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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 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
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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.
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PoolFactory { /** * Set the proxy to be used when making connections from this pool. */ setProxy(ProxyType type, String proxyAddress) } ClientCache { setPoolProxy(ProxyType type, String proxyAddress) } enum ProxyType { SNI; } |
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.
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- 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.
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Geode
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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?