[Linux-HA] grouping resources and other trivial questions
Lawrence Yann
Yann.Lawrence at aah.co.uk
Mon Jan 15 08:07:25 MST 2007
Hello all,
I'm currently configuring a two node HA cluster. It will be managing a
tomcat thingy and an in house xinetd type service. I've managed to get
one service on one machine and the other service on the second machine,
an active/active configuration of sorts.
Picking up HA-linux from scratch to get where I am today has proved both
interesting (exciting at times!) and at times (very) frustrating.
I have just a couple of questions:
1) I have grouped the resources for each service as follows:
TomCat_group:
TC_IP_address_resource
TC_LVM_Resource
TC_FileSystem_resource
TC_Tomcat_resource
Xinetd_group:
X_IP_address_resource
X_LVM_resource
X_Filesystem_resource
X_Service_resource
Constrains are:
TC_Tomcat_IP before TC_LVM
TC_LVM before TC_Filesystem
TC_Filesystem before TC_Tomcat
Similar thing for the Xinetd_group. I assumed that the ordering
constraints would take care of the order in which the actual group
components would start, in actual fact, it seems that it is the order
that they appear in the cib.xml file is the more significant. Troubles
bringing up the Tomcat resource were solved by moving the TC_Tomcat
resource from the top of the group to the bottom. Are constrains only
useful for whole groups of resources not in a group (i.e. Tomcat_group
before Xinetd_group)? If so, need I bother with the constraints is have
defined? Is there a better way to group resources or is this a good way
of doing it?
2) Despite putting in location preferences, it seems that if I manually
migrate a resource from one node to the other, the resource on the other
node will migrate over to the server from which I had just migrated...
is this expected. I realise that a location constraint is only a
suggestion to the cluster, but I did not expect it to balance services
in this way. Is the only way to move a service away from a specific
server to put that server into standby?
e.g.
server1 has Tomcat running
server2 has xinetd_service running
crm_resource -M -r xinetd_service -H server1 causes xinetd to migrate to
server1 but also tomcat to migrate to server2
3) It becomes necessary in the lifetime of a tomcat server to deploy
updated web service code. How is this best done. Stopping the tomcat
server manually sees the cluster helpfully restarting it. My thoughts
were to deploy the new tomcat files whilst the server was up and then
manually stop it. When the cluster restarts it, Tomcat will pick up the
new files. Is there a way of stopping a service without removing it from
the cib (e.g. cibadmin -D -X '< group id="AAH_group">')?
I am sure that these seem like trivial questions, but they are puzzling
to someone who three weeks ago, thought it might be a good idea to give
this linux-HA stuff a go.
By the way, I'm now able to migrate the Tomcat resource between machines
within 10 seconds. The cluster doesn't drop a 'ping'. All very
impressive. All that remains is to sort out logging...
Kind regards,
Yann
--------------------------
cibadmin -Ql
<cib generated="true" admin_epoch="0" have_quorum="true"
ccm_transition="2" num_peers="2" cib_feature_revision="1.3"
dc_uuid="1dbeef7c-e0bf-4890-9588-9e9248404ff4" epoch="2"
num_updates="235">
<configuration>
<crm_config>
<cluster_property_set id="cib-bootstrap-options">
<attributes>
<nvpair id="cib-bootstrap-options-no_quorum_policy"
name="no_quorum_policy" value="ignore"/>
<nvpair id="cib-bootstrap-options-last-lrm-refresh"
name="last-lrm-refresh" value="1168858391"/>
</attributes>
</cluster_property_set>
</crm_config>
<nodes>
<node uname="gbw607su1053" type="normal"
id="d3c109d4-0eaa-430f-ab28-0021e06898d9">
<instance_attributes
id="nodes-d3c109d4-0eaa-430f-ab28-0021e06898d9">
<attributes>
<nvpair name="standby"
id="standby-d3c109d4-0eaa-430f-ab28-0021e06898d9" value="off"/>
</attributes>
</instance_attributes>
</node>
<node uname="gbw607su1052" type="normal"
id="1dbeef7c-e0bf-4890-9588-9e9248404ff4">
<instance_attributes
id="nodes-1dbeef7c-e0bf-4890-9588-9e9248404ff4">
<attributes>
<nvpair name="standby"
id="standby-1dbeef7c-e0bf-4890-9588-9e9248404ff4" value="off"/>
</attributes>
</instance_attributes>
</node>
</nodes>
<resources>
<group id="AAH_group">
<primitive class="ocf" id="AAH_IPaddr_10_221_3_43"
provider="heartbeat" type="IPaddr">
<operations>
<op id="AAH_IPaddr_monitor" interval="5s" name="monitor"
timeout="5s"/>
</operations>
<instance_attributes id="AAH_ipaddr_10_221_3_43_attributes">
<attributes>
<nvpair id="AAH_IPaddr_attributes" name="ip"
value="10.221.3.43"/>
