HTTPS and authentication

Prometheus supports basic authentication and TLS. This is experimental and might change in the future.

To specify which web configuration file to load, use the --web.config.file flag.

The file is written in YAML format, defined by the scheme described below. Brackets indicate that a parameter is optional. For non-list parameters the value is set to the specified default.

The file is read upon every http request, such as any change in the configuration and the certificates is picked up immediately.

Generic placeholders are defined as follows:

  • <boolean>: a boolean that can take the values true or false
  • <filename>: a valid path in the current working directory
  • <secret>: a regular string that is a secret, such as a password
  • <string>: a regular string

A valid example file can be found here.

  1. tls_server_config:
  2.   # Certificate and key files for server to use to authenticate to client.
  3.   cert_file: <filename>
  4.   key_file: <filename>
  6.   # Server policy for client authentication. Maps to ClientAuth Policies.
  7.   # For more detail on clientAuth options:
  8.   # https://golang.org/pkg/crypto/tls/#ClientAuthType
  9.   #
  10.   # NOTE: If you want to enable client authentication, you need to use
  11.   # RequireAndVerifyClientCert. Other values are insecure.
  12.   [ client_auth_type: <string> | default = "NoClientCert" ]
  14.   # CA certificate for client certificate authentication to the server.
  15.   [ client_ca_file: <filename> ]
  17.   # Verify that the client certificate has a Subject Alternate Name (SAN)
  18.   # which is an exact match to an entry in this list, else terminate the
  19.   # connection. SAN match can be one or multiple of the following: DNS,
  20.   # IP, e-mail, or URI address from https://pkg.go.dev/crypto/x509#Certificate.
  21.   [ client_allowed_sans:
  22.     [ - <string> ] ]
  24.   # Minimum TLS version that is acceptable.
  25.   [ min_version: <string> | default = "TLS12" ]
  27.   # Maximum TLS version that is acceptable.
  28.   [ max_version: <string> | default = "TLS13" ]
  30.   # List of supported cipher suites for TLS versions up to TLS 1.2. If empty,
  31.   # Go default cipher suites are used. Available cipher suites are documented
  32.   # in the go documentation:
  33.   # https://golang.org/pkg/crypto/tls/#pkg-constants
  34.   #
  35.   # Note that only the cipher returned by the following function are supported:
  36.   # https://pkg.go.dev/crypto/tls#CipherSuites
  37.   [ cipher_suites:
  38.     [ - <string> ] ]
  40.   # prefer_server_cipher_suites controls whether the server selects the
  41.   # client's most preferred ciphersuite, or the server's most preferred
  42.   # ciphersuite. If true then the server's preference, as expressed in
  43.   # the order of elements in cipher_suites, is used.
  44.   [ prefer_server_cipher_suites: <boolean> | default = true ]
  46.   # Elliptic curves that will be used in an ECDHE handshake, in preference
  47.   # order. Available curves are documented in the go documentation:
  48.   # https://golang.org/pkg/crypto/tls/#CurveID
  49.   [ curve_preferences:
  50.     [ - <string> ] ]
  52. http_server_config:
  53.   # Enable HTTP/2 support. Note that HTTP/2 is only supported with TLS.
  54.   # This can not be changed on the fly.
  55.   [ http2: <boolean> | default = true ]
  56.   # List of headers that can be added to HTTP responses.
  57.   [ headers:
  58.     # Set the Content-Security-Policy header to HTTP responses.
  59.     # Unset if blank.
  60.     [ Content-Security-Policy: <string> ]
  61.     # Set the X-Frame-Options header to HTTP responses.
  62.     # Unset if blank. Accepted values are deny and sameorigin.
  63.     # https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Frame-Options
  64.     [ X-Frame-Options: <string> ]
  65.     # Set the X-Content-Type-Options header to HTTP responses.
  66.     # Unset if blank. Accepted value is nosniff.
  67.     # https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Content-Type-Options
  68.     [ X-Content-Type-Options: <string> ]
  69.     # Set the X-XSS-Protection header to all responses.
  70.     # Unset if blank.
  71.     # https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-XSS-Protection
  72.     [ X-XSS-Protection: <string> ]
  73.     # Set the Strict-Transport-Security header to HTTP responses.
  74.     # Unset if blank.
  75.     # Please make sure that you use this with care as this header might force
  76.     # browsers to load Prometheus and the other applications hosted on the same
  77.     # domain and subdomains over HTTPS.
  78.     # https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Strict-Transport-Security
  79.     [ Strict-Transport-Security: <string> ] ]
  81. # Usernames and hashed passwords that have full access to the web
  82. # server via basic authentication. If empty, no basic authentication is
  83. # required. Passwords are hashed with bcrypt.
  84. basic_auth_users:
  85.   [ <string>: <secret> ... ]

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