--- layout: "docs" page_title: "Catalog (HTTP)" sidebar_current: "docs-agent-http-catalog" description: > The Catalog is the endpoint used to register and deregister nodes, services, and checks. It also provides query endpoints. --- # Catalog HTTP Endpoint The Catalog is the endpoint used to register and deregister nodes, services, and checks. It also provides query endpoints. The following endpoints are supported: * [`/v1/catalog/register`](#catalog_register) : Registers a new node, service, or check * [`/v1/catalog/deregister`](#catalog_deregister) : Deregisters a node, service, or check * [`/v1/catalog/datacenters`](#catalog_datacenters) : Lists known datacenters * [`/v1/catalog/nodes`](#catalog_nodes) : Lists nodes in a given DC * [`/v1/catalog/services`](#catalog_services) : Lists services in a given DC * [`/v1/catalog/service/`](#catalog_service) : Lists the nodes in a given service * [`/v1/catalog/node/`](#catalog_nodes) : Lists the services provided by a node The `nodes` and `services` endpoints support blocking queries and tunable consistency modes. ### /v1/catalog/register The register endpoint is a low-level mechanism for registering or updating entries in the catalog. Note: it is usually preferrable instead to use the [agent endpoints](agent.html) for registration as they are simpler and perform [anti-entropy](/docs/internals/anti-entropy.html). The register endpoint expects a JSON request body to be PUT. The request body must look something like: ```javascript { "Datacenter": "dc1", "Node": "foobar", "Address": "192.168.10.10", "Service": { "ID": "redis1", "Service": "redis", "Tags": [ "master", "v1" ], "Address": "127.0.0.1", "Port": 8000 }, "Check": { "Node": "foobar", "CheckID": "service:redis1", "Name": "Redis health check", "Notes": "Script based health check", "Status": "passing", "ServiceID": "redis1" } } ``` The behavior of the endpoint depends on what keys are provided. The endpoint requires `Node` and `Address` to be provided while `Datacenter` will be defaulted to match that of the agent. If only those are provided, the endpoint will register the node with the catalog. If the `Service` key is provided, the service will also be registered. If `ID` is not provided, it will be defaulted to the value of the `Service.Service` property. Only one service with a given `ID` may be present per node. The service `Tags`, `Address`, and `Port` fields are all optional. If the `Check` key is provided, a health check will also be registered. Note: this register API manipulates the health check entry in the Catalog, but it does not setup the script, TTL, or HTTP check to monitor the node's health. To truly enable a new health check, the check must either be provided in agent configuration or set via the [agent endpoint](agent.html). The `CheckID` can be omitted and will default to the value of `Name`. As with `Service.ID`, the `CheckID` must be unique on this node. `Notes` is an opaque field that is meant to hold human-readable text. If a `ServiceID` is provided that matches the `ID` of a service on that node, the check is treated as a service level health check, instead of a node level health check. The `Status` must be one of `unknown`, `passing`, `warning`, or `critical`. The `unknown` status is used to indicate that the initial check has not been performed yet. It is important to note that `Check` does not have to be provided with `Service` and vice versa. A catalog entry can have either, neither, or both. An optional ACL token may be provided to perform the registration by including a `WriteRequest` block in the query payload, like this: ```javascript { "WriteRequest": { "Token": "foo" } } ``` If the API call succeeds, a 200 status code is returned. ### /v1/catalog/deregister The deregister endpoint is a low-level mechanism for directly removing entries from the Catalog. Note: it is usually preferrable instead to use the [agent endpoints](agent.html) for deregistration as they are simpler and perform [anti-entropy](/docs/internals/anti-entropy.html). The deregister endpoint expects a JSON request body to be PUT. The request body must look like one of the following: ```javascript { "Datacenter": "dc1", "Node": "foobar", } ``` ```javascript { "Datacenter": "dc1", "Node": "foobar", "CheckID": "service:redis1" } ``` ```javascript { "Datacenter": "dc1", "Node": "foobar", "ServiceID": "redis1", } ``` The behavior of the endpoint depends on what keys are provided. The endpoint requires `Node` to be provided while `Datacenter` will be defaulted to match that of the agent. If only `Node` is provided, the node and all associated services and checks are deleted. If `CheckID` is provided, only that check is removed. If `ServiceID` is provided, the service and its associated health check (if any) are removed. An optional ACL token may be provided to perform the deregister action by adding a `WriteRequest` block to the payload, like this: ```javascript { "WriteRequest": { "Token": "foo" } } ``` If the API call succeeds a 200 status code is returned. ### /v1/catalog/datacenters This endpoint is hit with a GET and is used to return all the datacenters that are known by the Consul server. The datacenters will be sorted in ascending order based on the estimated median round trip time from the server to the servers in that datacenter. It returns a JSON body like this: ```javascript ["dc1", "dc2"] ``` This endpoint does not require a cluster leader and will succeed even during an availability outage. Therefore, it can be used as a simple check to see if any Consul servers are routable. ### /v1/catalog/nodes This endpoint is hit with a GET and returns the nodes registered in a given DC. By default, the datacenter of the agent is queried; however, the dc can be provided using the "?dc=" query parameter. Adding the optional "?near=" parameter with a node name will sort the node list in ascending order based on the estimated round trip time from that node. Passing "?near=self" will use the agent's local node for the sort. It returns a JSON body like this: ```javascript [ { "Node": "baz", "Address": "10.1.10.11" }, { "Node": "foobar", "Address": "10.1.10.12" } ] ``` This endpoint supports blocking queries and all consistency modes. ### /v1/catalog/services This endpoint is hit with a GET and returns the services registered in a given DC. By default, the datacenter of the agent is queried; however, the dc can be provided using the "?dc=" query parameter. It returns a JSON body like this: ```javascript { "consul": [], "redis": [], "postgresql": [ "master", "slave" ] } ``` The keys are the service names, and the array values provide all known tags for a given service. This endpoint supports blocking queries and all consistency modes. ### /v1/catalog/service/\ This endpoint is hit with a GET and returns the nodes providing a service in a given DC. By default, the datacenter of the agent is queried; however, the dc can be provided using the "?dc=" query parameter. The service being queried must be provided on the path. By default all nodes in that service are returned. However, the list can be filtered by tag using the "?tag=" query parameter. Adding the optional "?near=" parameter with a node name will sort the node list in ascending order based on the estimated round trip time from that node. Passing "?near=self" will use the agent's local node for the sort. It returns a JSON body like this: ```javascript [ { "Node": "foobar", "Address": "10.1.10.12", "ServiceID": "redis", "ServiceName": "redis", "ServiceTags": null, "ServiceAddress": "", "ServicePort": 8000 } ] ``` This endpoint supports blocking queries and all consistency modes. ### /v1/catalog/node/\ This endpoint is hit with a GET and returns the node's registered services. By default, the datacenter of the agent is queried; however, the dc can be provided using the "?dc=" query parameter. The node being queried must be provided on the path. It returns a JSON body like this: ```javascript { "Node": { "Node": "foobar", "Address": "10.1.10.12" }, "Services": { "consul": { "ID": "consul", "Service": "consul", "Tags": null, "Port": 8300 }, "redis": { "ID": "redis", "Service": "redis", "Tags": [ "v1" ], "Port": 8000 } } } ``` This endpoint supports blocking queries and all consistency modes.