Manage cluster

A cluster is an object composed of multiple nodes, allowing users to perform management operations such as viewing, monitoring, and deleting. Below is how to manage a cluster.

caution

It is recommended to monitor and manage the system periodically to ensure that memory usage does not exceed 50% of the system's available memory.
The KakaoCloud MemStore service currently sets the maxmemory configuration to approximately 65% of the system's available memory. When maximum memory is reached, the allkeys-lru policy will delete the least recently used keys.

View cluster list

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

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

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

   Item	Description
   Cluster name	Name assigned by the user during cluster creation - Click the cluster name to view detailed information about the cluster
   Status	Current status of the cluster - For more details on status values, refer to Cluster lifecycle and status values
   Engine version	Redis OSS engine version running on the node
   Node type	Node type selected by the user during cluster creation - Hover over the node type value to view vCPU and Memory information for that type - For types of node types, refer to Node type
   Cluster mode	Indicates whether cluster mode is enabled
   High availability	Indicates whether automatic failover is enabled for node failures
   Automated backups retention period	Current automated backup retention period set for the cluster - Hover over the value to view the automated backup start time
   Number of shards	Number of shards within the cluster - If cluster mode is not enabled, the number of shards is displayed as a hyphen (-).
   Number of nodes	Number of nodes created within the cluster
   Uptime	Uptime of the cluster since the creation start time - Hover over the value to view the cluster creation date
   Creator	User who initially requested the cluster creation

View cluster information

You can view the information of the clusters created within a project.

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

2. Select the cluster to view detailed information from the Cluster menu.

3. Check the information from the tabs.

   Details tab

   Item	Information	Description
   Top information	Operational status	Current operational status of the cluster
   	Cluster mode	Indicates whether cluster mode is enabled
   	High availability	Indicates whether automatic failover is enabled for node failures
   	Endpoint - Primary endpoint	Read/Write-enabled endpoint
   	Endpoint - Read endpoint	Read-only endpoint - Read endpoints are not provided when cluster mode is enabled
   Details - Cluster	Cluster name	Name assigned by the user during cluster creation
   	Creator	User who initially requested the cluster creation
   	Cluster mode	Indicates whether cluster mode is enabled
   	High availability	Indicates whether automatic failover is enabled for node failures
   	Node type	Node type selected by the user during cluster creation. Refer to Node type for details.
   	vCPU per node	Number of Virtual CPUs allocated to the node type selected by the user during cluster creation
   	Memory per node	Memory size allocated to the node type selected by the user during cluster creation
   	Number of shards	Number of shards configured in the cluster
   	Number of nodes	Number of nodes created within the cluster - You can view the list and status of shards and nodes in the cluster in the Shard/Node List tab
   	Creation date and time	Time when the cluster creation was requested
   	Cluster ID	Object ID of the cluster
   Network	VPC	User VPC selected by the user during cluster creation
   	Availability zone	Availability zone distribution type of the cluster - Multi: The cluster is configured across 2 or more AZs - Single: The cluster is configured in 1 AZ
   	Primary endpoint	Read/Write-enabled endpoint
   	Read endpoint	Read-only endpoint - Read endpoints are not provided when cluster mode is enabled
   	Port	Connection port for the node, default is 6379
   Backup	Number of backups	Number of all created backups
   	Backup retention period	Automated backups retention period, selectable from a minimum of 1 day to a maximum of 35 days
   	Automated backups start time	Automated backups start time, backups start within 15 minutes of the selected time
   Redis compatibility settings	Engine version	Redis engine version running on the node
   	License	License information for the Redis OSS engine
   	User authentication	Indicates whether user authentication was enabled during cluster creation
   	ID	Administrator ID entered when user authentication is enabled - If user authentication is not enabled, the ID is not displayed
   	Parameter group	Displays the applied parameter group and the status of parameter application. For more details, refer to Parameter application status

   Shard/Node list tab

   Refer to How-to Guides > Manage shard and node

   Security tab

   Refer to How-to Guides > Create cluster > View security group

   Monitoring tab

   Refer to How-to Guides > Create cluster > Cluster monitoring

Cluster monitoring

The Monitoring tab allows you to check the status of nodes in detail within the cluster, enabling flexible and efficient node management while minimizing the resources required for management.

