Link a MySQL semi-sync cluster to a dedicated server

Last update: October 05 2026Open in Markdown

For your information

Some dedicated server configurations in the Chipcore Line cannot be added to the global router network because they lack a private network port. You can check for a private network port in the Control panel on the server page on the Ports tab.

1. Create a global router.
2. Connect the network and subnet to the global router up to the dedicated server VLAN.
3. Connect the network and subnet to the global router up to the Cloud Platform project.
4. Assign IP addresses from the created subnets to the dedicated server.
5. Configure routes on the dedicated server.
6. Create a Managed Databases cluster: a new one or from a backup of an existing Managed Databases cluster.

See the network layout example between a dedicated server and a managed database.

Example of networking between a Managed Database and a dedicated server

If you need to configure private connectivity between a dedicated server in the SPB-2 pool and a new Managed Database in the ru-2 pool:

1. Create a global router.
2. Connect two private subnets to the router: 192.168.0.0/29 with gateway 192.168.0.1 for the SPB-2 pool and 172.16.0.0/29 with gateway 172.16.0.1 for the ru-2 pool.
3. Assign an address from the 192.168.0.0/29 subnet to the dedicated server, for example, 192.168.0.2.
4. Configure routes on the dedicated server in the SPB-2 pool to the 172.16.0.0/29 subnet via the gateway 192.168.0.1.
5. Create a new Managed Databases cluster in the 172.16.0.0/29 subnet.

1. Create a global router

1. In the control panel, in the top menu, click Products and select Global Router.
2. Click Create router. Each account has a limit of five global routers.
3. Enter the router name.
4. Click Create.
5. If the router was created with the status ERROR or is stuck in one of the statuses, create a ticket.

2. Connect a network and subnet to a VLAN of a dedicated server to the global router

You can connect a new network to the router or an existing network if it is not already connected to any of the account's global routers.

1. In the Control panel, from the top menu, click Products and select Global Router.

2. Open the router page → Networks tab.

3. Click Create network.

4. Enter a network name. It will only be used in the control panel.

5. Select the Servers and hardware service.

6. Select the location of the network.

7. Select or enter a VLAN.

8. If you want to create a network to an internal segment (Q-in-Q), specify its tag — a number from 2 to 4094. If a network already exists for the VLAN, you must specify the Q-in-Q segment of this VLAN.

9. Enter a subnet name. It will only be used in the control panel.

10. Enter the CIDR — the IP address and mask of the private subnet. You can enter a new subnet or an existing private server subnet if it has not yet been added to any of the global routers in the account. The subnet must meet the following conditions:

    • belong to the RFC 1918 private address range: 10.0.0.0/8, 172.16.0.0/12, or 192.168.0.0/16;
    • have a size of at least /29, because three addresses will be occupied by Selectel network equipment;
    • do not overlap with other subnets added to this router — there must be no identical IP addresses within subnets on the same router;
    • if a Managed Kubernetes cluster on cloud servers is connected to the global router network, the subnet must not overlap with the ranges 10.10.0.0/16, 10.96.0.0/12, 10.250.0.0/16, and 10.251.0.0/24. If a cluster on dedicated servers is connected to the network — with the ranges 10.10.0.0/16, 10.222.0.0/16, 10.250.0.0/16, 10.251.0.0/24, and 172.250.0.0/14. These subnets are used in Managed Kubernetes internal addressing, and their use may lead to conflicts in the global router network.

11. Enter the gateway IP or leave the first address from the subnet, which is assigned by default. Do not assign this address to your devices to avoid network disruption.

12. Enter the service IPs or leave the last addresses from the subnet, which are assigned by default. Do not assign these addresses to your devices to avoid network disruption.

13. Click Create network.

14. Optional: check the network topology on the global router. In the Control panel, from the top menu, click Products → Global Router → router page → Network map.

15. If you specified a Q-in-Q tag in step 8, enable Q-in-Q on the switch port and configure the network interface of the private network specified in step 10. Learn more in the Configure Q-in-Q section of the Q-in-Q instructions.

