Managing Redis cluster hosts

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Updated at November 18, 2024

Getting a list of cluster hosts
Creating a host
Changing a host
Removing a host

You can add and remove cluster hosts and manage their settings. For information about moving cluster hosts to a different availability zone, see this guide.

Getting a list of cluster hosts

Management console

CLI

API

Go to the folder page and select Managed Service for Redis.
Click the name of the cluster you need and select the Hosts tab.

If you do not have the Yandex Cloud command line interface yet, install and initialize it.

The folder specified in the CLI profile is used by default. You can specify a different folder using the --folder-name or --folder-id parameter.

To get a list of cluster hosts, run the command:

yc managed-redis host list \
  --cluster-name=<cluster_name>

Result:

+---------------------------------+----------------------+------------+---------+--------+-------------------+
|              NAME               |      CLUSTER ID      | SHARD NAME |  ROLE   | HEALTH |      ZONE ID      |
+---------------------------------+----------------------+------------+---------+--------+-------------------+
| rc1a-...caf.mdb.yandexcloud.net | c9qb2q230gg1******** | shard1     | MASTER  | ALIVE  | ru-central1-a     |
| rc1b-...bgc.mdb.yandexcloud.net | c9qb2q230gg1******** | shard1     | REPLICA | ALIVE  | ru-central1-b     |
+---------------------------------+----------------------+------------+---------+--------+-------------------+

You can request the cluster name with the list of clusters in the folder.

To get a list of cluster hosts, use the listHosts REST API method for the Cluster resource or the ClusterService/ListHosts gRPC API call and provide the cluster ID in the clusterId request parameter.

To find out the cluster ID, get a list of clusters in the folder.

Creating a host

The number of hosts in Managed Service for Redis clusters is limited by the CPU and RAM quotas available to DB clusters in your cloud. To check the resources currently in use, open the Quotas page and find Managed Databases.

Note

Public access to hosts can only be configured for clusters created with enabled TLS support.

Management console

CLI

Terraform

API

To create a host:

Go to the folder page and select Managed Service for Redis.
Click the cluster name and go to the Hosts tab.
Click Create host.
Specify the host parameters:
- Availability zone.
- Subnet (if the required subnet is not on the list, create it).
- Priority for assigning the host as a master.
- If necessary, configure public access to the host.
- If you are adding a host to a sharded cluster, select a shard.

If you do not have the Yandex Cloud command line interface yet, install and initialize it.

The folder specified in the CLI profile is used by default. You can specify a different folder using the --folder-name or --folder-id parameter.

To create a host:

Request a list of cluster subnets to select one for the new host:

yc vpc subnet list

Result:

+----------------------+-----------+-----------------------+---------------+------------------+
|          ID          |   NAME    |       NETWORK ID      |     ZONE      |      RANGE       |
+----------------------+-----------+-----------------------+---------------+------------------+
| b0cl69a2b4c6******** | default-d | enp6rq72rndgr******** | ru-central1-d | [172.16.0.0/20]  |
| e2lkj9qwe762******** | default-b | enp6rq72rndgr******** | ru-central1-b | [10.10.0.0/16]   |
| e9b0ph42bn96******** | a-2       | enp6rq72rndgr******** | ru-central1-a | [172.16.32.0/20] |
| e9b9v22r88io******** | default-a | enp6rq72rndgr******** | ru-central1-a | [172.16.16.0/20] |
+----------------------+-----------+-----------------------+---------------+------------------+

If the required subnet is not in the list, create it.

View a description of the CLI command for adding a host:
```
yc managed-redis host add --help
```
Run the add host command:
```
yc managed-redis host add \
  --cluster-name=<cluster_name> \
  --host zone-id=<availability_zone>,`
    `subnet-id=<subnet_ID>,`
    `assign-public-ip=<public_access>,`
    `replica-priority=<host_priority>,`
    `shard-name=<shard_name>
```
Where:
- --cluster-name: Managed Service for Redis cluster name. You can retrieve it with a list of clusters in a folder.
- --host: Host parameters:
  - zone-id: Availability zone.
  - subnet-id: Subnet ID. Specify if two or more subnets are created in the selected availability zone.
  - assign-public-ip: Internet access to the host via a public IP address, true or false.
  - replica-priority: Priority for assigning the host as a master if the primary master fails. It is only available for non-sharded clusters.
  - shard-name: Name of the shard to create the host in if the cluster is sharded.

