case your CPU doesnt support VM extensions, you are limited to QEMU emulation in combination with KVM, which delivers a much worse performance in comparison. For this tutorial, Ill assume that the VM extensions are supported and enabled in the BIOS of the host system. KVM installation. The first step in the KVM installation is installing the necessary packages. Package virt manager, xauth and dejavu lgc sans fonts are also needed if you want to manage KVM with the graphical interface in combination with X1. X1. 1 forwardingTo install the required packagesjensdkvmhost nbsp sudoyuminstallkvmvirt managerlibvirtvirt installqemu kvmxauthdejavu lgc sans fonts y. Complete Networking. For the networking part, our KVM host will act as a router for its guests and we will need to create a bridge interface to allow the guest to communicate out of the host. Guests will use the bridge on the host to connect to the real network. To allow such type of setup its needed to allow ip forwarding in the kernel parameters. After allowing the host to do ip forwarding, we need to change the network configuration. Basically we will keep our original physical interface as it is but will assign its IP address to the brige. In the example host machine there is one real interface called eno. DEVICEeno. 16. 77. ONBOOTyes. IPADDR1. NETMASK2. 55. 2. GATEWAY1. HWADDR0. 0 0c 2. DNS11. The first thing to change here, is to comment out everything that is IP related and tell the interface which interface will be the bridge. Resulting in etcsysconfignetwork scriptsifcfg eno. DEVICEeno. 16. 77. ONBOOTyesIPADDR1. NETMASK2. 55. 2. GATEWAY1. HWADDR0. 0 0c 2. DNS11. BRIDGEvirbr. 0Next, we can create the config script for the bridge interface virbr. Most details can be copied from the original script for eno. DEVICEvirbr. 0TYPEBRIDGEONBOOTyes. BOOTPROTOstatic. IPADDR1. NETMASK2. 55. 2. GATEWAY1. DNS11. 92. 1. 68. Finish and check the KVM installation. Basically all components are now ok but before KVM can be used its a good idea to perform a reboot in order to load the kvm modules and to relaod the new network settings. After the reboot, we should check if the necessary kernel modules are loaded, which means that KVM successfully can handle the VM extensions of our CPU jensdkvmhostlsmodgrepkvmkvmintel. Check if the bridge is installed and in an up state jensdkvmhostipashowvirbr. BROADCAST,MULTICAST,UP,LOWERUP gt mtu. UPlinkether. 00 0c 2. Last thing to check is if we can connect to KVM by asking for a simple list of systems jensdkvmhostsudovirsh cqemu systemlist. Id. Name. State If it returns something else, then you should go trough the earlier steps to check where something went wrong. Part 2 Using KVM with the CLIAfter completing the KVM installation, its time to start using the host. First thing we need to do is to create a new domain or VM. Adding a new VMTo create a new virtual machine using the CLI, we need to know which template we will use to install the system. To get a list of templates that are known in our KVM installation, you can do the following 1. Short. ID             Name                                               Version  ID altlinux. Mandrake. RESpring. ALTLinux. 2. 0                                      2. ALTLinux. 2. 2                                      2. ALTLinux. 2. 4                                      2. ALTLinux. 3. 0                                      3. ALTLinux. 4. 0                                      4. ALTLinux. 4. 1                                      4. Java Progress Bar Not Updating. ALTLinux. 5. 0                                      5. ALTLinux. 6. 0                                      6. ALTLinux. 7. 0                                      7. Cent. OS6. 0                                         6. Cent. OS6. 1                                         6. Cent. OS6. 2                                         6. Cent. OS6. 3                                         6. Cent. OS6. 4                                         6. Cent. OS6. 5                                         6. Cent. OS6. 6                                         6. Cent. OS6. 7                                         6. Cent. OS7. 0                                         7. Debian. Buzz                                        1. Debian. Rex                                         1. Debian. Bo                                          1. Debian. Hamm                                        2. Debian. Slink                                       2. Debian. Potato                                      2. Debian. Woody                                       3        http debian. Debian. Sarge                                       3. Barman Manual. Barman Backup and Recovery Manager is an open source administration tool for disaster recovery of Postgre. SQL servers written in Python. It allows your organisation to perform remote backups of multiple servers in business critical environments to reduce risk and help DBAs during the recovery phase. Barman is distributed under GNU GPL 3 and maintained by 2nd. Quadrant, a platinum sponsor of the Postgre. SQL project. IMPORTANT This manual assumes that you are familiar with theoretical disaster recovery concepts, and that you have a grasp of Postgre. SQL fundamentals in terms of physical backup and disaster recovery. See section Before you start below for details. In a perfect world, there would be no need for a backup. However, it is important, especially in business environments, to be prepared for when the unexpected happens. In a database scenario, the unexpected could take any of the following forms data corruptionsystem failure including hardware failurehuman errornatural disaster. In such cases, any ICT manager or DBA should be able to fix the incident and recover the database in the shortest time possible. We normally refer to this discipline as disaster recovery, and more broadly business continuity. Within business continuity, it is important to familiarise with two fundamental metrics, as defined by Wikipedia Recovery Point Objective RPO maximum targeted