RFC Title
To be Reviewed By: March 11, 2020
Authors: Dan Smith, Ernie Burghardt
Status: Draft Draft | Discussion | Active | Dropped | Superseded
Superseded by: N/A
Related: N/A GEODE-7852
Problem
Users would like to be able to put Geode servers behind a proxy. This would allow users to avoid having to allocate public IP addresses for all of the servers, as well as being able to control and monitor access to the servers.
Currently, this is not very well supported. Geode clients discover servers using locators. It is possible to set the hostname-for-clients on all servers to point point to the proxy server, but this is not ideal. Geode clients rely on being able to connect to specific servers for features like PR single hop and client server queues. This means that the clients need a protocol that will allow them to tell the proxy which server they connect to.
Anti-Goals
- It is an anti-goal to deal with configuring the proxy itself.
- It is an anti-goal to support all different kinds of proxies. In the future we may consider supporting other types of proxies, but this proposal is to support one specific type - a SNI proxy.
- We're not recommending any specific SNI proxy
- This proposal does not include supporting a proxy for WAN or P2P connectivity. In the future we may add support for that as well.
Solution
Describe your solution and how it’s going to solve the problem. This is likely the largest section of your proposal and might even include some high-level diagrams if you are proposing code changes. While all important aspects need to be covered, also keep in mind that shorter documents are more likely to be read.
We will add a configuration option to the client to set a SNI proxy for the client to connect to the servers through. When this option is set, all connections from the client to the locator or the servers will use this SNI proxy. When configuring a Pool, the names of the locators or the names of the servers provided in the pool configuration will be passed as the Server Name Indicator field when the client connects to the proxy. The proxy must be able to resolve these names and connect to the correct locator or server.
This setting ideally should be at a pool level, because different pools may need to use different proxies. Therefore , we propose the following pool configuration option:
Code Block | ||
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PoolFactory { /** * Set the proxy to be used when making connections from this pool. * @param proxyAddress is host and port formatted like the authority part of a URL * but without any userinfo part. See RFC 3986 for details. Examples: * * "foo.bar.com:1234" is a fully-qualified domain name and port * "1.2.3.4:567" is an IPv4 address and port * "[1:2::1]:80" is an IPv6 address and port */ setProxy(ProxyType type, String proxyAddress) } ClientCacheFactory { /** * (see description of proxyAddress above) */ setPoolProxy(ProxyType type, String proxyAddress) } enum ProxyType { /** * Use a SNI proxy. With an SNI proxy, the proxyAddress field should be specified as host:port */ SNI; }} |
The proxyAddress parameter will be in the familiar URL format[1][2], specifically the authority part of a URL without any userinfo part.
Performance Impact
Connecting through a proxy may impact the performance of client/server messaging, but it is up to the user to decide if they want to use this feature or not. SNI proxies do require the use of TLS, which also adds overhead.
Backwards Compatibility and Upgrade Path
This is a client side setting, so there should be no backwards compatibility or upgrade concerns.
Prior Art
Alternative ways to introduce a proxy would be:
- Set the hostname-for-clients to point to the proxy. However this does not let the client connect to specific servers, because from the client's point of view there is only one server (the proxy). This makes client single hop no longer functional. It also makes it hard for the client to maintain redundancy of server to client queues, for subscriptions.
- Use a SOCKS5 proxy instead.
Geode
...
also added support to set the SNI field in the client hello as part of GEODE-7414. With those changes, a user can provide a SSLParameterExtension callback that can modify any of the SSLParameters, including the SNI server name. If a proxy of type SNI is set and the SSLParameterExtension is also set, the SSLParameterExtension will run after geode has set the SNI name, and can potential modify it.
FAQ
Is this platform specific?
- No this feature is intended to be platform agnostic.
Does this require a firewall?
- This is an implementation detail that will be left to the users discretion.
Errata
What are minor adjustments that had to be made to the proposal since it was approved?
References
[1] Description of URL syntax from Wikipedia article on URLs https://en.wikipedia.org/wiki/URL#Syntax
[2] RFC 3986 sections 3.2.2 and 3.2.3 describing host and port syntax in URLs https://tools.ietf.org/html/rfc3986#section-3.2.2