VictoriaMetrics/app/vmauth/README.md

# vmauth

`vmauth` is a simple auth proxy, router and [load balancer](#load-balancing) for [VictoriaMetrics](https://github.com/VictoriaMetrics/VictoriaMetrics).
It reads auth credentials from `Authorization` http header ([Basic Auth](https://en.wikipedia.org/wiki/Basic_access_authentication), `Bearer token` and [InfluxDB authorization](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1897) is supported),
matches them against configs pointed by [-auth.config](#auth-config) command-line flag and proxies incoming HTTP requests to the configured per-user `url_prefix` on successful match.
The `-auth.config` can point to either local file or to http url.

## Quick start

Just download `vmutils-*` archive from [releases page](https://github.com/VictoriaMetrics/VictoriaMetrics/releases), unpack it
and pass the following flag to `vmauth` binary in order to start authorizing and routing requests:

```console
/path/to/vmauth -auth.config=/path/to/auth/config.yml
```

After that `vmauth` starts accepting HTTP requests on port `8427` and routing them according to the provided [-auth.config](#auth-config).
The port can be modified via `-httpListenAddr` command-line flag.

The auth config can be reloaded either by passing `SIGHUP` signal to `vmauth` or by querying `/-/reload` http endpoint.

Docker images for `vmauth` are available [here](https://hub.docker.com/r/victoriametrics/vmauth/tags).

Pass `-help` to `vmauth` in order to see all the supported command-line flags with their descriptions.

Feel free [contacting us](mailto:info@victoriametrics.com) if you need customized auth proxy for VictoriaMetrics with the support of LDAP, SSO, RBAC, SAML,
accounting and rate limiting such as [vmgateway](https://docs.victoriametrics.com/vmgateway.html).

## Load balancing

Each `url_prefix` in the [-auth.config](#auth-config) may contain either a single url or a list of urls.
In the latter case `vmauth` balances load among the configured urls in least-loaded round-robin manner.
`vmauth` retries failing `GET` requests across the configured list of urls.
This feature is useful for balancing the load among multiple `vmselect` and/or `vminsert` nodes
in [VictoriaMetrics cluster](https://docs.victoriametrics.com/Cluster-VictoriaMetrics.html).

## Concurrency limiting

`vmauth` limits the number of concurrent requests it can proxy according to the following command-line flags:

- `-maxConcurrentRequests` limits the global number of concurrent requests `vmauth` can serve across all the configured users.
- `-maxConcurrentPerUserRequests` limits the number of concurrent requests `vmauth` can serve per each configured user.

It is also possible to set individual limits on the number of concurrent requests per each user
with the `max_concurrent_requests` option - see [auth config example](#auth-config).

`vmauth` responds with `429 Too Many Requests` HTTP error when the number of concurrent requests exceeds the configured limits.

The following [metrics](#monitoring) related to concurrency limits are exposed by `vmauth`:

- `vmauth_concurrent_requests_capacity` - the global limit on the number of concurrent requests `vmauth` can serve.
  It is set via `-maxConcurrentRequests` command-line flag.
- `vmauth_concurrent_requests_current` - the current number of concurrent requests `vmauth` processes.
- `vmauth_concurrent_requests_limit_reached_total` - the number of requests rejected with `429 Too Many Requests` error
  because of the global concurrency limit has been reached.
- `vmauth_user_concurrent_requests_capacity{username="..."}` - the limit on the number of concurrent requests for the given `username`.
- `vmauth_user_concurrent_requests_current{username="..."}` - the current number of concurrent requests for the given `username`.
- `vmauth_user_concurrent_requests_limit_reached_total{username="foo"}` - the number of requests rejected with `429 Too Many Requests` error
  because of the concurrency limit has been reached for the given `username`.