3. Connect a network and subnet to a Cloud Platform project to the global router

You can connect a new or existing network to the router if it is not already connected to any of the account's global routers.

Connect a new network

1. In the control panel, in the top menu, click Products and select Global Router.

2. Open the router page → the Networks tab.

3. Click Create network.

4. Enter a network name. It will only be used in the control panel.

5. Select the Cloud Platform service.

6. Select the location of the network.

7. Select a project.

8. Enter a subnet name. It will only be used in the control panel.

9. Enter the CIDR — IP address and subnet mask. The subnet must meet the following conditions:

   • belong to the private address range according to RFC 1918: 10.0.0.0/8, 172.16.0.0/12, or 192.168.0.0/16;
   • have a size of at least /29, because three addresses will be occupied by Selectel network equipment;
   • it does not overlap with other subnets added to this router — there must be no identical IP addresses within the subnets of one router;
   • if a Managed Kubernetes cluster on cloud servers is to be added to the global router network, the subnet must not overlap with the ranges 10.10.0.0/16, 10.96.0.0/12, 10.250.0.0/16, and 10.251.0.0/24. If a cluster on dedicated servers is to be added to the network — with the ranges 10.10.0.0/16, 10.222.0.0/16, 10.250.0.0/16, 10.251.0.0/24, and 172.250.0.0/14. These subnets participate in Managed Kubernetes internal addressing, and using them may lead to conflicts in the global router network.

10. Enter the gateway IP or leave the first address from the subnet, which is assigned by default. Do not assign this address to your devices to avoid disrupting network operation.

11. Enter the service IPs or leave the last addresses from the subnet, which are assigned by default. Do not assign these addresses to your devices to avoid disrupting network operation.

12. Click Create network.

13. Optional: check the network topology on the global router. In the control panel, in the top menu, click Products → Global Router → router page → Network map.

Connect an existing network

1. Make sure the network has not yet been added to any of the account's global routers. In the control panel, in the top menu, click Products → Cloud Servers → Network → the Private networks tab → check that the network card does not have the tag Global router.

2. Verify that the subnet meets the following conditions:

   • belongs to the private address range according to RFC 1918: 10.0.0.0/8, 172.16.0.0/12, or 192.168.0.0/16;
   • has a size of at least /29, because three addresses will be occupied by Selectel network equipment;
   • it does not overlap with other subnets added to this router: the IP addresses of each subnet on the router must not match the IP addresses of other subnets on it;
   • if a Managed Kubernetes cluster on cloud servers is to be added to the global router network, the subnet must not overlap with the ranges 10.10.0.0/16, 10.96.0.0/12, 10.250.0.0/16, and 10.251.0.0/24. If a cluster on dedicated servers is to be added to the network — with the ranges 10.10.0.0/16, 10.222.0.0/16, 10.250.0.0/16, 10.251.0.0/24, and 172.250.0.0/14. These subnets participate in Managed Kubernetes internal addressing, and using them may lead to conflicts in the global router network.

3. In the control panel, in the top menu, click Products and select Cloud Servers.

4. Go to Network → the Private networks tab.

5. In the menu of the network, select Connect to global router.

6. Select a global router.

7. For each subnet in the network, enter the IP address to be assigned to the router or leave the first available address from the subnet, which is assigned by default. Do not assign this address to your devices to avoid disrupting network operation. The last two available subnet addresses will be reserved as service addresses.

8. Click Connect. Do not close the window until a message appears stating that the network has been connected. After this, in the control panel:

   • the network will appear in the section Selectel Global Router on the page of the router to which you connected it;
   • in the section Cloud Servers → Network → on the Private networks tab, the network will have the tag Global router.

4. Assign an IP address to a dedicated server

Configure a local port on the dedicated server connected to the global router network. Assign an IP address to the port from the private subnet that you connected to the global router in step 2.

