mirror of https://github.com/status-im/consul.git
Connect production guide draft 1
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Paul Banks
Jack Pearkes
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@ -14,17 +14,17 @@ designed to work with minimal configuration out of the box, but completing the
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security model](/docs/internals/security.html) are prerequisites for production
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deployments.
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This guide aims to walk step-by-step through a cluster setup that meets all of
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those security-related goals.
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This guide aims to walk through the steps required to ensure the security
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guarantees hold.
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We assume a cluster is already running with an appropriate number of servers and
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clients. To follow along with this guide in a dev environment you can follow our
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[getting started guide](/intro/getting-started/install.html). For an actual
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production cluster we expect other reference material like the
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[getting started guide](/intro/getting-started/install.html). For a production
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cluster we expect other reference material like the
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[deployment](/docs/guides/deployment.html) and
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[performance](/docs/guides/performance.html) guides have been followed.
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The steps we need to take to get to a secure connect cluster are:
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The steps we need to get to a secure Connect cluster are:
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1. [Configure ACLs](#configure-acls)
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1. [Configure Agent Transport Encryption](#configure-agent-transport-encryption)
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@ -51,11 +51,12 @@ A secure ACL setup must meet these criteria:
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1. **[ACL default
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policy](https://private-docs.consul.io/docs/agent/options.html#acl_default_policy)
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must be `deny`.** It is technically sufficient to keep default `allow` but
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add an explicit ACL denying anonymous `service:write`. Note however that in
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this case the Connect intention graph will also default to `allow` and
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explicit `deny` intentions will be needed to restrict service access. It is
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assumed for the remainder of this guide that ACL policy defaults to `deny`.
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must be `deny`.** It is technically sufficient to keep the default policy of
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`allow` but add an explicit ACL denying anonymous `service:write`. Note
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however that in this case the Connect intention graph will also default to
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`allow` and explicit `deny` intentions will be needed to restrict service
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access. It is assumed for the remainder of this guide that ACL policy
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defaults to `deny`.
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2. **Each service must have a distinct ACL token** that is restricted to
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`service:write` only for the named service. Current Consul ACLs only support
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prefix matching but in a near-future release we will allow exact name
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@ -66,27 +67,30 @@ A secure ACL setup must meet these criteria:
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### Fine Grained Enforcement
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Connect intentions manage access based only on service identity so it is
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sufficient for ACL tokens to only be unique per service and shared between
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sufficient for ACL tokens to only be unique per _service_ and shared between
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instances.
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It is much better though if ACL tokens are unique per service _instance_ though.
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The reason for this is to limit the blast radius of a compromise.
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It is much better though if ACL tokens are unique per service _instance_ because
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it limit the blast radius of a compromise.
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A future release of Connect will support revoking specific certificates that
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have been issued. For example if a single node in a datacenter has been
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compromised, it will be possible to find all certificates issued to the agent on
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that node and revoke them blocking access to the intruder without taking
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unaffected instances of the service(s) on that node offline too.
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that node and revoke them. This will block all access to the intruder without
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taking unaffected instances of the service(s) on that node offline too.
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While this will work with service-unique tokens, there is nothing stopping an
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attacker from obtaining certificates while spoofing the agent ID of another
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agent - these certificates will not appear to have been issued to the
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compromised agent and so will not be revoked. If every service instance has a
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unique token however, it will be possible to revoke all certificates that were
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requested under that token which denies access to any certificate the attacker
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could generate.
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attacker from obtaining certificates while spoofing the agent ID or other
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identifier – these certificates will not appear to have been issued to the
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compromised agent and so will not be revoked.
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In practice managing per-instance tokens requires automated ACL provisioning,
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If every service instance has a unique token however, it will be possible to
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revoke all certificates that were requested under that token. Assuming the
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attacker can only access the tokens present on the compromised host, this
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guarantees that any certificate they might have access to or requested directly
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will be revoked.
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In practice, managing per-instance tokens requires automated ACL provisioning,
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for example using [HashiCorp's
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Vault](https://www.vaultproject.io/docs/secrets/consul/index.html).
