Manage cluster

A cluster is an object composed of multiple nodes that users can manage through tasks such as viewing, monitoring, and deleting.
You can manage clusters in the following ways:

caution

We recommend regular monitoring and management to ensure system available memory usage does not exceed 50%.
In KakaoCloud MemStore, the maxmemory setting is configured to about 65% of the system available memory.
When the max memory is reached, the allkeys-lru policy deletes the least recently used keys.

View cluster list

You can view a list of clusters created within your project.

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

2. In the Cluster tab, check the list of currently created clusters.

   Item	Description
   Name	The name assigned to the cluster at creation - Click the name to view detailed cluster information
   Status	The current status of the cluster - For detailed status values, see Cluster lifecycle and status
   Engine version	The Redis OSS engine version running on the nodes
   Node type	The node type selected during cluster creation - Hover over the node type to see vCPU and memory details - For types, refer to Node types
   Cluster mode	Whether cluster mode is enabled
   High availability	Whether automatic failover is enabled for node failures
   Auto backup retention	Retention period of automatic backups for the cluster - New backups follow updated retention settings - Hover to see backup start time
   Shard count	Number of shards in the cluster - If cluster mode is disabled, this shows as a hyphen (-)
   Node count	Number of nodes in the cluster
   Uptime	Time since the cluster was created - Hover to view the cluster creation date

View cluster information

You can check information about clusters created within your project.

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

2. In the Cluster tab, select a cluster to view its details.

3. Use the available tabs to view information:

   Details tab

   Section	Field	Description
   Top info	Operation status	Current operational status of the cluster
   	Cluster mode	Whether cluster mode is enabled
   	High availability	Whether automatic failover is enabled for node failures
   	Endpoint - Primary	Read/write-enabled endpoint
   	Endpoint - Read	Read-only endpoint - Not provided in cluster mode
   Details - Cluster	Cluster name	Name assigned at creation
   	Created by	User who initially requested cluster creation
   	Cluster mode	Whether cluster mode is enabled
   	High availability	Whether automatic failover is enabled
   	Node type	Node type selected during creation. See Node types
   	vCPU per node	Number of vCPUs allocated per node
   	Memory per node	Memory allocated per node
   	Shard count	Number of shards in the cluster
   	Node count	Number of nodes - See the Shard/Node list tab for shard and node status
   	Created at	Time of cluster creation
   	Cluster ID	Object ID of the cluster
   Network	VPC	VPC selected during cluster creation
   	Availability zone	AZ deployment - Multi: distributed across multiple AZs - Single: deployed in a single AZ
   	Primary endpoint	Read/write-enabled endpoint
   	Read endpoint	Read-only endpoint - Not provided in cluster mode
   	Port	Port running on the node (default: 6379)
   Backup	Backup count	Total number of backups created
   	Auto backup retention	Auto backup retention period - New backups follow updated settings - Hover to see backup start time
   	Auto backup start time	Time when the daily auto backup begins (within 15 minutes of selected time)
   Redis compatibility	Engine version	Redis engine version used
   	License	Redis OSS license information
   	User authentication	Whether user authentication was enabled
   	ID	Admin ID entered when authentication is enabled - Not displayed if disabled
   	Parameter group	Parameter group applied and its application status - See Parameter application status
   	TLS encryption	Whether TLS encryption is enabled - CA file can be downloaded after creation

   Shard/Node list tab

   See How-to guides > Manage shards and nodes

   Backup tab

   You can create and manage backups from the cluster.
   Backups created from this tab are manual backups.
   See Backup management > Create manual backup for details.

   Item	Description
   Name	Name of the backup
   Status	Current status of the backup - See Backup status values
   Type	Backup type (manual or automatic)
   Backup file size	Size of the backup file
   Cache size	Cache size of the backup
   Auto backup retention	Retention period for automatic backups - New backups follow updated retention settings - Hover to see backup start time
   Retention expiration	Applies to auto backups only; shows when the backup will expire and be deleted
   Backup start time	Time the backup started
   [⋮] menu	Options: Restore, Copy, Export, Delete - See Backup management for details

   Security tab

   See How-to guides > Manage cluster > View security group

   Monitoring tab

   See How-to guides > Manage cluster > Monitor cluster

Monitor cluster

In the Monitoring tab, you can check the detailed status of nodes within the cluster to manage them flexibly and efficiently while minimizing required resources.

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

2. Select the cluster you want to monitor from the Cluster tab.

3. Click the Monitoring tab to view information.

   Item	Description
   ① Monitoring node	Select a node to monitor
   ② Data period	Period of data displayed in the monitoring graph - 1 hour (default) / 3 hours / 12 hours / 1 day / 7 days
   ③ Metrics	Select metrics to monitor - MemStore / CPU / Memory / Network - All selected by default - Multiple selections allowed
   ④ View mode	Graph view mode - 1-column, 2-column, 3-column options
   ⑤ Auto refresh interval	Set auto-refresh interval - No refresh (default) / 10s / 30s / 1min / 5min
   ⑥ Manual refresh	Click to manually refresh monitoring results

   Monitoring data provided

   Category	Metric	Description
   MemStore	Calls by command (calls/sec)	Calls per second by Redis command over time
   MemStore	Connections (count)	Number of connections over time - Max Connections: Max number of clients - Active Connections: Current number of clients
   MemStore	Cache hit ratio (%)	Redis cache hit ratio over time
   MemStore	Expired/evicted keys (count)	Number of expired/evicted keys over time
   CPU	Total usage (%)	Total CPU usage over time
   Memory	Total usage (%)	Total memory usage over time
   Memory	Usage by type (Bytes)	Memory usage by type over time
   Network	RX per interface (Bytes/sec)	Received bytes per second over time
   Network	TX per interface (Bytes/sec)	Transmitted bytes per second over time
   Network	RX per interface (PPS)	Packets received per second over time
   Network	TX per interface (PPS)	Packets sent per second over time

Configure high availability

MemStore offers a high availability (HA) feature to ensure service continuity and stable operations.
If HA is enabled, the system takes automated actions in case of node failure. HA settings can be changed without downtime, but the cluster must be in Running status and have at least one replica node.

