Skills
skills/elastic/agent-skills/elasticsearch-authn

elasticsearch-authn

SKILL.md

Elasticsearch Authentication

Authenticate to an Elasticsearch cluster using any supported authentication realm that is already configured. This skill covers all built-in realms, credential verification, and the full API key lifecycle.

For roles, users, role assignment, and role mappings, see the elasticsearch-authz skill.

For detailed API endpoints, see references/api-reference.md.

Deployment note: Not all realms are available on every deployment type. See Deployment Compatibility for self-managed vs. ECH vs. Serverless details.

Critical principles

  • Never ask for credentials in chat. Do not ask the user to paste passwords, API keys, tokens, or any secret into the conversation. Secrets must not appear in conversation history.
  • Always use environment variables. All code examples in this skill reference environment variables (e.g. ELASTICSEARCH_PASSWORD, ELASTICSEARCH_API_KEY). When a required variable is missing, instruct the user to set it in a .env file in the project root — never prompt for the value directly.
  • Prefer .env over terminal exports. Agents may run commands in a sandboxed shell session that does not inherit the user's terminal environment. A .env file in the working directory is reliable across all execution contexts. Only suggest export as a fallback when the user explicitly prefers it.

Jobs to Be Done

  • Authenticate to a cluster using username and password (native realm)
  • Connect using an API key (bearer token)
  • Verify who is currently authenticated (_authenticate)
  • Choose the right authentication realm for a deployment
  • Create an API key with scoped privileges for automation or service access
  • Rotate or invalidate an existing API key
  • Set up service account tokens for Elastic stack components
  • Authenticate with PKI / mutual TLS certificate-based authentication after PKI/TLS setup
  • Authenticate with configured external identity providers (SAML, OIDC, LDAP, AD, Kerberos)
  • Grant API keys on behalf of other users

Prerequisites

Item Description
Elasticsearch URL Cluster endpoint (e.g. https://localhost:9200 or a Cloud deployment URL)
Credentials Depends on the realm — see the methods below
Realms configured Authentication realms and their identity backends must already be configured (realm chain, IdP, LDAP/AD, Kerberos, PKI/TLS)

If any required value is missing, instruct the user to add it to a .env file in the project root. Terminal exports may not be visible to agents running in a separate shell session — the .env file is the reliable default. Never ask the user to paste credentials into the chat — secrets must not appear in conversation history.

Authentication Realms

Elasticsearch evaluates realms in a configured order (the realm chain). The first realm that can authenticate the request wins. Internal realms are managed by Elasticsearch; external realms delegate to enterprise identity systems.

Internal realms

Native (username and password)

Users stored in a dedicated Elasticsearch index. Simplest method for interactive use. Managed via Kibana or the user management APIs (see the elasticsearch-authz skill).

curl -u "${ELASTICSEARCH_USERNAME}:${ELASTICSEARCH_PASSWORD}" "${ELASTICSEARCH_URL}/_security/_authenticate"

File

Users defined in flat files on each cluster node (elasticsearch-users CLI). Always active regardless of license state, making it the fallback for disaster recovery when paid realms are disabled. Only available on self-managed deployments.

curl -u "${FILE_USER}:${FILE_PASSWORD}" "${ELASTICSEARCH_URL}/_security/_authenticate"

External realms

LDAP

Authenticates against an external LDAP directory using username and password. Self-managed only — not available on ECH or Serverless. Typically combined with role mappings to translate LDAP groups to Elasticsearch roles.

curl -u "${LDAP_USER}:${LDAP_PASSWORD}" "${ELASTICSEARCH_URL}/_security/_authenticate"

The request is identical to native — Elasticsearch routes it to the LDAP realm via the realm chain.

