Configuration
The inventory may define these hosts:
observers: Set of hosts to observe the cluster (only the first is considering)Hypervisors: Set of machines to hosts VMs.
Remember that the cluster must contain an odd number of machines. For example, three hypervisors or one observer and two hypervisors.
Node redundancy
All nodes in the cluster have access to a shared storage via Ceph (see Shared storage section). With it, the cluster is in N to N redundancy mode.
- Corosync will provides messaging and membership services.
- Pacemaker will manage the cluster (synchronize resources between each node).
More details on Pacemaker here and Corosync here.
pacemaker-remote
pacemaker-remote is a component which can be installed inside a VM to allow Pacemaker to manage and monitor resources inside this VM.
For instance, with pacemaker-remote pacemaker can monitor services and containers directly inside a VM.
For more information about pacemaker-remote refer to https://clusterlabs.org/pacemaker/doc/2.1/Pacemaker_Remote/singlehtml/.
Management tool
The vm_manager project is an high-level interface of pacemaker and Ceph to manage the VM like a resource. He is installed during the installation step and provides the vm-mgr command.
Please refer to How to manage VM in SEAPATH for more detais.