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 HTTP response includes the X-Consul-Results-Filtered-By-ACLs: true header if the response array excludes results due to ACL policy configuration. Refer to the HTTP API documentation for more information.

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

Query Parameters

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

• ns (string: "") EnterpriseEnterprise - Return only the services in the specified namespace. You can also specify the namespace through other methods.

Sample Request

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

Sample Response

{
  "redis": {
    "ID": "redis",
    "Service": "redis",
    "Tags": [],
    "TaggedAddresses": {
      "lan": {
        "address": "127.0.0.1",
        "port": 8000
      },
      "wan": {
        "address": "198.51.100.53",
        "port": 80
      }
    },
    "Meta": {
      "redis_version": "4.0"
    },
    "Namespace": "default",
    "Port": 8000,
    "Address": "",
    "EnableTagOverride": false,
    "Datacenter": "dc1",
    "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.

Path Parameters

• service_id (string: <required>) - Specifies the ID of the service to fetch.

Query Parameters

• ns (string: "") EnterpriseEnterprise - Specifies the namespace of the service you lookup. You can also specify the namespace through other methods.

Sample Request

The following example request calls the web-sidecar-proxy service:

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

Sample Response

The response contains the fields specified in the service definition, but it includes an extra ContentHash field that contains the hash-based blocking query hash for the result. The same hash is also present in X-Consul-ContentHash.

{
  "Kind": "connect-proxy",
  "ID": "web-sidecar-proxy",
  "Service": "web-sidecar-proxy",
  "Tags": null,
  "Meta": null,
  "Namespace": "default",
  "Port": 18080,
  "Address": "",
  "TaggedAddresses": {
    "lan": {
      "address": "127.0.0.1",
      "port": 8000
    },
    "wan": {
      "address": "198.51.100.53",
      "port": 80
    }
  },
  "Weights": {
    "Passing": 1,
    "Warning": 1
  },
  "EnableTagOverride": false,
  "Datacenter": "dc1",
  "ContentHash": "4ecd29c7bc647ca8",
  "Proxy": {
    "DestinationServiceName": "web",
    "DestinationServiceID": "web",
    "LocalServiceAddress": "127.0.0.1",
    "LocalServicePort": 8080,
    "Mode": "transparent",
    "TransparentProxy": {
      "OutboundListenerPort": 22500
    },
    "Config": {
      "foo": "bar"
    },
    "Upstreams": [
      {
        "DestinationType": "service",
        "DestinationName": "db",
        "LocalBindPort": 9191
      }
    ]
  }
}

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 health checks for the service instance(s) and will return the corresponding HTTP codes:

Those endpoints might be useful 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 health check of alias uses http://localhost:8500/v1/agent/service/id/aliased_service_id health check)

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.

Path Parameters

• service_name (string: <required>) - Specifies the name of the service to retrieve.

Query Parameters

• ns (string: "") EnterpriseEnterprise - Specifies the namespace of the service you lookup. You can also specify the namespace through other methods.

Sample Requests

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

List the worst status across all instances of the web service (HTTP 503)

By Name, Text

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

By Name, JSON

For the JSON output, the response is an array containing the details of each passing, warning, or critical service.

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

[
  {
    "AggregatedStatus": "passing",
    "Service": {
      "ID": "web1",
      "Service": "web",
      "Tags": [
        "rails"
      ],
      "Meta": {},
      "Port": 80,
      "Address": "",
      "SocketPath": "",
      "TaggedAddresses": {
        "lan": {
          "Address": "127.0.0.1",
          "Port": 8000
        },
        "wan": {
          "Address": "198.51.100.53",
          "Port": 80
        }
      },
      "Weights": {
        "Passing": 1,
        "Warning": 1
      },
      "EnableTagOverride": false,
      "Namespace": "default",
      "Datacenter": "dc1"
    },
    "Checks": []
  },
  {
    "AggregatedStatus": "critical",
    "Service": {
      "ID": "web2",
      "Service": "web",
      "Tags": [
        "rails"
      ],
      "Meta": {},
      "Port": 80,
      "Address": "",
      "SocketPath": "",
      "TaggedAddresses": {
        "lan": {
          "Address": "127.0.0.1",
          "Port": 8000
        },
        "wan": {
          "Address": "198.51.100.54",
          "Port": 80
        }
      },
      "Weights": {
        "Passing": 1,
        "Warning": 1
      },
      "EnableTagOverride": false,
      "Namespace": "default",
      "Datacenter": "dc1"
    },
    "Checks": [
      {
        "Node": "server1",
        "CheckID": "service:web2",
        "Name": "Service 'web' check",
        "Status": "critical",
        "Notes": "",
        "Output": "Get \"http://localhost/health\": dial tcp [::1]:80: connect: connection refused",
        "ServiceID": "web2",
        "ServiceName": "web",
        "ServiceTags": [
          "rails"
        ],
        "Type": "",
        "Namespace": "default",
        "Definition": {
          "Interval": "0s",
          "Timeout": "0s",
          "DeregisterCriticalServiceAfter": "0s",
          "HTTP": "",
          "Header": null,
          "Method": "",
          "Body": "",
          "TLSServerName": "",
          "TLSSkipVerify": false,
          "TCP": ""
        },
        "CreateIndex": 0,
        "ModifyIndex": 0
      }
    ]
  }
]

Get local service health by ID

Retrieve the health state of a specific service on the local agent by ID.

The supported request parameters are the same as /v1/agent/health/service/name/:service_name.

Sample Requests

Query the health status of the service with ID web2.

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 for a query by ID is an object containing only the details for that service.