Active Directory

Authenticates against an Active Directory domain. Self-managed only — not available on ECH or Serverless. Similar to LDAP but uses AD-specific defaults (user principal name, sAMAccountName). Typically combined with role mappings for AD group-to-role translation.

curl -u "${AD_USER}:${AD_PASSWORD}" "${ELASTICSEARCH_URL}/_security/_authenticate"

PKI (TLS client certificates)

Authenticates using X.509 client certificates presented during the TLS handshake. Requires a PKI realm and TLS on the HTTP layer. On ECH, PKI support is limited — check deployment settings. Not available on Serverless. Best for service-to-service communication in mutual TLS environments.

curl --cert "${CLIENT_CERT}" --key "${CLIENT_KEY}" --cacert "${CA_CERT}" \
  "${ELASTICSEARCH_URL}/_security/_authenticate"

SAML

Enables SAML 2.0 Web Browser SSO, primarily for Kibana authentication. On self-managed, configure in elasticsearch.yml. On ECH, configure through the Cloud deployment settings UI. On Serverless, SAML is handled at the organization level and not configurable per project. Not usable by standard REST clients — the browser-based redirect flow is handled by Kibana. Configure another realm (e.g. native or API keys) alongside SAML for programmatic API access.

OIDC (OpenID Connect)

Enables OpenID Connect SSO, primarily for Kibana authentication. On self-managed, configure in elasticsearch.yml. On ECH, configure through the Cloud deployment settings UI. Not available on Serverless. Like SAML, it relies on browser redirects and is not suited for direct REST client use. For programmatic access alongside OIDC, use API keys or native users.

Custom applications can exchange OIDC tokens for Elasticsearch access tokens via POST /_security/oidc/authenticate, but this requires implementing the full OIDC redirect flow.

JWT (JSON Web Tokens)

Accepts JWTs issued by an external identity provider as bearer tokens. On self-managed, configure in elasticsearch.yml. On ECH, configure through the Cloud deployment settings UI. Not available on Serverless. Supports two token types:

  • id_token (default) — OpenID Connect ID tokens for user-on-behalf-of flows.
  • access_token — OAuth2 client credentials for application identity flows.
curl -H "Authorization: Bearer ${JWT_TOKEN}" "${ELASTICSEARCH_URL}/_security/_authenticate"

Each JWT realm handles one token type. Configure separate realms for id_token and access_token if both are needed.

Kerberos

Authenticates using Kerberos tickets via the SPNEGO mechanism. Self-managed only — not available on ECH or Serverless. Requires a working KDC infrastructure, proper DNS, and time synchronization.

kinit "${KERBEROS_PRINCIPAL}"
curl --negotiate -u : "${ELASTICSEARCH_URL}/_security/_authenticate"

The --negotiate flag enables SPNEGO. The -u : is required by curl but the username is ignored — the principal from kinit is used. Requires curl 7.49+ with GSS-API/SPNEGO support.

API keys

Not a realm, but a distinct authentication mechanism. Pass a Base64-encoded API key in the Authorization header. Preferred for programmatic and automated access.

curl -H "Authorization: ApiKey ${ELASTICSEARCH_API_KEY}" "${ELASTICSEARCH_URL}/_security/_authenticate"

ELASTICSEARCH_API_KEY is the encoded value (Base64 of id:api_key) returned when the key was created.

Verify authentication

Always verify credentials before proceeding:

curl <auth_flags> "${ELASTICSEARCH_URL}/_security/_authenticate"

Check username, roles, and authentication_realm.type to confirm identity and method:

authentication_realm.type Realm
native Native
file File
ldap LDAP
active_directory Active Directory
pki PKI
saml SAML
oidc OpenID Connect
jwt JWT
kerberos Kerberos

For API keys, authentication_type is "api_key" (not a realm type).

Manage API Keys

Create an API key

curl -X POST "${ELASTICSEARCH_URL}/_security/api_key" \
  <auth_flags> \
  -H "Content-Type: application/json" \
  -d '{
    "name": "'"${KEY_NAME}"'",
    "expiration": "30d",
    "role_descriptors": {
      "'"${ROLE_NAME}"'": {
        "cluster": [],
        "indices": [
          {
            "names": ["'"${INDEX_PATTERN}"'"],
            "privileges": ["read"]
          }
        ]
      }
    }
  }'

The response contains id, api_key, and encoded. Store encoded securely — it cannot be retrieved again.

Omit role_descriptors to inherit a snapshot of the authenticated user's current privileges.

Limitation: An API key cannot create another API key with privileges. The derived key is created with no effective access. Use POST /_security/api_key/grant with user credentials instead.

