>>> Antony Stone <antony.st...@ha.open.source.it> schrieb am 04.08.2021 um 23:01 in Nachricht <202108042301.19895.antony.st...@ha.open.source.it>: > 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. If cluster A is non-functional, no resoiurces of cluster A will run. > > 2. Cluster B resources running on cluster B if cluster B is functional and > not > running anywhere if cluster B is non‑functional. Likewise for cluster B. > > 3. Cluster C resources running on cluster C if cluster C is functional and > not > running anywhere if cluster C is non‑functional. Same here. > > 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. Part of the problem is your description: Actually you do not have a resource D, but you have three resources like D_A, D_B, and D_C Maybe things were easier if it it would all be one big cluster with location constraints. > > 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. > > 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? > > > Antony. > > ‑‑ > I don't know, maybe if we all waited then cosmic rays would write all our > software for us. Of course it might take a while. > > ‑ Ron Minnich, Los Alamos National Laboratory > > Please reply to the list; > please *don't* CC > me. > _______________________________________________ > Manage your subscription: > https://lists.clusterlabs.org/mailman/listinfo/users > > ClusterLabs home: https://www.clusterlabs.org/ _______________________________________________ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/