Creating a backend group

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

The folder specified when creating the CLI profile is used by default. To change the default folder, use the yc config set folder-id <folder_ID> command. You can specify a different folder using the --folder-name or --folder-id parameter.

1. See the description of the CLI command for creating a backend group:

   yc alb backend-group create --help
   

2. Create a backend group by running this command:

   yc alb backend-group create <backend_group_name>
   

   Result:

   id: a5dg2cv4ngne********
   name: test-backend-group
   folder_id: aoerb349v3h4********
   created_at: "2021-02-11T20:46:21.688940670Z"
   

3. Add a backend and a health check to the group.

   Alert

   If all backends with health checks enabled in an availability zone fail those checks, traffic will no longer route to that zone, even if functional backends without health checks remain.

   We recommend configuring health checks for all backends.

   All backends within the group must be of the same type: HTTP, gRPC, or Stream.

   HTTP backend

   Run this command:

   yc alb backend-group add-http-backend \
     --backend-group-name <backend_group_name> \
     --name <name_of_backend_you_are_adding> \
     --weight <backend_weight> \
     --port <backend_port> \
     --target-group-id=<target_group_ID> \
     --panic-threshold 90 \
     --http-healthcheck port=80,healthy-threshold=10,unhealthy-threshold=15,expected-statuses=211,\
   timeout=10s,interval=2s,host=<host_address>,path=<path>
   

   Where:

   • --name: The name of the backend you want to add or update.
   • --panic-threshold: Panic mode threshold.
   • --http-healthcheck: Health check settings:
     • port: Port.
     • healthy-threshold: Healthy threshold.
     • unhealthy-threshold: Unhealthy threshold.
     • expected-statuses: HTTP status code deemed valid during a backend health check. You can add multiple values separated by a comma: expected-statuses=201,expected-statuses=205,expected-statuses=302. You can use HTTP codes in the range between 100 and 599. If this setting is not specified, the response code will be 200.
     • timeout: Maximum connection time.
     • interval: Interval.
     • host: Host address.
     • path: Path.

   Result:

   id: a5dqkr2mk3rr********
   name: <backend_group_name>
   folder_id: aoe197919j8e********
   http:
     backends:
     - name: <backend_name>
       backend_weight: "1"
       load_balancing_config:
         panic_threshold: "90"
       port: "80"
       target_groups:
         target_group_ids:
         - a5d2iap3nue9********
       healthchecks:
       - timeout: 10s
         interval: 2s
         healthy_threshold: "10"
         unhealthy_threshold: "15"
         healthcheck_port: "80"
         http:
           host: <host_address>
           path: <path>
   created_at: "2021-02-11T20:46:21.688940670Z"
   

   gRPC backend

   Run this command:

   yc alb backend-group add-grpc-backend \
     --backend-group-name <backend_group_name> \
     --name <name_of_backend_you_are_adding> \
     --weight <backend_weight> \
     --port <backend_port> \
     --target-group-id=<target_group_ID> \
     --panic-threshold 90 \
     --grpc-healthcheck port=80,healthy-threshold=10,unhealthy-threshold=15,\
   timeout=10s,interval=2s,service-name=<gRPC_service_name>
   

   Where:

   • --panic-threshold: Panic mode threshold.
   • --grpc-healthcheck: Resource health check settings:
     • port: Port.
     • healthy-threshold: Healthy threshold.
     • unhealthy-threshold: Unhealthy threshold.
     • timeout: Maximum connection time.
     • interval: Interval.
     • service-name: Name of the gRPC service you want to check. If no service is specified, the system will check the backend overall health.

   Result:

   id: a5dqkr2mk3rr********
   name: <backend_group_name>
   folder_id: aoe197919j8e********
   grpc:
     backends:
       - name: <backend_name>
         backend_weight: "12"
         load_balancing_config:
           panic_threshold: "90"
         port: "80"
         target_groups:
           target_group_ids:
             - a5d2iap3nue9********
         healthchecks:
           - timeout: 10s
             interval: 2s
             healthy_threshold: "10"
             unhealthy_threshold: "15"
             healthcheck_port: "80"
             grpc:
               service_name: <gRPC_service_name>
   created_at: "2023-06-17T13:04:08.567141292Z"
   

   Stream backend

   Run this command:

   yc alb backend-group add-stream-backend \
     --backend-group-name <backend_group_name> \
     --name <name_of_backend_you_are_adding> \
     --weight <backend_weight> \
     --port <backend_port> \
     --target-group-id=<target_group_ID> \
     --panic-threshold 90 \
     --enable-proxy-protocol \
     --keep-connections-on-host-health-failure \
     --stream-healthcheck port=80,healthy-threshold=10,unhealthy-threshold=15,\
   timeout=10s,interval=2s,send-text=<data_to_endpoint>,receive-text=<data_from_endpoint>
   

   Where:

   • --panic-threshold: Panic mode threshold.
   • --enable-proxy-protocol: With this option enabled, the load balancer will send its client connection metadata, e.g. its IP address, to the backend via HAProxy protocol. If you do not set specific values for this option, the load balancer will only send its IP address to the backend.
   • --keep-connections-on-host-health-failure: Keeps the connection alive even if the health check fails.
   • --stream-healthcheck: Health check settings:
     • port: Port.
     • healthy-threshold: Healthy threshold.
     • unhealthy-threshold: Unhealthy threshold.
     • timeout: Maximum connection time.
     • interval: Interval.
     • send-text: Data sent to the endpoint for a health check.
     • receive-text: Data the endpoint must return to pass the health check.