## Auth config

`-auth.config` is represented in the following simple `yml` format:

```yml
# Arbitrary number of usernames may be put here.
# It is possible to set multiple identical usernames with different passwords.
# Such usernames can be differentiated by `name` option.

users:
  # Requests with the 'Authorization: Bearer XXXX' and 'Authorization: Token XXXX'
  # header are proxied to http://localhost:8428 .
  # For example, http://vmauth:8427/api/v1/query is proxied to http://localhost:8428/api/v1/query
  # Requests with the Basic Auth username=XXXX are proxied to http://localhost:8428 as well.
- bearer_token: "XXXX"
  url_prefix: "http://localhost:8428"

  # Requests with the 'Authorization: Bearer YYY' header are proxied to http://localhost:8428 ,
  # The `X-Scope-OrgID: foobar` http header is added to every proxied request.
  # For example, http://vmauth:8427/api/v1/query is proxied to http://localhost:8428/api/v1/query
- bearer_token: "YYY"
  url_prefix: "http://localhost:8428"
  headers:
  - "X-Scope-OrgID: foobar"

  # All the requests to http://vmauth:8427 with the given Basic Auth (username:password)
  # are proxied to http://localhost:8428 .
  # For example, http://vmauth:8427/api/v1/query is proxied to http://localhost:8428/api/v1/query
  #
  # The given user can send maximum 10 concurrent requests according to the provided max_concurrent_requests.
  # Excess concurrent requests are rejected with 429 HTTP status code.
  # See also -maxConcurrentPerUserRequests and -maxConcurrentRequests command-line flags.
- username: "local-single-node"
  password: "***"
  url_prefix: "http://localhost:8428"
  max_concurrent_requests: 10

  # All the requests to http://vmauth:8427 with the given Basic Auth (username:password)
  # are proxied to http://localhost:8428 with extra_label=team=dev query arg.
  # For example, http://vmauth:8427/api/v1/query is routed to http://localhost:8428/api/v1/query?extra_label=team=dev
- username: "local-single-node2"
  password: "***"
  url_prefix: "http://localhost:8428?extra_label=team=dev"

  # All the requests to http://vmauth:8427 with the given Basic Auth (username:password)
  # are load-balanced among http://vmselect1:8481/select/123/prometheus and http://vmselect2:8481/select/123/prometheus
  # For example, http://vmauth:8427/api/v1/query is proxied to the following urls in a round-robin manner:
  #   - http://vmselect1:8481/select/123/prometheus/api/v1/select
  #   - http://vmselect2:8481/select/123/prometheus/api/v1/select
- username: "cluster-select-account-123"
  password: "***"
  url_prefix:
  - "http://vmselect1:8481/select/123/prometheus"
  - "http://vmselect2:8481/select/123/prometheus"

  # All the requests to http://vmauth:8427 with the given Basic Auth (username:password)
  # are load-balanced between http://vminsert1:8480/insert/42/prometheus and http://vminsert2:8480/insert/42/prometheus
  # For example, http://vmauth:8427/api/v1/write is proxied to the following urls in a round-robin manner:
  #   - http://vminsert1:8480/insert/42/prometheus/api/v1/write
  #   - http://vminsert2:8480/insert/42/prometheus/api/v1/write
- username: "cluster-insert-account-42"
  password: "***"
  url_prefix:
  - "http://vminsert1:8480/insert/42/prometheus"
  - "http://vminsert2:8480/insert/42/prometheus"

  # A single user for querying and inserting data:
  # - Requests to http://vmauth:8427/api/v1/query, http://vmauth:8427/api/v1/query_range
  #   and http://vmauth:8427/api/v1/label/<label_name>/values are proxied to the following urls in a round-robin manner:
  #     - http://vmselect1:8481/select/42/prometheus
  #     - http://vmselect2:8481/select/42/prometheus
  #   For example, http://vmauth:8427/api/v1/query is proxied to http://vmselect1:8480/select/42/prometheus/api/v1/query
  #   or to http://vmselect2:8480/select/42/prometheus/api/v1/query .
  # - Requests to http://vmauth:8427/api/v1/write are proxied to http://vminsert:8480/insert/42/prometheus/api/v1/write .
  #   The "X-Scope-OrgID: abc" http header is added to these requests.
- username: "foobar"
  url_map:
  - src_paths:
    - "/api/v1/query"
    - "/api/v1/query_range"
    - "/api/v1/label/[^/]+/values"
    url_prefix:
    - "http://vmselect1:8481/select/42/prometheus"
    - "http://vmselect2:8481/select/42/prometheus"
  - src_paths: ["/api/v1/write"]
    url_prefix: "http://vminsert:8480/insert/42/prometheus"
    headers:
    - "X-Scope-OrgID: abc"
```

The config may contain `%{ENV_VAR}` placeholders, which are substituted by the corresponding `ENV_VAR` environment variable values.
This may be useful for passing secrets to the config.