</attributes>
</instance_attributes>
</primitive>
<primitive class="ocf" id="LVM_aahvg" provider="heartbeat"
type="LVM">
<operations>
<op id="LVM_aahvg_monitor" interval="60s" name="monitor"
timeout="5s"/>
</operations>
<instance_attributes id="LVM_aahvg-attributes">
<attributes>
<nvpair id="LVM_aahvg" name="volgrpname" value="aahvg"/>
</attributes>
</instance_attributes>
</primitive>
<primitive class="ocf" id="FS_aah" provider="heartbeat"
type="Filesystem">
<operations>
<op id="FS_aah-monitor" interval="60s" name="monitor"
timeout="15s"/>
</operations>
<instance_attributes id="FS_aah-attibutes">
<attributes>
<nvpair id="FS_aah_device" name="device"
value="/dev/mapper/aahvg-aah"/>
<nvpair id="FS_aah_directory" name="directory"
value="/aah"/>
<nvpair id="FS_aah_fstype" name="fstype" value="ext3"/>
</attributes>
</instance_attributes>
</primitive>
<primitive class="ocf" id="AAH_TomCat" provider="heartbeat"
type="tomcat2">
<operations>
<op id="AAH_tomcat_monitor" interval="60s" name="monitor"
timeout="15s"/>
</operations>
<instance_attributes id="AAH_tomcat_attributes">
<attributes>
<nvpair id="AAH_tomcat_attributes" name="user"
value="tc_testy"/>
<nvpair id="AAH_TomCat_target_role" name="target_role"
value="started"/>
</attributes>
</instance_attributes>
</primitive>
</group>
<group id="THREEPO_group">
<primitive class="ocf" id="THREEPO_IPaddr_10_221_3_44"
provider="heartbeat" type="IPaddr">
<operations>
<op id="THREEPO_IPaddr_monitor" interval="5s"
name="monitor" timeout="5s"/>
</operations>
<instance_attributes
id="THREEPO_ipaddr_10_221_3_44_attributes">
<attributes>
<nvpair id="THREEPO_IPaddr_attributes" name="ip"
value="10.221.3.44"/>
</attributes>
</instance_attributes>
</primitive>
<primitive class="ocf" id="LVM_threepovg" provider="heartbeat"
type="LVM">
<operations>
<op id="LVM_threepovg_monitor" interval="60s"
name="monitor" timeout="5s"/>
</operations>
<instance_attributes id="LVM_threepo-attributes">
<attributes>
<nvpair id="LVM_threepovg-attributes" name="volgrpname"
value="threepovg"/>
</attributes>
</instance_attributes>
</primitive>
<primitive class="ocf" id="FS_threepo" provider="heartbeat"
type="Filesystem">
<operations>
<op id="FS_threepo-monitor" interval="60s" name="monitor"
timeout="15s"/>
</operations>
<instance_attributes id="FS_threepo-attibutes">
<attributes>
<nvpair id="FS_threepo_device" name="device"
value="/dev/mapper/threepovg-threepo"/>
<nvpair id="FS_threepo_directory" name="directory"
value="/home/threepo"/>
<nvpair id="FS_threepo_fstype" name="fstype"
value="ext3"/>
</attributes>
</instance_attributes>
</primitive>
</group>
</resources>
<constraints>
<rsc_order id="AAH_IP_group-ordering"
from="AAH_IPaddr_10_221_3_43" action="start" type="before"
to="LVM_aahvg"/>
<rsc_order id="AAH_group_ordering" from="LVM_aahvg"
action="start" type="before" to="FS_aah"/>
<rsc_order id="AAH_TomCat_group_ordering" from="AAH_TomCat"
action="start" type="after" to="FS_aah"/>
<rsc_order id="THREEPO_IP_group-ordering"
from="THREEPO_IPaddr_10_221_3_44" action="start" type="before"
to="LVM_threepovg"/>
<rsc_order id="THREEPO_group_ordering" from="LVM_threepovg"
action="start" type="before" to="FS_threepo"/>
<rsc_location rsc="AAH_group" id="cli-prefer-AAH_group">
<rule score="INFINITY" id="cli-prefer-rule-AAH_group">
<expression attribute="#uname" operation="eq" type="string"
id="cli-prefer-expr-AAH_group" value="gbw607su1052"/>
</rule>
</rsc_location>
<rsc_location id="cli-prefer-THREEPO_group" rsc="THREEPO_group">
<rule id="prefered_cli-prefer-THREEPO_group" score="INFINITY">
<expression attribute="#uname"
id="cli-prefer-expr-THREEPO_group" operation="eq" value="gbw607su1053"/>
</rule>
</rsc_location>
</constraints>
</configuration>
**STATUS stuff ommited for clarity**
</cib>
************************************************************************
DISCLAIMER
The information contained in this e-mail is confidential and is intended
for the recipient only.
If you have received it in error, please notify us immediately by reply
e-mail and then delete it from your system. Please do not copy it or
use it for any other purposes, or disclose the content of the e-mail
to any other person or store or copy the information in any medium.
The views contained in this e-mail are those of the author and not
necessarily those of Admenta UK Group.
Admenta UK plc is a company incorporated in England and Wales
under company number 3011757 and whose registered office
is at Sapphire Court, Walsgrave Triangle, Coventry CV2 2TX
************************************************************************
More information about the Linux-HA
mailing list