|
|
Linux » Books » Administrative »
Linux FailSafe Administrator's Guide
(document number: 007-4322-002 / published: 2001-02-28)
table of contents | additional info | download
find in page
You can stop the execution of Linux FailSafe on a systemwide
basis, on all the nodes in a cluster, or on a specified node only. Deactivating a node or a cluster is a complex operation that involves
several steps and can take several minutes. Aborting a deactivate operation
can leave the nodes and the resources in an intended state. When deactivating HA services on a node or for a cluster, the operation
may fail if any resource groups are not in a stable clean state. Resource
groups which are in transition will cause any deactivate HA services command
to fail. In many cases, the command may succeed at a later time after resource
groups have settled into a stable state. After you have successfully deactivated a node or a cluster, the node
or cluster should have no resource groups and all HA services should be gone. Serially stopping HA services on every node in a cluster is not the
same as stopping HA services for the entire cluster. If the former case, an
attempt is made to keep resource groups online and highly available while
in the latter case resource groups are moved offline, as described in the
following sections. When you stop HA services, the Linux FailSafe daemons perform the following
actions: A shutdown request is sent to Linux FailSafe (FSD) FSD releases all resource groups and puts them in ONLINE-READY state All nodes in the cluster in the configuration database are
disabled (one node at a time and the local node last) Linux FailSafe waits until the node is removed from cluster
membership before disabling the node The shutdown is successful only when all nodes are not part
of cluster membership CMOND receives notification from the configuration database
when nodes are disabled The local CMOND sends SIGTERM to all HA processes and IFD. All HA processes clean up and exit with “don't restart”
code All other CMSD daemons remove the disabled node from the cluster
membership
The operation of deactivating a node tries to move all resource groups
from the node to some other node and then tries to disable the node in the
cluster, subsequently killing all HA processes. When HA services are stopped on a node, all resource groups owned by
the node are moved to some other node in the cluster that is capable of maintaining
these resource groups in a highly available state. This operation will fail
if there is no node that can take over these resource groups. This condition
will always occur if the last node in a cluster is shut down when you deactivate
HA services on that node. In this circumstance, you can specify the force option
to shut down the node even if resource groups cannot be moved or released.
This will normally leave resource groups allocated in a non-highly-available
state on that same node. Using the force option might
result in the node getting reset. In order to guarantee that the resource
groups remain allocated on the last node in a cluster, all online resource
groups should be detached. If you wish to move resource groups offline that are owned by the node
being shut down, you must do so prior to deactivating the node. The operation of deactivating a cluster attempts to release all resource
groups and disable all nodes in the cluster, subsequently killing all HA processes. When a cluster is deactivated and the Linux FailSafe HA services are
stopped on that cluster, resource groups are moved offline or deallocated.
If you want the resource groups to remain allocated, you must detach the resource
groups before attempting to deactivate the cluster. Serially stopping HA services on every node in a cluster is not the
same as stopping HA services for the entire cluster. If the former case, an
attempt is made to keep resource groups online and highly available while
in the latter case resource groups are moved offline. To stop Linux FailSafe services using the Cluster Manager GUI, perform
the following steps: On the left side of the display, click on the “Nodes
& Cluster” category. On the right side of the display click on the “Stop
FailSafe HA Services” task link to launch the task. Enter the selected inputs. Click on “OK” at the bottom of the screen to complete
the task.
To deactivate Linux FailSafe in a cluster and stop Linux FailSafe processing,
use the following command: cmgr> stop ha_services [on node A] [for cluster B][force] |
Linux FailSafe Administrator's Guide
(document number: 007-4322-002 / published: 2001-02-28)
table of contents | additional info | download
home/search |
what's new |
help
|
|
|
