Preventing split-brain scenario in a high-availability cluster
View Patent ↗As disclosed herein a method, executed by a computer, includes determining, by a processor, that a first node of a HA cluster is unable to communicate with a second node of the HA cluster, and initiating, by a processor, by the first node, a handshake operation with a connected client, wherein the handshake operation comprises requesting that the client determine a status of the second node and receiving, from the client, a response indicating the status of the second node. The method further includes accepting, by a processor, new requests in response to determining that the second node is unavailable, and requesting, by a processor, restoration of communications between the first node and the second node in response to determining that the second node is available. A computer system and computer program product corresponding to the above method are also disclosed herein.
1. A method, executed by one or more processors, the method comprising:
determining, by a processor, that a first node of a HA cluster is unable to communicate with a second node of the HA cluster;
initiating, by a processor, by the first node, a handshake operation with a connected client, wherein the handshake operation comprises requesting that the connected client determine a status of the second node and receiving, from the connected client, a response indicating the status of the second node;
accepting, by a processor, new requests in response to determining that the second node is unavailable; and
requesting, by a processor, restoration of communications between the first node and the second node in response to determining that the second node is available.
2. The method of claim 1 , wherein the handshake operation is performed by all connected clients.
3. The method of claim 1 , wherein the handshake operation is performed by each new client initiating a connection with the first node.
4. The method of claim 1 , wherein the handshake operation is performed by a selected number of clients.
5. The method of claim 1 , wherein the handshake operation is performed for a selected duration.
6. The method of claim 1 , wherein the status is either active or inactive.
7. The method of claim 1 , wherein the second node is unavailable if the response from each client indicates an inactive status.
8. The method of claim 1 , wherein the second node is available if the response from at least one client indicates an active status.
9. The method of claim 1 , wherein requesting that communication between the first node and the second node be restored comprises requesting administrative action.
10. A computer program product comprising:
one or more computer readable storage media and program instructions stored on the one or more computer readable storage media, the program instructions comprising instructions executable by a computer to perform:
determining, by a processor, that a first node of a HA cluster is unable to communicate with a second node of the HA cluster;
initiating, by a processor, by the first node, a handshake operation with a connected client, wherein the handshake operation comprises requesting that the connected client determine a status of the second node and receiving, from the connected client, a response indicating the status of the second node;
accepting, by a processor, new requests in response to determining that the second node is unavailable; and
requesting, by a processor, restoration of communications between the first node and the second node in response to determining that the second node is available.
11. The computer program product of claim 10 , wherein the handshake operation is performed by all connected clients.
12. The computer program product of claim 10 , wherein the handshake operation is performed by each new client initiating a connection with the first node.
13. The computer program product of claim 10 , wherein the handshake operation is performed by a selected number of clients.
14. The computer program product of claim 10 , wherein the handshake operation is performed for a selected duration.
15. The computer program product of claim 10 , wherein the second node is unavailable if the response from each client indicates an inactive status.
16. The computer program product of claim 10 , wherein the second node is available if the response from at least one client indicates an active status.
17. A computer system comprising:
one or more computer processors;
one or more computer readable storage media;
program instructions stored on the computer readable storage media for execution by at least one of the computer processors, the program instructions executable by a computer to perform:
determining, by a processor, that a first node of a HA cluster is unable to communicate with a second node of the HA cluster;
initiating, by a processor, by the first node, a handshake operation with a connected client, wherein the handshake operation comprises requesting that the connected client determine a status of the second node and receiving, from the connected client, a response indicating the status of the second node;
accepting, by a processor, new requests in response to determining that the second node is unavailable; and
requesting, by a processor, restoration of communications between the first node and the second node in response to determining that the second node is available.
18. The computer system of claim 17 , wherein the handshake operation is performed by all connected clients.
19. The computer system of claim 17 , wherein the handshake operation is performed by each new client initiating a connection with the first node.
20. The computer system of claim 17 , wherein the handshake operation is performed by a selected number of clients.