docs: add vmauth.md

app/vmauth/README.md

@@ -4,15 +4,16 @@
 and matches them against configs pointed by `-auth.config` command-line flag and proxies incoming HTTP requests to the configured per-user `url_prefix` on successful match.
 
 
-### Usage
+### Quick start
 
-Just pass path to [auth config](#auth-config) file to `vmauth` binary:
+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:
 
 ```
 /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`.
+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 by passing `SIGHUP` signal to `vmauth`.

docs/vmauth.md

@@ -0,0 +1,104 @@
+## vmauth
+
+`vmauth` is a simple auth proxy and router. It reads username and password from [Basic Auth headers](https://en.wikipedia.org/wiki/Basic_access_authentication)
+and matches them against configs pointed by `-auth.config` command-line flag and proxies incoming HTTP requests to the configured per-user `url_prefix` on successful match.
+
+
+### 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:
+
+```
+/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 by passing `SIGHUP` signal to `vmauth`.
+
+Pass `-help` to `vmauth` in order to see all the supported command-line flags with their descriptions.
+
+
+### Auth config
+
+Auth config is represented in the following simple `yml` format:
+
+```yml
+
+# Arbitrary number of usernames may be put here.
+# Usernames must be unique.
+
+users:
+
+  # The user for querying local single-node VictoriaMetrics
+- username: "local-single-node"
+  password: "***"
+  url_prefix: "http://localhost:8428"
+
+  # The user for querying account 123 in VictoriaMetrics cluster
+  # See https://github.com/VictoriaMetrics/VictoriaMetrics/blob/cluster/README.md#url-format
+- username: "cluster-select-account-123"
+  password: "***"
+  url_prefix: "http://vmselect:8481/select/123/prometheus"
+
+  # The user for inserting Prometheus data into VictoriaMetrics cluster under account 42
+  # See https://github.com/VictoriaMetrics/VictoriaMetrics/blob/cluster/README.md#url-format
+- username: "cluster-insert-account-42"
+  password: "***"
+  url_prefix: "http://localhost:8480/insert/42/prometheus"
+```
+
+
+### Security
+
+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`:
+
+```
+  -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`.
+
+
+### 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://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/app/vmagent/README.md) or via Prometheus, so the exported metrics could be analyzed later.
+
+
+### 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 1.13.
+2. Run `make vmauth` from the root folder of the repository.
+   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.
+   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`.
+
+By default the image is built on top of `scratch` image. It is possible to build the package on top of any other base image
+by setting it via `<ROOT_IMAGE>` environment variable. For example, the following command builds the image on top of `alpine:3.11` image:
+
+```bash
+ROOT_IMAGE=alpine:3.11 make package-vmauth
+```