kexec-tools/kdump-in-cluster-environment.txt
arthur 11bb4785f8 Add a kdump-in-cluster-environment.txt in RPM package
Since kdump already support dump in cluster environment, this patch
add a howto file to RPM package to describe how to configure kdump
in cluster environment.

Signed-off-by: arthur <zzou@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
2014-01-29 16:20:06 +08:00

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Kdump-in-cluster-environment HOWTO
Introduction
Kdump is a kexec based crash dumping mechansim for Linux. This docuement
illustrate how to configure kdump in cluster environment to allow the kdump
crash recovery service complete without being preempted by traditional power
fencing methods.
Overview
Kexec/Kdump
Details about Kexec/Kdump are available in Kexec-Kdump-howto file and will not
be described here.
fence_kdump
fence_kdump is an I/O fencing agent to be used with the kdump crash recovery
service. When the fence_kdump agent is invoked, it will listen for a message
from the failed node that acknowledges that the failed node is executing the
kdump crash kernel. Note that fence_kdump is not a replacement for traditional
fencing methods. The fence_kdump agent can only detect that a node has entered
the kdump crash recovery service. This allows the kdump crash recovery service
complete without being preempted by traditional power fencing methods.
fence_kdump_send
fence_kdump_send is a utility used to send messages that acknowledge that the
node itself has entered the kdump crash recovery service. The fence_kdump_send
utility is typically run in the kdump kernel after a cluster node has
encountered a kernel panic. Once the cluster node has entered the kdump crash
recovery service, fence_kdump_send will periodically send messages to all
cluster nodes. When the fence_kdump agent receives a valid message from the
failed nodes, fencing is complete.
How to configure cluster environment:
If we want to use kdump in cluster environment, fence-agents-kdump should be
installed in every nodes in the cluster. You can achieve this via the following
command:
# yum install -y fence-agents-kdump
Next is to add kdump_fence to the cluster. Assuming that the cluster consists
of three nodes, they are node1, node2 and node3, and use Pacemaker to perform
resource management and pcs as cli configuration tool.
With pcs it is easy to add a stonith resource to the cluster. For example, add
a stonith resource named mykdumpfence with fence type of fence_kdump via the
following commands:
# pcs stonith create mykdumpfence fence_kdump \
pcmk_host_check=static-list pcmk_host_list="node1 node2 node3"
# pcs stonith update mykdumpfence pcmk_monitor_action=metadata --force
# pcs stonith update mykdumpfence pcmk_status_action=metadata --force
# pcs stonith update mykdumpfence pcmk_reboot_action=off --force
Then enable stonith
# pcs property set stonith-enabled=true
How to configure kdump:
Actually there is nothing special in configuration between normal kdump and
cluster environment kdump. So please refer to Kexec-Kdump-howto file for more
information.