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

{
  "AggregatedStatus": "critical",
  "Service": {
    "ID": "web2",
    "Service": "web",
    "Tags": [
      "rails"
    ],
    "Meta": {},
    "Port": 80,
    "Address": "",
    "SocketPath": "",
    "TaggedAddresses": {
      "lan": {
        "Address": "127.0.0.1",
        "Port": 8000
      },
      "wan": {
        "Address": "198.51.100.54",
        "Port": 80
      }
    },
    "Weights": {
      "Passing": 1,
      "Warning": 1
    },
    "EnableTagOverride": false,
    "Namespace": "default",
    "Datacenter": "dc1"
  },
  "Checks": [
    {
      "Node": "server1",
      "CheckID": "service:web2",
      "Name": "Service 'web' check",
      "Status": "critical",
      "Notes": "",
      "Output": "Get \"http://localhost/health\": dial tcp [::1]:80: connect: connection refused",
      "ServiceID": "web2",
      "ServiceName": "web",
      "ServiceTags": [
        "rails"
      ],
      "Type": "",
      "Namespace": "default",
      "Definition": {
        "Interval": "0s",
        "Timeout": "0s",
        "DeregisterCriticalServiceAfter": "0s",
        "HTTP": "",
        "Header": null,
        "Method": "",
        "Body": "",
        "TLSServerName": "",
        "TLSSkipVerify": false,
        "TCP": ""
      },
      "CreateIndex": 0,
      "ModifyIndex": 0
    }
  ]
}

List status of web1 (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

{
  "AggregatedStatus": "passing",
  "Service": {
    "ID": "web1",
    "Service": "web",
    "Tags": [
      "rails"
    ],
    "Meta": {},
    "Port": 80,
    "Address": "",
    "SocketPath": "",
    "TaggedAddresses": {
      "lan": {
        "Address": "127.0.0.1",
        "Port": 8000
      },
      "wan": {
        "Address": "198.51.100.53",
        "Port": 80
      }
    },
    "Weights": {
      "Passing": 1,
      "Warning": 1
    },
    "EnableTagOverride": false,
    "Namespace": "default",
    "Datacenter": "dc1"
  },
  "Checks": []
}

Register Service

This endpoint adds a new service, with optional health checks, 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.

The corresponding CLI command is consul services register.

Query Parameters

• replace-existing-checks - Missing health checks from the request will be deleted from the agent. Using this parameter allows to idempotently register a service and its checks without having to manually deregister checks.

• ns (string: "") EnterpriseEnterprise - Specifies the namespace of the service you register. You can also specify the namespace through other methods.

JSON Request Body Schema

The /agent/service/register endpoint supports camel case and snake case for service definition keys. Snake case is a convention in which keys with two or more words have underscores between them. Snake case ensures compatibility with the agent configuration file format.

• Name (string: <required>) - Specifies the logical name of the service. Many service instances may share the same logical service name. We recommend using valid DNS labels for service definition names. Refer to the Internet Engineering Task Force's RFC 1123 for additional information. Service names that conform to standard usage ensures compatibility with external DNSs. Refer to Services Configuration Reference for additional information.

• 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. Tags enable you to filter when querying for the services and are exposed in Consul APIs. We recommend using valid DNS labels for tags. Refer to the Internet Engineering Task Force's RFC 1123 for additional information. Tags that conform to standard usage ensures compatibility with external DNSs. Refer to Services Configuration Reference for additional information.

• 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.

• TaggedAddresses (map<string|object>: nil) - Specifies a map of explicit LAN and WAN addresses for the service instance. Both the address and port can be specified within the map values.

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

• Namespace (string: "") EnterpriseEnterprise - Specifies the namespace of the service you register. This field takes precedence over the ns query parameter, one of several other methods to specify the namespace.

• 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 Connect proxies representing another service, "mesh-gateway" for instances of a mesh gateway, "terminating-gateway" for instances of a terminating gateway, or "ingress-gateway" for instances of a ingress gateway.

• Proxy (Proxy: nil) - From 1.2.3 on, specifies the configuration for a Connect service proxy instance. This is only valid if Kind defines a proxy or gateway. 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. Refer to Services Configuration Reference for additional information. Default is {"Passing": 1, "Warning": 1}.

  Weights only apply to the locally registered service. If multiple nodes register the same service, each node implements EnableTagOverride and other service configuration items independently. Updating the tags for the service registered on one node does not necessarily update the same tags on services with the same name registered on another node. If EnableTagOverride is not specified the default value is false. See anti-entropy syncs for additional information.

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"],
    "Interval": "10s",
    "Timeout": "5s"
  },
  "Weights": {
    "Passing": 10,
    "Warning": 1
  }
}

Sample Request

$ curl \
    --request PUT \
    --data @payload.json \
    http://127.0.0.1:8500/v1/agent/service/register?replace-existing-checks=true

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.

The corresponding CLI command is consul services deregister.

Path Parameters

• service_id (string: <required>) - Specifies the ID of the service to deregister.

Query Parameters

• ns (string: "") EnterpriseEnterprise - Specifies the namespace of the service you deregister. You can also specify the namespace through other methods.

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.

Path Parameters

• service_id (string: <required>) - Specifies the ID of the service to put in maintenance mode.

Query Parameters

• 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 is used instead. This parameter must be URI-encoded.

• ns (string: "") EnterpriseEnterprise - Specifies the namespace of the service you place into maintenance mode. You can also specify the namespace through other methods.

Sample Request

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

Methods to Specify Namespace EnterpriseEnterprise

Local agent service endpoints support several methods for specifying the namespace of service resources with the following order of precedence:

1. Namespace field of the JSON request body - only applies to the register endpoint
2. ns query parameter
3. X-Consul-Namespace request header
4. Namespace is inherited from the namespace of the request's ACL token (if any)
5. The default namespace