Manage shards and nodes

A node is a Virtual Machine (VM) included in a cluster, and a shard is a group of nodes that use the same cluster configuration. This guide explains how to manage shards and nodes within a MemStore cluster.

View shards and nodes

When using cluster mode

You can view the list and status of shards and nodes created in the cluster.

1. Go to the KakaoCloud Console > Data Store > MemStore menu.
2. Select the cluster for which you want to view details.
3. Click the Shards tab to view the information.

Shards list tab

Item	Info	Description
Menu button	Copy all endpoints	Copy all node endpoints in the cluster in newline format
	Add shard	Add a shard to the cluster
	Add node	Add a node to a shard
	Delete shard	Delete a shard from the cluster (not allowed if only one shard exists)
Shards list	Shard name	Automatically assigned (Format: {cluster-name} + {nnn})
	Status	Shard status - See Cluster lifecycle and status values
	Node count	Number of nodes in the shard
	Slots	Slot range assigned to the shard
	Uptime	Time since the shard was created
	Created at	Time the shard was created
Nodes list	Node name	Automatically assigned (Format: {cluster-name} + {nnn} + {nnn})
	Status	Node status - See Cluster lifecycle and status values
	Role	Role assigned to the node - See Node for role details
	Subnet	User-selected subnet during cluster creation
	AZ	Availability zone where the node was created
	Endpoint	Endpoint for cluster access
	Uptime	Time since the node was created
	Created at	Time the node was created

When not using cluster mode

You can view the list and status of nodes created in the cluster.

1. Go to the KakaoCloud Console > Data Store > MemStore menu.

2. Select the cluster for which you want to view details.

3. Click the Node list tab to view the information.

   Node list tab

   Item	Description
   Add node	Add a node to the cluster
   Node name	Automatically assigned (Format: {cluster-name} + {nnn})
   Status	Node status - See Cluster lifecycle and status values
   Subnet	User-selected subnet during cluster creation
   Role	Role assigned to the node - See Node for role details
   Uptime	Time since the node was created
   Created at	Time the node was created

Manage shards and nodes (when using cluster mode)

Add shard

You can add a shard to a cluster.

info

Adding or deleting shards involves slot migration, which may take several hours to complete.

1. Go to the KakaoCloud Console > Data Store > MemStore menu.
2. Select the cluster where you want to add a shard.
3. Click the Shards tab, then click the Add Shard button.
4. In the Add Shard popup, confirm the selected cluster and choose the subnet for the nodes, then click Add.
5. In the Cluster menu, the cluster's status will change to Modifying, and once the shard is added, the status will change to Running.

Delete shard

You can delete a shard that is no longer needed. All nodes within the shard will also be deleted. Deleted resources cannot be recovered.

1. Go to the KakaoCloud Console > Data Store > MemStore menu.
2. Select the cluster where you want to delete a shard.
3. Click the Shards tab, select the shard checkbox, and click the Delete Shard button.
4. In the Delete Shard popup, enter the shard name and click Delete.
5. Confirm the deletion status from the Cluster menu.

Add node

You can add a node to a cluster. Nodes are added as replicas without causing service downtime.

1. Go to the KakaoCloud Console > Data Store > MemStore menu.
2. Select the cluster where you want to add a node.
3. Click the Shards tab, select the target shard, and click the Add Node button.
4. In the Add Node popup, confirm the cluster and select the subnet to use, then click Add.
5. Verify the addition in the Cluster menu.

Delete node

You can delete nodes that are no longer in use without service interruption. Primary nodes cannot be deleted, and nodes cannot be deleted if the shard only has two nodes.

caution

Deleted node resources are completely released and cannot be recovered.

1. Go to the KakaoCloud Console > Data Store > MemStore menu.
2. Select the cluster where you want to delete a node.
3. Click the Shards tab, click the [More] icon for the shard, and then click Delete Node.
4. In the Delete Node popup, enter the node name and click Delete.
5. Check the deletion status in the Cluster menu.

Manage shards and nodes (when not using cluster mode)

Add node

You can add a node to a cluster. Nodes are added as replicas without service downtime.

1. Go to the KakaoCloud Console > Data Store > MemStore menu.
2. Select the cluster where you want to add a node.
3. Click the Node list tab and then click the Add Node button.
4. In the Add Node popup, confirm the selected cluster and click Add.
5. In the Cluster menu, the cluster's status will change to ScalingOut. Confirm that the node is added.
6. In the cluster detail page, wait until the newly added node status changes from Provisioning to Running in the Node list tab.
   • The role of the newly added node is set to Replica.
7. When all nodes are successfully added, the cluster status will change to Running.

Promote node

If you need to change the Primary node of a running cluster, you can promote one of the Replica nodes. However, you cannot promote a node in a high availability configuration or in a single-node cluster.

Conditions where promotion is not allowed	Description
High availability enabled node	When HA is enabled, automatic promotion occurs. Manual promotion is not supported.
Single-node cluster	Cannot promote because there is no Replica node. Add a Replica first to enable promotion.

info

Promotion is not supported when HA is enabled.

1. Go to the KakaoCloud Console > Data Store > MemStore menu.
2. Select the cluster where promotion is needed.
3. Click the Node list tab, check the target Replica node, and click Promote.
4. In the Promote popup, verify the node and click Promote.
5. The cluster status will temporarily change from Running to SwitchingOver. While switching, node roles will remain unchanged.
6. Once promotion completes, the cluster status will return to Running.
7. In the Node list tab, verify that the promoted node's role has changed from Replica to Primary.
   • Only one Primary node is allowed, so the previous Primary will be demoted to Replica.

Delete node

You can delete unused nodes without service interruption. Primary nodes can only be deleted when in Failed status. To delete an active Primary, demote it to Replica first.

caution

Deleted node resources are permanently released and cannot be recovered.

1. Go to the KakaoCloud Console > Data Store > MemStore menu.
2. Select the cluster containing the node to delete.
3. Click the Node list tab, check the node, and click Delete Node.
4. In the Delete Node popup, enter the node name and click Delete.
5. During deletion, the cluster status changes to ScalingIn, and the node status changes to Terminating.
6. Once complete, the cluster status returns to Running, and the deleted node is no longer visible.