On 05.08.2021 00:01, Antony Stone wrote: > On Wednesday 04 August 2021 at 22:06:39, Frank D. Engel, Jr. wrote: > >> There is no safe way to do what you are trying to do. >> >> If the resource is on cluster A and contact is lost between clusters A >> and B due to a network failure, how does cluster B know if the resource >> is still running on cluster A or not? >> >> It has no way of knowing if cluster A is even up and running. >> >> In that situation it cannot safely start the resource. > > I am perfectly happy to have an additional machine at a third location in > order to avoid this split-brain between two clusters. > > However, what I cannot have is for the resources which should be running on > cluster A to get started on cluster B. > > If cluster A is down, then its resources should simply not run - as happens > right now with two independent clusters. > > Suppose for a moment I had three clusters at three locations: A, B and C. > > Is there a method by which I can have: > > 1. Cluster A resources running on cluster A if cluster A is functional and > not > running anywhere if cluster A is non-functional. > > 2. Cluster B resources running on cluster B if cluster B is functional and > not > running anywhere if cluster B is non-functional. > > 3. Cluster C resources running on cluster C if cluster C is functional and > not > running anywhere if cluster C is non-functional. > > 4. Resource D running _somewhere_ on clusters A, B or C, but only a single > instance of D at a single location at any time. > > Requirements 1, 2 and 3 are easy to achieve - don't connect the clusters. > > Requirement 4 is the one I'm stuck with how to implement. >
You either have single cluster and define appropriate location constraints or you have multiple clusters and configure geo-cluster on top of them. But you already have been told it multiple times. > If the three nodes comprising cluster A can manage resources such that they > run on only one of the three nodes at any time, surely there must be a way of > doing the same thing with a resource running on one of three clusters? > > You need something that coordinates resources between three clusters and that is booth. _______________________________________________ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/