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7.3. Moving Resources Due to Connectivity Changes
Setting up the cluster to move resources when external connectivity is lost is a two-step process.
- Add a
pingresource to the cluster. Thepingresource uses the system utility of the same name to test if a list of machines (specified by DNS host name or IPv4/IPv6 address) are reachable and uses the results to maintain a node attribute calledpingd. - Configure a location constraint for the resource that will move the resource to a different node when connectivity is lost.
Table 5.1, “Resource Properties” describes the properties you can set for a
ping resource.
| Field | Description |
|---|---|
dampen
| |
multiplier
| |
host_list
|
The following example command creates a
ping resource that verifies connectivity to www.example.com. In practice, you would verify connectivity to your network gateway/router. You configure the ping resource as a clone so that the resource will run on all cluster nodes.
pcs resource create ping ocf:pacemaker:ping dampen=5s multiplier=1000 host_list=www.example.com --clone
# pcs resource create ping ocf:pacemaker:ping dampen=5s multiplier=1000 host_list=www.example.com --clone
The following example configures a location constraint rule for the existing resource named
Webserver. This will cause the Webserver resource to move to a host that is able to ping www.example.com if the host that it is currently running on cannot ping www.example.com
pcs constraint location Webserver rule score=-INFINITY pingd lt 1 or not_defined pingd
# pcs constraint location Webserver rule score=-INFINITY pingd lt 1 or not_defined pingd
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