## Security

It is expected that all the backend services protected by `vmauth` are located in an isolated private network, so they can be accessed by external users only via `vmauth`.

Do not transfer Basic Auth headers in plaintext over untrusted networks. Enable https. This can be done by passing the following `-tls*` command-line flags to `vmauth`:

```console
  -tls
     Whether to enable TLS (aka HTTPS) for incoming requests. -tlsCertFile and -tlsKeyFile must be set if -tls is set
  -tlsCertFile string
     Path to file with TLS certificate. Used only if -tls is set. Prefer ECDSA certs instead of RSA certs, since RSA certs are slow
  -tlsKeyFile string
     Path to file with TLS key. Used only if -tls is set
```

Alternatively, [https termination proxy](https://en.wikipedia.org/wiki/TLS_termination_proxy) may be put in front of `vmauth`.

It is recommended protecting  following endpoints with authKeys:
* `/-/reload` with `-reloadAuthKey` command-line flag, so external users couldn't trigger config reload.
* `/flags` with `-flagsAuthkey` command-line flag, so unauthorized users couldn't get application command-line flags.
* `/metrics` with `metricsAuthkey` command-line flag, so unauthorized users couldn't get access to [vmauth metrics](#monitoring).
* `/debug/pprof` with `pprofAuthKey` command-line flag, so unauthorized users couldn't get access to [profiling information](#profiling).

## Monitoring

`vmauth` exports various metrics in Prometheus exposition format at `http://vmauth-host:8427/metrics` page. It is recommended setting up regular scraping of this page
either via [vmagent](https://docs.victoriametrics.com/vmagent.html) or via Prometheus, so the exported metrics could be analyzed later.

`vmauth` exports `vmauth_user_requests_total` metric with `username` label. The `username` label value equals to `username` field value set in the `-auth.config` file. It is possible to override or hide the value in the label by specifying `name` field. For example, the following config will result in `vmauth_user_requests_total{username="foobar"}` instead of `vmauth_user_requests_total{username="secret_user"}`:

```yml
users:
- username: "secret_user"
  name: "foobar"
  # other config options here
```

## How to build from sources

It is recommended using [binary releases](https://github.com/VictoriaMetrics/VictoriaMetrics/releases) - `vmauth` is located in `vmutils-*` archives there.

### Development build

1. [Install Go](https://golang.org/doc/install). The minimum supported version is Go 1.19.
2. Run `make vmauth` from the root folder of [the repository](https://github.com/VictoriaMetrics/VictoriaMetrics).
   It builds `vmauth` binary and puts it into the `bin` folder.

### Production build

1. [Install docker](https://docs.docker.com/install/).
2. Run `make vmauth-prod` from the root folder of [the repository](https://github.com/VictoriaMetrics/VictoriaMetrics).
   It builds `vmauth-prod` binary and puts it into the `bin` folder.

### Building docker images

Run `make package-vmauth`. It builds `victoriametrics/vmauth:<PKG_TAG>` docker image locally.
`<PKG_TAG>` is auto-generated image tag, which depends on source code in the repository.
The `<PKG_TAG>` may be manually set via `PKG_TAG=foobar make package-vmauth`.

The base docker image is [alpine](https://hub.docker.com/_/alpine) but it is possible to use any other base image
by setting it via `<ROOT_IMAGE>` environment variable. For example, the following command builds the image on top of [scratch](https://hub.docker.com/_/scratch) image:

```console
ROOT_IMAGE=scratch make package-vmauth
```

## Profiling

`vmauth` provides handlers for collecting the following [Go profiles](https://blog.golang.org/profiling-go-programs):

* Memory profile. It can be collected with the following command (replace `0.0.0.0` with hostname if needed):

<div class="with-copy" markdown="1">

```console
curl http://0.0.0.0:8427/debug/pprof/heap > mem.pprof
```

</div>

* CPU profile. It can be collected with the following command (replace `0.0.0.0` with hostname if needed):

<div class="with-copy" markdown="1">

```console
curl http://0.0.0.0:8427/debug/pprof/profile > cpu.pprof
```

</div>

The command for collecting CPU profile waits for 30 seconds before returning.

