Monitors network interfaces
ethmonitor [start | stop | status | monitor | meta-data | validate-all]
Monitor the vitality of a local network interface.
You may setup this RA as a clone resource to monitor the network interfaces on different nodes, with the same interface name. This is not related to the IP adress or the network on which a interface is configured. You may use this RA to move resources away from a node, which has a faulty interface or prevent moving resources to such a node. This gives you independend control of the resources, without involving cluster intercommunication. But it requires your nodes to have more than one network interface.
The resource configuration requires a monitor operation, because the monitor does the main part of the work. In addition to the resource configuration, you need to configure some location contraints, based on a CIB attribute value. The name of the attribute value is configured in the 'name' option of this RA.
Example constraint configuration: location loc_connected_node my_resource_grp rule ="rule_loc_connected_node" -INF: ethmonitor eq 0
The ethmonitor works in 3 different modes to test the interface vitality. 1. call ip to see if the link status is up (if link is down -> error) 2. call ip an watch the RX counter (if packages come around in a certain time -> success) 3. call arping to check wether any of the IPs found in the lokal ARP cache answers an ARP REQUEST (one answer -> success) 4. return error
interface
The name of the network interface which should be monitored (e.g. eth0).
(unique, required, string, no default)
name
The name of the CIB attribute to set. This is the name to be used in the constraints. Defaults to "ethmonitor-'interface_name'".
(unique, optional, string, no default)
multiplier
Multiplier for the value of the CIB attriobute specified in parameter name.
(optional, integer, default 1)
repeat_count
Specify how often the interface will be monitored, before the status is set to failed. You need to set the timeout of the monitoring operation to at least repeat_count * repeat_interval
(optional, integer, default 5)
repeat_interval
Specify how long to wait in seconds between the repeat_counts.
(optional, integer, default 10)
pktcnt_timeout
Timeout for the RX packet counter. Stop listening for packet counter changes after the given number of seconds.
(optional, integer, default 5)
arping_count
Number of ARP REQUEST packets to send for every IP. Usually one ARP REQUEST (arping) is send
(optional, integer, default 1)
arping_timeout
Time in seconds to wait for ARP REQUESTs (all packets of arping_count). This is to limit the time for arp requests, to be able to send requests to more than one node, without running in the monitor operation timeout.
(optional, integer, default 1)
arping_cache_entries
Maximum number of IPs from ARP cache list to check for ARP REQUEST (arping) answers. Newest entries are tried first.
(optional, integer, default 5)
This resource agent supports the following actions (operations):
start
Starts the resource. Suggested minimum timeout: 20s.
stop
Stops the resource. Suggested minimum timeout: 20s.
status
Performs a status check. Suggested minimum timeout: 20s. Suggested interval: 10s.
monitor
Performs a detailed status check. Suggested minimum timeout: 20s. Suggested interval: 10s.
meta-data
Retrieves resource agent metadata (internal use only). Suggested minimum timeout: 5s.
validate-all
Performs a validation of the resource configuration. Suggested minimum timeout: 20s.
The following is an example configuration for a ethmonitor resource using the crm(8) shell:
primitive p_ethmonitor ocf:heartbeat:ethmonitor \
params \
interface=string \
op monitor depth="0" timeout="20s" interval="10s"
\m[blue]http://www.linux-ha.org/wiki/ethmonitor_(resource_agent)\m[]
Linux-HA contributors (see the resource agent source for information about individual authors)