[#521] Add documentation for multinet settings

Signed-off-by: Alex Vanin <a.vanin@yadro.com>

CHANGELOG.md

@@ -9,6 +9,7 @@ This document outlines major changes between releases.
 - Support new param `frostfs.graceful_close_on_switch_timeout` (#475)
 - Support patch object method (#479)
 - Add `sign` command to `frostfs-s3-authmate` (#467)
+- Multinet dial support (#521)
 
 ### Changed
 - Update go version to go1.19 (#470)

config/config.env

@@ -246,3 +246,16 @@ S3_GW_RETRY_STRATEGY=exponential
 # Containers properties
 S3_GW_CONTAINERS_CORS=AZjLTXfK4vs4ovxMic2xEJKSymMNLqdwq9JT64ASFCRj
 S3_GW_CONTAINERS_LIFECYCLE=AZjLTXfK4vs4ovxMic2xEJKSymMNLqdwq9JT64ASFCRj
+
+# Multinet properties
+# Enable multinet support
+S3_GW_MULTINET_ENABLED=false
+# Strategy to pick source IP address
+S3_GW_MULTINET_BALANCER=roundrobin
+# Restrict requests with unknown destination subnet
+S3_GW_MULTINET_RESTRICT=false
+# Delay between ipv6 to ipv4 fallback switch
+S3_GW_MULTINET_FALLBACK_DELAY=300ms
+# List of subnets and IP addresses to use as source for those subnets
+S3_GW_MULTINET_SUBNETS_1_MASK=1.2.3.4/24
+S3_GW_MULTINET_SUBNETS_1_SOURCE_IPS=1.2.3.4 1.2.3.5

config/config.yaml

@@ -289,3 +289,20 @@ retry:
 containers:
   cors: AZjLTXfK4vs4ovxMic2xEJKSymMNLqdwq9JT64ASFCRj
   lifecycle: AZjLTXfK4vs4ovxMic2xEJKSymMNLqdwq9JT64ASFCRj
+
+# Multinet properties
+multinet:
+  # Enable multinet support
+  enabled: false
+  # Strategy to pick source IP address
+  balancer: roundrobin
+  # Restrict requests with unknown destination subnet
+  restrict: false
+  # Delay between ipv6 to ipv4 fallback switch
+  fallback_delay: 300ms
+  # List of subnets and IP addresses to use as source for those subnets
+  subnets:
+    - mask: 1.2.3.4/24
+      source_ips:
+        - 1.2.3.4
+        - 1.2.3.5

docs/configuration.md

@@ -195,6 +195,7 @@ There are some custom types used for brevity:
 | `retry`            | [Retry configuration](#retry-section)                          |
 | `containers`       | [Containers configuration](#containers-section)                |
 | `vhs`              | [VHS configuration](#vhs-section)                              |
+| `multinet`         | [Multinet configuration](#multinet-section)                    |
 
 ### General section
 
@@ -788,3 +789,42 @@ vhs:
 | `vhs_header`        | `string`          | yes           | `X-Frostfs-S3-VHS`     | Header for determining whether VHS is enabled for the request.                                                                                                                                            |
 | `servername_header` | `string`          | yes           | `X-Frostfs-Servername` | Header for determining servername.                                                                                                                                                                        |
 | `namespaces`        | `map[string]bool` | yes           |                        | A map in which the keys are the name of the namespace, and the values are the flag responsible for enabling VHS for the specified namespace. Overrides global 'enabled' setting even when it is disabled. |
+
+# `multinet` section
+
+Configuration of multinet support.
+
+```yaml
+multinet:
+   enabled: false
+   balancer: roundrobin
+   restrict: false
+   fallback_delay: 300ms
+   subnets:
+      - mask: 1.2.3.4/24
+        source_ips:
+           - 1.2.3.4
+           - 1.2.3.5
+```
+
+| Parameter        | Type                           | SIGHUP reload | Default value | Description                                                                                |
+|------------------|--------------------------------|---------------|---------------|--------------------------------------------------------------------------------------------|
+| `enabled`        | `bool`                         | yes           | `false`       | Enables multinet setting to manage source ip of outcoming requests.                        |
+| `balancer`       | `string`                       | yes           | `""`          | Strategy to pick source IP. By default picks first address. Supports `roundrobin` setting. |
+| `restrict`       | `bool`                         | yes           | `false`       | Restricts requests to an undefined subnets.                                                |
+| `fallback_delay` | `duration`                     | yes           | `300ms`       | Delay between IPv6 and IPv4 fallback stack switch.                                         |
+| `subnets`        | [[]Subnet](#subnet-subsection) | yes           |               | Set of subnets to apply multinet dial settings.                                            |
+
+#### `subnet` subsection
+
+```yaml
+- mask: 1.2.3.4/24
+  source_ips:
+    - 1.2.3.4
+    - 1.2.3.5
+```
+
+| Parameter    | Type       | SIGHUP reload | Default value | Description                                                          |
+|--------------|------------|---------------|---------------|----------------------------------------------------------------------|
+| `mask`       | `string`   | yes           |               | Destination subnet.                                                  |
+| `source_ips` | `[]string` | yes           |               | Array of source IP addresses to use when dialing destination subnet. |