The collected profiles may be analyzed with [go tool pprof](https://github.com/google/pprof).
It is safe sharing the collected profiles from security point of view, since they do not contain sensitive information.

## Advanced usage

Pass `-help` command-line arg to `vmauth` in order to see all the configuration options:

```console
./vmauth -help

vmauth authenticates and authorizes incoming requests and proxies them to VictoriaMetrics.

See the docs at https://docs.victoriametrics.com/vmauth.html .

  -auth.config string
     Path to auth config. It can point either to local file or to http url. See https://docs.victoriametrics.com/vmauth.html for details on the format of this auth config
  -enableTCP6
     Whether to enable IPv6 for listening and dialing. By default only IPv4 TCP and UDP is used
  -envflag.enable
     Whether to enable reading flags from environment variables additionally to command line. Command line flag values have priority over values from environment vars. Flags are read only from command line if this flag isn't set. See https://docs.victoriametrics.com/#environment-variables for more details
  -envflag.prefix string
     Prefix for environment variables if -envflag.enable is set
  -eula
     By specifying this flag, you confirm that you have an enterprise license and accept the EULA https://victoriametrics.com/assets/VM_EULA.pdf . This flag is available only in VictoriaMetrics enterprise. See https://docs.victoriametrics.com/enterprise.html
  -flagsAuthKey string
     Auth key for /flags endpoint. It must be passed via authKey query arg. It overrides httpAuth.* settings
  -fs.disableMmap
     Whether to use pread() instead of mmap() for reading data files. By default mmap() is used for 64-bit arches and pread() is used for 32-bit arches, since they cannot read data files bigger than 2^32 bytes in memory. mmap() is usually faster for reading small data chunks than pread()
  -http.connTimeout duration
     Incoming http connections are closed after the configured timeout. This may help to spread the incoming load among a cluster of services behind a load balancer. Please note that the real timeout may be bigger by up to 10% as a protection against the thundering herd problem (default 2m0s)
  -http.disableResponseCompression
     Disable compression of HTTP responses to save CPU resources. By default compression is enabled to save network bandwidth
  -http.idleConnTimeout duration
     Timeout for incoming idle http connections (default 1m0s)
  -http.maxGracefulShutdownDuration duration
     The maximum duration for a graceful shutdown of the HTTP server. A highly loaded server may require increased value for a graceful shutdown (default 7s)
  -http.pathPrefix string
     An optional prefix to add to all the paths handled by http server. For example, if '-http.pathPrefix=/foo/bar' is set, then all the http requests will be handled on '/foo/bar/*' paths. This may be useful for proxied requests. See https://www.robustperception.io/using-external-urls-and-proxies-with-prometheus
  -http.shutdownDelay duration
     Optional delay before http server shutdown. During this delay, the server returns non-OK responses from /health page, so load balancers can route new requests to other servers
  -httpAuth.password string
     Password for HTTP Basic Auth. The authentication is disabled if -httpAuth.username is empty
  -httpAuth.username string
     Username for HTTP Basic Auth. The authentication is disabled if empty. See also -httpAuth.password
  -httpListenAddr string
     TCP address to listen for http connections. See also -httpListenAddr.useProxyProtocol (default ":8427")
  -httpListenAddr.useProxyProtocol
     Whether to use proxy protocol for connections accepted at -httpListenAddr . See https://www.haproxy.org/download/1.8/doc/proxy-protocol.txt
  -internStringMaxLen int
     The maximum length for strings to intern. Lower limit may save memory at the cost of higher CPU usage. See https://en.wikipedia.org/wiki/String_interning (default 500)
  -logInvalidAuthTokens
     Whether to log requests with invalid auth tokens. Such requests are always counted at vmauth_http_request_errors_total{reason="invalid_auth_token"} metric, which is exposed at /metrics page
  -loggerDisableTimestamps
     Whether to disable writing timestamps in logs
  -loggerErrorsPerSecondLimit int
     Per-second limit on the number of ERROR messages. If more than the given number of errors are emitted per second, the remaining errors are suppressed. Zero values disable the rate limit
  -loggerFormat string
     Format for logs. Possible values: default, json (default "default")
