With the latest version of pcs package there are some changes regarding the implementation of a highly available cluster which is based on centos/redhat operating system. Currently the latest package available for pcs is the 0.10.4 as shown below on which cluster with pacemaker 2.x and corosync 3.x are supported.
Firstly authenticate the nodes of the cluster (changed from previous versions)
Shutdown the node on which cluster resource IPaddr2 is running and verify that IP is still accessible. You can verify during the shutdown and the resource migration from one node to another that icmp package respond is a bit slower. (3ms instead of <1ms)
Verify that cluster resource cluster-ip is online on the second node.
The below error can occur when one tries to create a new HA cluster with pcs package. Corosync fails to start with the below description.
The error can be resolved by editing /etc/hosts file and by commenting the first two lines for localhost. At the end I appended a new line that maps localhost with a specific IPv4 IP but this could be unnecessary.
After that when one tries to create and enable the cluster the result would be successful.
Sometimes infrastructure servers are physical and directly connected to storage and not virtual ones. In virtualization cases, one has to assign a new virtual disk on the virtual server and proceed with the expand. In case of a physical server one should do the following in order to assign more space on a partition or a lvm.
Find storage adapters and rescan them:
echo"- - -">/sys/class/scsi_host/hostX/scan
where X is 0 to 10 in my system (some online and some offline)
After re scanning storage adapters a new multipath device will be visible and ready to be used.