Get and invalidate API keys

curl "${ELASTICSEARCH_URL}/_security/api_key?name=${KEY_NAME}" <auth_flags>
curl -X DELETE "${ELASTICSEARCH_URL}/_security/api_key" \
  <auth_flags> \
  -H "Content-Type: application/json" \
  -d '{"name": "'"${KEY_NAME}"'"}'

Examples

Create a scoped API key

Request: "Create an API key that can only read from metrics-*."

POST /_security/api_key
{
  "name": "metrics-reader-key",
  "expiration": "90d",
  "role_descriptors": {
    "metrics-reader": {
      "indices": [
        {
          "names": ["metrics-*"],
          "privileges": ["read", "view_index_metadata"]
        }
      ]
    }
  }
}

Verify which realm authenticated the user

GET /_security/_authenticate

{
  "username": "joe",
  "authentication_realm": { "name": "ldap1", "type": "ldap" },
  "authentication_type": "realm"
}

Authenticate with a JWT bearer token

curl -H "Authorization: Bearer ${JWT_TOKEN}" "https://my-cluster:9200/_security/_authenticate"

Confirm the response shows authentication_realm.type as "jwt".

Guidelines

Choosing an authentication method

Method Best for Trade-offs
Native user Interactive use, simple setups Password must be stored or prompted
File user Disaster recovery, bootstrap Must be configured on every node
API key Programmatic access, CI/CD, scoped access Cannot be retrieved after creation
LDAP / AD Enterprise directory integration Requires network access to directory server
PKI certificate Service-to-service, mutual TLS environments Requires PKI infrastructure and PKI realm
SAML Kibana SSO via enterprise IdP Browser-only; not for REST clients
OIDC Kibana SSO via OpenID Connect provider Browser-only; not for REST clients
JWT Token-based service and user authentication Requires external token issuer and realm config
Kerberos Windows/enterprise Kerberos environments Requires KDC, DNS, time sync infrastructure

Prefer API keys for automated workflows — they support fine-grained scoping and independent expiration. For Kibana SSO, use SAML or OIDC. For enterprise directory integration, use LDAP or AD with role mappings (see elasticsearch-authz).

Avoid superuser credentials

Never use the built-in elastic superuser or any superuser-role account for day-to-day operations, automation, or application access. Instead, create a dedicated user or API key with only the privileges the task requires. The elastic user should be reserved for initial cluster setup and emergency recovery only.

Security

  • An API key cannot create another API key with privileges. Use user credentials or POST /_security/api_key/grant for programmatic key creation.
  • Always set expiration on API keys. Avoid indefinite keys in production.
  • Scope API keys via role_descriptors. Never create unscoped keys for automated systems.
  • Never receive, echo, or log passwords, API keys, tokens, or any credentials in the chat. Instruct the user to manage secrets in their terminal, environment variables, or files directly.
  • Never store secrets in code, scripts, or version control. Load from environment variables.
  • Use GET /_security/_authenticate to verify credentials before running management operations.
  • When generating passwords for native users, use at least 16 characters mixing uppercase, lowercase, digits, and symbols. Never use placeholder values like changeme or password123.
  • SAML and OIDC are for browser-based SSO only. Always configure a companion realm (native, file, or API keys) for REST API access alongside them.

Deployment Compatibility

Not all authentication realms are available on every deployment type. Self-managed clusters support all realms. Elastic Cloud Hosted (ECH) is managed by Elastic with no node-level access. Serverless is fully managed SaaS.

Realm Self-managed ECH Serverless
Native Yes Yes Not available
File Yes Not available Not available
LDAP Yes Not available Not available
Active Directory Yes Not available Not available
PKI Yes Limited Not available
SAML Yes Yes (deployment config) Organization-level
OIDC Yes Yes (deployment config) Not available
JWT Yes Yes (deployment config) Not available
Kerberos Yes Not available Not available
API keys Yes Yes Yes

ECH notes:

  • No node access, so the file realm and elasticsearch-users CLI are not available.
  • LDAP, Active Directory, and Kerberos cannot be configured on ECH.
  • SAML, OIDC, and JWT are configurable via the Cloud deployment settings UI.
  • The elastic superuser is available but should still be avoided for routine use.

Serverless notes:

  • API keys are the primary authentication method.
  • Native users do not exist — users are managed at the Elastic Cloud organization level.
  • SAML SSO is configured at the organization level, not per project.
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