gcloud-help/gcloud/beta/compute/backend-services/update-backend

NAME
    gcloud beta compute backend-services update-backend - update an existing
        backend in a backend service

SYNOPSIS
    gcloud beta compute backend-services update-backend BACKEND_SERVICE_NAME
        ([--instance-group=INSTANCE_GROUP
          : --instance-group-region=INSTANCE_GROUP_REGION
          | --instance-group-zone=INSTANCE_GROUP_ZONE]
          | [--network-endpoint-group=NETWORK_ENDPOINT_GROUP
          : --network-endpoint-group-zone=NETWORK_ENDPOINT_GROUP_ZONE])
        [--balancing-mode=BALANCING_MODE] [--capacity-scaler=CAPACITY_SCALER]
        [--description=DESCRIPTION] [--failover]
        [--max-utilization=MAX_UTILIZATION] [--preference=PREFERENCE]
        [--global | --region=REGION]
        [--max-connections=MAX_CONNECTIONS
          | --max-connections-per-endpoint=MAX_CONNECTIONS_PER_ENDPOINT
          | --max-connections-per-instance=MAX_CONNECTIONS_PER_INSTANCE
          | --max-rate=MAX_RATE | --max-rate-per-endpoint=MAX_RATE_PER_ENDPOINT
          | --max-rate-per-instance=MAX_RATE_PER_INSTANCE]
        [GCLOUD_WIDE_FLAG ...]

DESCRIPTION
    (BETA) gcloud beta compute backend-services update-backend updates a
    backend that is part of a backend service. This is useful for changing the
    way a backend behaves. Example changes that can be made include changing
    the load balancing policy and draining a backend by setting its capacity
    scaler to zero.

    Backends are instance groups or network endpoint groups. One of the
    --network-endpoint-group or --instance-group flags is required to identify
    the backend that you are modifying. You cannot change the instance group or
    network endpoint group associated with a backend, but you can remove a
    backend and add a new one with backend-services remove-backend and
    backend-services add-backend.

    The gcloud compute backend-services edit command can also update a backend
    if the use of a text editor is desired.

    For more information about the available settings, see
    https://cloud.google.com/load-balancing/docs/backend-service.

POSITIONAL ARGUMENTS
     BACKEND_SERVICE_NAME
        Name of the backend service to operate on.

REQUIRED FLAGS
     Exactly one of these must be specified:

       Instance Group

         --instance-group=INSTANCE_GROUP
            Name of the instance group to update in the backend service. For
            details on valid instance names, refer to the criteria documented
            under the field 'name' at:
            https://cloud.google.com/compute/docs/reference/rest/v1/instances

            This flag argument must be specified if any of the other arguments
            in this group are specified.

         At most one of these can be specified:

           --instance-group-region=INSTANCE_GROUP_REGION
              Region of the instance group to update in the backend service. If
              not specified, you might be prompted to select a region
              (interactive mode only).

              To avoid prompting when this flag is omitted, you can set the
              compute/region property:

                  $ gcloud config set compute/region REGION

              A list of regions can be fetched by running:

                  $ gcloud compute regions list

              To unset the property, run:

                  $ gcloud config unset compute/region

              Alternatively, the region can be stored in the environment
              variable CLOUDSDK_COMPUTE_REGION.

           --instance-group-zone=INSTANCE_GROUP_ZONE
              Zone of the instance group to update in the backend service. If
              not specified and the compute/zone property isn't set, you might
              be prompted to select a zone (interactive mode only).

              To avoid prompting when this flag is omitted, you can set the
              compute/zone property:

                  $ gcloud config set compute/zone ZONE

              A list of zones can be fetched by running:

                  $ gcloud compute zones list

              To unset the property, run:

                  $ gcloud config unset compute/zone

              Alternatively, the zone can be stored in the environment variable
              CLOUDSDK_COMPUTE_ZONE.

       Network Endpoint Group

         --network-endpoint-group=NETWORK_ENDPOINT_GROUP
            Name of the network endpoint group to update in the backend
            service.

            This flag argument must be specified if any of the other arguments
            in this group are specified.

         --network-endpoint-group-zone=NETWORK_ENDPOINT_GROUP_ZONE
            Zone of the network endpoint group to update in the backend
            service. If not specified and the compute/zone property isn't set,
            you might be prompted to select a zone (interactive mode only).

            To avoid prompting when this flag is omitted, you can set the
            compute/zone property:

                $ gcloud config set compute/zone ZONE

            A list of zones can be fetched by running:

                $ gcloud compute zones list

            To unset the property, run:

                $ gcloud config unset compute/zone

            Alternatively, the zone can be stored in the environment variable
            CLOUDSDK_COMPUTE_ZONE.

OPTIONAL FLAGS
     --balancing-mode=BALANCING_MODE
        Defines how to measure whether a backend can handle additional traffic
        or is fully loaded. For more information, see
        https://cloud.google.com/load-balancing/docs/backend-service#balancing-mode.
        BALANCING_MODE must be one of:

         CONNECTION
            Available if the backend service's load balancing scheme is either
            INTERNAL or EXTERNAL. Available if the backend service's protocol
            is one of SSL, TCP, or UDP.

            Spreads load based on how many concurrent connections the backend
            can handle.

            For backend services with --load-balancing-scheme EXTERNAL, you
            must specify exactly one of these additional parameters:
            --max-connections, --max-connections-per-instance, or
            --max-connections-per-endpoint.

            For backend services where --load-balancing-scheme is INTERNAL, you
            must omit all of these parameters.

