» Service - Agent HTTP API

The /agent/service endpoints interact with services on the local agent in Consul. These should not be confused with services in the catalog.

» List Services

This endpoint returns all the services that are registered with the local agent. These services were either provided through configuration files or added dynamically using the HTTP API.

It is important to note that the services known by the agent may be different from those reported by the catalog. This is usually due to changes being made while there is no leader elected. The agent performs active anti-entropy, so in most situations everything will be in sync within a few seconds.

The table below shows this endpoint's support for blocking queries, consistency modes, agent caching, and required ACLs.

» Parameters

• filter (string: "") - Specifies the expression used to filter the queries results prior to returning the data.

» Sample Request

$ curl \
    http://127.0.0.1:8500/v1/agent/services

» Sample Response

{
  "redis": {
      "ID": "redis",
      "Service": "redis",
      "Tags": [],
      "Meta": {
          "redis_version": "4.0"
      },
      "Port": 8000,
      "Address": "",
      "EnableTagOverride": false,
      "Weights": {
          "Passing": 10,
          "Warning": 1
      }
  }
}

» Filtering

The filter is executed against each value in the service mapping with the following selectors and filter operations being supported:

» Get Service Configuration

This endpoint was added in Consul 1.3.0 and returns the full service definition for a single service instance registered on the local agent. It is used by Connect proxies to discover the embedded proxy configuration that was registered with the instance.

It is important to note that the services known by the agent may be different from those reported by the catalog. This is usually due to changes being made while there is no leader elected. The agent performs active anti-entropy, so in most situations everything will be in sync within a few seconds.

The table below shows this endpoint's support for blocking queries, consistency modes, agent caching, and required ACLs.

¹ Supports hash-based blocking only.

» Parameters

• service_id (string: <required>) - Specifies the ID of the service to fetch. This is specified as part of the URL.

» Sample Request

$ curl \
    http://127.0.0.1:8500/v1/agent/service/web-sidecar-proxy

» Sample Response

{
    "Kind": "connect-proxy",
    "ID": "web-sidecar-proxy",
    "Service": "web-sidecar-proxy",
    "Tags": null,
    "Meta": null,
    "Port": 18080,
    "Address": "",
    "Weights": {
        "Passing": 1,
        "Warning": 1
    },
    "EnableTagOverride": false,
    "ContentHash": "4ecd29c7bc647ca8",
    "Proxy": {
        "DestinationServiceName": "web",
        "DestinationServiceID": "web",
        "LocalServiceAddress": "127.0.0.1",
        "LocalServicePort": 8080,
        "Config": {
            "foo": "bar"
        },
        "Upstreams": [
            {
                "DestinationType": "service",
                "DestinationName": "db",
                "LocalBindPort": 9191
            }
        ]
    }
}

The response has the same structure as the service definition with one extra field ContentHash which contains the hash-based blocking query hash for the result. The same hash is also present in X-Consul-ContentHash.

» Get local service health

Retrieve an aggregated state of service(s) on the local agent by name.

This endpoints support JSON format and text/plain formats, JSON being the default. In order to get the text format, you can append ?format=text to the URL or use Mime Content negotiation by specifying a HTTP Header Accept starting with text/plain.

The table below shows this endpoint's support for blocking queries, consistency modes, agent caching, and required ACLs.

Those endpoints return the aggregated values of all healthchecks for the service instance(s) and will return the corresponding HTTP codes:

Those endpoints might be usefull for the following use-cases:

• a load-balancer wants to check IP connectivity with an agent and retrieve the aggregated status of given service
• create aliases for a given service (thus, the healthcheck of alias uses http://localhost:8500/v1/agent/service/id/aliased_service_id healthcheck)

» Note

If you know the ID of service you want to target, it is recommended to use /v1/agent/health/service/id/:service_id so you have the result for the service only. When requesting /v1/agent/health/service/name/:service_name, the caller will receive the worst state of all services having the given name.