Ubuntu

1. Connect to the server via SSH or via the KVM console.

2. Open the netplan utility configuration file with the vi text editor:

   vi /etc/netplan/01-netcfg.yaml

3. Add or change the values of the private network interface settings:

       <eth_name>:
               addresses: [<ip_address>]

   Specify:

   • <eth_name> – private network interface name;
   • <ip_address> – private IP address of the server with a subnet mask, for example, 192.168.0.2/24.

4. Press ESC.

5. Exit the vi text editor, saving the changes:

   :wq

6. Apply the configuration:

   netplan apply

7. Optional: reboot the server.

8. Optional: assign a private IP address to the server in the Control Panel.

Debian

1. Connect to the server via SSH or via the KVM console.

2. Open the network interfaces configuration file with the vi text editor:

   vi /etc/network/interfaces.d/50-cloud-init

3. Add or change the values of the private network interface settings:

   auto <eth_name>
   iface <eth_name> inet static
       address <ip_address>/<mask>

   Specify:

   • <eth_name> — private network interface name;
   • <ip_address> — private IP address of the server, for example, 192.168.0.2;
   • <mask> — subnet mask, for example, /24.

4. Press ESC.

5. Exit the vi text editor, saving the changes:

   :wq

6. Restart the network:

   service networking restart

7. Optional: reboot the server.

8. Optional: assign a private IP address to the server in the Control Panel.

CentOS

1. Connect to the server via SSH or via the KVM console.

2. Output information about the network interfaces:

   ip address

3. Create or open the private network interface configuration file with the vi text editor:

   vi /etc/sysconfig/network-scripts/ifcfg-<eth_name>

   Specify <eth_name> — the private network interface name.

4. Add or change the values of the network interface settings:

   NAME="<eth_name>"
   ONBOOT=yes
   BOOTPROTO=none
   IPADDR="<ip_address>"

   Specify:

   • <eth_name> — private network interface name;
   • <ip_address> — private IP address of the server with a subnet mask, for example, 192.168.0.2/24;

5. Press ESC.

6. Exit the vi text editor, saving the changes:

   :wq

7. Restart the network:

   systemctl restart network

8. Optional: reboot the server.

9. Optional: assign a private IP address to the server in the Control Panel.

An example of changing network settings in CentOS is described in the blog post Configuring the Network in CentOS 7.

Windows

1. Connect to the server via RDP or via the KVM console.

2. Open Network and Sharing Center.

3. Open the private network interface.

4. Click Properties.

5. Select IPv4 in the list.

6. Click Properties.

7. Specify the network interface parameters:

   • IP-address – private IP address of the server with a subnet mask, for example, 192.168.0.2;
   • Subnet mask — subnet mask.

8. Click OK.

9. Optional: assign a private IP address to the server in the Control Panel.

5. Specify a route on the dedicated server

On the server, configure a static route to the Cloud Platform subnet that you connected to the global router in step 3.

Ubuntu

1. Connect to the server.

2. Open the network configuration file:

   vi /etc/netplan/01-netcfg.yaml

3. At the end of the data block for the required network interface, add the route:

   routes:
     - to: <ip_address>/<mask>
       via: <gateway>

   Specify:

   • <ip_address>/<mask> — subnet to which the route is needed, specifying the mask, for example 192.168.0.0/28;
   • <gateway> — gateway for the subnet of the current server specified on the global router.

4. If you need to define multiple routes, add them sequentially in the same block, for example:

   routes:
   - to: 192.168.0.0/28
       via: 172.16.0.1
   - to: 192.168.1.0/28
       via: 172.16.0.1

5. Save the file.

6. Check the settings:

   sudo netplan try

7. Apply the changes:

   netplan apply

Debian

1. Connect to the server.

2. Open the network configuration file:

   vi  /etc/network/interfaces

3. At the end of the data block for the corresponding network interface, add the required route:

   up route add -net <ip_address> netmask <mask> gw <gateway>
   down route del -net <ip_address> netmask <mask> gw <gateway>

   Specify:

   • <ip_address> — subnet to which the route is needed, for example 192.168.0.0;
   • <mask> — mask of the subnet to which the route is needed, for example 255.255.255.0;
   • <gateway> — gateway for the subnet of the current server specified on the global router.