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

2. Select the cluster to be monitored in the Cluster menu.

3. Click the Monitoring tab and check the information.

   Monitoring tab

   Category	Description
   ① Monitoring node	Select the node to be monitored
   ② Data period	Period of data to be displayed in the monitoring graph - 1 hour (default) / 3 hours / 12 hours / 1 day / 7 days
   ③ View items	Select items to view for monitoring - MemStore / CPU / Memory / Network - All items are selected by default - Multiple items can be selected
   ④ View mode	Set the monitoring graph view mode - 1 column, 2 columns, 3 columns provided
   ⑤ Auto-refresh interval	Set the auto-refresh interval - No auto-refresh (default) / 10 seconds / 30 seconds / 1 minute / 5 minutes
   ⑥ Manual refresh	Click to manually refresh the monitoring results

   
   

   Provided monitoring data

   Category	Monitoring data	Description
   MemStore	Command calls (Count/sec)	Number of command calls per second over time
   MemStore	Connections (Count)	Number of connections over time - Max connections: Maximum number of clients that can be connected - Active connections: Number of currently connected clients
   MemStore	Cache hit ratio (%)	Redis hit ratio over time
   MemStore	Expired and evicted keys (Count)	Number of expired and 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 by interface (Bytes/sec)	Network RX usage per second over time
   Network	TX by interface (Bytes/sec)	Network TX usage per second over time
   Network	RX by interface (PPS)	Network RX packet usage per second over time
   Network	TX by interface (PPS)	Network TX packet usage per second

Configure High availability

The MemStore service provides high availability features to ensure convenience and stable operation for users.
When high availability is enabled, the service automatically takes action in the event of a node failure. High availability can be enabled without a separate service interruption. However, the cluster must be in Running status and have at least 1 Replica node to enable high availability.

info

When cluster mode is enabled, the cluster uses high availability by default, and settings cannot be changed.

1. Go to KakaoCloud Console > Data Store > MemStore menu.
2. In the Cluster menu, select the [More] icon for the cluster to enable high availability, and select Configure HA.
3. Configure the high availability settings and click the [Save] button.
4. Check the high availability status on the cluster's detail page to confirm that it has been updated correctly.

Delete cluster

You can delete clusters that are no longer needed.

caution

Resources of the deleted cluster will be completely returned after termination and cannot be restored, so proceed with caution.

1. Go to KakaoCloud Console > Data Store > MemStore menu.
2. In the Cluster menu, select the [More] icon for the cluster group to be deleted, and select Delete cluster.
3. In the popup, enter the name of the cluster to be deleted and click the [Delete] button.

MemStore user account

The MemStore service provides a user authentication option for users. When user authentication is enabled, users can access resources using the ID and password they set. If not enabled, access to resources is allowed using the default account without a password.

caution

User authentication is not supported for Redis OSS engine versions 5 or lower.

Command restrictions

For smooth service operation and management, the following commands are restricted. If you attempt to use them, a NOPERM error will be returned.

caution

Using keys, flushall, or flushdb commands when the instance has a large number of keys stored may cause the instance to crash.