   Result:

   id: ds77tero4f5********
   name: <backend_group_name>
   folder_id: b1gu6g9ielh6********
   stream:
     backends:
     - name: <backend_name>
   backend_weight: "1"
       port: "80"
       target_groups:
         target_group_ids:
         - ds7eof3r2cte********
       healthchecks:
         - timeout: 10s
           interval: 2s
           healthy_threshold: "10"
           unhealthy_threshold: "15"
           healthcheck_port: "80"
           stream:
             send:
               text: <data_to_endpoint>
             receive:
               text: <data_from_endpoint>
       enable_proxy_protocol: true
   created_at: "2022-04-06T09:17:57.104324513Z"
   

With Terraform, you can quickly create a cloud infrastructure in Yandex Cloud and manage it using configuration files. These files store the infrastructure description written in HashiCorp Configuration Language (HCL). If you change the configuration files, Terraform automatically detects which part of your configuration is already deployed, and what should be added or removed.

Terraform is distributed under the Business Source License. The Yandex Cloud provider for Terraform is distributed under the MPL-2.0 license.

For more information about the provider resources, see the documentation on the Terraform website or mirror website.

If you do not have Terraform yet, install it and configure its Yandex Cloud provider.

1. In the Terraform configuration file, describe the resource you want to create:

   resource "yandex_alb_backend_group" "test-backend-group" {
     name                     = "<backend_group_name>"
     session_affinity {
       connection {
         source_ip = <IP_address_session_affinity_mode>
       }
     }
     stream_backend {
       name                   = "<backend_name>"
       weight                 = 1
       port                   = 80
       target_group_ids       = ["<target_group_ID>"]
       load_balancing_config {
         panic_threshold      = 90
       }
       enable_proxy_protocol  = true
       healthcheck {
         timeout              = "10s"
         interval             = "2s"
         healthy_threshold    = 10
         unhealthy_threshold  = 15
         stream_healthcheck {
           send               = "<data_to_endpoint>"
           receive            = "<data_from_endpoint>"
         }
       }
     }
   }
   

   Where:

   • yandex_alb_backend_group: Backend group settings:

     • name: Backend group name.

     • session_affinity: Session affinity settings. This is an optional parameter.

       Note

       Currently, session affinity only works for a single active backend in a group, containing at least one target group and using the MAGLEV_HASH load balancing mode.

       • connection: Session affinity by the source_ip IP address. It can be either true or false. You can also choose cookie or header session affinity modes, but you can only specify one mode. If the backend group is of the Stream type, i.e., it consists of the stream_backend resources, you can only use the connection mode for session affinity.

     • http_backend, grpc_backend, and stream_backend: Backend type. All backends within a group must be of the same type: HTTP, gRPC, or Stream.

   Backend parameters:

   • name: Backend name.

   • port: Backend port.

   • weight: Backend weight.

   • target_group_ids: Target group ID. To get a list of available target groups, run the yc alb target-group list CLI command.

   • load_balancing_config: Balancing parameters:

     • panic_threshold: Panic mode threshold.

   • enable_proxy_protocol: With this option enabled, the load balancer will send its client connection metadata, e.g. its IP address, to the backend via HAProxy protocol. If you do not set specific values for this option, the load balancer will only send its IP address to the backend. This option is only available for Stream type backends.

   • healthcheck: Health check settings:

     • timeout: Maximum connection time.
     • interval: Interval.
     • healthy_threshold: Healthy threshold.
     • unhealthy_threshold: Unhealthy threshold.
     • http_healthcheck: HTTP health check settings:
       • path: Path.
       • host: Host address.
     • grpc_healthcheck: gRPC health check settings:
       • service_name: Name of the gRPC service you want to check. If no service is specified, the system will check the backend overall health.
     • stream_healthcheck: Stream health check settings:
       • send: Data sent to the endpoint for a health check.
       • receive: Data the endpoint must return to pass the health check.

     Alert

     If all backends with health checks enabled in an availability zone fail those checks, traffic will no longer route to that zone, even if functional backends without health checks remain.

     We recommend configuring health checks for all backends.

   For more information about yandex_alb_backend_group properties, see the relevant Terraform article.

2. Create the resources:

   1. In the terminal, change to the folder where you edited the configuration file.

   2. Make sure the configuration file is correct using the command:

      terraform validate
      

      If the configuration is correct, the following message is returned:

      Success! The configuration is valid.
      

   3. Run the command:

      terraform plan
      

      The terminal will display a list of resources with parameters. No changes are made at this step. If the configuration contains errors, Terraform will point them out.

   4. Apply the configuration changes:

      terraform apply
      

   5. Confirm the changes: type yes in the terminal and press Enter.

   Terraform will create all the required resources. You can check new resources in the management console or using this CLI command:

   yc alb backend-group list
   

Use the create REST API method for the BackendGroup resource or the BackendGroupService/Create gRPC API call.