         RATE
            Available if the backend service's load balancing scheme is
            INTERNAL_MANAGED, INTERNAL_SELF_MANAGED, or EXTERNAL. Available if
            the backend service's protocol is one of HTTP, HTTPS, or HTTP/2.

            Spreads load based on how many HTTP requests per second (RPS) the
            backend can handle.

            You must specify exactly one of these additional parameters:
            --max-rate, --max-rate-per-instance, or --max-rate-per-endpoint.

         UTILIZATION
            Available if the backend service's load balancing scheme is
            INTERNAL_MANAGED, INTERNAL_SELF_MANAGED, or EXTERNAL. Available
            only for managed or unmanaged instance group backends.

            Spreads load based on the backend utilization of instances in a
            backend instance group.

            The following additional parameters may be specified:
            --max-utilization, --max-rate, --max-rate-per-instance,
            --max-connections, --max-connections-per-instance. For valid
            combinations, see --max-utilization.

     --capacity-scaler=CAPACITY_SCALER
        Scales down the target capacity (max utilization, max rate, or max
        connections) without changing the target capacity. For usage guidelines
        and examples, see Capacity scaler
        (https://cloud.google.com/load-balancing/docs/backend-service#capacity_scaler).

     --description=DESCRIPTION
        An optional, textual description for the backend.

     --failover
        Designates whether this is a failover backend. More than one failover
        backend can be configured for a given BackendService. Not compatible
        with the --global flag

     --max-utilization=MAX_UTILIZATION
        Defines the maximum target for average utilization of the backend
        instance group. Supported values are 0.0 (0%) through 1.0 (100%). This
        is an optional parameter for the UTILIZATION balancing mode.

        You can use this parameter with other parameters for defining target
        capacity. For usage guidelines, see Balancing mode combinations
        (https://cloud.google.com/load-balancing/docs/backend-service#balancing-mode-combos).

     --preference=PREFERENCE
        Defines whether a backend should be fully utilized before sending
        traffic to backends with default preference. This parameter cannot be
        used with regional managed instance groups and when the endpoint type
        of an attached network endpoint group is INTERNET_IP_PORT,
        INTERNET_FQDN_PORT, or SERVERLESS. PREFERENCE must be one of:

         DEFAULT
            This is the default setting. If the designated preferred backends
            don't have enough capacity, backends in the default category are
            used. Traffic is distributed between default backends based on the
            load balancing algorithm you use.

         PREFERRED
            Backends with this preference setting are used up to their capacity
            limits first, while optimizing overall network latency.

     At most one of these can be specified:

       --global
          If set, the backend service is global.

       --region=REGION
          Region of the backend service to operate on. Overrides the default
          compute/region property value for this command invocation.

     At most one of these can be specified:

       --max-connections=MAX_CONNECTIONS
          Maximum concurrent connections that the backend can handle. Valid for
          network endpoint group and instance group backends (except for
          regional managed instance groups).

       --max-connections-per-endpoint=MAX_CONNECTIONS_PER_ENDPOINT
          Only valid for network endpoint group backends. Defines a maximum
          number of connections per endpoint if all endpoints are healthy. When
          one or more endpoints are unhealthy, an effective maximum average
          number of connections per healthy endpoint is calculated by
          multiplying MAX_CONNECTIONS_PER_ENDPOINT by the number of endpoints
          in the network endpoint group, and then dividing by the number of
          healthy endpoints.

       --max-connections-per-instance=MAX_CONNECTIONS_PER_INSTANCE
          Only valid for instance group backends. Defines a maximum number of
          concurrent connections per instance if all instances in the instance
          group are healthy. When one or more instances are unhealthy, an
          effective average maximum number of connections per healthy instance
          is calculated by multiplying MAX_CONNECTIONS_PER_INSTANCE by the
          number of instances in the instance group, and then dividing by the
          number of healthy instances.

       --max-rate=MAX_RATE
          Maximum number of HTTP requests per second (RPS) that the backend can
          handle. Valid for network endpoint group and instance group backends
          (except for regional managed instance groups). Must not be defined if
          the backend is a managed instance group using load balancing-based
          autoscaling.

       --max-rate-per-endpoint=MAX_RATE_PER_ENDPOINT
          Only valid for network endpoint group backends. Defines a maximum
          number of HTTP requests per second (RPS) per endpoint if all
          endpoints are healthy. When one or more endpoints are unhealthy, an
          effective maximum rate per healthy endpoint is calculated by
          multiplying MAX_RATE_PER_ENDPOINT by the number of endpoints in the
          network endpoint group, and then dividing by the number of healthy
          endpoints.

       --max-rate-per-instance=MAX_RATE_PER_INSTANCE
          Only valid for instance group backends. Defines a maximum number of
          HTTP requests per second (RPS) per instance if all instances in the
          instance group are healthy. When one or more instances are unhealthy,
          an effective maximum RPS per healthy instance is calculated by
          multiplying MAX_RATE_PER_INSTANCE by the number of instances in the
          instance group, and then dividing by the number of healthy instances.
          This parameter is compatible with managed instance group backends
          that use autoscaling based on load balancing.

GCLOUD WIDE FLAGS
    These flags are available to all commands: --access-token-file, --account,
    --billing-project, --configuration, --flags-file, --flatten, --format,
    --help, --impersonate-service-account, --log-http, --project, --quiet,
    --trace-token, --user-output-enabled, --verbosity.

    Run $ gcloud help for details.

NOTES
    This command is currently in beta and might change without notice. These
    variants are also available:

        $ gcloud compute backend-services update-backend

        $ gcloud alpha compute backend-services update-backend