With Cluster Mode Enabled

Command	Description
ACL	ACL-related commands
BGREWRITEAOF	Rewrite AOF file
BGSAVE	Background save
CLIENT PAUSE	Pause client
CLUSTER ADDSLOTS	Add slots
CLUSTER BUMPEPOCH	Increment cluster epoch
CLUSTER DELSLOTS	Remove slots
CLUSTER FAILOVER	Cluster failover
CLUSTER FLUSHSLOTS	Flush slots
CLUSTER FORGET	Disconnect nodes
CLUSTER MEET	Connect cluster nodes
CLUSTER REPLICATE	Replicate cluster node
CLUSTER RESET	Reset cluster
CLUSTER SAVECONFIG	Save cluster configuration
CLUSTER SET-CONFIG-EPOCH	Set cluster configuration epoch
CLUSTER SETSLOT	Change slot configuration
CONFIG	Configure Redis OSS
DEBUG	Debugging commands
FAILOVER	Failover commands
MIGRATE	Data migration
MODULE	Module-related commands
PSYNC	Check replication status
REPLCONF	Change replication settings
REPLICAOF	Set slave
RESTORE-ASKING	Request data restore
SAVE	Save data
SHUTDOWN	Shut down Redis
SLAVEOF	Set master
SORT	Sort commands
SYNC	Synchronization commands

Without Cluster Mode

Command	Description
ACL	ACL-related commands
BGREWRITEAOF	Rewrite AOF file
BGSAVE	Background save
CLIENT PAUSE	Pause client
CLUSTER	Cluster-related commands
CONFIG	Configure Redis OSS
DEBUG	Debugging commands
FAILOVER	Failover commands
MIGRATE	Data migration
MODULE	Module-related commands
PSYNC

View security group

In the Security tab of the detailed information, you can view the security group applied to the cluster and its policies.
To access the cluster, the security group must allow port 6379 or the user-specified port.
Click the connected security group name in the list to go to the VPC > Security Group details page for policy management.

Modify security group

You can modify the security group connected to the cluster. At least one security group must be connected.

1. Go to KakaoCloud Console > Data Store > MemStore.
2. In the Cluster menu, click the [More] icon for the instance to set the security group > Modify Security Group.
3. In the Modify Security Group popup, select the security group to apply to the cluster.

   Item	Description
   Selected cluster name	The name of the cluster to modify the security group
   Security group selection	Choose the security group to apply, displayed as chips at the bottom of the selection box
   Applied rules	View inbound and outbound rules for each security group

4. Click the Apply button.

info

Managing inbound and outbound rules can be done in VPC > Security Group.

Access MemStore cluster

The following describes how to access a cluster from an instance in the MemStore service.
After creating and configuring the cluster, use the Redis Client to connect the instances created with the cluster.

Prerequisites

To connect to the cluster, you need a Virtual Machine (VM) instance (node) using the same network as the cluster, and an accessible connection environment for the cluster's endpoint.
To achieve this, you need to allow TCP 6379 (default cluster port) in the outbound rules of the security group for the Virtual Machine (VM) instance.

Connect to the cluster

You can access the cluster from the instance.

1. Refer to Virtual Machine > Create and connect instance to access the instance and prepare the Redis Client. If Redis commands are not recognized, you will need to install a separate Redis Client.

2. Go to the MemStore menu in the KakaoCloud Console.

3. In the Cluster menu, select the cluster to connect to.

4. In the Details tab, check the Endpoint. This information is required for executing Redis commands, so please copy it to your clipboard or save it for reference.

5. To connect the cluster via Redis Client from the created instance, run the Redis connection command:

   Redis instance connection

   redis-cli -h {ENDPOINT} -p {PORT_NUMBER} {COMMAND}

   Item	Description
   {ENDPOINT}	Endpoint information obtained from the Details tab
   {PORT_NUMBER}	Port number for Redis connection, default is 6379 or the port number you specify.

info

For more details about the roles and types of instances, refer to Instances.

Change parameter group

You can change the parameter group associated with the cluster.
You can select the parameter group that matches the cluster's engine version and cluster mode, and changing the parameter group may affect the values of the parameters already set. Therefore, it is recommended to review the parameter values of the parameter group to be changed in advance, as changing the parameter group may impact the operational MemStore service. If a parameter group change is already in progress, the request may fail.
For more details, refer to the Create and Manage Parameter Groups guide.

1. Go to KakaoCloud Console > Data Store > MemStore menu.
2. In the Cluster menu, click the [More] icon for the cluster whose parameter group you want to change, and select Change parameter group.
3. In the Change parameter group popup, select the parameter group you want to change to and click [OK].