Manage shards and nodes

A shard distributes data in a cluster where cluster mode is enabled and consists of Primary and Replica nodes. A node is a VM (Virtual Machine) in a MemStore cluster and has either the Primary or Replica role.

The following sections explain how to view and manage shards and nodes in MemStore.

When cluster mode is enabled

When cluster mode is enabled, data is distributed by shard. You can view and manage shards and their nodes together.

View shards and nodes

On the Shard/Node tab, you can view the shard list and the nodes in each shard.

1. Go to the KakaoCloud Console > Data Store > MemStore.
2. In the Cluster menu, select the cluster whose details you want to view.
3. View the information on the Shard/Node tab.

• Shard table

Category	Item	Description
Menu button	Copy all endpoints	Copies all node endpoints in the cluster, separated by line breaks
	Add shard	Adds a shard to the cluster
Table button	Add node	Adds a Replica node to the selected shard
	Delete	Deletes the selected shard - A shard cannot be deleted if the cluster has the minimum number of shards
Shard list	Shard name	Automatically assigned name - Format: {cluster name} + {nnn}
	Status	Shard status - For details, see Shard
	Node count	Number of nodes in the shard
	Slot	Slot range assigned to the shard
	Uptime	Time elapsed since shard creation started
	Created at	Date and time when the shard was created

• Node table

Category	Item	Description
Node list	Node name	Automatically assigned name - Format: {cluster name} + {nnn} + {nnn}
	Role	Role assigned to the node - For details, see Node
	Status	Node status - For details, see Node
	Engine version	Engine version selected when the cluster was created
	Node type	Node type
	Subnet	User subnet selected when the cluster was created
	Availability zone	Availability zone where the node was created
	Endpoint	Endpoint for connecting to the cluster
	Uptime	Time elapsed since node creation started
	Created at	Date and time when the node was created
Promote		Promotes the selected Replica node to Primary - Available only for Valkey; a Primary node cannot be promoted
Delete icon	Delete node	Deletes the selected node - A Primary node cannot be deleted

Manage shards and nodes

Shard changes

Adding or deleting a shard moves slots and can take several hours to complete.

Add a shard

You can add a shard to a cluster.

1. Go to the KakaoCloud Console > Data Store > MemStore.
2. In the Cluster menu, select the cluster to which you want to add a shard.
3. On the Shard tab, click [Add shard].
4. In the popup, confirm the selected cluster, select the subnet for the nodes, and click [Add].
5. Confirm that the cluster status changes to Scaling(horizontal) and returns to Running when complete.

Delete a shard

You can delete a shard that is no longer needed. Deleting a shard also deletes all nodes in it, and deleted resources cannot be recovered. You cannot delete a shard if a Valkey cluster has three shards or a Redis OSS cluster has one shard.

Cannot recover after deletion

Deleted shard and node resources are permanently released and cannot be recovered.

1. Go to the KakaoCloud Console > Data Store > MemStore.
2. In the Cluster menu, select the cluster from which you want to delete a shard.
3. On the Shard tab, select the shard and click [Delete shard].
4. In the popup, enter Permanent deletion and click [Delete].
5. Confirm that the shard no longer appears on the cluster details page.

Add a node

You can add a node to the selected shard. The new node is assigned the Replica role without service interruption.

1. Go to the KakaoCloud Console > Data Store > MemStore.
2. In the Cluster menu, select the cluster to which you want to add a node.
3. On the Shard tab, select the shard and click [Add node].
4. In the popup, confirm the selected cluster, select the subnet for the node, and click [Add].
5. Confirm that the node appears on the cluster details page.

Delete a node

You can delete a node that is no longer needed. You cannot delete a Primary node or delete a node if the shard has only two nodes.

Cannot recover after deletion

Deleted node resources are permanently released and cannot be recovered.

1. Go to the KakaoCloud Console > Data Store > MemStore.
2. In the Cluster menu, select the cluster containing the node to delete.
3. On the Shard tab, click Delete for the node.
4. In the popup, enter Permanent deletion and click [Delete].
5. Confirm that the node no longer appears on the cluster details page.

When cluster mode is disabled

When cluster mode is disabled, the cluster uses a single-shard structure in which you can view and manage nodes.

View nodes

On the Node list tab, you can view the nodes in the cluster.

1. Go to the KakaoCloud Console > Data Store > MemStore.
2. In the Cluster menu, select the cluster whose details you want to view.
3. View the information on the Node list tab.

Category	Item	Description
Menu button	Add node	Adds a Replica node to the selected cluster
Table button	Promote	Promotes the selected Replica node to Primary - A Primary node cannot be promoted
Delete icon		Deletes the selected node - A Primary node cannot be deleted
	Name	Automatically assigned name - Format: {cluster name} + {nnn}
	Role	Role assigned to the node - For details, see Node
	Status	Node status - For details, see Cluster
	Engine version	Engine version selected when the cluster was created
	Node type	Node type
	Subnet	User subnet selected when the cluster was created
	Availability zone	Availability zone where the node was created
	Endpoint	Endpoint for connecting to the cluster
	Uptime	Time elapsed since node creation started
	Created at	Date and time when the node was created

Manage nodes

Add a node

You can add a node to a cluster. The new node is assigned the Replica role without service interruption.

1. Go to the KakaoCloud Console > Data Store > MemStore.
2. In the Cluster menu, select the cluster to which you want to add a node.
3. On the Node list tab, click [Add node].
4. In the popup, confirm the selected cluster and click [Add].
5. Confirm that the cluster status changes to Scaling(horizontal).
6. Wait until the new node status changes from Creating to Running for Valkey or from Provisioning to Running for Redis OSS.
   • The new node is assigned the Replica role.
7. Confirm that the cluster status returns to Running.

Promote a node

If you need to change the Primary node of an active cluster, you can promote a Replica node to Primary.

Node promotion restrictions

• For Redis OSS, manual promotion is unavailable when automatic failover is enabled because the service performs promotion automatically.
• A single-node cluster has no Replica to promote. Add a Replica node before promotion.

1. Go to the KakaoCloud Console > Data Store > MemStore.
2. In the Cluster menu, select the cluster containing the node to promote.
3. On the Node list tab, select the node and click [Promote].
4. In the popup, confirm the node and click [Promote].
5. Confirm that the cluster status changes to Switching for Valkey or SwitchingOver for Redis OSS during promotion.
6. Confirm that the cluster status returns to Running when promotion is complete.
7. Confirm that the promoted node role changed from Replica to Primary.
   • Because a cluster can have only one Primary node, the former Primary becomes a Replica.

Delete a node

You can delete a node that is no longer needed. A Primary node can be deleted only in the Failed state. To delete a Primary node in another state, first change its role to Replica.

Cannot recover after deletion

Deleted node resources are permanently released and cannot be recovered.

1. Go to the KakaoCloud Console > Data Store > MemStore.
2. In the Cluster menu, select the cluster containing the node to delete.
3. On the Node list tab, select the node and click [Delete node].
4. In the popup, enter Permanent deletion and click [Delete].
5. During deletion, confirm that the cluster status changes to Scaling(horizontal) and the node status changes to Deleting for Valkey or Terminating for Redis OSS.
6. When deletion is complete, confirm that the cluster status returns to Running and the deleted node no longer appears.