Hi Marc, though Digimer's RHCS tutorial is an excellent introducion to the RHCS cluster with a thourough step by step reference to setting up a Xen cluster, and I'd highly recommend you read it, you probably also would like to have look at these articles in the cluster wiki which focus a little more condensed on your questions. Here is described how to set up so called HA-LVM which avoids the clmvd overhead and is for settings like yours where you only require active/passive VG activation (i.e. a shared storage VG is only activated on a single cluster node at any time). This is achieved by tagging of the affected VGs/LVs. https://fedorahosted.org/cluster/wiki/LVMFailover Unfortunately, this article lacks mentioning of the required locking_type setting in lvm.conf. But if you have access to RHN this article on HA-LVM does, and it also outlines both methods, i.e. the so called "preferred clvmd" method and the so called "original" (or what I'd call "tagging") method which doesn't require clvmd: https://access.redhat.com/kb/docs/DOC-3068 Should you on the other hand require active/active VGs (i.e. simultaneous activation of the same shared VG on more than one cluster node), which I consider not a requirement for a KVM cluster (but I lack any experience in this field) the recommended procedure is described here: https://access.redhat.com/kb/docs/DOC-17651 Important aside, after you've edited the lvm.conf you are required to make a new initial ramdisk (or at least touch the mtime of the current initrd) or cluster services won't start on that node (watch entries in messages or whereever syslogd logs clulog stuff to). In this article you may find something treating KVM VMs' migration. https://fedorahosted.org/cluster/wiki/KvmMigration Regards Ralph (an RHCS newbie himself) ________________________________ From: linux-cluster-bounces@xxxxxxxxxx [mailto:linux-cluster-bounces@xxxxxxxxxx] On Behalf Of Marc Caubet Sent: Tuesday, July 19, 2011 4:19 PM To: linux-cluster@xxxxxxxxxx Subject: Linux Cluster + KVM + LVM2 Hi, we are testing RedHat Cluster to build a KVM virtualization infrastructure. This is the first time we use the Linux Cluster so we are a little bit lost. Hope someone can help. Actually we have 2 hypervisors connected via Fiber Channel to a shared storage (both servers see the same 15TB device /dev/mapper/mpathb). Our idea is a shared storage to hold KVM virtual machines by using LVM2. Both server should be able to run Virtual Machines from the same storage, but we should be able to migrate or start virtual machines on the other server node on crash. So the plan is: - Virtual Machine image = Logical Volume - CLVM2 cluster: only one server node at the same time will be able to manage the volume group- - KVM Virtual Machine High Availability. Machines will run on one server node. If for some reason the server node crashes, the second will start / migrate the virtual machine. Basically we woul like to know: - How can we create a cluster for the LVM2 shared storage (when we create it, it does not work since both server nodes have the VG as Active) - How can we create a cluster service for a virtual machine (we guess it has to be done 1 by 1) - Since we have 2 server nodes, how to increase the number of votes for quorum (qdisk over a heartbeat logical volume partition?) Thanks and best regards, -- Marc Caubet Serrabou PIC (Port d'Informació Científica) Campus UAB, Edificio D E-08193 Bellaterra, Barcelona Tel: +34 93 581 33 22 Fax: +34 93 581 41 10 http://www.pic.es Avis - Aviso - Legal Notice: http://www.ifae.es/legal.html -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