4. If you need to define multiple routes, add them sequentially in the same block.

5. Save the file.

6. Restart the network:

   sudo /etc/init.d/networking restart

CentOS

1. Connect to the server.

2. Create and fill out the file for configuring static routes:

   echo "<ip_address>/<mask> via <gateway>" >> /etc/sysconfig/network-scripts/route-<eth_name>

   Specify:

   • <ip_address>/<mask> — subnet to which the route is needed, specifying the mask, for example 192.168.1.0/28;
   • <gateway> — gateway for the subnet of the current server specified on the global router;
   • <eth_name> — name of the corresponding local network interface.

   If you need to add multiple routes, specify them in one command. List each route on a new line, for example:

   echo "192.168.0.0/28 via 172.16.0.1
   192.168.1.0/28 via 172.16.0.1" >> /etc/sysconfig/network-scripts/route-eno2

3. Restart the network:

   systemctl restart network

Windows

1. Connect to the server via RDP or via the KVM console.

2. Add the required routes one by one:

   route -p ADD <ip_address> MASK <mask> <gateway> METRIC <x>

   Specify:

   • <ip_address> — subnet to which the route is needed, for example 192.168.0.0;
   • <mask> — mask of the subnet to which the route is needed, for example 255.255.255.0;
   • <gateway> — gateway for the subnet of the current server specified on the global router;
   • <x> — parameter determining the priority of the specified gateway, 1 being the highest priority.

6. Create a Managed Database cluster

New

1. In the Control panel, in the top menu, click Products and select Managed Databases.

2. Click Create cluster.

3. Enter the cluster name.

4. Select a location. The location cannot be changed after creation.

5. Select a DBMS — MySQL semi-sync.

6. Select the MySQL semi-sync version. The version cannot be changed after creation.

7. Select a configuration line and specify the number of vCPUs, RAM size, and disk size.

   After creating a cluster, you can change the node configuration: scale the cluster.

8. Optional: to configure cluster fault tolerance, under Fault tolerance, specify the number of nodes in the cluster. The first node is the master node, and the rest are replicas. For a multi-node cluster, the SLA applies: we guarantee 99.95% write availability and 99.99% read availability.

9. Select the subnet that you connected to the global router up to the Cloud Platform project.

   You can restrict the list of IP addresses allowed to access the database cluster.

10. Optional: to change the DBMS settings, click Edit. We recommend modifying setting values only when necessary: improper values can degrade cluster performance.

11. Check the cluster price.

12. Click Create cluster. The cluster will be ready for use when its status changes to ACTIVE.

From backup

1. In the Control panel, in the top menu, click Products and select Managed Databases.

2. Click Create cluster.

3. Select the location of the existing Managed Databases cluster.

4. Select the Restore cluster from backup checkbox.

5. Select an existing Managed Database cluster.

6. Choose how to restore the cluster — from the latest available backup or to a specific point in time within the last 7 days.

7. Click Continue.

8. Select a configuration line and specify the number of vCPUs, RAM size, and disk size.

   After creating a cluster, you can change the node configuration: scale the cluster.

9. Optional: to configure cluster fault tolerance, under Fault tolerance, specify the number of nodes in the cluster. The first node is the master node, and the rest are replicas. For a multi-node cluster, the SLA applies: we guarantee 99.95% write availability and 99.99% read availability.

10. Select the subnet that you connected to the global router up to the Cloud Platform project.

    You can restrict the list of IP addresses allowed to access the database cluster.

11. Optional: to change the DBMS settings, click Edit. We recommend modifying setting values only when necessary: improper values can degrade cluster performance.

12. Check the cluster price.

13. Click Create cluster.

14. After restoring the cluster, the node addresses will change — update them in your application.