Replacing nodes

MemoryDB frequently upgrades its fleet with patches and upgrades, usually seamlessly. However, from time to time we need to relaunch your MemoryDB nodes to apply mandatory OS updates to the underlying host. These replacements are required to apply upgrades that strengthen security, reliability, and operational performance.

You have the option to manage these replacements yourself at any time before the scheduled node replacement window. When you manage a replacement yourself, your instance receives the OS update when you relaunch the node and your scheduled node replacement is canceled. You might continue to receive alerts indicating that the node replacement is to take place. If you've already manually mitigated the need for the maintenance, you can ignore these alerts.

Note

Replacement nodes automatically generated by MemoryDB for Redis may have different IP addresses. You are responsible for reviewing your application configuration to ensure that your nodes are associated with the appropriate IP addresses.

The following list identifies actions you can take when MemoryDB schedules one of your nodes for replacement:

MemoryDB node replacement options

• Do nothing – If you do nothing, MemoryDB replaces the node as scheduled.

  If the node is a member of a Multi-AZ cluster, MemoryDB provides improved availability during patching, updates, and other maintenance-related node replacements.

  Replacement completes while the cluster serves incoming write requests.

• Change your maintenance window – For scheduled maintenance events, you receive an email or a notification event from MemoryDB. In these cases, if you change your maintenance window before the scheduled replacement time, your node now is replaced at the new time. For more information, see Modifying a MemoryDB cluster.

  Note

  The ability to change your replacement window by moving your maintenance window is only available when the MemoryDB notification includes a maintenance window. If the notification does not include a maintenance window, you cannot change your replacement window.

  For example, let's say it's Thursday, November 9, at 15:00 and the next maintenance window is Friday, November 10, at 17:00. Following are three scenarios with their outcomes:

  • You change your maintenance window to Fridays at 16:00, after the current date and time and before the next scheduled maintenance window. The node is replaced on Friday, November 10, at 16:00.

  • You change your maintenance window to Saturday at 16:00, after the current date and time and after the next scheduled maintenance window. The node is replaced on Saturday, November 11, at 16:00.

  • You change your maintenance window to Wednesday at 16:00, earlier in the week than the current date and time. The node is replaced next Wednesday, November 15, at 16:00.

  For instructions, see Managing maintenance.