[ClusterLabs] Cannot ping a secondary address apart from the server which it is assigned to (on Azure)

[Paul Warwicker]

Hello,

I originally posted this in the Azure forums first but have had no 
replies. Trying here instead in case anyone has encountered it.

I am trying to setup up a High Availability Cluster in Azure using 
CentOS 8, Pacemaker and Corosync. Everything is deployed using terraform.

For our application, we need to migrate a floating IP address, a shared 
storage and our daemon between nodes. These resources are grouped into a 
service and these are successfully migrating between nodes as required. 
We are also using a private DNS zone and there is no firewall on either 
server. There is a DNS entry for the floating IP and that is resolvable 
by both servers and client.

The problem is that floating IP address is only pingable on the server 
which has the floating IP address assigned as a secondary address. All 
other nodes in the same subnet will get the error Destination Host 
Unreachable, but pings to the primary address will succeed. All the IP 
addresses are in the same subnet (172.16.31.0/24). Auto-registration is 
enabled for the servers and client which makes up the test environment. 
The floating address was a somewhat arbitrary choice, but remains in 
that same subnet and would not be otherwise allocated. I mentioned the 
auto registration because the floating IP is *not* auto-registered.

If I migrate the service to the other server node, the roles are 
reversed, the server which could not ping the address can now do so and 
the server which could, cannot.

Any insight would be welcome.

Additional detail considering the audience:

pcs host auth -u hacluster -p ******** haswmfs-lin-vm-000 haswmfs-lin-vm-001
pcs cluster setup haswmfs haswmfs-lin-vm-000 haswmfs-lin-vm-001
pcs cluster enable --all
pcs cluster start --all
sleep 30
pcs property set stonith-enabled=false
pcs resource create haswmfs-fs ocf:heartbeat:Filesystem device=/dev/sdc 
directory=/mnt/smallworld fstype=xfs
pcs resource create haswmfs-daemon lsb:smallworld_GIS
pcs resource create haswmfs-ip ocf:heartbeat:IPaddr2 
ip=${var.virtual_ip}cidr_netmask=24 nic=eth0 iflabel=haswmfs op monitor 
interval=30s
pcs resource group add haswmfs-service haswmfs-ip haswmfs-daemon haswmfs-fs
fence_azure_arm -l ${var.app_id}-p 
${data.external.service_principal.result.password}--resourceGroup 
${var.resource_group_name}--tenantId 
${data.azurerm_client_config.current.tenant_id}--subscriptionId 
${data.azurerm_client_config.current.subscription_id}-o list
pcs stonith create haswmfs-fence fence_azure_arm 
login=${var.app_id}passwd=${data.external.service_principal.result.password}resourceGroup=${var.resource_group_name} tenantId=${data.azurerm_client_config.current.tenant_id}subscriptionId=${data.azurerm_client_config.current.subscription_id}pcmk_host_list="haswmfs-lin-vm-000 
haswmfs-lin-vm-001" power_timeout=240 pcmk_reboot_timeout=480 
pcmk_reboot_retries=4 pcmk_reboot_action=reboot # op monitor interval=60s
pcs property set stonith-enabled=true
pcs property config --all | egrep "stonith|quorum"
sleep 60
pcs cluster verify --full # should be blank if ok
crm_verify -LV # should be blank if ok
pcs cluster config
pcs resource config haswmfs-service
pcs stonith config
pcs status

As mentioned in the original post, everything is failing over as 
expected and the only issue is the pinging of the virtual IP.

Thanks

-paul
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