119 lines
3.6 KiB
Plaintext
119 lines
3.6 KiB
Plaintext
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---
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layout: "docs"
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page_title: "Sentinel in Consul"
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sidebar_current: "docs-guides-sentinel"
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description: |-
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Consul Enterprise uses Sentinel to augment the built-in ACL system to provide advanced policy enforcement. Sentinel policies can currently execute on KV modify and service registration.
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---
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# Sentinel Overview
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[//]: # ( ~> The Sentinel functionality described here is available only in )
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[//]: # ( [Consul Enterprise](https://www.hashicorp.com/products/consul/) version 1.0.0 and later. )
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<%= enterprise_alert :consul %>
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Consul 1.0 adds integration with [Sentinel](https://hashicorp.com/sentinel) for policy enforcement.
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Sentinel policies help extend the ACL system in Consul beyond the static "read", "write", and "deny"
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policies to support full conditional logic, and integration with external systems.
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## Sentinel in Consul
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Sentinel policies are applied during writes to the KV Store and the service catalog in Consul.
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ACL policy definitions take a `sentinel` field specifying the code and the enforcement level.
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Here's an example:
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```text
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sentinel {
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code = "main = rule { port > 1024 and port < 32768 }"
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enforcementlevel = "soft-mandatory"
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}
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```
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This policy ensures that all services written to the Catalog must have a port number between 1024 and 32768.
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If the `enforcementlevel` property is not set, it defaults to "hard-mandatory".
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## Imports
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Consul imports all the [standard imports](https://docs.hashicorp.com/sentinel/imports/)
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from Sentinel. All functions in these imports are available to be used in policies.
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## Injected Variables
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Consul passes some context as variables into Sentinel, which are available to use inside any policies you write.
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#### Variables injected during KV store writes
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| Variable Name | Type | Description |
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| ------------- | -------- | ----------- |
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| `key` | `string` | Key being written |
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| `value` | `string` | Value being written |
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| `flags` | `uint64` | [Flags](/api/kv.html#flags) |
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#### Variables injected during service registration
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| Variable Name | Type | Description |
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| -------------- |-------------------- | ----------- |
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| `node_id` | `string` | ID of the agent registering the service |
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| `node` | `string` | Name of the agent registering the service |
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| `address` | `string` | Service address |
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| `port` | `int` | Service port |
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| `service_id` | `string` | Service ID |
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| `service` | `string` | Service name |
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| `node_meta` | `map[string]string` | Node metadata map |
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| `tags` | `list` | Service tags |
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## Examples
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The following are some examples of ACL policies with Sentinel rules.
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### All services must register with a valid IPv6 address.
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```text
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service "" {
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policy = "write"
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sentinel {
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import \"sockaddr\"
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code = "main = rule { sockaddr.is_ipv6(address) }"
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enforcementlevel = "soft-mandatory"
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}
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}
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```
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### Service names must end with "Service"
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```text
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service "" {
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policy = "write"
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sentinel {
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import \"strings\"
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code = "main = rule { strings.has_suffix(service,\"Service\") }"
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enforcementlevel = "soft-mandatory"
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}
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}
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```
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### The service "db" must be registered with either a "Leader" or a "Follower" tag
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```text
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service "db" {
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policy = "write"
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sentinel {
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main = rule { tags contains \"Leader\" or tags contains \"Follower\" }
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}
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}
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```
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### The key "foo" can only be updated during business hours.
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```text
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keys "foo" {
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policy = "write"
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sentinel {
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import "time"
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main = rule { time.hour > 8 and time.hour < 17 }
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}
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}
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```
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