» Sample Requests

Given 2 services with name web, with web2 critical and web1 passing:

» List worst statuses of all instances of web-demo services (HTTP 503)

» By Name, Text

curl http://localhost:8500/v1/agent/health/service/name/web?format=text
critical

» By Name, JSON

In JSON, the detail of passing/warning/critical services is present in output, in a array.

curl localhost:8500/v1/agent/health/service/name/web

{
    "critical": [
        {
            "ID": "web2",
            "Service": "web",
            "Tags": [
                "rails"
            ],
            "Address": "",
            "Meta": null,
            "Port": 80,
            "EnableTagOverride": false,
            "ProxyDestination": "",
            "Connect": {
                "Native": false,
                "Proxy": null
            },
            "CreateIndex": 0,
            "ModifyIndex": 0
        }
    ],
    "passing": [
        {
            "ID": "web1",
            "Service": "web",
            "Tags": [
                "rails"
            ],
            "Address": "",
            "Meta": null,
            "Port": 80,
            "EnableTagOverride": false,
            "ProxyDestination": "",
            "Connect": {
                "Native": false,
                "Proxy": null
            },
            "CreateIndex": 0,
            "ModifyIndex": 0
        }
    ]
}

» List status of web2 (HTTP 503)

» Failure By ID, Text

curl http://localhost:8500/v1/agent/health/service/id/web2?format=text
critical

» Failure By ID, JSON

In JSON, the output per ID is not an array, but only contains the value of service.

curl localhost:8500/v1/agent/health/service/id/web2

{
    "critical": {
        "ID": "web2",
        "Service": "web",
        "Tags": [
            "rails"
        ],
        "Address": "",
        "Meta": null,
        "Port": 80,
        "EnableTagOverride": false,
        "ProxyDestination": "",
        "Connect": {
            "Native": false,
            "Proxy": null
        },
        "CreateIndex": 0,
        "ModifyIndex": 0
    }
}

» List status of web2 (HTTP 200)

» Success By ID, Text

curl localhost:8500/v1/agent/health/service/id/web1?format=text
passing

» Success By ID, JSON

curl localhost:8500/v1/agent/health/service/id/web1

{
    "passing": {
        "ID": "web1",
        "Service": "web",
        "Tags": [
            "rails"
        ],
        "Address": "",
        "Meta": null,
        "Port": 80,
        "EnableTagOverride": false,
        "ProxyDestination": "",
        "Connect": {
            "Native": false,
            "Proxy": null
        },
        "CreateIndex": 0,
        "ModifyIndex": 0
    }
}

» Get local service health by its ID

Retrive an aggregated state of service(s) on the local agent by ID.

See:

Parameters and response format are the same as /v1/agent/health/service/name/:service_name.

» Register Service

This endpoint adds a new service, with an optional health check, to the local agent.

The agent is responsible for managing the status of its local services, and for sending updates about its local services to the servers to keep the global catalog in sync.

For "connect-proxy" kind services, the service:write ACL for the Proxy.DestinationServiceName value is also required to register the service.

The table below shows this endpoint's support for blocking queries, consistency modes, agent caching, and required ACLs.

» Parameters

Note that this endpoint, unlike most also supports snake_case service definition keys for compatibility with the config file format.

• Name (string: <required>) - Specifies the logical name of the service. Many service instances may share the same logical service name.

• ID (string: "") - Specifies a unique ID for this service. This must be unique per agent. This defaults to the Name parameter if not provided.

• Tags (array<string>: nil) - Specifies a list of tags to assign to the service. These tags can be used for later filtering and are exposed via the APIs.

• Address (string: "") - Specifies the address of the service. If not provided, the agent's address is used as the address for the service during DNS queries.

• Meta (map<string|string>: nil) - Specifies arbitrary KV metadata linked to the service instance.

• Port (int: 0) - Specifies the port of the service.

• Kind (string: "") - The kind of service. Defaults to "" which is a typical Consul service. This value may also be "connect-proxy" for services that are Connect-capable proxies representing another service.

• ProxyDestination (string: "") - Deprecated From 1.2.0 to 1.2.3 this was used for "connect-proxy" Kind services however the equivalent field is now in Proxy.DestinationServiceName. Registrations using this field will continue to work until some later major version where this will be removed entirely. It's strongly recommended to switch to using the new field.

• Proxy (Proxy: nil) - From 1.2.3 on, specifies the configuration for a Connect proxy instance. This is only valid if Kind == "connect-proxy". See the Proxy documentation for full details.

• Connect (Connect: nil) - Specifies the configuration for Connect. See the Connect Structure section below for supported fields.

• Check (Check: nil) - Specifies a check. Please see the check documentation for more information about the accepted fields. If you don't provide a name or id for the check then they will be generated. To provide a custom id and/or name set the CheckID and/or Name field.