To create a host:

Open the current Terraform configuration file with an infrastructure plan.

For more information about creating this file, see Creating clusters.

Add a host section to the Managed Service for Redis cluster description:

resource "yandex_mdb_redis_cluster" "<cluster_name>" {
  ...
  host {
    zone             = "<availability_zone>"
    subnet_id        = "<subnet_ID>"
    assign_public_ip = <public_access>
    replica_priority = <host_priority>
    shard_name       = "<shard_name>"
  }
}

Where assign_public_ip is public access to the host, true or false.

Make sure the settings are correct.
1. Using the command line, navigate to the folder that contains the up-to-date Terraform configuration files with an infrastructure plan.
2. Run the command:
```
terraform validate
```
  If there are errors in the configuration files, Terraform will point to them.
Confirm updating the resources.
1. Run the command to view planned changes:
```
terraform plan
```
  If the resource configuration descriptions are correct, the terminal will display a list of the resources to modify and their parameters. This is a test step. No resources are updated.
2. If you are happy with the planned changes, apply them:
  1. Run the command:
```
terraform apply
```
  2. Confirm the update of resources.
  3. Wait for the operation to complete.

For more information, see the Terraform provider documentation.

Time limits

A Terraform provider sets the timeout for Managed Service for Redis cluster operations:

Creating a cluster, including by restoring one from a backup: 15 minutes.
Editing a cluster: 60 minutes.
Deleting a cluster: 15 minutes.

Operations exceeding the set timeout are interrupted.

How do I change these limits?

Add the timeouts block to the cluster description, for example:

resource "yandex_mdb_redis_cluster" "<cluster_name>" {
  ...
  timeouts {
    create = "1h30m" # 1 hour 30 minutes
    update = "2h"    # 2 hours
    delete = "30m"   # 30 minutes
  }
}

To add a host, use the addHosts REST API method for the Cluster resource or the ClusterService/AddHosts gRPC API call and provide the following in the request:

Cluster ID in the clusterId parameter. To find out the cluster ID, get a list of clusters in the folder.
New host settings in one or more hostSpecs parameters.

Warning

If you cannot connect to the host you added, check that the cluster security group is configured correctly for the host's subnet.

Changing a host

Note

Access to hosts from the Internet via public IP addresses is possible only if the cluster has been created with TLS support enabled.

Management console

CLI

Terraform

API

To change the parameters of the cluster host:

Go to the folder page and select Managed Service for Redis.
Click the cluster name and open the Hosts tab.
Click in the host's row and select Edit.
Set new settings for the host:
1. Enable Public access if the host must be accessible from outside Yandex Cloud.
2. Specify the priority for assigning the host as a master.
Click Save.

If you do not have the Yandex Cloud command line interface yet, install and initialize it.

The folder specified in the CLI profile is used by default. You can specify a different folder using the --folder-name or --folder-id parameter.

To change the parameters of the host, run the command:

yc managed-redis host update <host_name> \
  --cluster-name=<cluster_name> \
  --assign-public-ip=<public_access> \
  --replica-priority=<host_priority>

Where --assign-public-ip is public access to the host, true or false.

You can request the host name with a list of cluster hosts, and the cluster name, with a list of clusters in the folder.

To change the parameters of the cluster host:

Open the current Terraform configuration file with an infrastructure plan.

For more information about creating this file, see Creating clusters.

In the Managed Service for Redis cluster description, change the attributes of the host block corresponding to the host you are updating.

resource "yandex_mdb_redis_cluster" "<cluster_name>" {
  ...
  host {
    zone             = "<availability_zone>"
    subnet_id        = "<subnet_ID>"
    assign_public_ip = <public_access>
    replica_priority = <host_priority>
    shard_name       = "<shard_name>"
  }
}

Where assign_public_ip is public access to the host, true or false.

Make sure the settings are correct.
1. Using the command line, navigate to the folder that contains the up-to-date Terraform configuration files with an infrastructure plan.
2. Run the command:
```
terraform validate
```
  If there are errors in the configuration files, Terraform will point to them.
Confirm updating the resources.
1. Run the command to view planned changes:
```
terraform plan
```
  If the resource configuration descriptions are correct, the terminal will display a list of the resources to modify and their parameters. This is a test step. No resources are updated.
2. If you are happy with the planned changes, apply them:
  1. Run the command:
```
terraform apply
```
  2. Confirm the update of resources.
  3. Wait for the operation to complete.