1. Go to the KakaoCloud Console > Data Store > MemStore.
2. From the Cluster tab, click the [⋮] menu of your cluster and select Configure high availability.
3. In the popup window, choose to enable or disable HA and click Save.
4. Check the detailed cluster page to confirm the change.

Delete cluster

You can delete clusters that are no longer in use.

1. Go to the KakaoCloud Console > Data Store > MemStore.
2. In the Cluster tab, click the [⋮] menu for the cluster and select Delete cluster.
3. In the popup, enter the cluster name.
4. To preserve automatic backups, check Preserve automatic backups.
5. Click Delete.

MemStore user account

MemStore provides an optional user authentication feature. If enabled, users must authenticate using the set ID and password. If not enabled, access is granted using a password-less default account.

Command restrictions

To ensure stable operation and management, the following Redis commands are restricted. Attempting to use them returns a NOPERM error.

When cluster mode is enabled

Command	Description
ACL	ACL-related commands
BGREWRITEAOF	AOF rewrite
BGSAVE	Background save
CLIENT PAUSE	Pause clients
CLUSTER ADDSLOTS	Add slots
CLUSTER BUMPEPOCH	Bump epoch
CLUSTER DELSLOTS	Remove slots
CLUSTER FAILOVER	Failover command
CLUSTER FLUSHSLOTS	Flush slots
CLUSTER FORGET	Remove node link
CLUSTER MEET	Connect cluster nodes
CLUSTER REPLICATE	Replicate node
CLUSTER RESET	Reset cluster
CLUSTER SAVECONFIG	Save config
CLUSTER SET-CONFIG-EPOCH	Set config epoch
CLUSTER SETSLOT	Set slot options
CONFIG	Configuration commands
DEBUG	Debugging commands
FAILOVER	Failover command
MIGRATE	Data migration
MODULE	Module-related commands
PSYNC	Replication status check
REPLCONF	Replication config
REPLICAOF	Set replica
RESTORE-ASKING	Restore data
SAVE	Save data
SHUTDOWN	Shutdown Redis
SLAVEOF	Set master
SORT	Sort command
SYNC	Sync command

When cluster mode is disabled

Command	Description
ACL	ACL-related commands
BGREWRITEAOF	AOF rewrite
BGSAVE	Background save
CLIENT PAUSE	Pause clients
CLUSTER	Cluster-related commands
CONFIG	Configuration commands
DEBUG	Debugging commands
FAILOVER	Failover command
MIGRATE	Data migration
MODULE	Module-related commands
PSYNC	Replication status check
REPLCONF	Replication config
REPLICAOF	Set replica
RESTORE-ASKING	Restore data
SAVE	Save data
SHUTDOWN	Shutdown Redis
SLAVEOF	Set master
SORT	Sort command
SYNC	Sync command

View security group

In the Security tab of the cluster details, you can view applied security groups and policies.
To access a cluster, port 6379 (or the port you specified) must be allowed in the security group.
Click a group name to manage it in VPC > Security Groups.

Modify security group

You can update the security groups attached to a cluster. At least one group must be attached.

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

2. From the Cluster tab, click the [⋮] menu for the cluster and select Modify security group.

3. In the popup, select the groups to attach.

   Item	Description
   Selected cluster name	Name of the cluster being modified
   Select security groups	Choose groups to apply. Selected groups appear as chips below
   Applied rules	View inbound/outbound rules for each group

4. Click Apply.

Access MemStore cluster

To access the cluster from an instance in MemStore, use a Redis Client after completing cluster setup.

Prerequisites

To connect, prepare an environment where the instance and cluster share the same network (VPC) and ensure TCP port 6379 (default) is allowed in the instance's outbound rules.

Connect to cluster

1. Refer to Virtual Machine > Create and connect to instance to access your VM. Install Redis Client if it's not already available.

2. Go to the KakaoCloud Console > MemStore.

3. Select the cluster.

4. In the Details tab, find the Endpoint. Copy it for use in the next step.

5. Connect to the cluster using the Redis Client with the following command:

   Connect to Redis instance

   redis-cli -h {ENDPOINT} -p {PORT}

   Parameter	Description
   {ENDPOINT}	The endpoint from the Details tab
   {PORT}	Port for Redis connection, default is 6379 or your custom port

Change parameter group

You can change the parameter group attached to a cluster.
Select a group that matches the engine version and cluster mode of the cluster. Be aware that changes in parameter values may impact service operations. If a parameter group change is already in progress, a new request may fail.
See Manage parameter groups for guidance.

1. Go to the KakaoCloud Console > Data Store > MemStore.
2. From the Cluster tab, click the [⋮] menu for the cluster and select Change parameter group.
3. In the popup, choose the new parameter group and click Confirm.