2.4. Creating the Resources and Resource Groups with the pcs Command
This use case requires that you create four cluster resources. To ensure these resources all run on the same node, they are configured as part of the resource group
apachegroup. The resources to create are as follows, listed in the order in which they will start.
- An
LVMresource namedmy_lvmthat uses the LVM volume group you created in Section 2.1, “Configuring an LVM Volume with an ext4 File System”. - A
Filesystemresource namedmy_fs, that uses the file system device/dev/my_vg/my_lvyou created in Section 2.1, “Configuring an LVM Volume with an ext4 File System”. - An
IPaddr2resource, which is a floating IP address for theapachegroupresource group. The IP address must not be one already associated with a physical node. If theIPaddr2resource's NIC device is not specified, the floating IP must reside on the same network as the statically assigned IP addresses used by the cluster nodes, otherwise the NIC device to assign the floating IP address cannot be properly detected. - An
apacheresource namedWebsitethat uses theindex.htmlfile and the Apache configuration you defined in Section 2.2, “Web Server Configuration”.
The following procedure creates the resource group
apachegroup and the resources that the group contains. The resources will start in the order in which you add them to the group, and they will stop in the reverse order in which they are added to the group. Run this procedure from one node of the cluster only.
- The following command creates the LVM resource
my_lvm. This command specifies theexclusive=trueparameter to ensure that only the cluster is capable of activating the LVM logical volume. Because the resource groupapachegroupdoes not yet exist, this command creates the resource group.[root@z1 ~]#
pcs resource create my_lvm LVM volgrpname=my_vg\exclusive=true --group apachegroupWhen you create a resource, the resource is started automatically. You can use the following command to confirm that the resource was created and has started.#
pcs resource showResource Group: apachegroup my_lvm (ocf::heartbeat:LVM): StartedYou can manually stop and start an individual resource with thepcs resource disableandpcs resource enablecommands. - The following commands create the remaining resources for the configuration, adding them to the existing resource group
apachegroup.[root@z1 ~]#
pcs resource create my_fs Filesystem\device="/dev/my_vg/my_lv" directory="/var/www" fstype="ext4" --group\apachegroup[root@z1 ~]#pcs resource create VirtualIP IPaddr2 ip=198.51.100.3\cidr_netmask=24 --group apachegroup[root@z1 ~]#pcs resource create Website apache\configfile="/etc/httpd/conf/httpd.conf"\statusurl="http://127.0.0.1/server-status" --group apachegroup - After creating the resources and the resource group that contains them, you can check the status of the cluster. Note that all four resources are running on the same node.
[root@z1 ~]#
pcs statusCluster name: my_cluster Last updated: Wed Jul 31 16:38:51 2013 Last change: Wed Jul 31 16:42:14 2013 via crm_attribute on z1.example.com Stack: corosync Current DC: z2.example.com (2) - partition with quorum Version: 1.1.10-5.el7-9abe687 2 Nodes configured 6 Resources configured Online: [ z1.example.com z2.example.com ] Full list of resources: myapc (stonith:fence_apc_snmp): Started z1.example.com Resource Group: apachegroup my_lvm (ocf::heartbeat:LVM): Started z1.example.com my_fs (ocf::heartbeat:Filesystem): Started z1.example.com VirtualIP (ocf::heartbeat:IPaddr2): Started z1.example.com Website (ocf::heartbeat:apache): Started z1.example.comNote that if you have not configured a fencing device for your cluster, as described in Section 1.3, “Fencing Configuration”, by default the resources do not start. - Once the cluster is up and running, you can point a browser to the IP address you defined as the
IPaddr2resource to view the sample display, consisting of the simple word "Hello".Hello
If you find that the resources you configured are not running, you can run thepcs resource debug-start resourcecommand to test the resource configuration. For information on thepcs resource debug-startcommand, see the High Availability Add-On Reference manual.
