February 2008
Heartbeat2 Xen cluster with drbd8 and OCFS2
by camelThe idea behind the whole set-up is to get a High availability two node Cluster with redundant data. The two identical Servers are installed with Xen hypervisor and almost same configuration as Cluster nodes. The configuration and image files of Xen virtual machines are stored on drbd device for redundancy. Drbd8 and OCFS2 allows simultaneous mounting on both nodes, which is required for live migration of xen virtual machines.
This Article describes Heartbeat2 Xen cluster Using Ubuntu (7.10) OS, drbd8 and OCFS2 (Ver. 1.39) File system. Although here Ubuntu is used it can be done in almost same way with Debian
November 2007
ssh on multiple servers Using cluster ssh -- Debian Admin
by camelEver had to make the same change on more than one Linux/unix server? Find it annoyingly painful to keep repeating the exact same commands again and again and again?
This tool addresses exactly this problem. You run a utility (cssh) providing a number of server names as parameters, and then xterms opens up to each server with an extra “console” window. Anything typed into the console is replicated into each server window (so, for examples, you can edit the same file on N machines at the same time, or run the same commands with the same parameters across those servers).
It is also possible to type into the server windows directly, or temporarily disable replication to one or more of the servers through the “Hosts” menu.
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