For more information, see the Terraform provider documentation.

To update host parameters, use the updateHosts REST API method for the Cluster resource or the ClusterService/UpdateHosts gRPC API call and provide the following in the request:

The ID of the cluster to update the host in, in the clusterId parameter. To find out the cluster ID, get a list of clusters in the folder.
The name of the host you need to update in the updateHostSpecs.hostName parameter. To find out the name, get a list of hosts in the cluster.
The host's public access settings in the updateHostSpecs.assignPublicIp parameter.
Host priority in the updateHostSpecs.replicaPriority parameter.
List of cluster configuration fields to update in the updateMask parameter.

Warning

The API method will assign default values to all the parameters of the object you are modifying unless you explicitly provide them in your request. To avoid this, list the settings you want to change in the updateMask parameter as a single comma-separated string.

Warning

If you cannot connect to the host you added, check that the cluster security group is configured correctly for the host's subnet.

Removing a host

You can remove a host from a Redis cluster if it is not the only host in it. To replace a single host, first create a new host and then remove the old one.

If the host is the master at the time of deletion, Managed Service for Redis will automatically assign another replica as the master.

You cannot remove a host if the number of hosts in a cluster or cluster shard is equal to the minimum value. For more information, see Quotas and limits.

Management console

CLI

Terraform

API

To remove a host from a cluster:

Go to the folder page and select Managed Service for Redis.
Click the cluster name and open the Hosts tab.
In the appropriate cluster row, click and select Delete.
In the window that opens, enable Delete host and click Confirm.

If you do not have the Yandex Cloud command line interface yet, install and initialize it.

The folder specified in the CLI profile is used by default. You can specify a different folder using the --folder-name or --folder-id parameter.

To remove a host from the cluster, run:

yc managed-redis host delete <host_name> \
  --cluster-name=<cluster_name>

You can request the host name with a list of cluster hosts, and the cluster name, with a list of clusters in the folder.

To remove a host from a cluster:

Open the current Terraform configuration file with an infrastructure plan.

For more information about creating this file, see Creating clusters.
Delete the host block from the Managed Service for Redis cluster description.
Make sure the settings are correct.
1. Using the command line, navigate to the folder that contains the up-to-date Terraform configuration files with an infrastructure plan.
2. Run the command:
```
terraform validate
```
  If there are errors in the configuration files, Terraform will point to them.
Type yes and press Enter.
1. Run the command to view planned changes:
```
terraform plan
```
  If the resource configuration descriptions are correct, the terminal will display a list of the resources to modify and their parameters. This is a test step. No resources are updated.
2. If you are happy with the planned changes, apply them:
  1. Run the command:
```
terraform apply
```
  2. Confirm the update of resources.
  3. Wait for the operation to complete.

For more information, see the Terraform provider documentation.

Time limits

A Terraform provider sets the timeout for Managed Service for Redis cluster operations:

Creating a cluster, including by restoring one from a backup: 15 minutes.
Editing a cluster: 60 minutes.
Deleting a cluster: 15 minutes.

Operations exceeding the set timeout are interrupted.

How do I change these limits?

Add the timeouts block to the cluster description, for example:

resource "yandex_mdb_redis_cluster" "<cluster_name>" {
  ...
  timeouts {
    create = "1h30m" # 1 hour 30 minutes
    update = "2h"    # 2 hours
    delete = "30m"   # 30 minutes
  }
}

To delete a host, use the deleteHosts REST API method for the Cluster resource or the ClusterService/DeleteHosts gRPC API call and provide the following in the request:

Cluster ID in the clusterId parameter. To find out the cluster ID, get a list of clusters in the folder.
Name or array of names of hosts to delete in the hostNames parameter.

Managing Redis cluster hosts

Getting a list of cluster hostsGetting a list of cluster hosts

Creating a hostCreating a host

Changing a hostChanging a host

Removing a hostRemoving a host

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Getting a list of cluster hosts

Creating a host

Changing a host

Removing a host