• Checks (array<Check>: nil) - Specifies a list of checks. Please see the check documentation for more information about the accepted fields. If you don't provide a name or id for the check then they will be generated. To provide a custom id and/or name set the CheckID and/or Name field. The automatically generated Name and CheckID depend on the position of the check within the array, so even though the behavior is deterministic, it is recommended for all checks to either let consul set the CheckID by leaving the field empty/omitting it or to provide a unique value.

• EnableTagOverride (bool: false) - Specifies to disable the anti-entropy feature for this service's tags. If EnableTagOverride is set to true then external agents can update this service in the catalog and modify the tags. Subsequent local sync operations by this agent will ignore the updated tags. For instance, if an external agent modified both the tags and the port for this service and EnableTagOverride was set to true then after the next sync cycle the service's port would revert to the original value but the tags would maintain the updated value. As a counter example, if an external agent modified both the tags and port for this service and EnableTagOverride was set to false then after the next sync cycle the service's port and the tags would revert to the original value and all modifications would be lost.

• Weights (Weights: nil) - Specifies weights for the service. Please see the service documentation for more information about weights. If this field is not provided weights will default to {"Passing": 1, "Warning": 1}.

  It is important to note that this applies only to the locally registered service. If you have multiple nodes all registering the same service their EnableTagOverride configuration and all other service configuration items are independent of one another. Updating the tags for the service registered on one node is independent of the same service (by name) registered on another node. If EnableTagOverride is not specified the default value is false. See anti-entropy syncs for more info.

» Connect Structure

For the Connect field, the parameters are:

• Native (bool: false) - Specifies whether this service supports the Connect protocol natively. If this is true, then Connect proxies, DNS queries, etc. will be able to service discover this service.
• Proxy (Proxy: nil) - Deprecated Specifies that a managed Connect proxy should be started for this service instance, and optionally provides configuration for the proxy. The format is as documented in Managed Proxy Deprecation.
• SidecarService (ServiceDefinition: nil) - Specifies an optional nested service definition to register. For more information see Sidecar Service Registration.

» Sample Payload

{
  "ID": "redis1",
  "Name": "redis",
  "Tags": [
    "primary",
    "v1"
  ],
  "Address": "127.0.0.1",
  "Port": 8000,
  "Meta": {
    "redis_version": "4.0"
  },
  "EnableTagOverride": false,
  "Check": {
    "DeregisterCriticalServiceAfter": "90m",
    "Args": ["/usr/local/bin/check_redis.py"],
    "HTTP": "http://localhost:5000/health",
    "Interval": "10s",
    "TTL": "15s"
  },
  "Weights": {
    "Passing": 10,
    "Warning": 1
  }
}

» Sample Request

$ curl \
    --request PUT \
    --data @payload.json \
    http://127.0.0.1:8500/v1/agent/service/register

» Deregister Service

This endpoint removes a service from the local agent. If the service does not exist, no action is taken.

The agent will take care of deregistering the service with the catalog. If there is an associated check, that is also deregistered.

The table below shows this endpoint's support for blocking queries, consistency modes, agent caching, and required ACLs.

» Parameters

• service_id (string: <required>) - Specifies the ID of the service to deregister. This is specified as part of the URL.

» Sample Request

$ curl \
    --request PUT \
    http://127.0.0.1:8500/v1/agent/service/deregister/my-service-id

» Enable Maintenance Mode

This endpoint places a given service into "maintenance mode". During maintenance mode, the service will be marked as unavailable and will not be present in DNS or API queries. This API call is idempotent. Maintenance mode is persistent and will be automatically restored on agent restart.

The table below shows this endpoint's support for blocking queries, consistency modes, agent caching, and required ACLs.

» Parameters

• service_id (string: <required>) - Specifies the ID of the service to put in maintenance mode. This is specified as part of the URL.

• enable (bool: <required>) - Specifies whether to enable or disable maintenance mode. This is specified as part of the URL as a query string parameter.

• reason (string: "") - Specifies a text string explaining the reason for placing the node into maintenance mode. This is simply to aid human operators. If no reason is provided, a default value will be used instead. This is specified as part of the URL as a query string parameter, and, as such, must be URI-encoded.

» Sample Request

$ curl \
    --request PUT \
    http://127.0.0.1:8500/v1/agent/service/maintenance/my-service-id?enable=true&reason=For+the+docs