proxy_topology_addresses - Request for documentation

[ilyabiryukov-r7]

zdm-proxy/proxy/pkg/common/types.go

Line 11 in 7e7b1f2

type TopologyConfig struct {

https://github.com/datastax/zdm-proxy/blob/main/docs/assets/zdm-config-reference.yml#L30

Hi, I am looking for some guidance regarding proxy_topology_addresses (and related index parameters), when deploying ZDM in production.

Is it mandatory to declare these "peer" IPs? What's the consequences of doing or not doing so when to comes to deploying multiple proxies (3 or 6 for example)?

Thanks

┆Issue is synchronized with this Jira Task by Unito
┆Components: Proxy
┆Issue Number: ZDM-614

[joao-r-reis]

Hi, the drivers look up the nodes of the cluster by querying the system.peers table. ZDM proxy needs those settings to be set in order to properly "fake" the results of that query so that drivers can look up all the ZDM "peers". If you don't set these settings, the proxy will default to assuming it's a single ZDM proxy deployment and so the application driver will typically only connect to a single ZDM proxy.

The addresses setting should contain the same list of addresses in the same order on all ZDM proxy configurations and the index should be unique on each zdm proxy (it should be the index on that list).

Example:

ZDM PROXY 0 (listening on 10.0.0.1:9042):
    proxy_topology_addresses: 10.0.0.1,10.0.0.2,10.0.0.3
    proxy_topology_index: 0


ZDM PROXY 1 (listening on 10.0.0.2:9042):
    proxy_topology_addresses: 10.0.0.1,10.0.0.2,10.0.0.3
    proxy_topology_index: 1


ZDM PROXY 2 (listening on 10.0.0.3:9042):
    proxy_topology_addresses: 10.0.0.1,10.0.0.2,10.0.0.3
    proxy_topology_index: 2

If the app driver's control connection connects to PROXY 1, then the results of the local/peers CQL queries will be the following:

system.local
- 10.0.0.2

system.peers
- 10.0.0.1
- 10.0.0.3