Manage shard and node

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

View shards and nodes

When using cluster mode

You can view a list of created shards and nodes in a cluster along with their statuses.

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

2. In the Cluster menu, select the cluster you want to check.

3. Click the Shards tab to view the information.

   Shard list tab

   Item	Info	Description
   Menu button	Copy all endpoints	Copies all node endpoints in the cluster (newline separated)
   	Add shard	Adds a shard within the cluster
   	Add node	Adds a node to a shard within the cluster
   	Delete shard	Deletes a shard in the cluster (cannot be deleted if only one exists)
   Shard list	Shard name	Automatically generated - Format: {cluster-name} + {nnn}
   	Status	Status of the shard - For detailed status values, see Cluster lifecycle and status
   	Node count	Number of nodes created within the shard
   	Slots	Slot range allocated to the shard
   	Uptime	Time elapsed since shard creation started
   	Created at	Shard creation time
   Node list	Node name	Automatically generated - Format: {cluster-name} + {nnn} + {nnn}
   	Status	Status of the node - For detailed status values, see Cluster lifecycle and status
   	Role	Role assigned to the node - See Node for details
   	Subnet	User-selected subnet during cluster creation
   	AZ	Availability Zone where the node was created
   	Endpoint	Endpoint used to access the cluster
   	Uptime	Time elapsed since node creation started
   	Created at	Node creation time

When not using cluster mode

You can view a list of created nodes and their statuses in the cluster.

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

2. In the Cluster menu, select the cluster you want to check.

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

   Node list tab

   Item	Description
   Add node	Adds a node within the cluster
   Node name	Automatically generated - Format: {cluster-name} + {nnn}
   Status	Node status - See Cluster lifecycle and status
   Subnet	User-selected subnet during cluster creation
   Role	Role assigned to the node - See Node for details
   Uptime	Time elapsed since node creation started
   Created at	Node creation time

Manage shards and nodes (cluster mode enabled)

Add shard

You can add shards to a cluster.

info

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

1. Go to the KakaoCloud Console > Data Store > MemStore.
2. In the Cluster menu, select the cluster where you want to add a shard.
3. Click the Shards tab, then click Add shard.
4. In the Add shard popup, check the selected cluster and choose a subnet for the nodes, then click Add.
5. The cluster status changes to Modifying and switches to Running once the shard addition is complete.

Delete shard

You can delete a shard that is no longer needed. Deleting a shard will also delete all nodes within it, and these resources cannot be recovered.

1. Go to the KakaoCloud Console > Data Store > MemStore.
2. In the Cluster menu, select the cluster where you want to delete a shard.
3. Click the Shards tab, select the shard you want to delete, and click Delete shard.
4. In the Delete shard popup, enter the shard name and click Delete.
5. Confirm that the shard has been deleted in the Cluster menu.

Add node

You can add nodes to a cluster. When added, a node is assigned the role of a Replica without any service interruption.

1. Go to the KakaoCloud Console > Data Store > MemStore.
2. In the Cluster menu, select the cluster where you want to add a node.
3. Click the Shards tab, select the shard to add the node, and click Add node.
4. In the Add node popup, confirm the selected cluster and choose the subnet for the node, then click Add.
5. Confirm that the node has been successfully added in the Cluster menu.

Delete node

You can delete nodes that are no longer needed without service interruption. Primary nodes cannot be deleted, and a shard with only 2 nodes cannot have a node deleted.

caution

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 where you want to delete a node.
3. Click the Shards tab, then click the [⋮] button of the node's shard > Delete node.
4. In the Delete node popup, enter the node name and click Delete.
5. Confirm that the node has been deleted in the Cluster menu.

Manage shards and nodes (cluster mode disabled)

Add node

You can add nodes to a cluster. New nodes are added as Replicas without service interruption.

1. Go to the KakaoCloud Console > Data Store > MemStore.
2. In the Cluster menu, select the cluster where you want to add a node.
3. Click the Node list tab, then click Add node.
4. In the Add node popup, confirm the selected cluster and click Add.
5. The cluster status will change to ScalingOut, and once the node is added, confirm its status.
6. In the Node list tab of the cluster detail page, wait until the new node's status changes from Provisioning to Running.
   • The newly added node will be assigned the Replica role.
7. Once all node additions are complete, the cluster status returns to Running.

Promote node

If the Primary node in an active cluster needs to be replaced, one of the Replica nodes can be promoted. Promotion is not available in clusters with High Availability enabled or clusters with only one node.

Not eligible for promotion	Description
Nodes with High Availability	HA handles promotion automatically, so manual promotion is not supported
Clusters with one node	No Replica exists to promote - Add a Replica node to enable promotion

info

Promotion is unavailable when High Availability is enabled.

1. Go to the KakaoCloud Console > Data Store > MemStore.
2. In the Cluster menu, select the cluster where you want to promote a node.
3. Click the Node list tab, check the node to promote, and click Promote.
4. In the Promote popup, confirm the node and click Promote.
5. Wait for the cluster status to change from Running to SwitchingOver. During this time, node roles remain unchanged until the process completes.
6. After promotion is complete, the cluster status returns to Running.
7. In the Node list tab, confirm 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 unnecessary nodes without service interruption. However, Primary nodes can only be deleted when in the Failed state. Otherwise, you must first promote another node and demote the Primary.

caution

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 that contains the node you want 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 will change to ScalingIn, and the node's status will change to Terminating.
6. Once deletion is complete, verify that the cluster status has returned to Running and that the deleted node is no longer listed.