Manage servers in a target group

Add a server to a target group

Control panel

1. In the Control panel, on the top menu, click Products and select Cloud Servers.
2. Go to the Load Balancers → Target Groups tab.
3. Open the target group page.
4. In the Servers block, click Add server.
5. Select a server.
6. Select an IP address.
7. The port value for the group will be selected automatically for the server — change it if necessary.
8. Specify the server weight; this is a proportional measure indicating the share of requests the server processes. If the weight values are equal, the servers handle an equal number of requests. For example, if a group has one server with a weight of “2” and two servers with a weight of “1”, the first server will receive 50% of all requests, and the other two will receive 25% each. The maximum weight value is 256.
9. If you need to make the server a backup server so that it accepts requests only when other servers in the group are unavailable, select the Backup checkbox.
10. Click .

OpenStack CLI

1. Open the OpenStack CLI.

2. Add a server to the target group:

   openstack loadbalancer member create \
     --subnet-id <subnet_uuid> \
     --address <server_ip_address> \
     --protocol-port <port> \
     --weight <weight> \
     --enable-backup \
     <pool>

   Specify:

   • <subnet_uuid> — ID of the server's private or public subnet. You can view the list using the openstack subnet list;
   • <server_ip_address> — private IP address of the server. You can copy it in the Control panel: in the top menu, click Products → Cloud Servers → server page → Ports tab → in the port card, click next to the IP address;
   • <port> — port number;
   • <weight> — server weight, a proportional measure that indicates the share of requests the server processes. If the weights are equal, the servers handle an equal number of requests. For example, if a group has one server with a weight of “2” and two servers with a weight of “1”, the first server will receive 50% of all requests, and the other two — 25% each. The maximum weight value is 256;
   • optional: --enable-backup — specify this parameter if you need to make the server a backup server, so that it only accepts requests when other servers in the group are unavailable;
   • <pool> — ID or name of the target group. You can view the list using the openstack loadbalancer pool list.

Make a server in the group a backup server

A cloud server in a target group can be made a backup server — it will be included in the group but will stop accepting requests while at least one other server in the group is available. If all servers in the group are unavailable, the backup server will be enabled.

Control panel

1. In the Control panel, on the top menu, click Products and select Cloud Servers.
2. Go to the Load Balancers → Target Groups tab.
3. Open the target group page.
4. In the Servers block, in the server row, enable the toggle in the Backup column.

OpenStack CLI

1. Open the OpenStack CLI.

2. Make the server a backup server:

   openstack loadbalancer member set --enable-backup <pool> <member>

   Specify:

   • <pool> — target group ID or name. You can view the list using the openstack loadbalancer pool list;
   • <member> — ID or name of the server. You can view the list using the openstack loadbalancer member list.

Suspend a server in a group

You can suspend a server during maintenance. For example, during an application update or restart, the server will temporarily stop processing requests for this target group. The server itself will continue to run.

There is no need to remove the server from the target group — it will resume processing traffic as soon as you resume its operation.

Control panel

1. In the Control panel, on the top menu, click Products and select Cloud Servers.
2. Go to the Load Balancers → Target Groups tab.
3. Open the target group page.
4. In the Servers block, in the server menu, select Do not accept requests.

OpenStack CLI

1. Open the OpenStack CLI.

2. Suspend the server:

   openstack loadbalancer member set --disable <pool> <member>

   Specify:

   • <pool> — target group ID or name. You can view the list using the openstack loadbalancer pool list;
   • <member> — ID or name of the server. You can view the list using the openstack loadbalancer member list.

Resume server operation in a group

Control panel

1. In the Control panel, on the top menu, click Products and select Cloud Servers.
2. Go to the Load Balancers → Target Groups tab.
3. Open the target group page.
4. In the Servers block, in the server menu, select Accept requests.

OpenStack CLI

1. Open the OpenStack CLI.

2. Resume the server:

   openstack loadbalancer member set --enable <pool> <member>

   Specify:

   • <pool> — target group ID or name. You can view the list using the openstack loadbalancer pool list;
   • <member> — ID or name of the server. You can view the list using the openstack loadbalancer member list.

Remove a server from a target group

If you remove a server from a target group, it will stop accepting requests. The server itself will not be deleted.

Control panel

1. In the Control panel, on the top menu, click Products and select Cloud Servers.
2. Go to the Load Balancers → Target Groups tab.
3. Open the target group page.
4. In the Servers block, in the server menu, select Remove server from group.

OpenStack CLI

1. Open the OpenStack CLI.

2. Remove the server from the target group:

   openstack loadbalancer member delete <pool> <member>

   Specify:

   • <pool> — target group ID or name. You can view the list using the openstack loadbalancer pool list;
   • <member> — ID or name of the server. You can view the list using the openstack loadbalancer member list.