  -loggerJSONFields string
     Allows renaming fields in JSON formatted logs. Example: "ts:timestamp,msg:message" renames "ts" to "timestamp" and "msg" to "message". Supported fields: ts, level, caller, msg
  -loggerLevel string
     Minimum level of errors to log. Possible values: INFO, WARN, ERROR, FATAL, PANIC (default "INFO")
  -loggerOutput string
     Output for the logs. Supported values: stderr, stdout (default "stderr")
  -loggerTimezone string
     Timezone to use for timestamps in logs. Timezone must be a valid IANA Time Zone. For example: America/New_York, Europe/Berlin, Etc/GMT+3 or Local (default "UTC")
  -loggerWarnsPerSecondLimit int
     Per-second limit on the number of WARN messages. If more than the given number of warns are emitted per second, then the remaining warns are suppressed. Zero values disable the rate limit
  -maxConcurrentPerUserRequests int
     The maximum number of concurrent requests vmauth can process per each configured user. Other requests are rejected with '429 Too Many Requests' http status code. See also -maxConcurrentRequests command-line option and max_concurrent_requests option in per-user config (default 300)
  -maxConcurrentRequests int
     The maximum number of concurrent requests vmauth can process. Other requests are rejected with '429 Too Many Requests' http status code. See also -maxConcurrentPerUserRequests and -maxIdleConnsPerBackend command-line options (default 1000)
  -maxIdleConnsPerBackend int
     The maximum number of idle connections vmauth can open per each backend host. See also -maxConcurrentRequests (default 100)
  -memory.allowedBytes size
     Allowed size of system memory VictoriaMetrics caches may occupy. This option overrides -memory.allowedPercent if set to a non-zero value. Too low a value may increase the cache miss rate usually resulting in higher CPU and disk IO usage. Too high a value may evict too much data from OS page cache resulting in higher disk IO usage
     Supports the following optional suffixes for size values: KB, MB, GB, TB, KiB, MiB, GiB, TiB (default 0)
  -memory.allowedPercent float
     Allowed percent of system memory VictoriaMetrics caches may occupy. See also -memory.allowedBytes. Too low a value may increase cache miss rate usually resulting in higher CPU and disk IO usage. Too high a value may evict too much data from OS page cache which will result in higher disk IO usage (default 60)
  -metricsAuthKey string
     Auth key for /metrics endpoint. It must be passed via authKey query arg. It overrides httpAuth.* settings
  -pprofAuthKey string
     Auth key for /debug/pprof/* endpoints. It must be passed via authKey query arg. It overrides httpAuth.* settings
  -pushmetrics.extraLabel array
     Optional labels to add to metrics pushed to -pushmetrics.url . For example, -pushmetrics.extraLabel='instance="foo"' adds instance="foo" label to all the metrics pushed to -pushmetrics.url
     Supports an array of values separated by comma or specified via multiple flags.
  -pushmetrics.interval duration
     Interval for pushing metrics to -pushmetrics.url (default 10s)
  -pushmetrics.url array
     Optional URL to push metrics exposed at /metrics page. See https://docs.victoriametrics.com/#push-metrics . By default metrics exposed at /metrics page aren't pushed to any remote storage
     Supports an array of values separated by comma or specified via multiple flags.
  -reloadAuthKey string
     Auth key for /-/reload http endpoint. It must be passed as authKey=...
  -responseTimeout duration
     The timeout for receiving a response from backend (default 5m0s)
  -tls
     Whether to enable TLS for incoming HTTP requests at -httpListenAddr (aka https). -tlsCertFile and -tlsKeyFile must be set if -tls is set
  -tlsCertFile string
     Path to file with TLS certificate if -tls is set. Prefer ECDSA certs instead of RSA certs as RSA certs are slower. The provided certificate file is automatically re-read every second, so it can be dynamically updated
  -tlsCipherSuites array
     Optional list of TLS cipher suites for incoming requests over HTTPS if -tls is set. See the list of supported cipher suites at https://pkg.go.dev/crypto/tls#pkg-constants
     Supports an array of values separated by comma or specified via multiple flags.
  -tlsKeyFile string
     Path to file with TLS key if -tls is set. The provided key file is automatically re-read every second, so it can be dynamically updated
  -tlsMinVersion string
     Optional minimum TLS version to use for incoming requests over HTTPS if -tls is set. Supported values: TLS10, TLS11, TLS12, TLS13
  -version
     Show VictoriaMetrics version
```