hardware-exporter metrics down if deployed on github runners

[ca-scribner]

The grafana-agent machine charm uses hardware-observer in its CI. We recently noticed that, after going from hardware-observer rev70 to rev84, our CI is failing because the hardware-exporter shows as down. We can see this by doing the following from inside the unit:

curl localhost:12345/agent/api/v1/metrics/targets

From that we can see target_group "hwo_1_default", which I think is the hardware-exporter since it is checking port 10200, is down:

{
    "status": "success",
    "data":
    [
        {
            "instance": "243a344db344241f404868d04272fc76",
            "target_group": "hwo_1_default",
            "endpoint": "http://localhost:10200/metrics",
            "state": "down",
            "labels":
            {
                "instance": "localhost:10200",
                "job": "hwo_1_default",
                "juju_application": "hwo",
                "juju_model": "test-juju-info-cos-agent-ylut",
                "juju_model_uuid": "671c70ef-a32d-449e-8a83-42f51a436e76",
                "juju_unit": "hwo/0"
            },
            "discovered_labels":
            {
                "__address__": "localhost:10200",
                "__metrics_path__": "/metrics",
                "__scheme__": "http",
                "__scrape_interval__": "1m",
                "__scrape_timeout__": "10s",
                "job": "hwo_1_default",
                "juju_application": "hwo",
                "juju_model": "test-juju-info-cos-agent-ylut",
                "juju_model_uuid": "671c70ef-a32d-449e-8a83-42f51a436e76",
                "juju_unit": "hwo/0"
            },
            "last_scrape": "2024-08-07T13:26:52.715197421Z",
            "scrape_duration_ms": 0,
            "scrape_error": "Get \"http://localhost:10200/metrics\": dial tcp 127.0.0.1:10200: connect: connection refused"
        },
        {
            "instance": "243a344db344241f404868d04272fc76",
            "target_group": "hwo_2_default",
            "endpoint": "http://localhost:10201/metrics",
            "state": "up",
            "labels":
            {
                "instance": "localhost:10201",
                "job": "hwo_2_default",
                "juju_application": "hwo",
                "juju_model": "test-juju-info-cos-agent-ylut",
                "juju_model_uuid": "671c70ef-a32d-449e-8a83-42f51a436e76",
                "juju_unit": "hwo/0"
            },
            "discovered_labels":
            {
                "__address__": "localhost:10201",
                "__metrics_path__": "/metrics",
                "__scheme__": "http",
                "__scrape_interval__": "1m",
                "__scrape_timeout__": "10s",
                "job": "hwo_2_default",
                "juju_application": "hwo",
                "juju_model": "test-juju-info-cos-agent-ylut",
                "juju_model_uuid": "671c70ef-a32d-449e-8a83-42f51a436e76",
                "juju_unit": "hwo/0"
            },
            "last_scrape": "2024-08-07T13:27:05.885981966Z",
            "scrape_duration_ms": 1,
            "scrape_error": ""
        },
        {
            "instance": "243a344db344241f404868d04272fc76",
            "target_group": "integrations/agent",
            "endpoint": "http://127.0.0.1:12345/integrations/agent/metrics",
            "state": "up",
            "labels":
            {
                "agent_hostname": "juju-436e76-0",
                "instance": "juju-436e76-0.lxd",
                "job": "juju_test-juju-info-cos-agent-ylut_671c70ef-a32d-449e-8a83-42f51a436e76_agent_self-monitoring",
                "juju_application": "agent",
                "juju_charm": "grafana-agent",
                "juju_model": "test-juju-info-cos-agent-ylut",
                "juju_model_uuid": "671c70ef-a32d-449e-8a83-42f51a436e76",
                "juju_unit": "agent/0"
            },
            "discovered_labels":
            {
                "__address__": "127.0.0.1:12345",
                "__metrics_path__": "/integrations/agent/metrics",
                "__scheme__": "http",
                "__scrape_interval__": "1m",
                "__scrape_timeout__": "10s",
                "agent_hostname": "juju-436e76-0",
                "job": "integrations/agent"
            },
            "last_scrape": "2024-08-07T13:27:38.0595359Z",
            "scrape_duration_ms": 3,
            "scrape_error": ""
        },
        {
            "instance": "243a344db344241f404868d04272fc76",
            "target_group": "integrations/node_exporter",
            "endpoint": "http://127.0.0.1:12345/integrations/node_exporter/metrics",
            "state": "up",
            "labels":
            {
                "agent_hostname": "juju-436e76-0",
                "instance": "juju-436e76-0.lxd",
                "job": "juju_test-juju-info-cos-agent-ylut_671c70ef-a32d-449e-8a83-42f51a436e76_agent_node-exporter",
                "juju_application": "agent",
                "juju_charm": "grafana-agent",
                "juju_model": "test-juju-info-cos-agent-ylut",
                "juju_model_uuid": "671c70ef-a32d-449e-8a83-42f51a436e76",
                "juju_unit": "agent/0"
            },
            "discovered_labels":
            {
                "__address__": "127.0.0.1:12345",
                "__metrics_path__": "/integrations/node_exporter/metrics",
                "__scheme__": "http",
                "__scrape_interval__": "1m",
                "__scrape_timeout__": "10s",
                "agent_hostname": "juju-436e76-0",
                "job": "integrations/node_exporter"
            },
            "last_scrape": "2024-08-07T13:27:16.881244688Z",
            "scrape_duration_ms": 64,
            "scrape_error": ""
        }
    ]
}

Not sure if this is expected behaviour or not, but it seems to have started happening after hardware-observer added the smartctl exporter.