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@ -99,6 +103,10 @@ between the server and client agents or between client agent and application.
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Follow the [encryption documentation](/docs/agent/encryption.html) to ensure
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both gossip encryption and RPC TLS are configured securely.
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For now client and server TLS certificates are still managed by manual
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configuration. In the future we plan to automate more of that with the same
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mechanisms connect offers to user applications.
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## Bootstrap Certificate Authority
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Consul Connect comes with a built in Certificate Authority (CA) that will
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@ -112,8 +120,6 @@ connect {
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}
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```
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Note that server agents running in `-dev` mode have this enabled by default.
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This config change requires a restart which you can perform one server at a time
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to maintain availability in an existing cluster.
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@ -131,23 +137,63 @@ integrated. We will expand the external CA systems that are supported in the
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future and will allow seamless online migration to a different CA or
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bootstrapping with an external CA.
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For production workloads we recommend using Vault as the CA such that the root
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key is not stored within Consul state at all.
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For production workloads we recommend using Vault or another external CA once
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available such that the root key is not stored within Consul state at all.
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TODO: link to vault config docs?
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## Setup Host Firewall
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If using [managed proxies]() Consul will by default assign them ports from [a
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configurable range]() the default range is 20000 - 20255. If this feature is
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used, the agent assumes all ports in that range are both free to use (no other
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processes listening on them) and are exposed in the firewall to accept
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connections from other service hosts.
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In order to enable inbound connections to connect proxies, you may need to
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configure host or network firewalls to allow incoming connections to proxy
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ports.
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TODO: could show example iptables rule but it seems kinda limited and obvious
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In addition to Consul agent's [communication
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ports](https://private-docs.consul.io/docs/agent/options.html#ports) any
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[managed proxies](/docs/connect/proxies.html#managed-proxies) will need to have
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ports open to accept incoming connections.
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Consul will by default assign them ports from [a configurable
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range](https://private-docs.consul.io/docs/agent/options.html#ports) the default
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range is 20000 - 20255. If this feature is used, the agent assumes all ports in
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that range are both free to use (no other processes listening on them) and are
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exposed in the firewall to accept connections from other service hosts.
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Alternatively, managed proxies can have their public ports specified as part of
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the [proxy configuration](#TODO) in the service registration. It is possible to use
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this exclusively and prevent automated port selection by [configuring
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`proxy_min_port` and
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`proxy_max_port`](https://private-docs.consul.io/docs/agent/options.html#ports)
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to both be `0`, forcing any managed proxies to have an explicit port configured.
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It then becomes the same problem as opening ports necessary for any other
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application and might be managed by configuration management or a scheduler.
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## Configure Service Instances
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TODO:
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- provide ACL token to API client/on disk
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- optionally configure manged proxy
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- notes about binding app only to localhost
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With [necessary ACL tokens](#configure-acls) in place, all service registrations
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need to have an appropriate ACL token present.
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For on-disk configuration the `token` parameter of the service definition must
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be set.
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For registration via the API [the token is passed in the request
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header](https://private-docs.consul.io/api/index.html#acls) or by using the [Go
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client configuration](https://godoc.org/github.com/hashicorp/consul/api#Config).
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Note that by default API registration will not allow managed proxies to be
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configured since it potentially opens a remote execution vulnerability if the
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agent API endpoints are publicly accessible. This can be [configured
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per-agent](https://private-docs.consul.io/docs/agent/options.html#connect_proxy).
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For examples of service definitions with managed or unmanaged proxies see
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[proxies documentation](/docs/connect/proxies.html#managed-proxies).
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To avoid the overhead of a proxy, applications may [natively
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integrate](/docs/connect/native.html) with connect.
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### Protect Application Listener
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If using any kind of proxy for connect, the application must ensure no untrusted
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connections can be made to it's unprotected listening port. This is typically
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done by binding to `localhost` and only allowing loopback traffic, but may also
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be achieved using firewall rules or network namespacing.
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