period in which data might be lost from an IT service due to a major incidentRecovery Time Objective RTO the targeted duration of time and a service level within which a business process must be restored after a disaster or disruption in order to avoid unacceptable consequences associated with a break in business continuityIn a few words, RPO represents the maximum amount of data you can afford to lose, while RTO represents the maximum down time you can afford for your service. Understandably, we all want RPO0 zero data loss and RTO0 zero down time, utopia even if it is our grandmotherss recipe website. In reality, a careful cost analysis phase allows you to determine your business continuity requirements. Fortunately, with an open source stack composed of Barman and Postgre. SQL, you can achieve RPO0 thanks to synchronous streaming replication. RTO is more the focus of a High Availability solution, like repmgr. Therefore, by integrating Barman and repmgr, you can dramatically reduce RTO to nearly zero. Based on our experience at 2nd. Quadrant, we can confirm that Postgre. SQL open source clusters with Barman and repmgr can easily achieve more than 9. In any case, it is important for us to emphasise more on cultural aspects related to disaster recovery, rather than the actual tools. Tools without human beings are useless. Our mission with Barman is to promote a culture of disaster recovery that focuses on backup proceduresfocuses even more on recovery proceduresrelies on education and training on strong theoretical and practical concepts of Postgre. SQLs crash recovery, backup, Point In Time Recovery, and replication for your team memberspromotes testing your backups only a backup that is tested can be considered to be valid, either manually or automatically be creative with Barmans hook scriptsfosters regular practice of recovery procedures, by all members of your devops team yes, developers too, not just system administrators and DBAssolicites to regularly scheduled drills and disaster recovery simulations with the team every 3 6 monthsrelies on continuous monitoring of Postgre. SQL and Barman, and that is able to promptly identify any anomalies. Moreover, do everything you can to prepare yourself and your team for when the disaster happens yes, when, because when it happens It is going to be a Friday evening, most likely right when you are about to leave the office. It is going to be when you are on holiday right in the middle of your cruise around the world and somebody else has to deal with it. It is certainly going to be stressful. You will regret not being sure that the last available backup is valid. Unless you know how long it approximately takes to recover, every second will seems like forever. Be prepared, dont be scared. In 2. 01. 1, with these goals in mind, 2nd. Quadrant started the development of Barman, now one of the most used backup tools for Postgre. SQL. Barman is an acronym for Backup and Recovery Manager. Currently, Barman works only on Linux and Unix operating systems. Before you start using Barman, it is fundamental that you get familiar with Postgre. SQL and the concepts around physical backups, Point In Time Recovery and replication, such as base backups, WAL archiving, etc. Below you can find a non exhaustive list of resources that we recommend for you to read Professional training on these topics is another effective way of learning these concepts. At any time of the year you can find many courses available all over the world, delivered by Postgre. SQL companies such as 2nd. Quadrant. One of the foundations of Barman is the ability to operate remotely from the database server, via the network. Theoretically, you could have your Barman server located in a data centre in another part of the world, thousands of miles away from your Postgre. SQL server. Realistically, you do not want your Barman server to be too far from your Postgre. SQL server, so that both backup and recovery times are kept under control. Even though there is no one size fits all way to setup Barman, there are a couple of recommendations that we suggest you abide by, in particular Install Barman on a dedicated server. Do not share the same storage with your Postgre. SQL server. Integrate Barman with your monitoring infrastructure 2. Test everything before you deploy it to production. A reasonable way to start modelling your disaster recovery architecture is to design a couple of possibile architectures in respect to Postgre. SQL and Barman, such as. SPOF of your system, with cost benefit analysismake your decision and implement the initial solution. Having said this, a very common setup for Barman is to be installed in the same data centre where your Postgre. SQL servers are. In this case, the single point of failure is the data centre. Fortunately, the impact of such a SPOF can be alleviated thanks to a feature called hook scripts. Indeed, backups of Barman can be exported on different media, such as tape via tar, or locations, like an S3 bucket in the Amazon cloud. Remember that no decision is forever. You can start this way and adapt over time to the solution that suits you best. However, try and keep it simple to start with. Another relevant feature that was first introduced by Barman is support for multiple servers. Barman can store backup data coming from multiple Postgre. SQL instances, even with different versions, in a centralised way. As a result, you can model complex disaster recovery architectures, forming a star schema, where Postgre. SQL servers rotate around a central Barman server. Every architecture makes sense in its own way. Choose the one that resonates with you, and most importantly, the one you trust, based on real experimentation and testing. From this point forward, for the sake of simplicity, this guide will assume a basic architecture one Postgre. SQL instance with host name pgone backup server with Barman with host name backupTraditionally, Barman has always operated remotely via SSH, taking advantage of rsync for physical backup operations.