Load balancer(ALB) on anbox-stream-agent does not work

[Yoshi Kadokawa]

We have an anbox cloud deployment on AWS environment, and using AWS load balancers for the following services.

- ALB for anbox-stream-gateway
- NLB for AMS
- NLB for coturn
- ALB for anbox-stream-agent

However, with the DNS name set to the location for anbox-stream-agent, streaming the anbox application will fail.
I have confirmed that

- The SSL certificate for the ALB of anbox-stream-agent is valid
- ALB of anbox-stream-agent is reachable from the anbox container
- ALB is configured with stickiness enabled (1 day)
- From the logs in anbox-stream-agent, I can confirm that signaling and supervisor websocket got connected

When I unset the location for anbox-stream-agent, the streaming will work.

$ juju config anbox-stream-agent --reset location

Here is the attribute of the loadbalancer:
{
    "Attributes": [
        {
            "Key": "access_logs.s3.enabled",
            "Value": "false"
        },
        {
            "Key": "access_logs.s3.bucket",
            "Value": ""
        },
        {
            "Key": "access_logs.s3.prefix",
            "Value": ""
        },
        {
            "Key": "idle_timeout.timeout_seconds",
            "Value": "300"
        },
        {
            "Key": "deletion_protection.enabled",
            "Value": "false"
        },
        {
            "Key": "routing.http2.enabled",
            "Value": "true"
        },
        {
            "Key": "routing.http.drop_invalid_header_fields.enabled",
            "Value": "false"
        },
        {
            "Key": "routing.http.xff_client_port.enabled",
            "Value": "false"
        },
        {
            "Key": "routing.http.preserve_host_header.enabled",
            "Value": "false"
        },
        {
            "Key": "routing.http.xff_header_processing.mode",
            "Value": "append"
        },
        {
            "Key": "load_balancing.cross_zone.enabled",
            "Value": "true"
        },
        {
            "Key": "routing.http.desync_mitigation_mode",
            "Value": "defensive"
        },
        {
            "Key": "waf.fail_open.enabled",
            "Value": "false"
        },
        {
            "Key": "routing.http.x_amzn_tls_version_and_cipher_suite.enabled",
            "Value": "false"
        }
    ]
}

And the attribute for the target group:
{
    "Attributes": [
        {
            "Key": "target_group_health.unhealthy_state_routing.minimum_healthy_targets.count",
            "Value": "1"
        },
        {
            "Key": "stickiness.enabled",
            "Value": "true"
        },
        {
            "Key": "target_group_health.unhealthy_state_routing.minimum_healthy_targets.percentage",
            "Value": "off"
        },
        {
            "Key": "deregistration_delay.timeout_seconds",
            "Value": "300"
        },
        {
            "Key": "target_group_health.dns_failover.minimum_healthy_targets.count",
            "Value": "1"
        },
        {
            "Key": "stickiness.app_cookie.cookie_name",
            "Value": ""
        },
        {
            "Key": "stickiness.type",
            "Value": "lb_cookie"
        },
        {
            "Key": "stickiness.lb_cookie.duration_seconds",
            "Value": "86400"
        },
        {
            "Key": "slow_start.duration_seconds",
            "Value": "0"
        },
        {
            "Key": "stickiness.app_cookie.duration_seconds",
            "Value": "86400"
        },
        {
            "Key": "target_group_health.dns_failover.minimum_healthy_targets.percentage",
            "Value": "off"
        },
        {
            "Key": "load_balancing.cross_zone.enabled",
            "Value": "use_load_balancer_configuration"
        },
        {
            "Key": "load_balancing.algorithm.type",
            "Value": "round_robin"
        }
    ]
}