FQDNs of MySQL® hosts

To connect to a host, you need its fully qualified domain name (FQDN). You can use the FQDN of a particular host in the cluster or a special FQDN always pointing to the current master host or the most recent replica.

Here is a host FQDN example:

rc1a-goh2a9tr********.mdb.yandexcloud.net

Getting a host FQDNGetting a host FQDN

There are several ways to get a MySQL® host's FQDN:

• Look up the FQDN in the management console:

  1. Navigate to the cluster page.
  2. Navigate to Hosts.
  3. Copy the Host FQDN column value.

• In the management console, copy the cluster connection command (it contains the host’s FQDN). To get this command, navigate to the cluster page and click Connect.

• Get the list of cluster hosts using the CLI or API.

Special FQDNsSpecial FQDNs

Managed Service for MySQL® provides the following special FQDNs:

• Current master FQDN.
• Most recent replica FQDN.

In multi-host clusters, special FQDNs may temporarily point to the old host, even if it has switched its role (e.g., from master to replica). If using a special FQDN which points to the current master, some write requests may fail if routed to the replica. This is because it takes time to update DNS records for special FQDNs. If your write request returns an error, repeat it later.

Current masterCurrent master

An FQDN in c-<cluster_ID>.rw.mdb.yandexcloud.net format always points to the current master host in the cluster. You can get the cluster ID with the list of clusters in the folder.

When connecting to this FQDN, you can perform read and write operations.

Most recent replicaMost recent replica

An FQDN in c-<cluster_ID>.ro.mdb.yandexcloud.net format points to the replica that is most up-to-date with the current master. You can get the cluster ID with the list of clusters in the folder.

Specifics:

• When connecting to this FQDN, you can only perform read operations.
• If there are no active replicas in the cluster, you cannot connect to this FQDN as the respective DNS CNAME record will point to a null object.

AliasesAliases

With aliases, you can access the master, most recent replica, or each specific host in your Managed Service for MySQL® cluster using a human-readable name instead of their internal FQDNs. Aliases are user-defined and can be used alongside regular and special FQDNs.

Cluster aliasCluster alias

A cluster alias always points to the current master host in a Managed Service for MySQL® cluster. It has the following format:

c-<short_name>-my-<folder_ID>.rw.mdb.yandexcloud.net

Where <short_name> is a name set by the user when creating the alias.

A cluster alias must be unique within the folder. You can assign only one alias per cluster.

With cluster aliases, you can switch workloads from one cluster to another, e.g., after restoring from a backup. To do this, simply reassign the alias to the new cluster, no application-side updates required.

Host aliasesHost aliases

An alias pointing to a specific cluster host has the following format:

h-<host_short_name>-my-<folder_ID>.mdb.yandexcloud.net

Where <host_short_name> is a name set by the user when creating the host alias.

Each host alias must be unique within the folder. You can assign only one alias per host.