[Pacemaker] Pacemaker unnecessarily (?) restarts a vm on active node when other node brought out of standby - possible solution?

[Andrew Beekhof]

On 16 May 2014, at 3:41 am, Ian <cl-3627 at jusme.com> wrote:

> Doing some experiments and Reading TFM, I found this:
> 
> 5.2.2. Advisory Ordering
> When the kind=Optional option is specified for an order constraint, the constraint is considered optional and only has an effect when both resources are stopping and/or starting. Any change in state of the first resource you specified has no effect on the second resource you specified.
> 
> (From https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Configuring_the_Red_Hat_High_Availability_Add-On_with_Pacemaker/index.html)
> 
> This seems to tickle the right area. Adding "kind=Optional" to the gfs2 -> drbd order constraint makes it all work as desired (start-up and shut-down is correctly ordered,

Not really, it allows gfs2 to start even if drbd can't run anywhere.

> and bringing the other node out of standby doesn't force a gratuitous restart of the gfs2 filesystem and the vms that rely on it on the already active node).
> 
> Is that the correct solution I wonder?

Unlikely

> The term "optional" makes me nervous, but the description matches the desired behavior, in normal cases at least.
> 
> 
> FYI, Here's the "working" configuration:
> 
> # pcs config
> Cluster Name: jusme
> Corosync Nodes:
> 
> Pacemaker Nodes:
> sv06 sv07
> 
> Resources:
> Master: vm_storage_core_dev-master
>  Meta Attrs: master-max=2 master-node-max=1 clone-max=2 clone-node-max=1 notify=true
>  Group: vm_storage_core_dev
>   Resource: res_drbd_vm1 (class=ocf provider=linbit type=drbd)
>    Attributes: drbd_resource=vm1
>    Operations: monitor interval=60s (res_drbd_vm1-monitor-interval-60s)
> Clone: vm_storage_core-clone
>  Group: vm_storage_core
>   Resource: res_fs_vm1 (class=ocf provider=heartbeat type=Filesystem)
>    Attributes: device=/dev/drbd/by-res/vm1 directory=/data/vm1 fstype=gfs2 options=noatime,nodiratime
>    Operations: monitor interval=60s (res_fs_vm1-monitor-interval-60s)
> Master: nfs_server_dev-master
>  Meta Attrs: master-max=1 master-node-max=1 clone-max=2 clone-node-max=1 notify=true
>  Group: nfs_server_dev
>   Resource: res_drbd_live (class=ocf provider=linbit type=drbd)
>    Attributes: drbd_resource=live
>    Operations: monitor interval=60s (res_drbd_live-monitor-interval-60s)
> Resource: res_vm_nfs_server (class=ocf provider=heartbeat type=VirtualDomain)
>  Attributes: config=/etc/libvirt/qemu/vm09.xml
>  Meta Attrs: resource-stickiness=100
>  Operations: monitor interval=60s (res_vm_nfs_server-monitor-interval-60s)
> 
> Stonith Devices:
> Fencing Levels:
> 
> Location Constraints:
> Ordering Constraints:
>  promote vm_storage_core_dev-master then start vm_storage_core-clone (Optional) (id:order-vm_storage_core_dev-master-vm_storage_core-clone-Optional)
>  promote nfs_server_dev-master then start res_vm_nfs_server (Mandatory) (id:order-nfs_server_dev-master-res_vm_nfs_server-mandatory)
>  start vm_storage_core-clone then start res_vm_nfs_server (Mandatory) (id:order-vm_storage_core-clone-res_vm_nfs_server-mandatory)
> Colocation Constraints:
>  vm_storage_core-clone with vm_storage_core_dev-master (INFINITY) (rsc-role:Started) (with-rsc-role:Master) (id:colocation-vm_storage_core-clone-vm_storage_core_dev-master-INFINITY)
>  res_vm_nfs_server with nfs_server_dev-master (INFINITY) (rsc-role:Started) (with-rsc-role:Master) (id:colocation-res_vm_nfs_server-nfs_server_dev-master-INFINITY)
>  res_vm_nfs_server with vm_storage_core-clone (INFINITY) (id:colocation-res_vm_nfs_server-vm_storage_core-clone-INFINITY)
> 
> 
> Ian.
> 
> 
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